diff --git a/package-lock.json b/package-lock.json
index c7287b4..c049f81 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -9,11 +9,11 @@
             "version": "1.0.0",
             "license": "GPL-3.0-only",
             "dependencies": {
+                "@ffprobe-installer/ffprobe": "^2.1.2",
                 "bcryptjs": "^3.0.3",
                 "better-sqlite3": "^12.5.0",
                 "express": "^4.18.2",
                 "express-session": "^1.18.2",
-                "ffmpeg-static": "^5.3.0",
                 "jsonwebtoken": "^9.0.3",
                 "passport": "^0.7.0",
                 "passport-jwt": "^4.0.1",
@@ -44,6 +44,135 @@
                 "node": ">=6.0.0"
             }
         },
+        "node_modules/@ffprobe-installer/darwin-arm64": {
+            "version": "5.0.1",
+            "resolved": "https://registry.npmjs.org/@ffprobe-installer/darwin-arm64/-/darwin-arm64-5.0.1.tgz",
+            "integrity": "sha512-vwNCNjokH8hfkbl6m95zICHwkSzhEvDC3GVBcUp5HX8+4wsX10SP3B+bGur7XUzTIZ4cQpgJmEIAx6TUwRepMg==",
+            "cpu": [
+                "arm64"
+            ],
+            "hasInstallScript": true,
+            "license": "LGPL-2.1",
+            "optional": true,
+            "os": [
+                "darwin"
+            ]
+        },
+        "node_modules/@ffprobe-installer/darwin-x64": {
+            "version": "5.1.0",
+            "resolved": "https://registry.npmjs.org/@ffprobe-installer/darwin-x64/-/darwin-x64-5.1.0.tgz",
+            "integrity": "sha512-J+YGscZMpQclFg31O4cfVRGmDpkVsQ2fZujoUdMAAYcP0NtqpC49Hs3SWJpBdsGB4VeqOt5TTm1vSZQzs1NkhA==",
+            "cpu": [
+                "x64"
+            ],
+            "hasInstallScript": true,
+            "license": "GPL-3.0",
+            "optional": true,
+            "os": [
+                "darwin"
+            ]
+        },
+        "node_modules/@ffprobe-installer/ffprobe": {
+            "version": "2.1.2",
+            "resolved": "https://registry.npmjs.org/@ffprobe-installer/ffprobe/-/ffprobe-2.1.2.tgz",
+            "integrity": "sha512-ZNvwk4f2magF42Zji2Ese16SMj9BS7Fui4kRjg6gTYTxY3gWZNpg85n4MIfQyI9nimHg4x/gT6FVkp/bBDuBwg==",
+            "license": "LGPL-2.1",
+            "engines": {
+                "node": ">=14.21.2"
+            },
+            "optionalDependencies": {
+                "@ffprobe-installer/darwin-arm64": "5.0.1",
+                "@ffprobe-installer/darwin-x64": "5.1.0",
+                "@ffprobe-installer/linux-arm": "5.2.0",
+                "@ffprobe-installer/linux-arm64": "5.2.0",
+                "@ffprobe-installer/linux-ia32": "5.2.0",
+                "@ffprobe-installer/linux-x64": "5.2.0",
+                "@ffprobe-installer/win32-ia32": "5.1.0",
+                "@ffprobe-installer/win32-x64": "5.1.0"
+            }
+        },
+        "node_modules/@ffprobe-installer/linux-arm": {
+            "version": "5.2.0",
+            "resolved": "https://registry.npmjs.org/@ffprobe-installer/linux-arm/-/linux-arm-5.2.0.tgz",
+            "integrity": "sha512-PF5HqEhCY7WTWHtLDYbA/+rLS+rhslWvyBlAG1Fk8VzVlnRdl93o6hy7DE2kJgxWQbFaR3ZktPQGEzfkrmQHvQ==",
+            "cpu": [
+                "arm"
+            ],
+            "hasInstallScript": true,
+            "license": "GPL-3.0",
+            "optional": true,
+            "os": [
+                "linux"
+            ]
+        },
+        "node_modules/@ffprobe-installer/linux-arm64": {
+            "version": "5.2.0",
+            "resolved": "https://registry.npmjs.org/@ffprobe-installer/linux-arm64/-/linux-arm64-5.2.0.tgz",
+            "integrity": "sha512-X1VvWtlLs6ScP73biVLuHD5ohKJKsMTa0vafCESOen4mOoNeLAYbxOVxDWAdFz9cpZgRiloFj5QD6nDj8E28yQ==",
+            "cpu": [
+                "arm64"
+            ],
+            "hasInstallScript": true,
+            "license": "GPL-3.0",
+            "optional": true,
+            "os": [
+                "linux"
+            ]
+        },
+        "node_modules/@ffprobe-installer/linux-ia32": {
+            "version": "5.2.0",
+            "resolved": "https://registry.npmjs.org/@ffprobe-installer/linux-ia32/-/linux-ia32-5.2.0.tgz",
+            "integrity": "sha512-TFVK5sasXyXhbIG7LtPRDmtkrkOsInwKcL43iEvEw+D9vCS2rc//mn9/0Q+BR0UoJEiMK4+ApYr/3LLVUBPOCQ==",
+            "cpu": [
+                "ia32"
+            ],
+            "hasInstallScript": true,
+            "license": "GPL-3.0",
+            "optional": true,
+            "os": [
+                "linux"
+            ]
+        },
+        "node_modules/@ffprobe-installer/linux-x64": {
+            "version": "5.2.0",
+            "resolved": "https://registry.npmjs.org/@ffprobe-installer/linux-x64/-/linux-x64-5.2.0.tgz",
+            "integrity": "sha512-D3UeqTLYPNs7pBWPLUYGehPdRVqU8eACox4OZy3pZUZatxye2YKlvBwEfaLdL1v2Z4FOAlLUhms0kY8m8kqSRA==",
+            "cpu": [
+                "x64"
+            ],
+            "hasInstallScript": true,
+            "license": "GPL-3.0",
+            "optional": true,
+            "os": [
+                "linux"
+            ]
+        },
+        "node_modules/@ffprobe-installer/win32-ia32": {
+            "version": "5.1.0",
+            "resolved": "https://registry.npmjs.org/@ffprobe-installer/win32-ia32/-/win32-ia32-5.1.0.tgz",
+            "integrity": "sha512-5O3vOoNRxmut0/Nu9vSazTdSHasrr+zPT2B3Hm7kjmO3QVFcIfVImS6ReQnZeSy8JPJOqXts5kX5x/3KOX54XQ==",
+            "cpu": [
+                "ia32"
+            ],
+            "license": "GPL-3.0",
+            "optional": true,
+            "os": [
+                "win32"
+            ]
+        },
+        "node_modules/@ffprobe-installer/win32-x64": {
+            "version": "5.1.0",
+            "resolved": "https://registry.npmjs.org/@ffprobe-installer/win32-x64/-/win32-x64-5.1.0.tgz",
+            "integrity": "sha512-jMGYeAgkrdn4e2vvYt/qakgHRE3CPju4bn5TmdPfoAm1BlX1mY9cyMd8gf5vSzI8gH8Zq5WQAyAkmekX/8TSTg==",
+            "cpu": [
+                "x64"
+            ],
+            "license": "GPL-3.0",
+            "optional": true,
+            "os": [
+                "win32"
+            ]
+        },
         "node_modules/@types/node": {
             "version": "10.17.60",
             "resolved": "https://registry.npmjs.org/@types/node/-/node-10.17.60.tgz",
diff --git a/package.json b/package.json
index 71b158e..daaf792 100644
--- a/package.json
+++ b/package.json
@@ -9,6 +9,7 @@
         "dev": "node --watch server/index.js"
     },
     "dependencies": {
+        "@ffprobe-installer/ffprobe": "^2.1.2",
         "bcryptjs": "^3.0.3",
         "better-sqlite3": "^12.5.0",
         "express": "^4.18.2",
diff --git a/public/index.html b/public/index.html
index e2942b4..9017815 100644
--- a/public/index.html
+++ b/public/index.html
@@ -451,6 +451,17 @@
 
             <div class="settings-section">
               <h3>Streaming</h3>
+              <div class="setting-item">
+                <label class="setting-toggle">
+                  <input type="checkbox" id="setting-auto-transcode">
+                  <span class="toggle-slider"></span>
+                </label>
+                <div class="setting-info">
+                  <span class="setting-label">Auto Transcode (Smart)</span>
+                  <span class="setting-hint">Automatically detect stream codecs and only transcode/remux when needed.
+                    Adds ~1-3s probe delay on first play.</span>
+                </div>
+              </div>
               <div class="setting-item">
                 <label class="setting-toggle">
                   <input type="checkbox" id="setting-force-proxy">
diff --git a/public/js/components/VideoPlayer.js b/public/js/components/VideoPlayer.js
index fe558e3..8adaf39 100644
--- a/public/js/components/VideoPlayer.js
+++ b/public/js/components/VideoPlayer.js
@@ -45,6 +45,7 @@ class VideoPlayer {
             forceProxy: false,
             forceTranscode: false,
             forceRemux: false,
+            autoTranscode: true,
             streamFormat: 'm3u8',
             epgRefreshInterval: '24'
         };
@@ -667,10 +668,55 @@ class VideoPlayer {
             // Determine if HLS or direct stream
             this.currentUrl = streamUrl;
 
+            // CHECK: Auto Transcode (Smart) - probe first, then decide
+            if (this.settings.autoTranscode) {
+                console.log('[Player] Auto Transcode enabled. Probing stream...');
+                try {
+                    const probeRes = await fetch(`/api/probe?url=${encodeURIComponent(streamUrl)}`);
+                    const info = await probeRes.json();
+                    console.log(`[Player] Probe result: video=${info.video}, audio=${info.audio}, compatible=${info.compatible}`);
+
+                    if (info.needsTranscode) {
+                        // Incompatible audio (AC3/EAC3/DTS) - use transcode
+                        console.log('[Player] Auto: Using transcode (incompatible audio)');
+                        const transcodeUrl = `/api/transcode?url=${encodeURIComponent(streamUrl)}`;
+                        this.currentUrl = transcodeUrl;
+                        this.video.src = transcodeUrl;
+                        this.video.play().catch(e => {
+                            if (e.name !== 'AbortError') console.log('[Player] Autoplay prevented:', e);
+                        });
+                        this.updateNowPlaying(channel);
+                        this.showNowPlayingOverlay();
+                        this.fetchEpgData(channel);
+                        window.dispatchEvent(new CustomEvent('channelChanged', { detail: channel }));
+                        return;
+                    } else if (info.needsRemux) {
+                        // Raw .ts container - use remux
+                        console.log('[Player] Auto: Using remux (.ts container)');
+                        const remuxUrl = `/api/remux?url=${encodeURIComponent(streamUrl)}`;
+                        this.currentUrl = remuxUrl;
+                        this.video.src = remuxUrl;
+                        this.video.play().catch(e => {
+                            if (e.name !== 'AbortError') console.log('[Player] Autoplay prevented:', e);
+                        });
+                        this.updateNowPlaying(channel);
+                        this.showNowPlayingOverlay();
+                        this.fetchEpgData(channel);
+                        window.dispatchEvent(new CustomEvent('channelChanged', { detail: channel }));
+                        return;
+                    }
+                    // Compatible - fall through to normal HLS.js path
+                    console.log('[Player] Auto: Using HLS.js (compatible)');
+                } catch (err) {
+                    console.warn('[Player] Probe failed, using normal playback:', err.message);
+                    // Continue with normal playback on probe failure
+                }
+            }
+
             // CHECK: Force Transcode Priority - transcoded streams bypass HLS.js
             if (this.settings.forceTranscode) {
                 console.log('[Player] Force Transcode enabled. Routing through ffmpeg...');
-                const transcodeUrl = this.getTranscodeUrl(streamUrl);
+                const transcodeUrl = `/api/transcode?url=${encodeURIComponent(streamUrl)}`;
                 this.currentUrl = transcodeUrl;
 
                 // Transcoded streams are fragmented MP4 - play directly with <video> element
diff --git a/public/js/pages/Settings.js b/public/js/pages/Settings.js
index c567489..25239ae 100644
--- a/public/js/pages/Settings.js
+++ b/public/js/pages/Settings.js
@@ -34,6 +34,7 @@ class SettingsPage {
         const forceProxyToggle = document.getElementById('setting-force-proxy');
         const forceTranscodeToggle = document.getElementById('setting-force-transcode');
         const forceRemuxToggle = document.getElementById('setting-force-remux');
+        const autoTranscodeToggle = document.getElementById('setting-auto-transcode');
 
         // Load current settings
         if (this.app.player?.settings) {
@@ -52,6 +53,9 @@ class SettingsPage {
             if (forceRemuxToggle) {
                 forceRemuxToggle.checked = this.app.player.settings.forceRemux || false;
             }
+            if (autoTranscodeToggle) {
+                autoTranscodeToggle.checked = this.app.player.settings.autoTranscode || false;
+            }
         }
 
         // Arrow keys toggle
@@ -106,6 +110,12 @@ class SettingsPage {
             this.app.player.saveSettings();
         });
 
+        // Auto transcode (smart) toggle
+        autoTranscodeToggle?.addEventListener('change', () => {
+            this.app.player.settings.autoTranscode = autoTranscodeToggle.checked;
+            this.app.player.saveSettings();
+        });
+
         // EPG refresh interval
         const epgRefreshSelect = document.getElementById('epg-refresh-interval');
         if (epgRefreshSelect && this.app.player?.settings) {
@@ -271,6 +281,7 @@ class SettingsPage {
             const forceProxyToggle = document.getElementById('setting-force-proxy');
             const forceTranscodeToggle = document.getElementById('setting-force-transcode');
             const forceRemuxToggle = document.getElementById('setting-force-remux');
+            const autoTranscodeToggle = document.getElementById('setting-auto-transcode');
             const epgRefreshSelect = document.getElementById('epg-refresh-interval');
             const streamFormatSelect = document.getElementById('setting-stream-format');
 
@@ -283,6 +294,7 @@ class SettingsPage {
             if (forceProxyToggle) forceProxyToggle.checked = s.forceProxy || false;
             if (forceTranscodeToggle) forceTranscodeToggle.checked = s.forceTranscode || false;
             if (forceRemuxToggle) forceRemuxToggle.checked = s.forceRemux || false;
+            if (autoTranscodeToggle) autoTranscodeToggle.checked = s.autoTranscode || false;
             if (epgRefreshSelect) epgRefreshSelect.value = s.epgRefreshInterval || '24';
             if (streamFormatSelect) streamFormatSelect.value = s.streamFormat || 'm3u8';
         }
diff --git a/public/js/pages/WatchPage.js b/public/js/pages/WatchPage.js
index b6b64d6..331f1ad 100644
--- a/public/js/pages/WatchPage.js
+++ b/public/js/pages/WatchPage.js
@@ -229,6 +229,41 @@ class WatchPage {
         const isRawTs = url.includes('.ts') && !url.includes('.m3u8');
         const isDirectVideo = url.includes('.mp4') || url.includes('.mkv') || url.includes('.avi');
 
+        // Priority 0: Auto Transcode (Smart) - probe first, then decide
+        if (settings.autoTranscode) {
+            console.log('[WatchPage] Auto Transcode enabled. Probing stream...');
+            try {
+                const probeRes = await fetch(`/api/probe?url=${encodeURIComponent(url)}`);
+                const info = await probeRes.json();
+                console.log(`[WatchPage] Probe result: video=${info.video}, audio=${info.audio}, compatible=${info.compatible}`);
+
+                if (info.needsTranscode) {
+                    console.log('[WatchPage] Auto: Using transcode (incompatible audio)');
+                    const finalUrl = `/api/transcode?url=${encodeURIComponent(url)}`;
+                    this.video.src = finalUrl;
+                    this.video.play().catch(e => {
+                        if (e.name !== 'AbortError') console.error('[WatchPage] Autoplay error:', e);
+                    });
+                    this.setVolumeFromStorage();
+                    return;
+                } else if (info.needsRemux) {
+                    console.log('[WatchPage] Auto: Using remux (.ts container)');
+                    const finalUrl = `/api/remux?url=${encodeURIComponent(url)}`;
+                    this.video.src = finalUrl;
+                    this.video.play().catch(e => {
+                        if (e.name !== 'AbortError') console.error('[WatchPage] Autoplay error:', e);
+                    });
+                    this.setVolumeFromStorage();
+                    return;
+                }
+                // Compatible - fall through to normal playback
+                console.log('[WatchPage] Auto: Using normal playback (compatible)');
+            } catch (err) {
+                console.warn('[WatchPage] Probe failed, using normal playback:', err.message);
+                // Continue with normal playback on probe failure
+            }
+        }
+
         // Priority 1: Force Transcode - route through FFmpeg
         if (settings.forceTranscode) {
             console.log('[WatchPage] Force Transcode enabled');
diff --git a/server/db.js b/server/db.js
index 0f5648c..9368912 100644
--- a/server/db.js
+++ b/server/db.js
@@ -65,6 +65,7 @@ function getDefaultSettings() {
     forceProxy: false,
     forceTranscode: false,
     forceRemux: false,
+    autoTranscode: true,
     streamFormat: 'm3u8',
     epgRefreshInterval: '24'
   };
diff --git a/server/index.js b/server/index.js
index 3adc594..f4057b9 100644
--- a/server/index.js
+++ b/server/index.js
@@ -52,7 +52,33 @@ function findFFmpeg() {
     }
 }
 
+function findFFprobe() {
+    // Try system ffprobe first
+    try {
+        execSync('ffprobe -version', { stdio: 'ignore' });
+        console.log('FFprobe binary configured at: ffprobe (system)');
+        return 'ffprobe';
+    } catch (e) {
+        // Not found in system
+    }
+
+    // Try @ffprobe-installer/ffprobe package
+    try {
+        const ffprobePath = require('@ffprobe-installer/ffprobe').path;
+        if (ffprobePath) {
+            console.log('FFprobe binary configured at:', ffprobePath);
+            return ffprobePath;
+        }
+    } catch (err) {
+        // Package not available
+    }
+
+    console.warn('FFprobe not available - auto transcode will fallback to always transcode');
+    return null;
+}
+
 app.locals.ffmpegPath = findFFmpeg();
+app.locals.ffprobePath = findFFprobe();
 
 // API Routes
 app.use('/api/auth', require('./routes/auth'));
@@ -62,6 +88,7 @@ app.use('/api/channels', require('./routes/channels'));
 app.use('/api/favorites', require('./routes/favorites'));
 app.use('/api/transcode', require('./routes/transcode'));
 app.use('/api/remux', require('./routes/remux'));
+app.use('/api/probe', require('./routes/probe'));
 app.use('/api/settings', require('./routes/settings'));
 
 // SPA fallback - serve index.html for all non-API routes
diff --git a/server/routes/probe.js b/server/routes/probe.js
new file mode 100644
index 0000000..11d2648
--- /dev/null
+++ b/server/routes/probe.js
@@ -0,0 +1,181 @@
+const express = require('express');
+const router = express.Router();
+const { spawn } = require('child_process');
+
+/**
+ * Probe endpoint - detects stream codecs and container
+ * GET /api/probe?url=...
+ * 
+ * Returns:
+ * {
+ *   video: "h264",
+ *   audio: "aac",
+ *   container: "mpegts",
+ *   compatible: true,
+ *   needsRemux: false,
+ *   needsTranscode: false
+ * }
+ */
+
+// Probe cache (URL → result)
+const probeCache = new Map();
+const CACHE_TTL = 5 * 60 * 1000; // 5 minutes
+
+// Browser-compatible codecs
+const BROWSER_VIDEO_CODECS = ['h264', 'avc', 'avc1'];
+const BROWSER_AUDIO_CODECS = ['aac', 'mp3', 'opus', 'vorbis'];
+
+/**
+ * Probe stream with ffprobe
+ */
+function probeStream(url, ffprobePath, timeout = 15000) {
+    return new Promise((resolve, reject) => {
+        const args = [
+            '-v', 'error',
+            '-print_format', 'json',
+            '-show_streams',
+            '-show_format',
+            '-probesize', '5000000',
+            '-analyzeduration', '5000000',
+            url
+        ];
+
+        const proc = spawn(ffprobePath, args);
+        let stdout = '';
+        let stderr = '';
+
+        const timer = setTimeout(() => {
+            proc.kill('SIGKILL');
+            reject(new Error('Probe timeout'));
+        }, timeout);
+
+        proc.stdout.on('data', (data) => { stdout += data; });
+        proc.stderr.on('data', (data) => { stderr += data; });
+
+        proc.on('close', (code) => {
+            clearTimeout(timer);
+            if (code !== 0) {
+                reject(new Error(`ffprobe exited with code ${code}: ${stderr}`));
+                return;
+            }
+            try {
+                const result = JSON.parse(stdout);
+                resolve(result);
+            } catch (e) {
+                reject(new Error('Failed to parse ffprobe output'));
+            }
+        });
+
+        proc.on('error', (err) => {
+            clearTimeout(timer);
+            reject(err);
+        });
+    });
+}
+
+/**
+ * Analyze probe result and determine compatibility
+ */
+function analyzeProbeResult(probeResult, url) {
+    const streams = probeResult.streams || [];
+    const format = probeResult.format || {};
+
+    const videoStream = streams.find(s => s.codec_type === 'video');
+    const audioStream = streams.find(s => s.codec_type === 'audio');
+
+    const videoCodec = videoStream?.codec_name?.toLowerCase() || 'unknown';
+    const audioCodec = audioStream?.codec_name?.toLowerCase() || 'unknown';
+    const container = format.format_name?.toLowerCase() || 'unknown';
+
+    // Check codec compatibility
+    const videoOk = BROWSER_VIDEO_CODECS.some(c => videoCodec.includes(c));
+    const audioOk = BROWSER_AUDIO_CODECS.some(c => audioCodec.includes(c));
+
+    // Browser-safe containers
+    // Note: We exclude 'webm' because ffprobe reports MKV as "matroska,webm", 
+    // and H.264/AAC in MKV/WebM is not universally supported. Best to remux to MP4.
+    const BROWSER_CONTAINERS = ['hls', 'mp4', 'mov'];
+    const containerOk = BROWSER_CONTAINERS.some(c => container.includes(c));
+
+    // Check if it's a raw TS stream (not HLS)
+    const isRawTs = (container.includes('mpegts') || url.endsWith('.ts')) && !url.includes('.m3u8');
+
+    // Determine what processing is needed
+    // 1. Incompatible audio -> Transcode (highest priority)
+    const needsTranscode = !audioOk;
+
+    // 2. Compatible audio/video but incompatible container -> Remux
+    // This catches raw TS, MKV, AVI, etc. that have H.264/AAC but wrong container
+    const needsRemux = !needsTranscode && (!containerOk || isRawTs);
+
+    const compatible = !needsTranscode && !needsRemux;
+
+    return {
+        video: videoCodec,
+        audio: audioCodec,
+        container: container,
+        compatible: compatible,
+        needsRemux: needsRemux,
+        needsTranscode: needsTranscode
+    };
+}
+
+router.get('/', async (req, res) => {
+    const { url } = req.query;
+    if (!url) {
+        return res.status(400).json({ error: 'URL parameter is required' });
+    }
+
+    const ffprobePath = req.app.locals.ffprobePath;
+
+    if (!ffprobePath) {
+        // No ffprobe available - assume needs transcoding to be safe
+        console.log('[Probe] FFprobe not available, assuming transcode needed');
+        return res.json({
+            video: 'unknown',
+            audio: 'unknown',
+            container: 'unknown',
+            compatible: false,
+            needsRemux: false,
+            needsTranscode: true
+        });
+    }
+
+    // Check cache
+    const cached = probeCache.get(url);
+    if (cached && (Date.now() - cached.timestamp < CACHE_TTL)) {
+        console.log(`[Probe] Cache hit for: ${url.substring(0, 50)}...`);
+        return res.json(cached.result);
+    }
+
+    console.log(`[Probe] Probing: ${url.substring(0, 80)}...`);
+
+    try {
+        const probeResult = await probeStream(url, ffprobePath);
+        const analysis = analyzeProbeResult(probeResult, url);
+
+        // Cache result
+        probeCache.set(url, { result: analysis, timestamp: Date.now() });
+
+        console.log(`[Probe] Result: video=${analysis.video}, audio=${analysis.audio}, ` +
+            `container=${analysis.container}, compatible=${analysis.compatible}, ` +
+            `needsRemux=${analysis.needsRemux}, needsTranscode=${analysis.needsTranscode}`);
+
+        res.json(analysis);
+    } catch (err) {
+        console.error('[Probe] Failed:', err.message);
+
+        // On error, assume transcode needed to be safe
+        res.json({
+            video: 'unknown',
+            audio: 'unknown',
+            container: 'unknown',
+            compatible: false,
+            needsRemux: false,
+            needsTranscode: true,
+            error: err.message
+        });
+    }
+});
+
+module.exports = router;
diff --git a/server/routes/remux.js b/server/routes/remux.js
index a9e49fa..cf5c6d1 100644
--- a/server/routes/remux.js
+++ b/server/routes/remux.js
@@ -40,9 +40,13 @@ router.get('/', (req, res) => {
         '-reconnect_streamed', '1',
         '-reconnect_delay_max', '5',
         '-i', url,
-        // Map all streams explicitly
-        '-map', '0',
-        // Copy ALL streams without re-encoding
+        // STRICT MAPPING: Only map video and audio, ignore subtitles/data/attachments
+        // This prevents remux failure when source container has incompatible subtitle tracks (e.g. MKV -> MP4)
+        '-map', '0:v',
+        '-map', '0:a',
+        // Drop subtitles (-sn) and data (-dn) explicitly
+        '-sn', '-dn',
+        // Copy streams without re-encoding
         '-c', 'copy',
         // NOTE: We intentionally do NOT use -bsf:a aac_adtstoasc here
         // That filter only works for AAC audio and breaks AC3/EAC3/MP3.