How to load multiple subtitles before preparing player and switch subtitles on runtime dynamically without preparing the player again? i am using exo player version 2.16.1

[smkhurramkhan]

this is how i am loading subttiles. it's working fine for one but i want to pass list of subtitles before preparing media player and than switch subtitles from the list

 private fun preparePlayer(videoUrl: String) {
        videoWatchedTime = simpleExoplayer.currentPosition
        val uri = Uri.parse(videoUrl)


        val mediaItemBuilder = MediaItem.Builder()
            .setUri(uri)

        val uriSubtitle =
            Uri.parse(subTitle)


    
        val subtitle = subTiltesList?.let {
            listOf(
                MediaItem.Subtitle(
                    Uri.parse(it[i]),
                    MimeTypes.TEXT_VTT,  // The correct MIME type.
                    "en",
                    C.SELECTION_FLAG_DEFAULT
                ) )
        }


    Timber.d("immutable list is ${immutableListOf(subtitle).size}")
    val mediaItem = mediaItemBuilder
            .setSubtitles(subtitle)
            .build()


        val mediaSource =
            DefaultMediaSourceFactory(dataSourceFactory).createMediaSource(mediaItem)


        simpleExoplayer.prepare(mediaSource)
        simpleExoplayer.seekTo(videoWatchedTime)


}

[ojw28]

I think you're creating the source correctly, except that generally you'd expect each subtitle to differ somehow other than just the Uri. For example, are all of the subtitles really in English? If not you should be specifying a different language when you create each MediaItem.Subtitle. Also, normally only one of the subtitles will use C.SELECTION_FLAG_DEFAULT, since this flag is indicating which subtitle you'd like to be selected by default (i.e., you have to pick one!).

During playback, you can change the selected subtitle track using ExoPlayer's track selection APIs. these are documented here.

[smkhurramkhan]

yes the subtitles are of different language i.e Arabic and English but the thing is i can only parse one uri of subtitle before preparing the player. all i need to know is how to load list of subtitles and than prepare media player than i can change them dynamically without preparing the media player again.

[ojw28]

You need all of the subtitle URIs available in advance to build the MediaItem.Subtitle list. If you don't have the list of URIs in advance then this is a duplicate of #1649, which is a feature request (i.e., it's not yet supported).

[smkhurramkhan]

No i have list of subtitles before preparing the media player. All i want to do is load that list of subtitles before preparing the player and than i want to change the subtitles on button click. i have two button in the app one for english and one for arabic when i click on arabic it should show arabic subtitles and when click on english should show english subtitles. i want to load both subtitles before preparing the player. right now i am loading single subtitle and it is working good. but my question is how to load both subtitles before preparing media player.

[ojw28]

I think I've already answered the question.

1. Pass a list of MediaItem.Subtitle elements to setSubtitles when building the MediaItem, rather than just a single subtitle. I'd expect each of the Subtitle objects to have a different Uri and a different language, and at most one of them should use C.SELECTION_FLAG_DEFAULT.
2. Use ExoPlayer's track selection APIs to switch between them during playback. These APIs are documented here.

[smkhurramkhan]

val subtitle = subTiltesList?.let {
listOf(
MediaItem.Subtitle(
Uri.parse(it[i]),
MimeTypes.TEXT_VTT, // The correct MIME type.
"en",
C.SELECTION_FLAG_DEFAULT
) )
}
val mediaItem = mediaItemBuilder
.setSubtitles(subtitle)
.build()

see this i have list but Uri.parse(it[i]) it takes one item not list. also mediaitem.Builder.setSubtitles(subtitles) it takes one item. how i should pass a list?

[smkhurramkhan]

can you provide me a sample code to load subtitles list that will be really helpful

[ojw28]

MediaItem.Builder.setSubtitles takes a list, as per our documentation here:

https://exoplayer.dev/doc/reference/com/google/android/exoplayer2/MediaItem.Builder.html#setSubtitles(java.util.List)

and the actual source code here:

https://github.com/google/ExoPlayer/blob/r2.16.0/library/common/src/main/java/com/google/android/exoplayer2/MediaItem.java#L369

If you need help on creating a list in Kotlin, I'd suggest you ask on StackOverflow since this is a general programming question unrelated to ExoPlayer.

[smkhurramkhan]

Thanks that's what i needed