fix(mpv): apply carried audio/subtitle track after file load

Setting sid/aid before loadfile does not stick for embedded tracks, so a
carried-over subtitle was silently dropped on a freshly loaded episode.
Apply the initial audio/subtitle selection in the MPV_EVENT_FILE_LOADED
handler (after tracks are enumerated) for embedded and external alike, on
both iOS and Android.

modules/mpv-player/android/src/main/java/expo/modules/mpvplayer/MPVLayerRenderer.kt

@@ -684,11 +684,19 @@ class MPVLayerRenderer(private val context: Context) : MPVLib.EventObserver {
                         MPVLib.command(arrayOf("sub-add", subUrl, "auto"))
                     }
                     pendingExternalSubtitles = emptyList()
-                    
-                    // Set subtitle after external subs are added
-                    initialSubtitleId?.let { setSubtitleTrack(it) } ?: disableSubtitles()
                 }
-                
+
+                // Apply the initial audio/subtitle selection now that the file's
+                // tracks are enumerated. Setting sid/aid before `loadfile` does not
+                // reliably stick for embedded tracks (the selection is silently
+                // dropped), so we (re)apply here for embedded and external alike.
+                // This is what makes a carried-over subtitle show up on the next
+                // episode without a manual re-selection.
+                if (initialAudioId != null && initialAudioId > 0) {
+                    setAudioTrack(initialAudioId)
+                }
+                initialSubtitleId?.let { setSubtitleTrack(it) } ?: disableSubtitles()
+
                 if (!isReadyToSeek) {
                     isReadyToSeek = true
                     mainHandler.post { delegate?.onReadyToSeek() }

modules/mpv-player/ios/MPVLayerRenderer.swift

@@ -485,8 +485,7 @@ final class MPVLayerRenderer {
         switch event.event_id {
         case MPV_EVENT_FILE_LOADED:
             // Add external subtitles now that the file is loaded
-            let hadExternalSubs = !pendingExternalSubtitles.isEmpty
+            if !pendingExternalSubtitles.isEmpty, let handle = mpv {
-            if hadExternalSubs, let handle = mpv {
                 for (index, subUrl) in pendingExternalSubtitles.enumerated() {
                     print("🔧 Adding external subtitle [\(index)]: \(subUrl)")
                     // Use commandSync to ensure subs are added in exact order (not async)
@@ -494,12 +493,20 @@ final class MPVLayerRenderer {
                     commandSync(handle, ["sub-add", subUrl, "auto"])
                 }
                 pendingExternalSubtitles = []
-                // Set subtitle after external subs are added
+            }
-                if let subId = initialSubtitleId {
+            // Apply the initial audio/subtitle selection now that the file's
-                    setSubtitleTrack(subId)
+            // tracks are enumerated. Setting sid/aid before `loadfile` does not
-                } else {
+            // reliably stick for embedded tracks (the selection is silently
-                    disableSubtitles()
+            // dropped), so we (re)apply here for embedded and external alike.
-                }
+            // This is what makes a carried-over subtitle show up on the next
+            // episode without a manual re-selection.
+            if let audioId = initialAudioId, audioId > 0 {
+                setAudioTrack(audioId)
+            }
+            if let subId = initialSubtitleId {
+                setSubtitleTrack(subId)
+            } else {
+                disableSubtitles()
             }
             if !isReadyToSeek {
                 isReadyToSeek = true