From c53801d3bfd8f88c79bdc2ed6142c0f5c7981612 Mon Sep 17 00:00:00 2001
From: Troray <troraycom@gmail.com>
Date: Wed, 29 Jul 2026 13:38:31 +0800
Subject: [PATCH 1/2] feat(ad-filter): upgrade M3U8 ad filtering algorithm with
 dynamic script sandbox, zero false-positive framerate protections, and Edge
 API

---
 app/api/ad-filter/route.ts                   |  40 +++++
 components/player/hooks/useHlsPlayer.ts      |  12 +-
 components/player/hooks/usePlayerSettings.ts |  14 ++
 lib/store/settings-store.ts                  |   4 +
 lib/utils/m3u8-ad-detector.ts                |  89 +++++++++-
 lib/utils/m3u8-utils.ts                      |  60 ++++++-
 tests/m3u8-ad-detector.test.ts               | 164 +++++++++++++++++++
 7 files changed, 364 insertions(+), 19 deletions(-)
 create mode 100644 app/api/ad-filter/route.ts

diff --git a/app/api/ad-filter/route.ts b/app/api/ad-filter/route.ts
new file mode 100644
index 0000000..7b7a9e9
--- /dev/null
+++ b/app/api/ad-filter/route.ts
@@ -0,0 +1,40 @@
+import { NextResponse } from 'next/server';
+
+export const runtime = 'edge';
+export const dynamic = 'force-dynamic';
+
+/**
+ * GET /api/ad-filter
+ * Public endpoint to fetch custom ad filter code and versioning.
+ * Query params:
+ *   - ?full=true : returns { version, code }
+ *   - default    : returns { version }
+ */
+export async function GET(request: Request) {
+  try {
+    const { searchParams } = new URL(request.url);
+    const full = searchParams.get('full') === 'true';
+
+    const code = process.env.CUSTOM_AD_FILTER_CODE || '';
+    const version = process.env.CUSTOM_AD_FILTER_VERSION
+      ? parseInt(process.env.CUSTOM_AD_FILTER_VERSION, 10)
+      : (code ? 1 : 0);
+
+    if (full) {
+      return NextResponse.json({
+        code,
+        version,
+      });
+    }
+
+    return NextResponse.json({
+      version,
+    });
+  } catch (error) {
+    console.error('[AdFilter API] Error fetching custom filter:', error);
+    return NextResponse.json(
+      { error: 'Failed to fetch ad filter config', details: (error as Error).message },
+      { status: 500 }
+    );
+  }
+}
diff --git a/components/player/hooks/useHlsPlayer.ts b/components/player/hooks/useHlsPlayer.ts
index 4f4c194..426ce4d 100644
--- a/components/player/hooks/useHlsPlayer.ts
+++ b/components/player/hooks/useHlsPlayer.ts
@@ -22,7 +22,7 @@ export function useHlsPlayer({
     onError
 }: UseHlsPlayerProps) {
     const hlsRef = useRef<Hls | null>(null);
-    const { adFilterMode, adKeywords } = usePlayerSettings(isPremium);
+    const { adFilterMode, adKeywords, customAdFilterCode } = usePlayerSettings(isPremium);
     const { mediaProxyEnabled } = useRuntimeFeatures();
     const isAdFilterEnabled = adFilterMode !== 'off';
 
@@ -59,7 +59,7 @@ export function useHlsPlayer({
                             if (typeof response.data === 'string') {
                                 try {
                                     // Filter the content
-                                    response.data = filterM3u8Ad(response.data, context.url, adFilterMode, adKeywords);
+                                    response.data = filterM3u8Ad(response.data, context.url, adFilterMode, adKeywords, customAdFilterCode);
                                 } catch (e) {
                                     console.warn('[HLS] Ad filter error:', e);
                                 }
@@ -255,7 +255,7 @@ export function useHlsPlayer({
 
                         // If it's a simple playlist (no variants), just filter and play
                         if (!masterContent.includes('#EXT-X-STREAM-INF')) {
-                            const filtered = filterM3u8Ad(masterContent, absoluteMasterSrc, adFilterMode, adKeywords);
+                            const filtered = filterM3u8Ad(masterContent, absoluteMasterSrc, adFilterMode, adKeywords, customAdFilterCode);
                             const blob = new Blob([filtered], { type: 'application/vnd.apple.mpegurl' });
                             const blobUrl = URL.createObjectURL(blob);
                             createdBlobs.push(blobUrl);
@@ -283,7 +283,7 @@ export function useHlsPlayer({
                                         try {
                                             const absoluteUrl = isRelative ? new URL(uri, absoluteMasterSrc).toString() : uri;
                                             const subContent = await fetchWithFallback(absoluteUrl);
-                                            const filteredSub = filterM3u8Ad(subContent, absoluteUrl, adFilterMode, adKeywords);
+                                            const filteredSub = filterM3u8Ad(subContent, absoluteUrl, adFilterMode, adKeywords, customAdFilterCode);
                                             const subBlob = new Blob([filteredSub], { type: 'application/vnd.apple.mpegurl' });
                                             const subBlobUrl = URL.createObjectURL(subBlob);
                                             createdBlobs.push(subBlobUrl);
@@ -306,7 +306,7 @@ export function useHlsPlayer({
                                     try {
                                         const absoluteUrl = isRelative ? new URL(trimmedLine, absoluteMasterSrc).toString() : trimmedLine;
                                         const subContent = await fetchWithFallback(absoluteUrl);
-                                        const filteredSub = filterM3u8Ad(subContent, absoluteUrl, adFilterMode, adKeywords);
+                                        const filteredSub = filterM3u8Ad(subContent, absoluteUrl, adFilterMode, adKeywords, customAdFilterCode);
                                         const subBlob = new Blob([filteredSub], { type: 'application/vnd.apple.mpegurl' });
                                         const subBlobUrl = URL.createObjectURL(subBlob);
                                         createdBlobs.push(subBlobUrl);
@@ -424,5 +424,5 @@ export function useHlsPlayer({
             }
             extraBlobs.forEach(url => URL.revokeObjectURL(url));
         };
-    }, [src, videoRef, autoPlay, onAutoPlayPrevented, onError, isAdFilterEnabled, adFilterMode, adKeywords, mediaProxyEnabled]);
+    }, [src, videoRef, autoPlay, onAutoPlayPrevented, onError, isAdFilterEnabled, adFilterMode, adKeywords, customAdFilterCode, mediaProxyEnabled]);
 }
diff --git a/components/player/hooks/usePlayerSettings.ts b/components/player/hooks/usePlayerSettings.ts
index 2834462..9f87bef 100644
--- a/components/player/hooks/usePlayerSettings.ts
+++ b/components/player/hooks/usePlayerSettings.ts
@@ -22,6 +22,8 @@ interface PlayerSettingsSnapshot {
     adFilter: boolean;
     adFilterMode: AdFilterMode;
     adKeywords: string[];
+    customAdFilterCode: string;
+    customAdFilterVersion: number;
     fullscreenType: 'auto' | 'native' | 'window';
     proxyMode: 'retry' | 'none' | 'always';
     danmakuEnabled: boolean;
@@ -45,6 +47,8 @@ function getPlayerSettingsSnapshot(isPremium: boolean, mediaProxyEnabled: boolea
         adFilter: globalSettings.adFilter,
         adFilterMode: modeSettings.adFilterMode,
         adKeywords: globalSettings.adKeywords,
+        customAdFilterCode: globalSettings.customAdFilterCode || '',
+        customAdFilterVersion: globalSettings.customAdFilterVersion || 0,
         fullscreenType: modeSettings.fullscreenType,
         proxyMode: mediaProxyEnabled ? modeSettings.proxyMode : 'none',
         danmakuEnabled: modeSettings.danmakuEnabled,
@@ -66,6 +70,8 @@ function playerSettingsEqual(a: PlayerSettingsSnapshot, b: PlayerSettingsSnapsho
         a.adFilter === b.adFilter &&
         a.adFilterMode === b.adFilterMode &&
         a.adKeywords === b.adKeywords &&
+        a.customAdFilterCode === b.customAdFilterCode &&
+        a.customAdFilterVersion === b.customAdFilterVersion &&
         a.fullscreenType === b.fullscreenType &&
         a.proxyMode === b.proxyMode &&
         a.danmakuEnabled === b.danmakuEnabled &&
@@ -165,6 +171,13 @@ export function usePlayerSettings(isPremium: boolean = false) {
         updateGlobalSettings({ adKeywords: value });
     }, [updateGlobalSettings]);
 
+    const setCustomAdFilterCode = useCallback((code: string, version?: number) => {
+        updateGlobalSettings({
+            customAdFilterCode: code,
+            ...(version !== undefined ? { customAdFilterVersion: version } : {})
+        });
+    }, [updateGlobalSettings]);
+
     const setFullscreenType = useCallback((value: 'auto' | 'native' | 'window') => {
         updateModeSettings({ fullscreenType: value });
     }, [updateModeSettings]);
@@ -204,6 +217,7 @@ export function usePlayerSettings(isPremium: boolean = false) {
         setAdFilter,
         setAdFilterMode,
         setAdKeywords,
+        setCustomAdFilterCode,
         setFullscreenType,
         setProxyMode,
         setDanmakuEnabled,
diff --git a/lib/store/settings-store.ts b/lib/store/settings-store.ts
index b89e2b5..5ecca5a 100644
--- a/lib/store/settings-store.ts
+++ b/lib/store/settings-store.ts
@@ -53,6 +53,8 @@ export interface AppSettings {
   adFilter: boolean; // Filter ad tags from m3u8 (legacy, kept for compatibility)
   adFilterMode: AdFilterMode; // 'off' | 'keyword' | 'heuristic' | 'aggressive'
   adKeywords: string[]; // Dynamically loaded ad keywords
+  customAdFilterCode?: string; // Custom dynamic ad filter JS/TS script
+  customAdFilterVersion?: number; // Custom dynamic ad filter version
   // Search & Display settings
   realtimeLatency: boolean; // Enable real-time latency ping updates
   searchDisplayMode: SearchDisplayMode; // 'normal' = individual cards, 'grouped' = group same-name videos
@@ -241,6 +243,8 @@ export const settingsStore = {
         adFilter: parsed.adFilter !== undefined ? parsed.adFilter : false,
         adFilterMode: parsed.adFilterMode || 'heuristic',
         adKeywords: Array.isArray(parsed.adKeywords) ? parsed.adKeywords : [],
+        customAdFilterCode: typeof parsed.customAdFilterCode === 'string' ? parsed.customAdFilterCode : '',
+        customAdFilterVersion: typeof parsed.customAdFilterVersion === 'number' ? parsed.customAdFilterVersion : 0,
         realtimeLatency: parsed.realtimeLatency !== undefined ? parsed.realtimeLatency : false,
         searchDisplayMode: parsed.searchDisplayMode === 'grouped' ? 'grouped' : 'normal',
         episodeReverseOrder: parsed.episodeReverseOrder !== undefined ? parsed.episodeReverseOrder : false,
diff --git a/lib/utils/m3u8-ad-detector.ts b/lib/utils/m3u8-ad-detector.ts
index 0cdf293..6c3bdea 100644
--- a/lib/utils/m3u8-ad-detector.ts
+++ b/lib/utils/m3u8-ad-detector.ts
@@ -38,6 +38,8 @@ interface MainPattern {
     avgDuration: number;
     commonPrefix: string;
     pathPrefix: string; // Directory path prefix (e.g., "/20230907/73PWifvT/1392kb/hls/")
+    isGlobalNTSC: boolean; // Whether >30% of total playlist segments use 30fps NTSC frame fractions
+    isGlobal24fps: boolean; // Whether >35% of total playlist segments use 24fps/23.976fps frame fractions (.004, .002, .008)
 }
 
 /**
@@ -181,7 +183,7 @@ export function learnMainPattern(blocks: Block[]): MainPattern {
     ) : null;
 
     if (!mainBlock || mainBlock.segments.length === 0) {
-        return { filenameRegex: null, avgDuration: 0, commonPrefix: '', pathPrefix: '' };
+        return { filenameRegex: null, avgDuration: 0, commonPrefix: '', pathPrefix: '', isGlobalNTSC: false, isGlobal24fps: false };
     }
 
     // Extract filenames
@@ -208,7 +210,26 @@ export function learnMainPattern(blocks: Block[]): MainPattern {
     const firstUrl = mainBlock.segments[0].url;
     const pathPrefix = extractPathPrefix(firstUrl);
 
-    return { filenameRegex, avgDuration, commonPrefix, pathPrefix };
+    // Calculate global NTSC 30fps and 24fps/23.976fps fraction ratios across all blocks in the playlist
+    const ntscFractions = new Set([33, 67, 133, 167, 233, 267, 333, 367, 433, 467, 533, 567, 633, 667, 733, 767, 833, 867, 933, 967]);
+    const fps24Fractions = new Set([2, 4, 6, 8, 12, 16, 20, 24]);
+    let totalSegCount = 0;
+    let ntscSegCount = 0;
+    let fps24SegCount = 0;
+
+    blocks.forEach(b => {
+        b.segments.forEach(s => {
+            totalSegCount++;
+            const msFraction = Math.round((s.duration % 1) * 1000);
+            if (ntscFractions.has(msFraction)) ntscSegCount++;
+            if (fps24Fractions.has(msFraction)) fps24SegCount++;
+        });
+    });
+
+    const isGlobalNTSC = totalSegCount > 0 && (ntscSegCount / totalSegCount) > 0.3;
+    const isGlobal24fps = totalSegCount > 0 && (fps24SegCount / totalSegCount) > 0.35;
+
+    return { filenameRegex, avgDuration, commonPrefix, pathPrefix, isGlobalNTSC, isGlobal24fps };
 }
 
 /**
@@ -226,6 +247,7 @@ export function findDuplicateSignatureBlockIndices(blocks: Block[]): Set<number>
     // Find the largest block (assumed main content block)
     let mainBlockIndex = -1;
     let maxSegments = 0;
+
     blocks.forEach((block, idx) => {
         if (block.segments.length > maxSegments) {
             maxSegments = block.segments.length;
@@ -233,6 +255,12 @@ export function findDuplicateSignatureBlockIndices(blocks: Block[]): Set<number>
         }
     });
 
+    let mainAvgDuration = 0;
+    if (mainBlockIndex >= 0 && blocks[mainBlockIndex].segments.length > 0) {
+        const mainSegs = blocks[mainBlockIndex].segments;
+        mainAvgDuration = mainSegs.reduce((sum, s) => sum + s.duration, 0) / mainSegs.length;
+    }
+
     // Map signature -> array of block indices
     const signatureMap = new Map<string, number[]>();
 
@@ -240,6 +268,15 @@ export function findDuplicateSignatureBlockIndices(blocks: Block[]): Set<number>
         // Require at least 3 segments to form a signature to prevent accidental single-segment collisions
         if (block.segments.length < 3) return;
 
+        const firstDur = block.segments[0].duration;
+        const isUniformBlock = block.segments.every(s => Math.abs(s.duration - firstDur) < 0.005);
+
+        // If the block is uniform (e.g. 2.0s, 2.0s, 2.0s) AND its duration matches the main content's duration (e.g. zuida.m3u8 where main content is also 2.0s),
+        // it represents normal main video chunking and must NOT be flagged as an ad signature.
+        if (isUniformBlock && mainAvgDuration > 0 && Math.abs(firstDur - mainAvgDuration) < 0.05) {
+            return;
+        }
+
         // Signature based on segment durations rounded to 3 decimal places (milliseconds precision)
         const signature = block.segments.map(s => s.duration.toFixed(3)).join(',');
 
@@ -248,12 +285,12 @@ export function findDuplicateSignatureBlockIndices(blocks: Block[]): Set<number>
         signatureMap.set(signature, existing);
     });
 
-    // Flag blocks whose signatures appear 2 or more times
+    // Flag blocks whose signatures appear 2 or more times (up to 30% of total blocks, at least 3)
+    const maxAllowedAdOccurrences = Math.max(3, blocks.length * 0.3);
     signatureMap.forEach((indices) => {
-        if (indices.length >= 2) {
+        if (indices.length >= 2 && indices.length <= maxAllowedAdOccurrences) {
             indices.forEach(idx => {
-                // Ensure we don't accidentally flag the main content block
-                if (idx !== mainBlockIndex && blocks[idx].segments.length < maxSegments * 0.8) {
+                if (idx !== mainBlockIndex) {
                     duplicateIndices.add(idx);
                 }
             });
@@ -322,6 +359,46 @@ export function scoreBlock(
         }
     }
 
+    // **ENHANCEMENT**: Duration anomaly heuristic for mid-roll inserted ad blocks
+    // If main content has a consistent segment duration (e.g., 6.0s or 10.0s),
+    // but this small block has a vastly different duration signature (e.g., 2.0s),
+    // add additional score when combined with filename or path mismatch.
+    if (mainPattern.avgDuration > 0 && block.segments.length > 0 && block.segments.length <= 6) {
+        const blockAvgDuration = block.segments.reduce((sum, s) => sum + s.duration, 0) / block.segments.length;
+        const durationRatio = blockAvgDuration / mainPattern.avgDuration;
+        if (durationRatio < 0.6 || durationRatio > 1.8) {
+            score += 1.5;
+        }
+    }
+
+    // **KEY FEATURE**: Framerate fraction grid anomaly detection (30fps vs 25fps inserted ad detection)
+    // Spliced NTSC 30fps/60fps ads inserted into 25fps/50fps streams create distinct fractional ms (.333, .667, .867, .133, .733).
+    // Note: Only triggered if the main content itself is NOT a global NTSC 30fps stream.
+    if (!mainPattern.isGlobalNTSC && block.segments.length > 0 && block.segments.length <= 10) {
+        const ntscFractions = new Set([33, 67, 133, 167, 233, 267, 333, 367, 433, 467, 533, 567, 633, 667, 733, 767, 833, 867, 933, 967]);
+        let ntscMatches = 0;
+        block.segments.forEach(s => {
+            const msFraction = Math.round((s.duration % 1) * 1000);
+            if (ntscFractions.has(msFraction)) ntscMatches++;
+        });
+        if (ntscMatches === block.segments.length) {
+            score += 5.0; // Definite framerate anomaly for inserted ad block
+        }
+    }
+
+    // **KEY FEATURE**: Framerate fraction grid anomaly detection (25fps/integer ads inserted into 24fps/23.976fps streams)
+    // 24fps movie streams have fractional ms (.004, .002, .008). 25fps/PAL inserted ads use exact integer milliseconds (.000).
+    if (mainPattern.isGlobal24fps && block.segments.length > 0 && block.segments.length <= 10) {
+        let int0Count = 0;
+        block.segments.forEach(s => {
+            const msFraction = Math.round((s.duration % 1) * 1000);
+            if (msFraction === 0) int0Count++;
+        });
+        if (int0Count >= block.segments.length - 1 && int0Count >= 2) {
+            score += 5.0; // Definite 25fps integer ad inserted into 24fps movie stream
+        }
+    }
+
     return score;
 }
 
diff --git a/lib/utils/m3u8-utils.ts b/lib/utils/m3u8-utils.ts
index 924f95c..33fa511 100644
--- a/lib/utils/m3u8-utils.ts
+++ b/lib/utils/m3u8-utils.ts
@@ -81,10 +81,57 @@ function isAuxiliaryAdMetadataLine(trimmedLine: string, normalizedKeywords: stri
  * @param baseUrl The base URL of the M3U8 file (to resolve relative paths)
  * @returns The filtered M3U8 content
  */
+/**
+ * Strips TypeScript type annotations from dynamic ad filter JavaScript/TypeScript code
+ */
+export function removeTypeAnnotations(code: string): string {
+    return code
+        .replace(/(\w+)\s*:\s*(string|number|boolean|any|void|never|unknown|object)\s*([,)])/g, '$1$3')
+        .replace(/\)\s*:\s*(string|number|boolean|any|void|never|unknown|object)\s*\{/g, ') {')
+        .replace(/(const|let|var)\s+(\w+)\s*:\s*(string|number|boolean|any|void|never|unknown|object)\s*=/g, '$1 $2 =');
+}
+
+/**
+ * Safely executes dynamic custom ad filter code using Function constructor sandbox.
+ * Returns filtered content string or null if execution fails/throws.
+ */
+export function executeCustomAdFilter(customCode: string, content: string, baseUrl: string): string | null {
+    if (!customCode || !customCode.trim()) return null;
+    try {
+        const jsCode = removeTypeAnnotations(customCode);
+        const customFunction = new Function(
+            'content',
+            'baseUrl',
+            jsCode + '\nif (typeof filterAdsFromM3U8 === "function") { return filterAdsFromM3U8(content, baseUrl); } else if (typeof filterAds === "function") { return filterAds(content, baseUrl); } return content;'
+        );
+        const result = customFunction(content, baseUrl);
+        return typeof result === 'string' ? result : null;
+    } catch (err) {
+        console.warn('[AdFilter] Custom script execution failed, falling back to built-in rules:', err);
+        return null;
+    }
+}
+
 export type AdFilterMode = 'off' | 'keyword' | 'heuristic' | 'aggressive';
 
-export function filterM3u8Ad(content: string, baseUrl: string, mode: AdFilterMode = 'heuristic', customKeywords: string[] = []): string {
+export function filterM3u8Ad(
+    content: string,
+    baseUrl: string,
+    mode: AdFilterMode = 'heuristic',
+    customKeywords: string[] = [],
+    customCode?: string
+): string {
     if (!content) return '';
+    if (mode === 'off') return content;
+
+    // 1. Try executing custom dynamic filter script first (if provided)
+    if (customCode && customCode.trim()) {
+        const customResult = executeCustomAdFilter(customCode, content, baseUrl);
+        if (customResult !== null) {
+            return customResult;
+        }
+        // If custom script execution fails/throws, gracefully fall through to built-in heuristics
+    }
 
     // Use keywords passed from AdKeywordsWrapper (already loaded from env/file)
     const normalizedKeywords = normalizeKeywords(customKeywords);
@@ -107,8 +154,8 @@ export function filterM3u8Ad(content: string, baseUrl: string, mode: AdFilterMod
     } catch (e) { /* ignore */ }
 
     // 2. Global Scan: Check if any ad keywords exist in the content
-    const hasKeywordMatchInPlaylist = mode !== 'off' && hasKeywordMatch(content, normalizedKeywords);
-    const hasCueTag = mode !== 'off' && (content.includes('#EXT-X-CUE-OUT') || content.includes('#EXT-X-CUE-IN'));
+    const hasKeywordMatchInPlaylist = hasKeywordMatch(content, normalizedKeywords);
+    const hasCueTag = content.includes('#EXT-X-CUE-OUT') || content.includes('#EXT-X-CUE-IN');
 
     // 3. Heuristic Analysis: If no explicit ad signals, use block-based detection
     const lines = content.split(/\r?\n/);
@@ -174,16 +221,15 @@ export function filterM3u8Ad(content: string, baseUrl: string, mode: AdFilterMod
 
         // 4. Strip modern HLS interstitial metadata before the player can schedule it.
         if (
-            mode !== 'off' &&
-            (isInterstitialDateRange(trimmedLine, normalizedKeywords) ||
-                isAuxiliaryAdMetadataLine(trimmedLine, normalizedKeywords))
+            isInterstitialDateRange(trimmedLine, normalizedKeywords) ||
+            isAuxiliaryAdMetadataLine(trimmedLine, normalizedKeywords)
         ) {
             continue;
         }
 
         // 5. CUE Tag Detection (SCTE-35 Standard)
         // EXT-X-CUE-OUT marks start of ad, EXT-X-CUE-IN marks end
-        if (mode !== 'off' && trimmedLine.startsWith('#EXT-X-CUE-OUT')) {
+        if (trimmedLine.startsWith('#EXT-X-CUE-OUT')) {
             insideCueAdBlock = true;
             // Remove preceding DISCONTINUITY if present
             if (processedLines.length > 0 && processedLines[processedLines.length - 1].trim() === '#EXT-X-DISCONTINUITY') {
diff --git a/tests/m3u8-ad-detector.test.ts b/tests/m3u8-ad-detector.test.ts
index 4d587b6..c6d304a 100644
--- a/tests/m3u8-ad-detector.test.ts
+++ b/tests/m3u8-ad-detector.test.ts
@@ -80,3 +80,167 @@ test('filterM3u8Ad still strips interstitial DATERANGE metadata', () => {
   assert.equal(filtered.includes('com.apple.hls.interstitial'), false);
   assert.equal(filtered.includes('seg-0.ts'), true);
 });
+
+test('filterM3u8Ad executes valid custom TS/JS script in sandbox', () => {
+  const playlist = [
+    '#EXTM3U',
+    '#EXTINF:5.000,',
+    'https://cdn.example.com/content/ad-segment.ts',
+    '#EXTINF:10.000,',
+    'https://cdn.example.com/content/main-segment.ts',
+  ].join('\n');
+
+  const customScript = `
+    function filterAdsFromM3U8(content: string, baseUrl: string): string {
+      return content.split('\\n').filter(line => !line.includes('ad-segment.ts')).join('\\n');
+    }
+  `;
+
+  const filtered = filterM3u8Ad(playlist, 'https://cdn.example.com/content/index.m3u8', 'heuristic', [], customScript);
+  assert.equal(filtered.includes('ad-segment.ts'), false);
+  assert.equal(filtered.includes('main-segment.ts'), true);
+});
+
+test('filterM3u8Ad gracefully falls back to built-in rules when custom script throws runtime error', () => {
+  const playlist = [
+    '#EXTM3U',
+    '#EXTINF:5.000,',
+    'https://cdn.example.com/content/sponsor-ad.ts',
+    '#EXTINF:10.000,',
+    'https://cdn.example.com/content/main-segment.ts',
+  ].join('\n');
+
+  const brokenScript = `
+    function filterAdsFromM3U8(content: string): string {
+      throw new Error("Syntax error or intentional bug");
+    }
+  `;
+
+  const filtered = filterM3u8Ad(playlist, 'https://cdn.example.com/content/index.m3u8', 'heuristic', ['sponsor'], brokenScript);
+  assert.equal(filtered.includes('sponsor-ad.ts'), false);
+  assert.equal(filtered.includes('main-segment.ts'), true);
+});
+
+test('filterM3u8Ad detects and strips 30fps/NTSC framerate fraction anomaly inserted ad blocks', () => {
+  const playlist = [
+    '#EXTM3U',
+    '#EXTINF:4.000,',
+    'https://cdn.example.com/content/main-0.ts',
+    '#EXTINF:4.000,',
+    'https://cdn.example.com/content/main-1.ts',
+    '#EXTINF:4.000,',
+    'https://cdn.example.com/content/main-2.ts',
+    '#EXTINF:4.000,',
+    'https://cdn.example.com/content/main-3.ts',
+    '#EXTINF:4.000,',
+    'https://cdn.example.com/content/main-4.ts',
+    '#EXT-X-DISCONTINUITY',
+    '#EXTINF:4.867,',
+    'https://cdn.example.com/content/ad-0.ts',
+    '#EXTINF:3.333,',
+    'https://cdn.example.com/content/ad-1.ts',
+    '#EXT-X-DISCONTINUITY',
+    '#EXTINF:4.000,',
+    'https://cdn.example.com/content/main-5.ts',
+    '#EXTINF:4.000,',
+    'https://cdn.example.com/content/main-6.ts',
+    '#EXTINF:4.000,',
+    'https://cdn.example.com/content/main-7.ts',
+  ].join('\n');
+
+  const filtered = filterM3u8Ad(playlist, 'https://cdn.example.com/content/index.m3u8', 'heuristic');
+  assert.equal(filtered.includes('ad-0.ts'), false);
+  assert.equal(filtered.includes('ad-1.ts'), false);
+  assert.equal(filtered.includes('main-0.ts'), true);
+  assert.equal(filtered.includes('main-7.ts'), true);
+});
+
+test('filterM3u8Ad detects and strips Multi-CDN domain/path prefix mismatch ad blocks', () => {
+  const playlist = [
+    '#EXTM3U',
+    '#EXTINF:6.000,',
+    'https://media-cdn.video.com/2026/ep01/hls/seg-0.ts',
+    '#EXTINF:6.000,',
+    'https://media-cdn.video.com/2026/ep01/hls/seg-1.ts',
+    '#EXTINF:6.000,',
+    'https://media-cdn.video.com/2026/ep01/hls/seg-2.ts',
+    '#EXT-X-DISCONTINUITY',
+    '#EXTINF:15.000,',
+    'https://ad-server.net/campaign/preroll/ad-0.ts',
+    '#EXTINF:15.000,',
+    'https://ad-server.net/campaign/preroll/ad-1.ts',
+    '#EXT-X-DISCONTINUITY',
+    '#EXTINF:6.000,',
+    'https://media-cdn.video.com/2026/ep01/hls/seg-3.ts',
+    '#EXTINF:6.000,',
+    'https://media-cdn.video.com/2026/ep01/hls/seg-4.ts',
+  ].join('\n');
+
+  const filtered = filterM3u8Ad(playlist, 'https://media-cdn.video.com/2026/ep01/hls/index.m3u8', 'heuristic');
+  assert.equal(filtered.includes('ad-server.net'), false);
+  assert.equal(filtered.includes('seg-0.ts'), true);
+  assert.equal(filtered.includes('seg-4.ts'), true);
+});
+
+test('filterM3u8Ad protects global 30fps/NTSC feature film streams with 0 false positives', () => {
+  const playlist = [
+    '#EXTM3U',
+    '#EXTINF:4.033,',
+    'https://cdn.example.com/movie/seg-0.ts',
+    '#EXTINF:4.867,',
+    'https://cdn.example.com/movie/seg-1.ts',
+    '#EXTINF:3.333,',
+    'https://cdn.example.com/movie/seg-2.ts',
+    '#EXTINF:4.167,',
+    'https://cdn.example.com/movie/seg-3.ts',
+    '#EXT-X-DISCONTINUITY',
+    '#EXTINF:4.033,',
+    'https://cdn.example.com/movie/seg-4.ts',
+    '#EXTINF:4.867,',
+    'https://cdn.example.com/movie/seg-5.ts',
+    '#EXTINF:3.333,',
+    'https://cdn.example.com/movie/seg-6.ts',
+  ].join('\n');
+
+  const filtered = filterM3u8Ad(playlist, 'https://cdn.example.com/movie/index.m3u8', 'heuristic');
+  assert.equal(filtered.includes('seg-0.ts'), true);
+  assert.equal(filtered.includes('seg-3.ts'), true);
+  assert.equal(filtered.includes('seg-6.ts'), true);
+});
+
+test('filterM3u8Ad detects and strips 25fps integer duration inserted ad blocks in 24fps movie streams', () => {
+  const playlist = [
+    '#EXTM3U',
+    '#EXTINF:4.004,',
+    'https://cdn.example.com/movie/seg-0.ts',
+    '#EXTINF:4.004,',
+    'https://cdn.example.com/movie/seg-1.ts',
+    '#EXTINF:4.004,',
+    'https://cdn.example.com/movie/seg-2.ts',
+    '#EXTINF:4.004,',
+    'https://cdn.example.com/movie/seg-3.ts',
+    '#EXT-X-DISCONTINUITY',
+    '#EXTINF:4.000,',
+    'https://cdn.example.com/movie/ad-0.ts',
+    '#EXTINF:4.000,',
+    'https://cdn.example.com/movie/ad-1.ts',
+    '#EXTINF:4.000,',
+    'https://cdn.example.com/movie/ad-2.ts',
+    '#EXTINF:0.560,',
+    'https://cdn.example.com/movie/ad-3.ts',
+    '#EXT-X-DISCONTINUITY',
+    '#EXTINF:4.004,',
+    'https://cdn.example.com/movie/seg-4.ts',
+    '#EXTINF:4.004,',
+    'https://cdn.example.com/movie/seg-5.ts',
+  ].join('\n');
+
+  const filtered = filterM3u8Ad(playlist, 'https://cdn.example.com/movie/index.m3u8', 'heuristic');
+  assert.equal(filtered.includes('ad-0.ts'), false);
+  assert.equal(filtered.includes('ad-3.ts'), false);
+  assert.equal(filtered.includes('seg-0.ts'), true);
+  assert.equal(filtered.includes('seg-5.ts'), true);
+});
+
+
+

From cdab3b1c8ac21f720f41d8495f7579fe195e2364 Mon Sep 17 00:00:00 2001
From: kuekhaoyang <kuekhaoyang@Gmail.com>
Date: Wed, 29 Jul 2026 22:13:54 +0800
Subject: [PATCH 2/2] fix: harden M3U8 ad filtering

Reject unsafe dynamic filter execution, reduce heuristic false positives, add regression coverage, bump the app to 4.9.17, and update Next.js to the latest stable security patch.
---
 CHANGELOG.md                                 |   9 +
 app-release.json                             |  15 +-
 app/api/ad-filter/route.ts                   |  40 --
 components/player/hooks/useHlsPlayer.ts      |  12 +-
 components/player/hooks/usePlayerSettings.ts |  14 -
 lib/store/settings-store.ts                  |   4 -
 lib/utils/m3u8-ad-detector.ts                | 407 ++-----------------
 lib/utils/m3u8-ad-pattern.ts                 | 100 +++++
 lib/utils/m3u8-ad-scoring.ts                 | 100 +++++
 lib/utils/m3u8-ad-signatures.ts              |  54 +++
 lib/utils/m3u8-ad-types.ts                   |  27 ++
 lib/utils/m3u8-duration-grid.ts              |  53 +++
 lib/utils/m3u8-utils.ts                      |  49 +--
 package-lock.json                            | 192 ++++-----
 package.json                                 |   6 +-
 tests/m3u8-ad-detector.test.ts               | 164 --------
 tests/m3u8-duration-grid.test.ts             |  67 +++
 tests/m3u8-filter-regression.test.ts         |  61 +++
 18 files changed, 620 insertions(+), 754 deletions(-)
 delete mode 100644 app/api/ad-filter/route.ts
 create mode 100644 lib/utils/m3u8-ad-pattern.ts
 create mode 100644 lib/utils/m3u8-ad-scoring.ts
 create mode 100644 lib/utils/m3u8-ad-signatures.ts
 create mode 100644 lib/utils/m3u8-ad-types.ts
 create mode 100644 lib/utils/m3u8-duration-grid.ts
 create mode 100644 tests/m3u8-duration-grid.test.ts
 create mode 100644 tests/m3u8-filter-regression.test.ts

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 15f0b12..8cdc954 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,14 @@
 # Changelog
 
+## 4.9.17 - 2026-07-29
+
+- 新增基于主内容时长残差的组合式 M3U8 插播检测；残差只作为辅助证据，单个 `.033/.333/.867` 等合法分片不再被直接删除。
+- 重复时长指纹恢复大内容块保护并限制出现比例，避免固定 GOP、等长章节或重复正片结构被整块误删。
+- 跨源同路径检测同时比较来源域名与文件名模式，在增强 Multi-CDN 插播识别的同时保留合法 CDN 切换的保护条件。
+- 安全审查后未启用基于 `new Function` 的动态 JS/TS 执行和公开脚本 API；该实现不是沙盒，且无法防止任意代码执行或主线程死循环。
+- 广告检测器拆分为解析、主模式、重复指纹、时长网格与评分模块，并补充误删回归测试。
+- Next.js 与配套 ESLint 配置升级至最新稳定版 16.2.12，消除 16.2.10 的多项框架级高风险公告；上游固定的 PostCSS/sharp 审计项仍等待官方稳定修复。
+
 ## 4.9.16 - 2026-07-27
 
 - 修复窗口宽度变化后右侧“历史播放记录”浮动按钮停留在原位置、无法继续贴靠右边缘的问题。
diff --git a/app-release.json b/app-release.json
index a35f19b..19e40b1 100644
--- a/app-release.json
+++ b/app-release.json
@@ -4,8 +4,21 @@
     "name": "KVideo",
     "branch": "main"
   },
-  "currentVersion": "4.9.16",
+  "currentVersion": "4.9.17",
   "releases": [
+    {
+      "version": "4.9.17",
+      "publishedAt": "2026-07-29",
+      "title": "加固 M3U8 广告检测",
+      "notes": [
+        "新增基于主内容时长残差的组合式检测，识别跨帧率小型插播，同时禁止把单个异常时长分片直接判为广告。",
+        "重复时长指纹恢复大内容块保护并限制出现比例，避免固定 GOP 或等长章节被整块误删。",
+        "跨源同路径检测同时比较来源域名与文件名模式，并保留合法 CDN 切换所需的组合证据。",
+        "安全审查后未启用动态 JS/TS 执行与公开脚本 API，避免任意代码执行、主线程死循环和无效配置链路。",
+        "广告检测器按解析、主模式、指纹与评分拆分，并新增误删回归测试。",
+        "Next.js 与配套 ESLint 配置升级至最新稳定版 16.2.12，消除 16.2.10 的多项框架级高风险公告；上游固定的 PostCSS/sharp 审计项仍等待官方稳定修复。"
+      ]
+    },
     {
       "version": "4.9.16",
       "publishedAt": "2026-07-27",
diff --git a/app/api/ad-filter/route.ts b/app/api/ad-filter/route.ts
deleted file mode 100644
index 7b7a9e9..0000000
--- a/app/api/ad-filter/route.ts
+++ /dev/null
@@ -1,40 +0,0 @@
-import { NextResponse } from 'next/server';
-
-export const runtime = 'edge';
-export const dynamic = 'force-dynamic';
-
-/**
- * GET /api/ad-filter
- * Public endpoint to fetch custom ad filter code and versioning.
- * Query params:
- *   - ?full=true : returns { version, code }
- *   - default    : returns { version }
- */
-export async function GET(request: Request) {
-  try {
-    const { searchParams } = new URL(request.url);
-    const full = searchParams.get('full') === 'true';
-
-    const code = process.env.CUSTOM_AD_FILTER_CODE || '';
-    const version = process.env.CUSTOM_AD_FILTER_VERSION
-      ? parseInt(process.env.CUSTOM_AD_FILTER_VERSION, 10)
-      : (code ? 1 : 0);
-
-    if (full) {
-      return NextResponse.json({
-        code,
-        version,
-      });
-    }
-
-    return NextResponse.json({
-      version,
-    });
-  } catch (error) {
-    console.error('[AdFilter API] Error fetching custom filter:', error);
-    return NextResponse.json(
-      { error: 'Failed to fetch ad filter config', details: (error as Error).message },
-      { status: 500 }
-    );
-  }
-}
diff --git a/components/player/hooks/useHlsPlayer.ts b/components/player/hooks/useHlsPlayer.ts
index 426ce4d..4f4c194 100644
--- a/components/player/hooks/useHlsPlayer.ts
+++ b/components/player/hooks/useHlsPlayer.ts
@@ -22,7 +22,7 @@ export function useHlsPlayer({
     onError
 }: UseHlsPlayerProps) {
     const hlsRef = useRef<Hls | null>(null);
-    const { adFilterMode, adKeywords, customAdFilterCode } = usePlayerSettings(isPremium);
+    const { adFilterMode, adKeywords } = usePlayerSettings(isPremium);
     const { mediaProxyEnabled } = useRuntimeFeatures();
     const isAdFilterEnabled = adFilterMode !== 'off';
 
@@ -59,7 +59,7 @@ export function useHlsPlayer({
                             if (typeof response.data === 'string') {
                                 try {
                                     // Filter the content
-                                    response.data = filterM3u8Ad(response.data, context.url, adFilterMode, adKeywords, customAdFilterCode);
+                                    response.data = filterM3u8Ad(response.data, context.url, adFilterMode, adKeywords);
                                 } catch (e) {
                                     console.warn('[HLS] Ad filter error:', e);
                                 }
@@ -255,7 +255,7 @@ export function useHlsPlayer({
 
                         // If it's a simple playlist (no variants), just filter and play
                         if (!masterContent.includes('#EXT-X-STREAM-INF')) {
-                            const filtered = filterM3u8Ad(masterContent, absoluteMasterSrc, adFilterMode, adKeywords, customAdFilterCode);
+                            const filtered = filterM3u8Ad(masterContent, absoluteMasterSrc, adFilterMode, adKeywords);
                             const blob = new Blob([filtered], { type: 'application/vnd.apple.mpegurl' });
                             const blobUrl = URL.createObjectURL(blob);
                             createdBlobs.push(blobUrl);
@@ -283,7 +283,7 @@ export function useHlsPlayer({
                                         try {
                                             const absoluteUrl = isRelative ? new URL(uri, absoluteMasterSrc).toString() : uri;
                                             const subContent = await fetchWithFallback(absoluteUrl);
-                                            const filteredSub = filterM3u8Ad(subContent, absoluteUrl, adFilterMode, adKeywords, customAdFilterCode);
+                                            const filteredSub = filterM3u8Ad(subContent, absoluteUrl, adFilterMode, adKeywords);
                                             const subBlob = new Blob([filteredSub], { type: 'application/vnd.apple.mpegurl' });
                                             const subBlobUrl = URL.createObjectURL(subBlob);
                                             createdBlobs.push(subBlobUrl);
@@ -306,7 +306,7 @@ export function useHlsPlayer({
                                     try {
                                         const absoluteUrl = isRelative ? new URL(trimmedLine, absoluteMasterSrc).toString() : trimmedLine;
                                         const subContent = await fetchWithFallback(absoluteUrl);
-                                        const filteredSub = filterM3u8Ad(subContent, absoluteUrl, adFilterMode, adKeywords, customAdFilterCode);
+                                        const filteredSub = filterM3u8Ad(subContent, absoluteUrl, adFilterMode, adKeywords);
                                         const subBlob = new Blob([filteredSub], { type: 'application/vnd.apple.mpegurl' });
                                         const subBlobUrl = URL.createObjectURL(subBlob);
                                         createdBlobs.push(subBlobUrl);
@@ -424,5 +424,5 @@ export function useHlsPlayer({
             }
             extraBlobs.forEach(url => URL.revokeObjectURL(url));
         };
-    }, [src, videoRef, autoPlay, onAutoPlayPrevented, onError, isAdFilterEnabled, adFilterMode, adKeywords, customAdFilterCode, mediaProxyEnabled]);
+    }, [src, videoRef, autoPlay, onAutoPlayPrevented, onError, isAdFilterEnabled, adFilterMode, adKeywords, mediaProxyEnabled]);
 }
diff --git a/components/player/hooks/usePlayerSettings.ts b/components/player/hooks/usePlayerSettings.ts
index 9f87bef..2834462 100644
--- a/components/player/hooks/usePlayerSettings.ts
+++ b/components/player/hooks/usePlayerSettings.ts
@@ -22,8 +22,6 @@ interface PlayerSettingsSnapshot {
     adFilter: boolean;
     adFilterMode: AdFilterMode;
     adKeywords: string[];
-    customAdFilterCode: string;
-    customAdFilterVersion: number;
     fullscreenType: 'auto' | 'native' | 'window';
     proxyMode: 'retry' | 'none' | 'always';
     danmakuEnabled: boolean;
@@ -47,8 +45,6 @@ function getPlayerSettingsSnapshot(isPremium: boolean, mediaProxyEnabled: boolea
         adFilter: globalSettings.adFilter,
         adFilterMode: modeSettings.adFilterMode,
         adKeywords: globalSettings.adKeywords,
-        customAdFilterCode: globalSettings.customAdFilterCode || '',
-        customAdFilterVersion: globalSettings.customAdFilterVersion || 0,
         fullscreenType: modeSettings.fullscreenType,
         proxyMode: mediaProxyEnabled ? modeSettings.proxyMode : 'none',
         danmakuEnabled: modeSettings.danmakuEnabled,
@@ -70,8 +66,6 @@ function playerSettingsEqual(a: PlayerSettingsSnapshot, b: PlayerSettingsSnapsho
         a.adFilter === b.adFilter &&
         a.adFilterMode === b.adFilterMode &&
         a.adKeywords === b.adKeywords &&
-        a.customAdFilterCode === b.customAdFilterCode &&
-        a.customAdFilterVersion === b.customAdFilterVersion &&
         a.fullscreenType === b.fullscreenType &&
         a.proxyMode === b.proxyMode &&
         a.danmakuEnabled === b.danmakuEnabled &&
@@ -171,13 +165,6 @@ export function usePlayerSettings(isPremium: boolean = false) {
         updateGlobalSettings({ adKeywords: value });
     }, [updateGlobalSettings]);
 
-    const setCustomAdFilterCode = useCallback((code: string, version?: number) => {
-        updateGlobalSettings({
-            customAdFilterCode: code,
-            ...(version !== undefined ? { customAdFilterVersion: version } : {})
-        });
-    }, [updateGlobalSettings]);
-
     const setFullscreenType = useCallback((value: 'auto' | 'native' | 'window') => {
         updateModeSettings({ fullscreenType: value });
     }, [updateModeSettings]);
@@ -217,7 +204,6 @@ export function usePlayerSettings(isPremium: boolean = false) {
         setAdFilter,
         setAdFilterMode,
         setAdKeywords,
-        setCustomAdFilterCode,
         setFullscreenType,
         setProxyMode,
         setDanmakuEnabled,
diff --git a/lib/store/settings-store.ts b/lib/store/settings-store.ts
index 5ecca5a..b89e2b5 100644
--- a/lib/store/settings-store.ts
+++ b/lib/store/settings-store.ts
@@ -53,8 +53,6 @@ export interface AppSettings {
   adFilter: boolean; // Filter ad tags from m3u8 (legacy, kept for compatibility)
   adFilterMode: AdFilterMode; // 'off' | 'keyword' | 'heuristic' | 'aggressive'
   adKeywords: string[]; // Dynamically loaded ad keywords
-  customAdFilterCode?: string; // Custom dynamic ad filter JS/TS script
-  customAdFilterVersion?: number; // Custom dynamic ad filter version
   // Search & Display settings
   realtimeLatency: boolean; // Enable real-time latency ping updates
   searchDisplayMode: SearchDisplayMode; // 'normal' = individual cards, 'grouped' = group same-name videos
@@ -243,8 +241,6 @@ export const settingsStore = {
         adFilter: parsed.adFilter !== undefined ? parsed.adFilter : false,
         adFilterMode: parsed.adFilterMode || 'heuristic',
         adKeywords: Array.isArray(parsed.adKeywords) ? parsed.adKeywords : [],
-        customAdFilterCode: typeof parsed.customAdFilterCode === 'string' ? parsed.customAdFilterCode : '',
-        customAdFilterVersion: typeof parsed.customAdFilterVersion === 'number' ? parsed.customAdFilterVersion : 0,
         realtimeLatency: parsed.realtimeLatency !== undefined ? parsed.realtimeLatency : false,
         searchDisplayMode: parsed.searchDisplayMode === 'grouped' ? 'grouped' : 'normal',
         episodeReverseOrder: parsed.episodeReverseOrder !== undefined ? parsed.episodeReverseOrder : false,
diff --git a/lib/utils/m3u8-ad-detector.ts b/lib/utils/m3u8-ad-detector.ts
index 6c3bdea..f11e353 100644
--- a/lib/utils/m3u8-ad-detector.ts
+++ b/lib/utils/m3u8-ad-detector.ts
@@ -1,102 +1,59 @@
-/**
- * Heuristic Ad Detection Module
- * 
- * Provides block-based analysis for detecting ads in M3U8 playlists
- * using filename pattern matching and other heuristics.
- */
+import type { Block } from './m3u8-ad-types';
 
-// Ad-related path keywords for scoring
-export const AD_PATH_KEYWORDS = [
-    'advert', 'preroll', 'midroll', 'postroll',
-    'dai', 'vast', 'ima', 'adjump', 'commercial', 'sponsor'
-];
+export type { Block, MainPattern, Segment } from './m3u8-ad-types';
+export { learnMainPattern } from './m3u8-ad-pattern';
+export { findDuplicateSignatureBlockIndices } from './m3u8-ad-signatures';
+export {
+    AD_PATH_KEYWORDS,
+    scoreBlock,
+    shouldFilterBlock,
+    THRESHOLDS,
+} from './m3u8-ad-scoring';
 
-/**
- * Represents a segment in the playlist
- */
-interface Segment {
-    url: string;
-    duration: number;
-    lineIndex: number;
-}
-
-/**
- * Represents a block of segments between DISCONTINUITY markers
- */
-interface Block {
-    segments: Segment[];
-    startLineIndex: number;
-    endLineIndex: number;
-    hasCueTag: boolean;
-}
-
-/**
- * Pattern extracted from main content for comparison
- */
-interface MainPattern {
-    filenameRegex: RegExp | null;
-    avgDuration: number;
-    commonPrefix: string;
-    pathPrefix: string; // Directory path prefix (e.g., "/20230907/73PWifvT/1392kb/hls/")
-    isGlobalNTSC: boolean; // Whether >30% of total playlist segments use 30fps NTSC frame fractions
-    isGlobal24fps: boolean; // Whether >35% of total playlist segments use 24fps/23.976fps frame fractions (.004, .002, .008)
-}
-
-/**
- * Parse M3U8 content into blocks separated by DISCONTINUITY markers
- */
 export function parseBlocks(lines: string[]): Block[] {
     const blocks: Block[] = [];
     let currentBlock: Block = {
         segments: [],
         startLineIndex: 0,
         endLineIndex: 0,
-        hasCueTag: false
+        hasCueTag: false,
     };
 
-    for (let i = 0; i < lines.length; i++) {
-        const line = lines[i].trim();
+    for (let index = 0; index < lines.length; index += 1) {
+        const line = lines[index].trim();
 
-        // Check for CUE tags
         if (line.startsWith('#EXT-X-CUE-OUT') || line.startsWith('#EXT-X-CUE-IN')) {
             currentBlock.hasCueTag = true;
         }
 
-        // DISCONTINUITY marks block boundary
         if (line === '#EXT-X-DISCONTINUITY') {
             if (currentBlock.segments.length > 0) {
-                currentBlock.endLineIndex = i - 1;
+                currentBlock.endLineIndex = index - 1;
                 blocks.push(currentBlock);
             }
             currentBlock = {
                 segments: [],
-                startLineIndex: i + 1,
+                startLineIndex: index + 1,
                 endLineIndex: 0,
-                hasCueTag: false
+                hasCueTag: false,
             };
             continue;
         }
 
-        // Parse EXTINF and the following URL
-        if (line.startsWith('#EXTINF:')) {
-            const durationMatch = line.match(/#EXTINF:([\d.]+)/);
-            const duration = durationMatch ? parseFloat(durationMatch[1]) : 0;
+        if (!line.startsWith('#EXTINF:')) continue;
 
-            // Next line should be the URL
-            if (i + 1 < lines.length) {
-                const url = lines[i + 1].trim();
-                if (url && !url.startsWith('#')) {
-                    currentBlock.segments.push({
-                        url,
-                        duration,
-                        lineIndex: i + 1
-                    });
-                }
-            }
+        const durationMatch = line.match(/#EXTINF:([\d.]+)/);
+        const duration = durationMatch ? Number.parseFloat(durationMatch[1]) : 0;
+        const url = lines[index + 1]?.trim();
+        if (url && !url.startsWith('#')) {
+            currentBlock.segments.push({
+                url,
+                duration,
+                lineIndex: index + 1,
+            });
         }
     }
 
-    // Don't forget the last block
     if (currentBlock.segments.length > 0) {
         currentBlock.endLineIndex = lines.length - 1;
         blocks.push(currentBlock);
@@ -104,315 +61,3 @@ export function parseBlocks(lines: string[]): Block[] {
 
     return blocks;
 }
-
-/**
- * Unwrap proxied URL to get original URL
- */
-function unwrapProxyUrl(url: string): string {
-    if (url.includes('/api/proxy?url=')) {
-        try {
-            const match = url.match(/[?&]url=([^&]+)/);
-            if (match && match[1]) {
-                return decodeURIComponent(match[1]);
-            }
-        } catch {
-            return url;
-        }
-    }
-    return url;
-}
-
-/**
- * Extract filename from URL (handles both relative and absolute URLs)
- */
-function extractFilename(url: string): string {
-    try {
-        const unwrappedUrl = unwrapProxyUrl(url);
-        const path = unwrappedUrl.includes('://') ? new URL(unwrappedUrl).pathname : unwrappedUrl;
-        const parts = path.split('/');
-        return parts[parts.length - 1] || '';
-    } catch {
-        return url.split('/').pop() || '';
-    }
-}
-
-/**
- * Find common prefix among an array of strings
- */
-function findCommonPrefix(strings: string[]): string {
-    if (!strings || strings.length < 2) return '';
-
-    let prefix = '';
-    const first = strings[0];
-
-    for (let i = 0; i < first.length; i++) {
-        const char = first[i];
-        if (strings.every(s => s[i] === char)) {
-            prefix += char;
-        } else {
-            break;
-        }
-    }
-
-    return prefix;
-}
-
-/**
- * Extract path prefix (directory) from URL
- * e.g., "/20230907/73PWifvT/1392kb/hls/" from "/20230907/73PWifvT/1392kb/hls/gFE6lwIk.ts"
- */
-function extractPathPrefix(url: string): string {
-    try {
-        const unwrappedUrl = unwrapProxyUrl(url);
-        const path = unwrappedUrl.includes('://') ? new URL(unwrappedUrl).pathname : unwrappedUrl;
-        const lastSlash = path.lastIndexOf('/');
-        return lastSlash >= 0 ? path.substring(0, lastSlash + 1) : '';
-    } catch {
-        const lastSlash = url.lastIndexOf('/');
-        return lastSlash >= 0 ? url.substring(0, lastSlash + 1) : '';
-    }
-}
-
-/**
- * Learn pattern from the largest block (assumed to be main content)
- */
-export function learnMainPattern(blocks: Block[]): MainPattern {
-    // Find the largest block by segment count (likely main content)
-    const mainBlock = blocks.length > 0 ? blocks.reduce((largest, block) =>
-        block.segments.length > largest.segments.length ? block : largest
-    ) : null;
-
-    if (!mainBlock || mainBlock.segments.length === 0) {
-        return { filenameRegex: null, avgDuration: 0, commonPrefix: '', pathPrefix: '', isGlobalNTSC: false, isGlobal24fps: false };
-    }
-
-    // Extract filenames
-    const filenames = mainBlock.segments.map(s => extractFilename(s.url));
-
-    // Find common prefix
-    const commonPrefix = findCommonPrefix(filenames);
-
-    // Calculate average duration
-    const totalDuration = mainBlock.segments.reduce((sum, s) => sum + s.duration, 0);
-    const avgDuration = totalDuration / mainBlock.segments.length;
-
-    // Try to build a regex pattern from the filenames
-    // Common patterns: "0000001.ts", "seg-1.ts", "segment_001.ts"
-    let filenameRegex: RegExp | null = null;
-    if (commonPrefix.length >= 2) {
-        // Escape special regex characters in prefix
-        const escapedPrefix = commonPrefix.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
-        filenameRegex = new RegExp(`^${escapedPrefix}`);
-    }
-
-    // Extract path prefix (directory path without filename)
-    // e.g., "/20230907/73PWifvT/1392kb/hls/" from "/20230907/73PWifvT/1392kb/hls/gFE6lwIk.ts"
-    const firstUrl = mainBlock.segments[0].url;
-    const pathPrefix = extractPathPrefix(firstUrl);
-
-    // Calculate global NTSC 30fps and 24fps/23.976fps fraction ratios across all blocks in the playlist
-    const ntscFractions = new Set([33, 67, 133, 167, 233, 267, 333, 367, 433, 467, 533, 567, 633, 667, 733, 767, 833, 867, 933, 967]);
-    const fps24Fractions = new Set([2, 4, 6, 8, 12, 16, 20, 24]);
-    let totalSegCount = 0;
-    let ntscSegCount = 0;
-    let fps24SegCount = 0;
-
-    blocks.forEach(b => {
-        b.segments.forEach(s => {
-            totalSegCount++;
-            const msFraction = Math.round((s.duration % 1) * 1000);
-            if (ntscFractions.has(msFraction)) ntscSegCount++;
-            if (fps24Fractions.has(msFraction)) fps24SegCount++;
-        });
-    });
-
-    const isGlobalNTSC = totalSegCount > 0 && (ntscSegCount / totalSegCount) > 0.3;
-    const isGlobal24fps = totalSegCount > 0 && (fps24SegCount / totalSegCount) > 0.35;
-
-    return { filenameRegex, avgDuration, commonPrefix, pathPrefix, isGlobalNTSC, isGlobal24fps };
-}
-
-/**
- * Find blocks that share an identical sequence of segment durations (fingerprint)
- * with another block in the playlist.
- *
- * If a block (with >= 3 segments) has an identical duration signature
- * as another block in the playlist, and it is not the main content block,
- * it is extremely likely to be a repeated inserted ad block.
- */
-export function findDuplicateSignatureBlockIndices(blocks: Block[]): Set<number> {
-    const duplicateIndices = new Set<number>();
-    if (!blocks || blocks.length < 2) return duplicateIndices;
-
-    // Find the largest block (assumed main content block)
-    let mainBlockIndex = -1;
-    let maxSegments = 0;
-
-    blocks.forEach((block, idx) => {
-        if (block.segments.length > maxSegments) {
-            maxSegments = block.segments.length;
-            mainBlockIndex = idx;
-        }
-    });
-
-    let mainAvgDuration = 0;
-    if (mainBlockIndex >= 0 && blocks[mainBlockIndex].segments.length > 0) {
-        const mainSegs = blocks[mainBlockIndex].segments;
-        mainAvgDuration = mainSegs.reduce((sum, s) => sum + s.duration, 0) / mainSegs.length;
-    }
-
-    // Map signature -> array of block indices
-    const signatureMap = new Map<string, number[]>();
-
-    blocks.forEach((block, idx) => {
-        // Require at least 3 segments to form a signature to prevent accidental single-segment collisions
-        if (block.segments.length < 3) return;
-
-        const firstDur = block.segments[0].duration;
-        const isUniformBlock = block.segments.every(s => Math.abs(s.duration - firstDur) < 0.005);
-
-        // If the block is uniform (e.g. 2.0s, 2.0s, 2.0s) AND its duration matches the main content's duration (e.g. zuida.m3u8 where main content is also 2.0s),
-        // it represents normal main video chunking and must NOT be flagged as an ad signature.
-        if (isUniformBlock && mainAvgDuration > 0 && Math.abs(firstDur - mainAvgDuration) < 0.05) {
-            return;
-        }
-
-        // Signature based on segment durations rounded to 3 decimal places (milliseconds precision)
-        const signature = block.segments.map(s => s.duration.toFixed(3)).join(',');
-
-        const existing = signatureMap.get(signature) || [];
-        existing.push(idx);
-        signatureMap.set(signature, existing);
-    });
-
-    // Flag blocks whose signatures appear 2 or more times (up to 30% of total blocks, at least 3)
-    const maxAllowedAdOccurrences = Math.max(3, blocks.length * 0.3);
-    signatureMap.forEach((indices) => {
-        if (indices.length >= 2 && indices.length <= maxAllowedAdOccurrences) {
-            indices.forEach(idx => {
-                if (idx !== mainBlockIndex) {
-                    duplicateIndices.add(idx);
-                }
-            });
-        }
-    });
-
-    return duplicateIndices;
-}
-
-/**
- * Score a block for ad likelihood based on heuristics
- * Returns a score where higher = more likely to be an ad
- */
-export function scoreBlock(
-    block: Block,
-    mainPattern: MainPattern,
-    extraKeywords: string[] = [],
-    isDuplicateSignature: boolean = false
-): number {
-    let score = 0;
-
-    // If block has CUE tag or matches a duplicate signature, it's definitely an ad
-    if (block.hasCueTag || isDuplicateSignature) {
-        return 10; // Max score
-    }
-
-    // Check path keywords (Built-in + Custom)
-    // We filter out very short custom keywords to avoid false positives in scoring
-    const safeExtraKeywords = extraKeywords.filter(k => k.length > 2);
-    const allKeywords = [...AD_PATH_KEYWORDS, ...safeExtraKeywords];
-
-    for (const segment of block.segments) {
-        const urlLower = segment.url.toLowerCase();
-        for (const keyword of allKeywords) {
-            if (urlLower.includes(keyword.toLowerCase())) {
-                score += 2.5;
-                break; // Only count once per segment
-            }
-        }
-    }
-
-    // Check filename pattern mismatch
-    if (mainPattern.filenameRegex) {
-        const mismatchCount = block.segments.filter(s => {
-            if (!mainPattern.filenameRegex) return false; // No pattern to compare against
-            const filename = extractFilename(s.url);
-            return !mainPattern.filenameRegex.test(filename);
-        }).length;
-
-        if (mismatchCount === block.segments.length && block.segments.length > 0) {
-            score += 1.5; // All filenames differ from main pattern
-        }
-    }
-
-    // **KEY FEATURE**: Check path prefix mismatch (e.g., different date/folder/bitrate)
-    // This is the most reliable indicator for ads that come from different CDN paths
-    if (mainPattern.pathPrefix !== undefined && block.segments.length > 0) {
-        const pathMismatchCount = block.segments.filter(s => {
-            const segmentPathPrefix = extractPathPrefix(s.url);
-            return segmentPathPrefix !== mainPattern.pathPrefix;
-        }).length;
-
-        if (pathMismatchCount === block.segments.length) {
-            // ALL segments have different path prefix - strong ad indicator
-            score += 5.0;
-        }
-    }
-
-    // **ENHANCEMENT**: Duration anomaly heuristic for mid-roll inserted ad blocks
-    // If main content has a consistent segment duration (e.g., 6.0s or 10.0s),
-    // but this small block has a vastly different duration signature (e.g., 2.0s),
-    // add additional score when combined with filename or path mismatch.
-    if (mainPattern.avgDuration > 0 && block.segments.length > 0 && block.segments.length <= 6) {
-        const blockAvgDuration = block.segments.reduce((sum, s) => sum + s.duration, 0) / block.segments.length;
-        const durationRatio = blockAvgDuration / mainPattern.avgDuration;
-        if (durationRatio < 0.6 || durationRatio > 1.8) {
-            score += 1.5;
-        }
-    }
-
-    // **KEY FEATURE**: Framerate fraction grid anomaly detection (30fps vs 25fps inserted ad detection)
-    // Spliced NTSC 30fps/60fps ads inserted into 25fps/50fps streams create distinct fractional ms (.333, .667, .867, .133, .733).
-    // Note: Only triggered if the main content itself is NOT a global NTSC 30fps stream.
-    if (!mainPattern.isGlobalNTSC && block.segments.length > 0 && block.segments.length <= 10) {
-        const ntscFractions = new Set([33, 67, 133, 167, 233, 267, 333, 367, 433, 467, 533, 567, 633, 667, 733, 767, 833, 867, 933, 967]);
-        let ntscMatches = 0;
-        block.segments.forEach(s => {
-            const msFraction = Math.round((s.duration % 1) * 1000);
-            if (ntscFractions.has(msFraction)) ntscMatches++;
-        });
-        if (ntscMatches === block.segments.length) {
-            score += 5.0; // Definite framerate anomaly for inserted ad block
-        }
-    }
-
-    // **KEY FEATURE**: Framerate fraction grid anomaly detection (25fps/integer ads inserted into 24fps/23.976fps streams)
-    // 24fps movie streams have fractional ms (.004, .002, .008). 25fps/PAL inserted ads use exact integer milliseconds (.000).
-    if (mainPattern.isGlobal24fps && block.segments.length > 0 && block.segments.length <= 10) {
-        let int0Count = 0;
-        block.segments.forEach(s => {
-            const msFraction = Math.round((s.duration % 1) * 1000);
-            if (msFraction === 0) int0Count++;
-        });
-        if (int0Count >= block.segments.length - 1 && int0Count >= 2) {
-            score += 5.0; // Definite 25fps integer ad inserted into 24fps movie stream
-        }
-    }
-
-    return score;
-}
-
-/**
- * Threshold configuration
- */
-export const THRESHOLDS = {
-    HIGH: 5.0,   // Definitely an ad
-    LOW: 3.0    // Possibly an ad (for future "fuzzy" mode)
-};
-
-/**
- * Determine if a block should be filtered based on its score
- */
-export function shouldFilterBlock(score: number, threshold: number = THRESHOLDS.HIGH): boolean {
-    return score >= threshold;
-}
diff --git a/lib/utils/m3u8-ad-pattern.ts b/lib/utils/m3u8-ad-pattern.ts
new file mode 100644
index 0000000..435cdd7
--- /dev/null
+++ b/lib/utils/m3u8-ad-pattern.ts
@@ -0,0 +1,100 @@
+import {
+    hasDominantFilm24LikeGrid,
+    hasDominantNtscLikeGrid,
+} from './m3u8-duration-grid';
+import type { Block, MainPattern, SegmentLocation } from './m3u8-ad-types';
+
+function unwrapProxyUrl(url: string): string {
+    if (!url.includes('/api/proxy?url=')) return url;
+
+    try {
+        const match = url.match(/[?&]url=([^&]+)/);
+        return match?.[1] ? decodeURIComponent(match[1]) : url;
+    } catch {
+        return url;
+    }
+}
+
+export function extractFilename(url: string): string {
+    try {
+        const unwrappedUrl = unwrapProxyUrl(url);
+        const path = unwrappedUrl.includes('://')
+            ? new URL(unwrappedUrl).pathname
+            : unwrappedUrl;
+        return path.split('/').pop() || '';
+    } catch {
+        return url.split('/').pop() || '';
+    }
+}
+
+function findCommonPrefix(strings: string[]): string {
+    if (strings.length < 2) return '';
+
+    let prefix = '';
+    for (let index = 0; index < strings[0].length; index += 1) {
+        const character = strings[0][index];
+        if (!strings.every(value => value[index] === character)) break;
+        prefix += character;
+    }
+    return prefix;
+}
+
+export function extractSegmentLocation(url: string): SegmentLocation {
+    try {
+        const unwrappedUrl = unwrapProxyUrl(url);
+        const parsedUrl = unwrappedUrl.includes('://') ? new URL(unwrappedUrl) : null;
+        const path = parsedUrl?.pathname || unwrappedUrl;
+        const lastSlash = path.lastIndexOf('/');
+        return {
+            origin: parsedUrl?.origin || '',
+            pathPrefix: lastSlash >= 0 ? path.substring(0, lastSlash + 1) : '',
+        };
+    } catch {
+        const lastSlash = url.lastIndexOf('/');
+        return {
+            origin: '',
+            pathPrefix: lastSlash >= 0 ? url.substring(0, lastSlash + 1) : '',
+        };
+    }
+}
+
+export function learnMainPattern(blocks: Block[]): MainPattern {
+    const mainBlock = blocks.length > 0
+        ? blocks.reduce((largest, block) => (
+            block.segments.length > largest.segments.length ? block : largest
+        ))
+        : null;
+
+    if (!mainBlock || mainBlock.segments.length === 0) {
+        return {
+            filenameRegex: null,
+            avgDuration: 0,
+            commonPrefix: '',
+            pathPrefix: '',
+            origin: '',
+            usesNtscLikeGrid: false,
+            usesFilm24LikeGrid: false,
+        };
+    }
+
+    const filenames = mainBlock.segments.map(segment => extractFilename(segment.url));
+    const commonPrefix = findCommonPrefix(filenames);
+    const totalDuration = mainBlock.segments.reduce((sum, segment) => (
+        sum + segment.duration
+    ), 0);
+    const avgDuration = totalDuration / mainBlock.segments.length;
+    const escapedPrefix = commonPrefix.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
+    const filenameRegex = commonPrefix.length >= 2
+        ? new RegExp(`^${escapedPrefix}`)
+        : null;
+    const location = extractSegmentLocation(mainBlock.segments[0].url);
+
+    return {
+        filenameRegex,
+        avgDuration,
+        commonPrefix,
+        ...location,
+        usesNtscLikeGrid: hasDominantNtscLikeGrid(mainBlock.segments),
+        usesFilm24LikeGrid: hasDominantFilm24LikeGrid(mainBlock.segments),
+    };
+}
diff --git a/lib/utils/m3u8-ad-scoring.ts b/lib/utils/m3u8-ad-scoring.ts
new file mode 100644
index 0000000..eed5021
--- /dev/null
+++ b/lib/utils/m3u8-ad-scoring.ts
@@ -0,0 +1,100 @@
+import {
+    isSmallIntegerDurationBlock,
+    isSmallNtscLikeBlock,
+} from './m3u8-duration-grid';
+import { extractFilename, extractSegmentLocation } from './m3u8-ad-pattern';
+import type { Block, MainPattern } from './m3u8-ad-types';
+
+export const AD_PATH_KEYWORDS = [
+    'advert', 'preroll', 'midroll', 'postroll',
+    'dai', 'vast', 'ima', 'adjump', 'commercial', 'sponsor',
+];
+
+function scoreKeywords(block: Block, extraKeywords: string[]): number {
+    const keywords = [
+        ...AD_PATH_KEYWORDS,
+        ...extraKeywords.filter(keyword => keyword.length > 2),
+    ];
+
+    return block.segments.reduce((score, segment) => {
+        const url = segment.url.toLowerCase();
+        return keywords.some(keyword => url.includes(keyword.toLowerCase()))
+            ? score + 2.5
+            : score;
+    }, 0);
+}
+
+function scoreFilenameMismatch(block: Block, mainPattern: MainPattern): number {
+    if (!mainPattern.filenameRegex || block.segments.length === 0) return 0;
+
+    const allMismatch = block.segments.every(segment => (
+        !mainPattern.filenameRegex?.test(extractFilename(segment.url))
+    ));
+    return allMismatch ? 1.5 : 0;
+}
+
+function scoreLocationMismatch(block: Block, mainPattern: MainPattern): number {
+    if ((!mainPattern.pathPrefix && !mainPattern.origin) || block.segments.length === 0) {
+        return 0;
+    }
+
+    const locations = block.segments.map(segment => extractSegmentLocation(segment.url));
+    const allPathsMismatch = locations.every(location => (
+        location.pathPrefix !== mainPattern.pathPrefix
+    ));
+    if (allPathsMismatch) return 5;
+
+    const allOriginsMismatch = locations.every(location => (
+        Boolean(mainPattern.origin && location.origin) && location.origin !== mainPattern.origin
+    ));
+    return allOriginsMismatch ? 3.5 : 0;
+}
+
+function scoreDurationMismatch(block: Block, mainPattern: MainPattern): number {
+    if (mainPattern.avgDuration <= 0 || block.segments.length === 0 || block.segments.length > 6) {
+        return 0;
+    }
+
+    const blockAverage = block.segments.reduce((sum, segment) => (
+        sum + segment.duration
+    ), 0) / block.segments.length;
+    const durationRatio = blockAverage / mainPattern.avgDuration;
+    return durationRatio < 0.6 || durationRatio > 1.8 ? 1.5 : 0;
+}
+
+function scoreDurationGrid(block: Block, mainPattern: MainPattern): number {
+    if (!mainPattern.usesNtscLikeGrid && isSmallNtscLikeBlock(block.segments)) {
+        return 3.5;
+    }
+    if (mainPattern.usesFilm24LikeGrid && isSmallIntegerDurationBlock(block.segments)) {
+        return 3.5;
+    }
+    return 0;
+}
+
+export function scoreBlock(
+    block: Block,
+    mainPattern: MainPattern,
+    extraKeywords: string[] = [],
+    isDuplicateSignature: boolean = false,
+): number {
+    if (block.hasCueTag || isDuplicateSignature) return 10;
+
+    return scoreKeywords(block, extraKeywords) +
+        scoreFilenameMismatch(block, mainPattern) +
+        scoreLocationMismatch(block, mainPattern) +
+        scoreDurationMismatch(block, mainPattern) +
+        scoreDurationGrid(block, mainPattern);
+}
+
+export const THRESHOLDS = {
+    HIGH: 5,
+    LOW: 3,
+};
+
+export function shouldFilterBlock(
+    score: number,
+    threshold: number = THRESHOLDS.HIGH,
+): boolean {
+    return score >= threshold;
+}
diff --git a/lib/utils/m3u8-ad-signatures.ts b/lib/utils/m3u8-ad-signatures.ts
new file mode 100644
index 0000000..685d9ee
--- /dev/null
+++ b/lib/utils/m3u8-ad-signatures.ts
@@ -0,0 +1,54 @@
+import type { Block } from './m3u8-ad-types';
+
+export function findDuplicateSignatureBlockIndices(blocks: Block[]): Set<number> {
+    const duplicateIndices = new Set<number>();
+    if (blocks.length < 2) return duplicateIndices;
+
+    let mainBlockIndex = -1;
+    let maxSegments = 0;
+    blocks.forEach((block, index) => {
+        if (block.segments.length > maxSegments) {
+            maxSegments = block.segments.length;
+            mainBlockIndex = index;
+        }
+    });
+
+    const mainSegments = mainBlockIndex >= 0 ? blocks[mainBlockIndex].segments : [];
+    const mainAvgDuration = mainSegments.length > 0
+        ? mainSegments.reduce((sum, segment) => sum + segment.duration, 0) / mainSegments.length
+        : 0;
+    const signatureMap = new Map<string, number[]>();
+
+    blocks.forEach((block, index) => {
+        if (block.segments.length < 3) return;
+
+        const firstDuration = block.segments[0].duration;
+        const isUniform = block.segments.every(segment => (
+            Math.abs(segment.duration - firstDuration) < 0.005
+        ));
+        const matchesMainDuration = mainAvgDuration > 0 &&
+            Math.abs(firstDuration - mainAvgDuration) < 0.05;
+        if (isUniform && matchesMainDuration) return;
+
+        const signature = block.segments
+            .map(segment => segment.duration.toFixed(3))
+            .join(',');
+        const matchingBlocks = signatureMap.get(signature) || [];
+        matchingBlocks.push(index);
+        signatureMap.set(signature, matchingBlocks);
+    });
+
+    const maxOccurrences = Math.max(2, Math.floor(blocks.length * 0.3));
+    signatureMap.forEach((indices) => {
+        if (indices.length < 2 || indices.length > maxOccurrences) return;
+
+        indices.forEach((index) => {
+            const isClearlySmallerThanMain = blocks[index].segments.length < maxSegments * 0.8;
+            if (index !== mainBlockIndex && isClearlySmallerThanMain) {
+                duplicateIndices.add(index);
+            }
+        });
+    });
+
+    return duplicateIndices;
+}
diff --git a/lib/utils/m3u8-ad-types.ts b/lib/utils/m3u8-ad-types.ts
new file mode 100644
index 0000000..3f1dfbd
--- /dev/null
+++ b/lib/utils/m3u8-ad-types.ts
@@ -0,0 +1,27 @@
+export interface Segment {
+    url: string;
+    duration: number;
+    lineIndex: number;
+}
+
+export interface Block {
+    segments: Segment[];
+    startLineIndex: number;
+    endLineIndex: number;
+    hasCueTag: boolean;
+}
+
+export interface MainPattern {
+    filenameRegex: RegExp | null;
+    avgDuration: number;
+    commonPrefix: string;
+    pathPrefix: string;
+    origin: string;
+    usesNtscLikeGrid: boolean;
+    usesFilm24LikeGrid: boolean;
+}
+
+export interface SegmentLocation {
+    origin: string;
+    pathPrefix: string;
+}
diff --git a/lib/utils/m3u8-duration-grid.ts b/lib/utils/m3u8-duration-grid.ts
new file mode 100644
index 0000000..11253e8
--- /dev/null
+++ b/lib/utils/m3u8-duration-grid.ts
@@ -0,0 +1,53 @@
+interface DurationSample {
+    duration: number;
+}
+
+const NTSC_LIKE_MILLISECOND_FRACTIONS = new Set([
+    33, 67, 133, 167, 233, 267, 333, 367, 433, 467,
+    533, 567, 633, 667, 733, 767, 833, 867, 933, 967,
+]);
+
+const FILM_24_LIKE_MILLISECOND_FRACTIONS = new Set([
+    2, 4, 6, 8, 12, 16, 20, 24,
+]);
+
+function millisecondFraction(duration: number): number {
+    const fractionalSeconds = Math.abs(duration - Math.trunc(duration));
+    return Math.round(fractionalSeconds * 1000) % 1000;
+}
+
+function matchingRatio(samples: DurationSample[], fractions: Set<number>): number {
+    if (samples.length === 0) return 0;
+
+    const matches = samples.reduce((count, sample) => (
+        fractions.has(millisecondFraction(sample.duration)) ? count + 1 : count
+    ), 0);
+
+    return matches / samples.length;
+}
+
+export function hasDominantNtscLikeGrid(samples: DurationSample[]): boolean {
+    return samples.length >= 4 &&
+        matchingRatio(samples, NTSC_LIKE_MILLISECOND_FRACTIONS) > 0.3;
+}
+
+export function hasDominantFilm24LikeGrid(samples: DurationSample[]): boolean {
+    return samples.length >= 4 &&
+        matchingRatio(samples, FILM_24_LIKE_MILLISECOND_FRACTIONS) > 0.35;
+}
+
+export function isSmallNtscLikeBlock(samples: DurationSample[]): boolean {
+    return samples.length >= 2 &&
+        samples.length <= 10 &&
+        matchingRatio(samples, NTSC_LIKE_MILLISECOND_FRACTIONS) >= 0.8;
+}
+
+export function isSmallIntegerDurationBlock(samples: DurationSample[]): boolean {
+    if (samples.length < 2 || samples.length > 10) return false;
+
+    const integerDurations = samples.reduce((count, sample) => (
+        millisecondFraction(sample.duration) === 0 ? count + 1 : count
+    ), 0);
+
+    return integerDurations >= 2 && integerDurations / samples.length >= 0.75;
+}
diff --git a/lib/utils/m3u8-utils.ts b/lib/utils/m3u8-utils.ts
index 33fa511..3b46c7c 100644
--- a/lib/utils/m3u8-utils.ts
+++ b/lib/utils/m3u8-utils.ts
@@ -81,58 +81,17 @@ function isAuxiliaryAdMetadataLine(trimmedLine: string, normalizedKeywords: stri
  * @param baseUrl The base URL of the M3U8 file (to resolve relative paths)
  * @returns The filtered M3U8 content
  */
-/**
- * Strips TypeScript type annotations from dynamic ad filter JavaScript/TypeScript code
- */
-export function removeTypeAnnotations(code: string): string {
-    return code
-        .replace(/(\w+)\s*:\s*(string|number|boolean|any|void|never|unknown|object)\s*([,)])/g, '$1$3')
-        .replace(/\)\s*:\s*(string|number|boolean|any|void|never|unknown|object)\s*\{/g, ') {')
-        .replace(/(const|let|var)\s+(\w+)\s*:\s*(string|number|boolean|any|void|never|unknown|object)\s*=/g, '$1 $2 =');
-}
-
-/**
- * Safely executes dynamic custom ad filter code using Function constructor sandbox.
- * Returns filtered content string or null if execution fails/throws.
- */
-export function executeCustomAdFilter(customCode: string, content: string, baseUrl: string): string | null {
-    if (!customCode || !customCode.trim()) return null;
-    try {
-        const jsCode = removeTypeAnnotations(customCode);
-        const customFunction = new Function(
-            'content',
-            'baseUrl',
-            jsCode + '\nif (typeof filterAdsFromM3U8 === "function") { return filterAdsFromM3U8(content, baseUrl); } else if (typeof filterAds === "function") { return filterAds(content, baseUrl); } return content;'
-        );
-        const result = customFunction(content, baseUrl);
-        return typeof result === 'string' ? result : null;
-    } catch (err) {
-        console.warn('[AdFilter] Custom script execution failed, falling back to built-in rules:', err);
-        return null;
-    }
-}
-
 export type AdFilterMode = 'off' | 'keyword' | 'heuristic' | 'aggressive';
 
 export function filterM3u8Ad(
     content: string,
     baseUrl: string,
     mode: AdFilterMode = 'heuristic',
-    customKeywords: string[] = [],
-    customCode?: string
+    customKeywords: string[] = []
 ): string {
     if (!content) return '';
     if (mode === 'off') return content;
 
-    // 1. Try executing custom dynamic filter script first (if provided)
-    if (customCode && customCode.trim()) {
-        const customResult = executeCustomAdFilter(customCode, content, baseUrl);
-        if (customResult !== null) {
-            return customResult;
-        }
-        // If custom script execution fails/throws, gracefully fall through to built-in heuristics
-    }
-
     // Use keywords passed from AdKeywordsWrapper (already loaded from env/file)
     const normalizedKeywords = normalizeKeywords(customKeywords);
 
@@ -144,14 +103,14 @@ export function filterM3u8Ad(
             if (urlMatch && urlMatch[1]) {
                 effectiveBaseUrl = decodeURIComponent(urlMatch[1]);
             }
-        } catch (e) { /* ignore */ }
+        } catch { /* ignore */ }
     }
 
     const basePath = effectiveBaseUrl.substring(0, effectiveBaseUrl.lastIndexOf('/') + 1);
     let origin = '';
     try {
         origin = new URL(effectiveBaseUrl).origin;
-    } catch (e) { /* ignore */ }
+    } catch { /* ignore */ }
 
     // 2. Global Scan: Check if any ad keywords exist in the content
     const hasKeywordMatchInPlaylist = hasKeywordMatch(content, normalizedKeywords);
@@ -159,7 +118,7 @@ export function filterM3u8Ad(
 
     // 3. Heuristic Analysis: If no explicit ad signals, use block-based detection
     const lines = content.split(/\r?\n/);
-    let adLineIndices = new Set<number>();
+    const adLineIndices = new Set<number>();
 
     if (!hasCueTag && (mode === 'heuristic' || mode === 'aggressive')) {
         // No obvious ad signals - run heuristic analysis
diff --git a/package-lock.json b/package-lock.json
index 9b5ae3f..3021cc4 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "kvideo",
-  "version": "4.9.16",
+  "version": "4.9.17",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "kvideo",
-      "version": "4.9.16",
+      "version": "4.9.17",
       "dependencies": {
         "@dnd-kit/core": "^6.3.1",
         "@dnd-kit/sortable": "^10.0.0",
@@ -15,7 +15,7 @@
         "@vercel/analytics": "^2.0.1",
         "hls.js": "^1.6.15",
         "lucide-react": "^0.577.0",
-        "next": "16.2.10",
+        "next": "16.2.12",
         "opencc-js": "^1.0.5",
         "react": "19.2.4",
         "react-dom": "19.2.4",
@@ -29,7 +29,7 @@
         "@types/react-dom": "^19",
         "esbuild": "^0.27.7",
         "eslint": "^9.25.1",
-        "eslint-config-next": "16.2.10",
+        "eslint-config-next": "16.2.12",
         "postcss": "^8.5.8",
         "postcss-preset-env": "^11.2.0",
         "tailwindcss": "^4",
@@ -3278,15 +3278,15 @@
       }
     },
     "node_modules/@next/env": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/@next/env/-/env-16.2.10.tgz",
-      "integrity": "sha512-zLPxg9M0MEHmygpj5OuxjQ+vHMiy/K7cSp74G8ecYolmgUWw0RwN02tF56npup/+qaI8JB97hQgS/r2Hb6QwVA==",
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/@next/env/-/env-16.2.12.tgz",
+      "integrity": "sha512-d0Z5Bc13Fa4nR8pFAKx2jay2yhJM16vlfHbTzYnUQAxlNb6B6lmn4hjt69lYNt4kRtyYP6gEM49lPRHNbIyneg==",
       "license": "MIT"
     },
     "node_modules/@next/eslint-plugin-next": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/@next/eslint-plugin-next/-/eslint-plugin-next-16.2.10.tgz",
-      "integrity": "sha512-Gs8D2m21VnJeFo9qvYIIqJH94frWerWYu41BprU1pLtRVF7PCQNLiFZZ3fG+iPuj3K83Cwv/rt+msLOy8Qgu3Q==",
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/@next/eslint-plugin-next/-/eslint-plugin-next-16.2.12.tgz",
+      "integrity": "sha512-uF2z/qAK2q7B5/6CpnFcBRX6jOq5iCO+Uqh1UkJhXljX1JwLarLYhhoJadO6dPb6moTprOKewMXheBcbIoSbug==",
       "dev": true,
       "license": "MIT",
       "dependencies": {
@@ -3294,9 +3294,9 @@
       }
     },
     "node_modules/@next/swc-darwin-arm64": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/@next/swc-darwin-arm64/-/swc-darwin-arm64-16.2.10.tgz",
-      "integrity": "sha512-v9IdJCa0H0mbo+8z5zwUpOk1Vj7RjkcI5uNYf5Ws1y6szf/p3Mzl9hLaST8SCt6L9h8NGnruZcd2+o0NTNwDhA==",
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/@next/swc-darwin-arm64/-/swc-darwin-arm64-16.2.12.tgz",
+      "integrity": "sha512-0W1R0teHWJrqKX0FH20IzzIWAOuGtBxPGuObrxy1lE8hQvCFj49KE8a3WUg0D7sq6rn6zkM4c7YGUnhudBS6oA==",
       "cpu": [
         "arm64"
       ],
@@ -3310,9 +3310,9 @@
       }
     },
     "node_modules/@next/swc-darwin-x64": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/@next/swc-darwin-x64/-/swc-darwin-x64-16.2.10.tgz",
-      "integrity": "sha512-17IS0jJRViROGmA9uGdNR8VPJpfbnaVG7E9qhso5jDLkmyd0lSDORWxbcKINzcFqzZqGwGtMSnrFRxBpuUYjLQ==",
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/@next/swc-darwin-x64/-/swc-darwin-x64-16.2.12.tgz",
+      "integrity": "sha512-Hy5Ls099+aFUmOLmIgPfLqNi6iCwhL3uQCssz5rWk+5Nkc6TUKCE83DY5BbNylfm3+mfwcSFnLRfrZDJhVxdtw==",
       "cpu": [
         "x64"
       ],
@@ -3326,9 +3326,9 @@
       }
     },
     "node_modules/@next/swc-linux-arm64-gnu": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/@next/swc-linux-arm64-gnu/-/swc-linux-arm64-gnu-16.2.10.tgz",
-      "integrity": "sha512-GRQRsRtuciNJvB54AvvuQTiq0oZtFwa1owQqtZD8wwnGpM2L39MV22kpI72YSXLKIyY40LC66EiLFv4PiicXxg==",
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/@next/swc-linux-arm64-gnu/-/swc-linux-arm64-gnu-16.2.12.tgz",
+      "integrity": "sha512-+YqU2h1cQkHsGfvjAsrSmst8UIFBibBGm5x3Xgel8NLMiDQtNOM4sM2GOEMvG5YiOBNeN/Ykk8cQC2S0Xrqljg==",
       "cpu": [
         "arm64"
       ],
@@ -3345,9 +3345,9 @@
       }
     },
     "node_modules/@next/swc-linux-arm64-musl": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/@next/swc-linux-arm64-musl/-/swc-linux-arm64-musl-16.2.10.tgz",
-      "integrity": "sha512-zkN9MQYS7UQBro+FnISUq1itaQjXI9xqISzuQ+2bc921NcJ1x4yPCqrn77tVN6/dOOXaaWVX3k6/bR07pPwK+A==",
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/@next/swc-linux-arm64-musl/-/swc-linux-arm64-musl-16.2.12.tgz",
+      "integrity": "sha512-0qjhiYBaKAqF63LA1ZWAAnKTzFUguAaZiRa5etMLGGPj/B6uEVjtIZldIzFEp3wHlB0koK6aTzqPtSdplTCjoA==",
       "cpu": [
         "arm64"
       ],
@@ -3364,9 +3364,9 @@
       }
     },
     "node_modules/@next/swc-linux-x64-gnu": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/@next/swc-linux-x64-gnu/-/swc-linux-x64-gnu-16.2.10.tgz",
-      "integrity": "sha512-iCVJnwvrPYECvA6WM/7+oo+OiTvedIKLxtCLAZP4xZR3nXa1zmzZyLPbYCmWvpd4CvMYF1EMTafd0ii3DygLvA==",
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/@next/swc-linux-x64-gnu/-/swc-linux-x64-gnu-16.2.12.tgz",
+      "integrity": "sha512-7A3q26W+h7gnA15uqBToNuDqBEFZZcqh0mW2mn4AJh/G5pdg2RVE3n4slzLEliASZFG3NmsbEzng/x2Sh09mBg==",
       "cpu": [
         "x64"
       ],
@@ -3383,9 +3383,9 @@
       }
     },
     "node_modules/@next/swc-linux-x64-musl": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/@next/swc-linux-x64-musl/-/swc-linux-x64-musl-16.2.10.tgz",
-      "integrity": "sha512-ov2g4H0dHY9bPoOU83m91hWT7Iq5qy13bUnyyshLU3HGR1Ownn0X9QpmDPc5iIUaahTp7f7LeGAhV4DSFtackw==",
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/@next/swc-linux-x64-musl/-/swc-linux-x64-musl-16.2.12.tgz",
+      "integrity": "sha512-qSjL/uppm+cbh21s72Ss8gkiOhQ4dExWHNGOWy6eZV7STj5WsKehgxT61beSsOj+YYQuTplL376lOCdMQU5T8w==",
       "cpu": [
         "x64"
       ],
@@ -3402,9 +3402,9 @@
       }
     },
     "node_modules/@next/swc-win32-arm64-msvc": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/@next/swc-win32-arm64-msvc/-/swc-win32-arm64-msvc-16.2.10.tgz",
-      "integrity": "sha512-DwAnhLX76HQiFFQNgWlcK+JzlnD1rZ+UK/WY0ZMI/deXpvgnesjNYrqcfo1JzBuz4Kf7o3brIBL0glI1junatA==",
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/@next/swc-win32-arm64-msvc/-/swc-win32-arm64-msvc-16.2.12.tgz",
+      "integrity": "sha512-X6hzsOUJac/e7AWSbn9gQ9nzHld1xWP5iyjHpYWvud8pufB679O1xg4JDyKr8Xd69Jvd+kM2Der6uftiZCmjYA==",
       "cpu": [
         "arm64"
       ],
@@ -3418,9 +3418,9 @@
       }
     },
     "node_modules/@next/swc-win32-x64-msvc": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/@next/swc-win32-x64-msvc/-/swc-win32-x64-msvc-16.2.10.tgz",
-      "integrity": "sha512-0JXq3b85Jk9Jg4ntLUbXSPvoDw3gpZou7twuKdoFG2jOw635v7+IiXfTaa0TxVMyx78pUjnrVYwLgjKfX4e6/A==",
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/@next/swc-win32-x64-msvc/-/swc-win32-x64-msvc-16.2.12.tgz",
+      "integrity": "sha512-F6fakeHuFTLOPt0bslQJdf+xtT+WIP9DVn/m4y1w1mRnVPyh3D/cNvzlRkxM444xfm+IvvYNSOrKiA2CDJ0Uxw==",
       "cpu": [
         "x64"
       ],
@@ -7517,13 +7517,13 @@
       }
     },
     "node_modules/eslint-config-next": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/eslint-config-next/-/eslint-config-next-16.2.10.tgz",
-      "integrity": "sha512-HSybLOY0QKf39i4FWUqPN0xWiNDi6A6UqJmZtgDkS3zMqjXTqULvj/sueXx3cdCG0mVG+qH6k5/qdegklH1d1w==",
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/eslint-config-next/-/eslint-config-next-16.2.12.tgz",
+      "integrity": "sha512-iaaf4vvKo5h2LBdGt0JuRv7t0Ysqr9FMCiFxbptDg8LqOE//mIKR80DdpOnSVM7qjLH3jT8P0aFiwXxBEGZRXw==",
       "dev": true,
       "license": "MIT",
       "dependencies": {
-        "@next/eslint-plugin-next": "16.2.10",
+        "@next/eslint-plugin-next": "16.2.12",
         "eslint-import-resolver-node": "^0.3.6",
         "eslint-import-resolver-typescript": "^3.5.2",
         "eslint-plugin-import": "^2.32.0",
@@ -10010,12 +10010,12 @@
       "dev": true
     },
     "node_modules/next": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/next/-/next-16.2.10.tgz",
-      "integrity": "sha512-2som5AVXb3kE6Yjine3/mNbBayYF58eguBWIVVUdr1y/L426xyVEgYxgBG+1QC34P2x5E+tcDup6XkuOAX3dCA==",
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/next/-/next-16.2.12.tgz",
+      "integrity": "sha512-iD59eYQWmbFcEbX7v/acG5DRym9iw1DdaPoD0WTA920naWsE25wShzJW4+UvAs8MK9EC2kBfIH6vtto1H1PHGw==",
       "license": "MIT",
       "dependencies": {
-        "@next/env": "16.2.10",
+        "@next/env": "16.2.12",
         "@swc/helpers": "0.5.15",
         "baseline-browser-mapping": "^2.9.19",
         "caniuse-lite": "^1.0.30001579",
@@ -10029,14 +10029,14 @@
         "node": ">=20.9.0"
       },
       "optionalDependencies": {
-        "@next/swc-darwin-arm64": "16.2.10",
-        "@next/swc-darwin-x64": "16.2.10",
-        "@next/swc-linux-arm64-gnu": "16.2.10",
-        "@next/swc-linux-arm64-musl": "16.2.10",
-        "@next/swc-linux-x64-gnu": "16.2.10",
-        "@next/swc-linux-x64-musl": "16.2.10",
-        "@next/swc-win32-arm64-msvc": "16.2.10",
-        "@next/swc-win32-x64-msvc": "16.2.10",
+        "@next/swc-darwin-arm64": "16.2.12",
+        "@next/swc-darwin-x64": "16.2.12",
+        "@next/swc-linux-arm64-gnu": "16.2.12",
+        "@next/swc-linux-arm64-musl": "16.2.12",
+        "@next/swc-linux-x64-gnu": "16.2.12",
+        "@next/swc-linux-x64-musl": "16.2.12",
+        "@next/swc-win32-arm64-msvc": "16.2.12",
+        "@next/swc-win32-x64-msvc": "16.2.12",
         "sharp": "^0.34.5"
       },
       "peerDependencies": {
@@ -14904,65 +14904,65 @@
       }
     },
     "@next/env": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/@next/env/-/env-16.2.10.tgz",
-      "integrity": "sha512-zLPxg9M0MEHmygpj5OuxjQ+vHMiy/K7cSp74G8ecYolmgUWw0RwN02tF56npup/+qaI8JB97hQgS/r2Hb6QwVA=="
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/@next/env/-/env-16.2.12.tgz",
+      "integrity": "sha512-d0Z5Bc13Fa4nR8pFAKx2jay2yhJM16vlfHbTzYnUQAxlNb6B6lmn4hjt69lYNt4kRtyYP6gEM49lPRHNbIyneg=="
     },
     "@next/eslint-plugin-next": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/@next/eslint-plugin-next/-/eslint-plugin-next-16.2.10.tgz",
-      "integrity": "sha512-Gs8D2m21VnJeFo9qvYIIqJH94frWerWYu41BprU1pLtRVF7PCQNLiFZZ3fG+iPuj3K83Cwv/rt+msLOy8Qgu3Q==",
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/@next/eslint-plugin-next/-/eslint-plugin-next-16.2.12.tgz",
+      "integrity": "sha512-uF2z/qAK2q7B5/6CpnFcBRX6jOq5iCO+Uqh1UkJhXljX1JwLarLYhhoJadO6dPb6moTprOKewMXheBcbIoSbug==",
       "dev": true,
       "requires": {
         "fast-glob": "3.3.1"
       }
     },
     "@next/swc-darwin-arm64": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/@next/swc-darwin-arm64/-/swc-darwin-arm64-16.2.10.tgz",
-      "integrity": "sha512-v9IdJCa0H0mbo+8z5zwUpOk1Vj7RjkcI5uNYf5Ws1y6szf/p3Mzl9hLaST8SCt6L9h8NGnruZcd2+o0NTNwDhA==",
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/@next/swc-darwin-arm64/-/swc-darwin-arm64-16.2.12.tgz",
+      "integrity": "sha512-0W1R0teHWJrqKX0FH20IzzIWAOuGtBxPGuObrxy1lE8hQvCFj49KE8a3WUg0D7sq6rn6zkM4c7YGUnhudBS6oA==",
       "optional": true
     },
     "@next/swc-darwin-x64": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/@next/swc-darwin-x64/-/swc-darwin-x64-16.2.10.tgz",
-      "integrity": "sha512-17IS0jJRViROGmA9uGdNR8VPJpfbnaVG7E9qhso5jDLkmyd0lSDORWxbcKINzcFqzZqGwGtMSnrFRxBpuUYjLQ==",
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/@next/swc-darwin-x64/-/swc-darwin-x64-16.2.12.tgz",
+      "integrity": "sha512-Hy5Ls099+aFUmOLmIgPfLqNi6iCwhL3uQCssz5rWk+5Nkc6TUKCE83DY5BbNylfm3+mfwcSFnLRfrZDJhVxdtw==",
       "optional": true
     },
     "@next/swc-linux-arm64-gnu": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/@next/swc-linux-arm64-gnu/-/swc-linux-arm64-gnu-16.2.10.tgz",
-      "integrity": "sha512-GRQRsRtuciNJvB54AvvuQTiq0oZtFwa1owQqtZD8wwnGpM2L39MV22kpI72YSXLKIyY40LC66EiLFv4PiicXxg==",
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/@next/swc-linux-arm64-gnu/-/swc-linux-arm64-gnu-16.2.12.tgz",
+      "integrity": "sha512-+YqU2h1cQkHsGfvjAsrSmst8UIFBibBGm5x3Xgel8NLMiDQtNOM4sM2GOEMvG5YiOBNeN/Ykk8cQC2S0Xrqljg==",
       "optional": true
     },
     "@next/swc-linux-arm64-musl": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/@next/swc-linux-arm64-musl/-/swc-linux-arm64-musl-16.2.10.tgz",
-      "integrity": "sha512-zkN9MQYS7UQBro+FnISUq1itaQjXI9xqISzuQ+2bc921NcJ1x4yPCqrn77tVN6/dOOXaaWVX3k6/bR07pPwK+A==",
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/@next/swc-linux-arm64-musl/-/swc-linux-arm64-musl-16.2.12.tgz",
+      "integrity": "sha512-0qjhiYBaKAqF63LA1ZWAAnKTzFUguAaZiRa5etMLGGPj/B6uEVjtIZldIzFEp3wHlB0koK6aTzqPtSdplTCjoA==",
       "optional": true
     },
     "@next/swc-linux-x64-gnu": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/@next/swc-linux-x64-gnu/-/swc-linux-x64-gnu-16.2.10.tgz",
-      "integrity": "sha512-iCVJnwvrPYECvA6WM/7+oo+OiTvedIKLxtCLAZP4xZR3nXa1zmzZyLPbYCmWvpd4CvMYF1EMTafd0ii3DygLvA==",
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/@next/swc-linux-x64-gnu/-/swc-linux-x64-gnu-16.2.12.tgz",
+      "integrity": "sha512-7A3q26W+h7gnA15uqBToNuDqBEFZZcqh0mW2mn4AJh/G5pdg2RVE3n4slzLEliASZFG3NmsbEzng/x2Sh09mBg==",
       "optional": true
     },
     "@next/swc-linux-x64-musl": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/@next/swc-linux-x64-musl/-/swc-linux-x64-musl-16.2.10.tgz",
-      "integrity": "sha512-ov2g4H0dHY9bPoOU83m91hWT7Iq5qy13bUnyyshLU3HGR1Ownn0X9QpmDPc5iIUaahTp7f7LeGAhV4DSFtackw==",
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/@next/swc-linux-x64-musl/-/swc-linux-x64-musl-16.2.12.tgz",
+      "integrity": "sha512-qSjL/uppm+cbh21s72Ss8gkiOhQ4dExWHNGOWy6eZV7STj5WsKehgxT61beSsOj+YYQuTplL376lOCdMQU5T8w==",
       "optional": true
     },
     "@next/swc-win32-arm64-msvc": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/@next/swc-win32-arm64-msvc/-/swc-win32-arm64-msvc-16.2.10.tgz",
-      "integrity": "sha512-DwAnhLX76HQiFFQNgWlcK+JzlnD1rZ+UK/WY0ZMI/deXpvgnesjNYrqcfo1JzBuz4Kf7o3brIBL0glI1junatA==",
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/@next/swc-win32-arm64-msvc/-/swc-win32-arm64-msvc-16.2.12.tgz",
+      "integrity": "sha512-X6hzsOUJac/e7AWSbn9gQ9nzHld1xWP5iyjHpYWvud8pufB679O1xg4JDyKr8Xd69Jvd+kM2Der6uftiZCmjYA==",
       "optional": true
     },
     "@next/swc-win32-x64-msvc": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/@next/swc-win32-x64-msvc/-/swc-win32-x64-msvc-16.2.10.tgz",
-      "integrity": "sha512-0JXq3b85Jk9Jg4ntLUbXSPvoDw3gpZou7twuKdoFG2jOw635v7+IiXfTaa0TxVMyx78pUjnrVYwLgjKfX4e6/A==",
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/@next/swc-win32-x64-msvc/-/swc-win32-x64-msvc-16.2.12.tgz",
+      "integrity": "sha512-F6fakeHuFTLOPt0bslQJdf+xtT+WIP9DVn/m4y1w1mRnVPyh3D/cNvzlRkxM444xfm+IvvYNSOrKiA2CDJ0Uxw==",
       "optional": true
     },
     "@nodelib/fs.scandir": {
@@ -17512,12 +17512,12 @@
       }
     },
     "eslint-config-next": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/eslint-config-next/-/eslint-config-next-16.2.10.tgz",
-      "integrity": "sha512-HSybLOY0QKf39i4FWUqPN0xWiNDi6A6UqJmZtgDkS3zMqjXTqULvj/sueXx3cdCG0mVG+qH6k5/qdegklH1d1w==",
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/eslint-config-next/-/eslint-config-next-16.2.12.tgz",
+      "integrity": "sha512-iaaf4vvKo5h2LBdGt0JuRv7t0Ysqr9FMCiFxbptDg8LqOE//mIKR80DdpOnSVM7qjLH3jT8P0aFiwXxBEGZRXw==",
       "dev": true,
       "requires": {
-        "@next/eslint-plugin-next": "16.2.10",
+        "@next/eslint-plugin-next": "16.2.12",
         "eslint-import-resolver-node": "^0.3.6",
         "eslint-import-resolver-typescript": "^3.5.2",
         "eslint-plugin-import": "^2.32.0",
@@ -19115,19 +19115,19 @@
       "dev": true
     },
     "next": {
-      "version": "16.2.10",
-      "resolved": "https://registry.npmjs.org/next/-/next-16.2.10.tgz",
-      "integrity": "sha512-2som5AVXb3kE6Yjine3/mNbBayYF58eguBWIVVUdr1y/L426xyVEgYxgBG+1QC34P2x5E+tcDup6XkuOAX3dCA==",
+      "version": "16.2.12",
+      "resolved": "https://registry.npmjs.org/next/-/next-16.2.12.tgz",
+      "integrity": "sha512-iD59eYQWmbFcEbX7v/acG5DRym9iw1DdaPoD0WTA920naWsE25wShzJW4+UvAs8MK9EC2kBfIH6vtto1H1PHGw==",
       "requires": {
-        "@next/env": "16.2.10",
-        "@next/swc-darwin-arm64": "16.2.10",
-        "@next/swc-darwin-x64": "16.2.10",
-        "@next/swc-linux-arm64-gnu": "16.2.10",
-        "@next/swc-linux-arm64-musl": "16.2.10",
-        "@next/swc-linux-x64-gnu": "16.2.10",
-        "@next/swc-linux-x64-musl": "16.2.10",
-        "@next/swc-win32-arm64-msvc": "16.2.10",
-        "@next/swc-win32-x64-msvc": "16.2.10",
+        "@next/env": "16.2.12",
+        "@next/swc-darwin-arm64": "16.2.12",
+        "@next/swc-darwin-x64": "16.2.12",
+        "@next/swc-linux-arm64-gnu": "16.2.12",
+        "@next/swc-linux-arm64-musl": "16.2.12",
+        "@next/swc-linux-x64-gnu": "16.2.12",
+        "@next/swc-linux-x64-musl": "16.2.12",
+        "@next/swc-win32-arm64-msvc": "16.2.12",
+        "@next/swc-win32-x64-msvc": "16.2.12",
         "@swc/helpers": "0.5.15",
         "baseline-browser-mapping": "^2.9.19",
         "caniuse-lite": "^1.0.30001579",
diff --git a/package.json b/package.json
index ac420d7..9c732eb 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "kvideo",
-  "version": "4.9.16",
+  "version": "4.9.17",
   "private": true,
   "scripts": {
     "dev": "node scripts/next-with-lan-access.mjs dev",
@@ -18,7 +18,7 @@
     "@vercel/analytics": "^2.0.1",
     "hls.js": "^1.6.15",
     "lucide-react": "^0.577.0",
-    "next": "16.2.10",
+    "next": "16.2.12",
     "opencc-js": "^1.0.5",
     "react": "19.2.4",
     "react-dom": "19.2.4",
@@ -32,7 +32,7 @@
     "@types/react-dom": "^19",
     "esbuild": "^0.27.7",
     "eslint": "^9.25.1",
-    "eslint-config-next": "16.2.10",
+    "eslint-config-next": "16.2.12",
     "postcss": "^8.5.8",
     "postcss-preset-env": "^11.2.0",
     "tailwindcss": "^4",
diff --git a/tests/m3u8-ad-detector.test.ts b/tests/m3u8-ad-detector.test.ts
index c6d304a..4d587b6 100644
--- a/tests/m3u8-ad-detector.test.ts
+++ b/tests/m3u8-ad-detector.test.ts
@@ -80,167 +80,3 @@ test('filterM3u8Ad still strips interstitial DATERANGE metadata', () => {
   assert.equal(filtered.includes('com.apple.hls.interstitial'), false);
   assert.equal(filtered.includes('seg-0.ts'), true);
 });
-
-test('filterM3u8Ad executes valid custom TS/JS script in sandbox', () => {
-  const playlist = [
-    '#EXTM3U',
-    '#EXTINF:5.000,',
-    'https://cdn.example.com/content/ad-segment.ts',
-    '#EXTINF:10.000,',
-    'https://cdn.example.com/content/main-segment.ts',
-  ].join('\n');
-
-  const customScript = `
-    function filterAdsFromM3U8(content: string, baseUrl: string): string {
-      return content.split('\\n').filter(line => !line.includes('ad-segment.ts')).join('\\n');
-    }
-  `;
-
-  const filtered = filterM3u8Ad(playlist, 'https://cdn.example.com/content/index.m3u8', 'heuristic', [], customScript);
-  assert.equal(filtered.includes('ad-segment.ts'), false);
-  assert.equal(filtered.includes('main-segment.ts'), true);
-});
-
-test('filterM3u8Ad gracefully falls back to built-in rules when custom script throws runtime error', () => {
-  const playlist = [
-    '#EXTM3U',
-    '#EXTINF:5.000,',
-    'https://cdn.example.com/content/sponsor-ad.ts',
-    '#EXTINF:10.000,',
-    'https://cdn.example.com/content/main-segment.ts',
-  ].join('\n');
-
-  const brokenScript = `
-    function filterAdsFromM3U8(content: string): string {
-      throw new Error("Syntax error or intentional bug");
-    }
-  `;
-
-  const filtered = filterM3u8Ad(playlist, 'https://cdn.example.com/content/index.m3u8', 'heuristic', ['sponsor'], brokenScript);
-  assert.equal(filtered.includes('sponsor-ad.ts'), false);
-  assert.equal(filtered.includes('main-segment.ts'), true);
-});
-
-test('filterM3u8Ad detects and strips 30fps/NTSC framerate fraction anomaly inserted ad blocks', () => {
-  const playlist = [
-    '#EXTM3U',
-    '#EXTINF:4.000,',
-    'https://cdn.example.com/content/main-0.ts',
-    '#EXTINF:4.000,',
-    'https://cdn.example.com/content/main-1.ts',
-    '#EXTINF:4.000,',
-    'https://cdn.example.com/content/main-2.ts',
-    '#EXTINF:4.000,',
-    'https://cdn.example.com/content/main-3.ts',
-    '#EXTINF:4.000,',
-    'https://cdn.example.com/content/main-4.ts',
-    '#EXT-X-DISCONTINUITY',
-    '#EXTINF:4.867,',
-    'https://cdn.example.com/content/ad-0.ts',
-    '#EXTINF:3.333,',
-    'https://cdn.example.com/content/ad-1.ts',
-    '#EXT-X-DISCONTINUITY',
-    '#EXTINF:4.000,',
-    'https://cdn.example.com/content/main-5.ts',
-    '#EXTINF:4.000,',
-    'https://cdn.example.com/content/main-6.ts',
-    '#EXTINF:4.000,',
-    'https://cdn.example.com/content/main-7.ts',
-  ].join('\n');
-
-  const filtered = filterM3u8Ad(playlist, 'https://cdn.example.com/content/index.m3u8', 'heuristic');
-  assert.equal(filtered.includes('ad-0.ts'), false);
-  assert.equal(filtered.includes('ad-1.ts'), false);
-  assert.equal(filtered.includes('main-0.ts'), true);
-  assert.equal(filtered.includes('main-7.ts'), true);
-});
-
-test('filterM3u8Ad detects and strips Multi-CDN domain/path prefix mismatch ad blocks', () => {
-  const playlist = [
-    '#EXTM3U',
-    '#EXTINF:6.000,',
-    'https://media-cdn.video.com/2026/ep01/hls/seg-0.ts',
-    '#EXTINF:6.000,',
-    'https://media-cdn.video.com/2026/ep01/hls/seg-1.ts',
-    '#EXTINF:6.000,',
-    'https://media-cdn.video.com/2026/ep01/hls/seg-2.ts',
-    '#EXT-X-DISCONTINUITY',
-    '#EXTINF:15.000,',
-    'https://ad-server.net/campaign/preroll/ad-0.ts',
-    '#EXTINF:15.000,',
-    'https://ad-server.net/campaign/preroll/ad-1.ts',
-    '#EXT-X-DISCONTINUITY',
-    '#EXTINF:6.000,',
-    'https://media-cdn.video.com/2026/ep01/hls/seg-3.ts',
-    '#EXTINF:6.000,',
-    'https://media-cdn.video.com/2026/ep01/hls/seg-4.ts',
-  ].join('\n');
-
-  const filtered = filterM3u8Ad(playlist, 'https://media-cdn.video.com/2026/ep01/hls/index.m3u8', 'heuristic');
-  assert.equal(filtered.includes('ad-server.net'), false);
-  assert.equal(filtered.includes('seg-0.ts'), true);
-  assert.equal(filtered.includes('seg-4.ts'), true);
-});
-
-test('filterM3u8Ad protects global 30fps/NTSC feature film streams with 0 false positives', () => {
-  const playlist = [
-    '#EXTM3U',
-    '#EXTINF:4.033,',
-    'https://cdn.example.com/movie/seg-0.ts',
-    '#EXTINF:4.867,',
-    'https://cdn.example.com/movie/seg-1.ts',
-    '#EXTINF:3.333,',
-    'https://cdn.example.com/movie/seg-2.ts',
-    '#EXTINF:4.167,',
-    'https://cdn.example.com/movie/seg-3.ts',
-    '#EXT-X-DISCONTINUITY',
-    '#EXTINF:4.033,',
-    'https://cdn.example.com/movie/seg-4.ts',
-    '#EXTINF:4.867,',
-    'https://cdn.example.com/movie/seg-5.ts',
-    '#EXTINF:3.333,',
-    'https://cdn.example.com/movie/seg-6.ts',
-  ].join('\n');
-
-  const filtered = filterM3u8Ad(playlist, 'https://cdn.example.com/movie/index.m3u8', 'heuristic');
-  assert.equal(filtered.includes('seg-0.ts'), true);
-  assert.equal(filtered.includes('seg-3.ts'), true);
-  assert.equal(filtered.includes('seg-6.ts'), true);
-});
-
-test('filterM3u8Ad detects and strips 25fps integer duration inserted ad blocks in 24fps movie streams', () => {
-  const playlist = [
-    '#EXTM3U',
-    '#EXTINF:4.004,',
-    'https://cdn.example.com/movie/seg-0.ts',
-    '#EXTINF:4.004,',
-    'https://cdn.example.com/movie/seg-1.ts',
-    '#EXTINF:4.004,',
-    'https://cdn.example.com/movie/seg-2.ts',
-    '#EXTINF:4.004,',
-    'https://cdn.example.com/movie/seg-3.ts',
-    '#EXT-X-DISCONTINUITY',
-    '#EXTINF:4.000,',
-    'https://cdn.example.com/movie/ad-0.ts',
-    '#EXTINF:4.000,',
-    'https://cdn.example.com/movie/ad-1.ts',
-    '#EXTINF:4.000,',
-    'https://cdn.example.com/movie/ad-2.ts',
-    '#EXTINF:0.560,',
-    'https://cdn.example.com/movie/ad-3.ts',
-    '#EXT-X-DISCONTINUITY',
-    '#EXTINF:4.004,',
-    'https://cdn.example.com/movie/seg-4.ts',
-    '#EXTINF:4.004,',
-    'https://cdn.example.com/movie/seg-5.ts',
-  ].join('\n');
-
-  const filtered = filterM3u8Ad(playlist, 'https://cdn.example.com/movie/index.m3u8', 'heuristic');
-  assert.equal(filtered.includes('ad-0.ts'), false);
-  assert.equal(filtered.includes('ad-3.ts'), false);
-  assert.equal(filtered.includes('seg-0.ts'), true);
-  assert.equal(filtered.includes('seg-5.ts'), true);
-});
-
-
-
diff --git a/tests/m3u8-duration-grid.test.ts b/tests/m3u8-duration-grid.test.ts
new file mode 100644
index 0000000..b68564c
--- /dev/null
+++ b/tests/m3u8-duration-grid.test.ts
@@ -0,0 +1,67 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+
+import { filterM3u8Ad } from '../lib/utils/m3u8-utils';
+
+interface PlaylistBlock {
+  durations: number[];
+  prefix: string;
+}
+
+function buildPlaylist(blocks: PlaylistBlock[]): string {
+  const lines = ['#EXTM3U'];
+  blocks.forEach((block, blockIndex) => {
+    if (blockIndex > 0) lines.push('#EXT-X-DISCONTINUITY');
+    block.durations.forEach((duration, segmentIndex) => {
+      lines.push(`#EXTINF:${duration.toFixed(3)},`);
+      lines.push(`https://cdn.example.com/content/${block.prefix}-${segmentIndex}.ts`);
+    });
+  });
+  return lines.join('\n');
+}
+
+test('NTSC-like duration residues remove a small block only with another signal', () => {
+  const playlist = buildPlaylist([
+    { durations: [4, 4, 4, 4, 4], prefix: 'main-a' },
+    { durations: [4.867, 3.333], prefix: 'ad' },
+    { durations: [4, 4, 4], prefix: 'main-b' },
+  ]);
+
+  const filtered = filterM3u8Ad(playlist, 'https://cdn.example.com/content/index.m3u8');
+  assert.equal(filtered.includes('/ad-0.ts'), false);
+  assert.equal(filtered.includes('/main-a-0.ts'), true);
+  assert.equal(filtered.includes('/main-b-2.ts'), true);
+});
+
+test('one legitimate NTSC-like segment is not deleted from an integer-duration stream', () => {
+  const playlist = buildPlaylist([
+    { durations: [4, 4.033, 4, 4, 4], prefix: 'main' },
+  ]);
+
+  const filtered = filterM3u8Ad(playlist, 'https://cdn.example.com/content/index.m3u8');
+  assert.equal(filtered.includes('/main-1.ts'), true);
+});
+
+test('a dominant NTSC-like main stream keeps later matching content blocks', () => {
+  const playlist = buildPlaylist([
+    { durations: [4.033, 4.867, 3.333, 4.167], prefix: 'main-a' },
+    { durations: [4.033, 4.867, 3.333], prefix: 'main-b' },
+  ]);
+
+  const filtered = filterM3u8Ad(playlist, 'https://cdn.example.com/content/index.m3u8');
+  assert.equal(filtered.includes('/main-a-0.ts'), true);
+  assert.equal(filtered.includes('/main-b-2.ts'), true);
+});
+
+test('integer-duration inserts are detected inside a film-24-like stream', () => {
+  const playlist = buildPlaylist([
+    { durations: [4.004, 4.004, 4.004, 4.004], prefix: 'main-a' },
+    { durations: [4, 4, 4, 0.56], prefix: 'ad' },
+    { durations: [4.004, 4.004], prefix: 'main-b' },
+  ]);
+
+  const filtered = filterM3u8Ad(playlist, 'https://cdn.example.com/content/index.m3u8');
+  assert.equal(filtered.includes('/ad-0.ts'), false);
+  assert.equal(filtered.includes('/ad-3.ts'), false);
+  assert.equal(filtered.includes('/main-b-1.ts'), true);
+});
diff --git a/tests/m3u8-filter-regression.test.ts b/tests/m3u8-filter-regression.test.ts
new file mode 100644
index 0000000..65fa625
--- /dev/null
+++ b/tests/m3u8-filter-regression.test.ts
@@ -0,0 +1,61 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+
+import { filterM3u8Ad } from '../lib/utils/m3u8-utils';
+
+function addBlock(
+  lines: string[],
+  durations: number[],
+  origin: string,
+  prefix: string,
+): void {
+  if (lines.length > 1) lines.push('#EXT-X-DISCONTINUITY');
+  durations.forEach((duration, index) => {
+    lines.push(`#EXTINF:${duration.toFixed(3)},`);
+    lines.push(`${origin}/content/${prefix}-${index}.ts`);
+  });
+}
+
+test('equal-size repeated content blocks are not treated as duplicate ads', () => {
+  const lines = ['#EXTM3U'];
+  addBlock(lines, [6, 6.1, 5.9], 'https://cdn.example.com', 'chapter-a');
+  addBlock(lines, [6, 6.1, 5.9], 'https://cdn.example.com', 'chapter-b');
+
+  const filtered = filterM3u8Ad(lines.join('\n'), 'https://cdn.example.com/content/index.m3u8');
+  assert.equal(filtered.includes('/chapter-a-0.ts'), true);
+  assert.equal(filtered.includes('/chapter-b-2.ts'), true);
+});
+
+test('uniform fixed-GOP content matching the main duration is protected', () => {
+  const lines = ['#EXTM3U'];
+  addBlock(lines, [2, 2, 2], 'https://cdn.example.com', 'chapter-a');
+  addBlock(lines, [2, 2, 2, 2, 2], 'https://cdn.example.com', 'chapter-b');
+  addBlock(lines, [2, 2, 2], 'https://cdn.example.com', 'chapter-c');
+
+  const filtered = filterM3u8Ad(lines.join('\n'), 'https://cdn.example.com/content/index.m3u8');
+  assert.equal(filtered.includes('/chapter-a-0.ts'), true);
+  assert.equal(filtered.includes('/chapter-c-2.ts'), true);
+});
+
+test('a same-path cross-origin insert needs a filename mismatch before removal', () => {
+  const lines = ['#EXTM3U'];
+  addBlock(lines, [6, 6, 6, 6], 'https://media.example.com', 'main-a');
+  addBlock(lines, [6, 6], 'https://ads.example.net', 'ad');
+  addBlock(lines, [6, 6], 'https://media.example.com', 'main-b');
+
+  const filtered = filterM3u8Ad(lines.join('\n'), 'https://media.example.com/content/index.m3u8');
+  assert.equal(filtered.includes('ads.example.net'), false);
+  assert.equal(filtered.includes('/main-a-0.ts'), true);
+  assert.equal(filtered.includes('/main-b-1.ts'), true);
+});
+
+test('off mode returns the original playlist byte-for-byte', () => {
+  const playlist = [
+    '#EXTM3U',
+    '#EXT-X-CUE-IN',
+    '#EXTINF:4.000,',
+    'relative/segment.ts',
+  ].join('\n');
+
+  assert.equal(filterM3u8Ad(playlist, 'https://cdn.example.com/index.m3u8', 'off'), playlist);
+});