Prevent the UI refresh when it's triggered by the playback saving meta data

Fixes #2936

application/vlc-android/src/org/videolan/vlc/media/PlaylistManager.kt

@@ -46,6 +46,10 @@ class PlaylistManager(val service: PlaybackService) : MediaWrapperList.EventList
 
     companion object {
         val showAudioPlayer = MutableLiveData<Boolean>().apply { value = false }
+        // The playback will periodically modify the media by saving its meta
+        // When playing audio, it will have no impact on UI but will trigger the media modified ML callback
+        // On slow devices, it will trigger an unwanted "refresh animation". This flag prevents it
+        var skipMediaUpdateRefresh = false
         private val mediaList = MediaWrapperList()
         fun hasMedia() = mediaList.size() != 0
     }
@@ -575,6 +579,7 @@ class PlaylistManager(val service: PlaybackService) : MediaWrapperList.EventList
                         }
                     }
                 }
+            if (media.type != MediaWrapper.TYPE_VIDEO && !canSwitchToVideo && !media.isPodcast) skipMediaUpdateRefresh = true
             media.setStringMeta(MediaWrapper.META_SPEED, rate.toString())
 
         }

application/vlc-android/src/org/videolan/vlc/viewmodels/CallBackDelegate.kt

@@ -30,6 +30,7 @@ import kotlinx.coroutines.channels.actor
 import org.videolan.medialibrary.interfaces.Medialibrary
 import org.videolan.resources.AppContextProvider
 import org.videolan.tools.conflatedActor
+import org.videolan.vlc.media.PlaylistManager
 import org.videolan.vlc.util.FileUtils
 import java.io.File
 
@@ -195,7 +196,13 @@ class CallBackDelegate : ICallBackHandler,
 
     override fun onMediaAdded() { refreshActor.trySend(Unit) }
 
-    override fun onMediaModified() { refreshActor.trySend(Unit) }
+    override fun onMediaModified() {
+        if (PlaylistManager.skipMediaUpdateRefresh) {
+            PlaylistManager.skipMediaUpdateRefresh = false
+            return
+        }
+        refreshActor.trySend(Unit)
+    }
 
     override fun onMediaDeleted(ids: LongArray) {
         refreshActor.trySend(Unit)