feat: add subtitle extraction and display for MKV/container streams

2026-01-10 12:35:39 -08:00
parent 346a0519e9
commit 8d36a2c07e
6 changed files with 96 additions and 1 deletions
@@ -0,0 +1,58 @@
+const express = require('express');
+const router = express.Router();
+const { spawn } = require('child_process');
+
+/**
+ * Subtitle extraction endpoint
+ * GET /api/subtitle?url=...&index=...
+ * 
+ * Extracts a specific subtitle track and converts it to WebVTT on the fly.
+ */
+router.get('/', (req, res) => {
+    const { url, index } = req.query;
+
+    if (!url || index === undefined) {
+        return res.status(400).json({ error: 'URL and index parameters are required' });
+    }
+
+    const ffmpegPath = req.app.locals.ffmpegPath || 'ffmpeg';
+    // console.log(`[Subtitle] Extracting track ${index} from: ${url}`);
+
+    const args = [
+        '-hide_banner',
+        '-loglevel', 'warning',
+        '-user_agent', 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36',
+        '-probesize', '5000000',
+        '-analyzeduration', '5000000',
+        '-i', url,
+        '-map', `0:${index}`,
+        '-c:s', 'webvtt',
+        '-f', 'webvtt',
+        '-'
+    ];
+
+    const ffmpeg = spawn(ffmpegPath, args);
+
+    res.setHeader('Content-Type', 'text/vtt');
+    res.setHeader('Access-Control-Allow-Origin', '*');
+
+    // Pipe stdout to response
+    ffmpeg.stdout.pipe(res);
+
+    ffmpeg.stderr.on('data', (data) => {
+        // console.error(`[Subtitle FFmpeg] ${data}`);
+    });
+
+    req.on('close', () => {
+        ffmpeg.kill('SIGKILL');
+    });
+
+    ffmpeg.on('error', (err) => {
+        console.error('[Subtitle] Failed to spawn FFmpeg:', err);
+        if (!res.headersSent) {
+            res.status(500).send('Subtitle extraction failed');
+        }
+    });
+});
+
+module.exports = router;