Optimize screen sharing latency and frame rate

web/backend/src/MediaPlayer.ts

@@ -375,29 +375,27 @@ export class MediaPlayer {
             siteName: "Screen Sharing",
         });
 
-        // Special options for mpv to better handle screen sharing (AI recommended...)
+        // Start from mpv's maintained low-latency profile, then keep only a
+        // couple of frames of demuxed data ready for smooth 60 fps playback.
         await this.loadFile(url, "replace", false, [
-            "demuxer-lavf-o=fflags=+nobuffer+discardcorrupt",  // Reduce buffering and discard corrupt frames
-            "demuxer-lavf-o=analyzeduration=100000",           // Reduce analyze duration
-            "demuxer-lavf-o=probesize=1000000",                // Reduce probe size
-            "untimed=yes",                                     // Ignore timing info
-            "cache=no",                                        // Disable cache
-            "force-seekable=yes",                              // Force seekable
-            "no-cache=yes",                                    // Disable cache
-            "demuxer-max-bytes=500K",                          // Limit demuxer buffer
-            "demuxer-readahead-secs=0.1",                      // Reduce readahead
-            "hr-seek=no",                                      // Disable high-res seeking
-            "video-sync=display-resample",                     // Better sync mode
-            "video-latency-hacks=yes",                         // Enable latency hacks
-            "audio-sync=yes",                                  // Enable audio sync
-            "audio-buffer=0.1",                                // Reduce audio buffer
-            "audio-channels=stereo",                           // Force stereo audio
-            "audio-samplerate=44100",                          // Match sample rate
-            "audio-format=s16",                                // Use 16-bit audio
+            "profile=low-latency",
+            "cache=no",
+            "force-seekable=no",
+            "demuxer-readahead-secs=0.05",
+            "demuxer-max-bytes=256K",
+            "demuxer-mkv-probe-start-time=no",
+            "vd-lavc-threads=2",
+            "vd-lavc-fast=yes",
+            "audio-buffer=0",
+            "pulse-buffer=20",
+            "pipewire-buffer=20",
+            "alsa-buffer-time=20000",
+            "initial-audio-sync=no",
         ]);
 
-        // Make sure it's playing
-        setTimeout(() => this.play(), 100);
+        // loadfile normally unpauses, but make that explicit without adding the
+        // previous fixed 100 ms startup delay.
+        await this.play();
     }
 
     public async play() {
@@ -475,13 +473,18 @@ export class MediaPlayer {
     private async loadFile(url: string, mode: string, fetchMetadata: boolean = true, options: string[] = []) {
         this.lastLoadCandidate = url;
         this.playbackErrors.delete(url);
-        this.modify(UserEvent.PlaylistUpdate, () => this.writeCommand("loadfile", [url, mode, "-1", options.join(',')]));
+        const loadPromise = this.modify(
+            UserEvent.PlaylistUpdate,
+            () => this.writeCommand("loadfile", [url, mode, "-1", options.join(',')]),
+        );
 
         if (fetchMetadata && this.shouldFetchLinkPreview(url)) {
             this.fetchMetadataAndNotify(url).catch(error => {
                 console.warn(`Failed to fetch metadata for ${this.loggableUrl(url)}:`, error);
             });
         }
+
+        await loadPromise;
     }
 
     private async modify<T>(event: UserEvent, func: () => Promise<T>): Promise<T> {