onMediaBrowserChanged not called when setting MediaMetadata first

Version

Media3 1.4.1

Summary

We have a stream from a radio station that supplies data about the currently playing track. The standard way to observe or receive updates is through the onMediaMetadataChanged callback.

This approach works well, as I can see the title being updated. However, if I set some metadata on the MediaItem initially, the callback is never triggered.

I am wondering if this behavior is by design and, if so, what the purpose is, or if it might be a bug.

Devices that reproduce the issue

Pixel 7 Android 15

Devices that do not reproduce the issue

No response

Reproducible in the demo app?

No, because you need to set MediaMetaData to prevent an exception.
java.lang.IllegalArgumentException: mediaMetadata must specify isBrowsable. So you will never see MetaData changes coming through.

Reproduction steps

1: Play a media item without setting the MetaData:

    val mediaItemWithOutMetaData = MediaItem.Builder()
        .setMediaId("some_id")
        .setMimeType(MimeTypes.AUDIO_UNKNOWN)
        .setUri("https://icecast-qmusicnl-cdp.triple-it.nl/Qmusic_nl_live_high.aac")
        .build()

2: Listen to onMediaMetadataChanged

        player?.addListener(object : Player.Listener {
            override fun onMediaMetadataChanged(mediaMetadata: MediaMetadata) {
                super.onMediaMetadataChanged(mediaMetadata)
                Log.d("[DEBUG]", "onMediaMetadataChanged: ${mediaMetadata.title}")
            }
        })

3: Observe that the mediaMetadata.title is coming through.

4: Now play the mediaItem with Metadata

    val mediaItemWithMetaData = MediaItem.Builder()
        .setMediaId("some_id")
        .setMimeType(MimeTypes.AUDIO_UNKNOWN)
        .setMediaMetadata(MediaMetadata.Builder().setTitle("a title").build())
        .setUri("https://icecast-qmusicnl-cdp.triple-it.nl/Qmusic_nl_live_high.aac")
        .build()
        
5: Observe that the title is not coming through.
        

Expected result

onMediaMetadataChanged is called, with or without setting MediaMetaData on the MediaItem we are playing.__

Actual result

onMediaMetadataChanged is only triggered if we are not setting MediaMetaData first.

Media

https://icecast-qmusicnl-cdp.triple-it.nl/Qmusic_nl_live_high.aac

Bug Report

• You will email the zip file produced by adb bugreport to android-media-github@google.com after filing this issue.