What is the best way to get an audio file duration in Android?

Question

I'm using a SoundPool to play audio clips in my app. All is fine but I need to know when the clip playback has finished.

At the moment I track it in my app by obtaining the duration of each clip using a MediaPlayer instance. That works fine but it looks wasteful to load each file twice, just to get the duration. I could roughly calculate the duration myself knowing the length of the file (available from the AssetFileDescriptor) but I'd still need to know the sample rate and the number of channels.

I see two potential solutions to that problem:

1. Figuring out when a clip has finished playing (doesn't seem to be possible with SoundClip).
2. Having a class which could load just the header of an audio file and give me the sample rate/number of channels (and, ideally, the sample count to get the exact duration).

Any suggestions?

Thanks, Max

The code I'm using at the moment (works fine but is rather heavy for the purpose):

String[] fileNames = ...
MediaPlayer mp = new MediaPlayer();
for (String fileName : fileNames) {
    AssetFileDescriptor d = context.getAssets().openFd(fileName);
    mp.reset();
    mp.setDataSource(d.getFileDescriptor(), d.getStartOffset(), d.getLength());
    mp.prepare();
    int duration = mp.getDuration();
    // ...
}

On a side note, this question has already been asked but got no answers.

Answer 1

Did you try this:

String mediaPath = Uri.parse("android.resource://<your-package-name>/raw/filename").getPath();
MediaMetadataRetriever mmr = new MediaMetadataRetriever();
mmr.setDataSource(mediaPath);
String duration = mmr.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION);
mmr.release();

But i am not exactly sure that this is lighter than exisiting code.