From 4d9e3cb6de14adde20b69d104f87473c10b1ef22 Mon Sep 17 00:00:00 2001
From: Ray <154766448+damontecres@users.noreply.github.com>
Date: Fri, 2 Jan 2026 14:13:03 -0500
Subject: [PATCH] Fix MPV race condition causing no video output (#619)

## Description
Fixes a race condition where `libmpv` is beginning playback before it
has been attached to the output video surface.

The solution is for the handler to re-enqueue commands if MPV is either
not initialized or not attached yet. Once `libmpv` is ready, the
commands will be processed.

### Related issues
Should fix #576
---
 .../wholphin/util/mpv/MpvPlayer.kt            | 43 +++++++++++++------
 1 file changed, 29 insertions(+), 14 deletions(-)

diff --git a/app/src/main/java/com/github/damontecres/wholphin/util/mpv/MpvPlayer.kt b/app/src/main/java/com/github/damontecres/wholphin/util/mpv/MpvPlayer.kt
index 4777e977..81eb8669 100644
--- a/app/src/main/java/com/github/damontecres/wholphin/util/mpv/MpvPlayer.kt
+++ b/app/src/main/java/com/github/damontecres/wholphin/util/mpv/MpvPlayer.kt
@@ -109,6 +109,7 @@ class MpvPlayer(
         Timber.v("config-dir=${context.filesDir.path}")
         MPVLib.addLogObserver(mpvLogger)
 
+        Timber.v("Creating MPVLib")
         MPVLib.create(context)
         MPVLib.setOptionString("config", "yes")
         MPVLib.setOptionString("config-dir", context.filesDir.path)
@@ -127,6 +128,7 @@ class MpvPlayer(
         MPVLib.setOptionString("demuxer-max-bytes", "${cacheMegs * 1024 * 1024}")
         MPVLib.setOptionString("demuxer-max-back-bytes", "${cacheMegs * 1024 * 1024}")
 
+        Timber.v("Initializing MPVLib")
         MPVLib.initialize()
 
         MPVLib.setOptionString("force-window", "no")
@@ -466,7 +468,6 @@ class MpvPlayer(
     override fun clearVideoSurfaceHolder(surfaceHolder: SurfaceHolder?): Unit = throw UnsupportedOperationException()
 
     override fun setVideoSurfaceView(surfaceView: SurfaceView?) {
-        throwIfReleased()
         if (DEBUG) Timber.v("setVideoSurfaceView")
         val surface = surfaceView?.holder?.surface
         if (surface != null && surface.isValid) {
@@ -635,9 +636,9 @@ class MpvPlayer(
                         val title = it.label ?: "External Subtitles"
                         Timber.v("Adding external subtitle track '$title'")
                         if (it.language.isNotNullOrBlank()) {
-                            MPVLib.command(arrayOf("sub-add", url, "auto", title, it.language!!))
+                            MPVLib.command(arrayOf("sub-add", url, "select", title, it.language!!))
                         } else {
-                            MPVLib.command(arrayOf("sub-add", url, "auto", title))
+                            MPVLib.command(arrayOf("sub-add", url, "select", title))
                         }
                     }
                 }
@@ -837,7 +838,18 @@ class MpvPlayer(
 
     override fun handleMessage(msg: Message): Boolean {
         val cmd = MpvCommand.entries[msg.what]
-        Timber.v("handleMessage: cmd=$cmd")
+        Timber.d("handleMessage: cmd=$cmd")
+        if (isReleased && cmd != MpvCommand.DESTROY) {
+            Timber.w("Player is released, ignoring command %s", cmd)
+            return true
+        }
+        if (surface == null && !cmd.isLifecycle) {
+            // If libmpv isn't ready, re-enqueue the messages
+            // Note: this means nothing will play until it is attached to a surface,
+            // so MpvPlayer can't be used for background audio/music playback
+            Timber.v("MPV is not initialized/attached yet, requeue cmd %s", cmd)
+            internalHandler.sendMessageDelayed(Message.obtain(msg), 50)
+        }
         when (cmd) {
             MpvCommand.PLAY_PAUSE -> {
                 val playWhenReady = msg.obj as Boolean
@@ -894,6 +906,7 @@ class MpvPlayer(
                     MPVLib.detachSurface()
                     MPVLib.setPropertyString("vo", "null")
                     MPVLib.setPropertyString("force-window", "no")
+                    Timber.d("Detached surface")
                 }
                 if (surface != null) {
                     MPVLib.attachSurface(surface)
@@ -1035,14 +1048,16 @@ private data class MediaAndPosition(
     val startPositionMs: Long,
 )
 
-enum class MpvCommand {
-    PLAY_PAUSE,
-    SEEK,
-    SET_TRACK_SELECTION,
-    SET_SPEED,
-    SET_SUBTITLE_DELAY,
-    LOAD_FILE,
-    ATTACH_SURFACE,
-    INITIALIZE,
-    DESTROY,
+enum class MpvCommand(
+    val isLifecycle: Boolean,
+) {
+    PLAY_PAUSE(false),
+    SEEK(false),
+    SET_TRACK_SELECTION(false),
+    SET_SPEED(false),
+    SET_SUBTITLE_DELAY(false),
+    LOAD_FILE(false),
+    ATTACH_SURFACE(true),
+    INITIALIZE(true),
+    DESTROY(true),
 }