Omit unsupported ffmpeg reconnect retry option

AGENTS.md

@@ -180,7 +180,7 @@ Runtime:
 - `FFMPEG_INPUT_SEEKABLE`: HTTP input seekable option, default `0`.
 - `FFMPEG_HTTP_RECONNECT`: enable ffmpeg HTTP reconnect options for HTTP inputs, default `1`.
 - `FFMPEG_HTTP_RECONNECT_DELAY_MAX`: max ffmpeg reconnect delay, default `2`.
-- `FFMPEG_HTTP_RECONNECT_MAX_RETRIES`: max ffmpeg reconnect retries, default `4`.
+- `FFMPEG_HTTP_RECONNECT_MAX_RETRIES`: max ffmpeg reconnect retries, default `4`, applied only when the installed ffmpeg supports `reconnect_max_retries`.
 - `FFMPEG_HTTP_RECONNECT_ON_HTTP_ERROR`: HTTP status list for reconnect, default `5xx`.
 - `METADATA_PROBE_ENABLED`: probe session duration with ffprobe, default `1` except in `relay`, where default is `0`.
 - `METADATA_PROBE_TIMEOUT_MS`: ffprobe duration timeout, default `4000`.

README.md

@@ -48,7 +48,7 @@ Recently played URLs and favorites are stored globally by the backend. In Docker
 docker logs -f frame-stream-player
 ```
 
-The app sets `FFMPEG_INPUT_SEEKABLE=0` by default so `ffmpeg` reads stream inputs sequentially and avoids extra HTTP range connections. If a specific VOD file requires seeking for metadata, set `FFMPEG_INPUT_SEEKABLE=-1` to restore ffmpeg's automatic behavior. For ffmpeg-owned HTTP inputs, reconnect handling is enabled by default with `FFMPEG_HTTP_RECONNECT=1`.
+The app sets `FFMPEG_INPUT_SEEKABLE=0` by default so `ffmpeg` reads stream inputs sequentially and avoids extra HTTP range connections. If a specific VOD file requires seeking for metadata, set `FFMPEG_INPUT_SEEKABLE=-1` to restore ffmpeg's automatic behavior. For ffmpeg-owned HTTP inputs, reconnect handling is enabled by default with `FFMPEG_HTTP_RECONNECT=1`. `FFMPEG_HTTP_RECONNECT_MAX_RETRIES` is applied only when the installed `ffmpeg` supports that HTTP protocol option.
 
 YouTube URLs are resolved server-side with `yt-dlp` before they enter the existing ffmpeg pipeline. Recents and favorites keep the original YouTube URL, while the short-lived playback session uses the resolved media URL and headers returned by `yt-dlp`. Tune the selected format with `YT_DLP_FORMAT` and the resolver timeout with `YT_DLP_TIMEOUT_MS`.
 

server/index.js

@@ -28,6 +28,7 @@ const FFMPEG_HTTP_RECONNECT = parseBoolean(process.env.FFMPEG_HTTP_RECONNECT, tr
 const FFMPEG_HTTP_RECONNECT_DELAY_MAX = clampInteger(process.env.FFMPEG_HTTP_RECONNECT_DELAY_MAX, 2, 0, 30);
 const FFMPEG_HTTP_RECONNECT_MAX_RETRIES = clampInteger(process.env.FFMPEG_HTTP_RECONNECT_MAX_RETRIES, 4, 0, 20);
 const FFMPEG_HTTP_RECONNECT_ON_HTTP_ERROR = process.env.FFMPEG_HTTP_RECONNECT_ON_HTTP_ERROR ?? '5xx';
+const FFMPEG_CAPABILITY_TIMEOUT_MS = 3000;
 const PLAYBACK_CONNECTION_MODE = parsePlaybackConnectionMode(process.env.PLAYBACK_CONNECTION_MODE ?? process.env.PLAYBACK_MODE);
 const METADATA_PROBE_ENABLED = parseBoolean(process.env.METADATA_PROBE_ENABLED, PLAYBACK_CONNECTION_MODE !== 'relay');
 const METADATA_PROBE_TIMEOUT_MS = clampInteger(process.env.METADATA_PROBE_TIMEOUT_MS, 4 * 1000, 1000, 30 * 1000);
@@ -77,6 +78,7 @@ let recentUrls = [];
 let recentWrite = Promise.resolve();
 let favorites = [];
 let favoritesWrite = Promise.resolve();
+let ffmpegSupportsReconnectMaxRetries = false;
 
 app.disable('x-powered-by');
 app.use(express.json({ limit: '256kb' }));
@@ -429,6 +431,7 @@ setInterval(() => {
 await Promise.all([
   loadRecentUrls(),
   loadFavorites(),
+  detectFfmpegHttpReconnectSupport(),
 ]);
 
 server.listen(PORT, () => {
@@ -889,6 +892,80 @@ function runFfprobe(args) {
   });
 }
 
+async function detectFfmpegHttpReconnectSupport() {
+  if (!FFMPEG_HTTP_RECONNECT || FFMPEG_HTTP_RECONNECT_MAX_RETRIES <= 0) {
+    return;
+  }
+
+  try {
+    const output = await runFfmpegCapabilityCheck(['-hide_banner', '-h', 'protocol=http']);
+    ffmpegSupportsReconnectMaxRetries = /^\s*-reconnect_max_retries\b/m.test(output);
+
+    if (!ffmpegSupportsReconnectMaxRetries) {
+      logWarn('ffmpeg http option reconnect_max_retries is unsupported; omitting FFMPEG_HTTP_RECONNECT_MAX_RETRIES');
+    }
+  } catch (error) {
+    ffmpegSupportsReconnectMaxRetries = false;
+    logWarn(`ffmpeg http option detection failed; omitting FFMPEG_HTTP_RECONNECT_MAX_RETRIES error=${oneLine(error.message)}`);
+  }
+}
+
+function runFfmpegCapabilityCheck(args) {
+  return new Promise((resolve, reject) => {
+    const ffmpeg = spawn(FFMPEG_PATH, args, {
+      stdio: ['ignore', 'pipe', 'pipe'],
+    });
+    let output = '';
+    let timedOut = false;
+    let settled = false;
+
+    const finish = (callback) => {
+      if (settled) {
+        return;
+      }
+
+      settled = true;
+      clearTimeout(timer);
+      callback();
+    };
+
+    const timer = setTimeout(() => {
+      timedOut = true;
+      stopProcess(ffmpeg);
+    }, FFMPEG_CAPABILITY_TIMEOUT_MS);
+    timer.unref();
+
+    ffmpeg.stdout.on('data', (chunk) => {
+      output = appendTail(output, chunk);
+    });
+
+    ffmpeg.stderr.on('data', (chunk) => {
+      output = appendTail(output, chunk);
+    });
+
+    ffmpeg.on('error', (error) => {
+      finish(() => reject(error));
+    });
+
+    ffmpeg.on('close', (code, signal) => {
+      finish(() => {
+        if (timedOut) {
+          reject(new Error('ffmpeg capability check timed out.'));
+          return;
+        }
+
+        if (code === 0) {
+          resolve(output);
+          return;
+        }
+
+        const detail = redactSecrets(output).trim();
+        reject(new Error(detail ? `ffmpeg capability check exited with code ${code}: ${detail}` : `ffmpeg capability check exited with code ${code ?? 'null'} signal ${signal ?? 'none'}.`));
+      });
+    });
+  });
+}
+
 async function loadRecentUrls() {
   try {
     const raw = await fs.readFile(RECENT_URLS_PATH, 'utf8');
@@ -2507,10 +2584,12 @@ function buildInputArgs(inputUrl, { seekable = true, startTime = 0 } = {}) {
       '1',
       '-reconnect_delay_max',
       String(FFMPEG_HTTP_RECONNECT_DELAY_MAX),
-      '-reconnect_max_retries',
-      String(FFMPEG_HTTP_RECONNECT_MAX_RETRIES),
     );
 
+    if (FFMPEG_HTTP_RECONNECT_MAX_RETRIES > 0 && ffmpegSupportsReconnectMaxRetries) {
+      args.push('-reconnect_max_retries', String(FFMPEG_HTTP_RECONNECT_MAX_RETRIES));
+    }
+
     if (FFMPEG_HTTP_RECONNECT_ON_HTTP_ERROR) {
       args.push('-reconnect_on_http_error', FFMPEG_HTTP_RECONNECT_ON_HTTP_ERROR);
     }