Reduce relay playback overhead

server/index.js

@@ -26,16 +26,17 @@ const FFMPEG_HTTP_RECONNECT_DELAY_MAX = clampInteger(process.env.FFMPEG_HTTP_REC
 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 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);
 const RECENT_URLS_PATH = process.env.RECENT_URLS_PATH ?? path.join(__dirname, '..', 'data', 'recent-urls.json');
 const RECENT_URL_LIMIT = clampInteger(process.env.RECENT_URL_LIMIT, 12, 1, 50);
 const FAVORITES_PATH = process.env.FAVORITES_PATH ?? path.join(__dirname, '..', 'data', 'favorites.json');
 const FAVORITES_LIMIT = clampInteger(process.env.FAVORITES_LIMIT, 50, 1, 200);
 const SESSION_TTL_MS = 60 * 60 * 1000;
-const METADATA_PROBE_TIMEOUT_MS = 8 * 1000;
 const PLAYBACK_READY_TIMEOUT_MS = 15 * 1000;
 const MAX_WS_BUFFER_BYTES = clampInteger(process.env.MAX_WS_BUFFER_BYTES, 512 * 1024, 128 * 1024, 64 * 1024 * 1024);
-const MAX_AUDIO_QUEUE_BYTES = clampInteger(process.env.MAX_AUDIO_QUEUE_BYTES, 16 * 1024 * 1024, 256 * 1024, 128 * 1024 * 1024);
-const MAX_RELAY_BRANCH_QUEUE_BYTES = clampInteger(process.env.MAX_RELAY_BRANCH_QUEUE_BYTES, 16 * 1024 * 1024, 512 * 1024, 256 * 1024 * 1024);
+const MAX_AUDIO_QUEUE_BYTES = clampInteger(process.env.MAX_AUDIO_QUEUE_BYTES, 4 * 1024 * 1024, 256 * 1024, 128 * 1024 * 1024);
+const MAX_RELAY_BRANCH_QUEUE_BYTES = clampInteger(process.env.MAX_RELAY_BRANCH_QUEUE_BYTES, 8 * 1024 * 1024, 512 * 1024, 256 * 1024 * 1024);
 const RELAY_BRANCH_PAUSE_BYTES = Math.floor(MAX_RELAY_BRANCH_QUEUE_BYTES / 2);
 const JPEG_SOI = Buffer.from([0xff, 0xd8]);
 const JPEG_EOI = Buffer.from([0xff, 0xd9]);
@@ -116,18 +117,23 @@ app.post('/api/session', async (request, response) => {
   const options = parsePlaybackOptions(request.body);
   const id = randomUUID();
 
+  const metadataStatus = METADATA_PROBE_ENABLED ? 'pending' : 'disabled';
+
   sessions.set(id, {
     id,
     url,
     options,
     duration: null,
-    metadataStatus: 'pending',
+    metadataStatus,
     seekSeconds: 0,
     seekGeneration: 0,
     createdAt: Date.now(),
     lastUsedAt: Date.now(),
   });
-  startSessionMetadataProbe(sessions.get(id));
+
+  if (METADATA_PROBE_ENABLED) {
+    startSessionMetadataProbe(sessions.get(id));
+  }
 
   try {
     await addRecentUrl(url);
@@ -1126,7 +1132,7 @@ function createRelayPlayback(session) {
           return;
         }
 
-        const buffer = Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk);
+        const buffer = toBufferView(chunk);
         sourceBytes += buffer.length;
 
         if (!audioInput.write(buffer) || !frameInput.write(buffer)) {
@@ -1704,6 +1710,18 @@ function copyJpegFrame(jpeg, packet, offset) {
   }
 }
 
+function toBufferView(chunk) {
+  if (Buffer.isBuffer(chunk)) {
+    return chunk;
+  }
+
+  if (chunk instanceof ArrayBuffer) {
+    return Buffer.from(chunk);
+  }
+
+  return Buffer.from(chunk.buffer, chunk.byteOffset, chunk.byteLength);
+}
+
 function createSourceInput(sessionId, kind) {
   const token = randomUUID();
   sourceTokens.set(token, { sessionId, kind, createdAt: Date.now() });