What is the best way to get an audio file duration

问题:

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.

回答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.

回答2:

Try FFmpegMediaMetadataRetriever:

String[] fileNames = ...
FFmpegMediaMetadataRetriever mmr = new FFmpegMediaMetadataRetriever();

for (String fileName : fileNames) {
    AssetFileDescriptor d = context.getAssets().openFd(fileName);
    mmr.setDataSource(d.getFileDescriptor(), d.getStartOffset(), d.getLength());
    String duration = mmr.extractMetadata(FFmpegMediaMetadataRetriever.METADATA_KEY_DURATION);
}

mmr.release();

回答3:

this is work for me to get assets audio file duration in total seconds=====>

MediaMetadataRetriever mmr = new MediaMetadataRetriever();
AssetFileDescriptor d = context.getAssets().openFd(fileName);
mmr.setDataSource(d.getFileDescriptor(), d.getStartOffset(), d.getLength());
String duration = 
mmr.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION);
mmr.release();

Updated

method to get assets audio file duration in seconds

  public String gettotaltimeassets() {

   MediaMetadataRetriever mmr = new MediaMetadataRetriever();
    AssetFileDescriptor d = null;
    try {
        d = getApplicationContext().getAssets().openFd("ASSETS FILE NAME");
    } catch (IOException e) {
        e.printStackTrace();
    }
    mmr.setDataSource(d.getFileDescriptor(), d.getStartOffset(), d.getLength());
    String duration = mmr.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION);
    long dur = Long.parseLong(duration);
    String seconds = String.valueOf((dur % 60000) / 1000);
    Log.d("seconds===========>", seconds);
    mmr.release();
    return  seconds;
}

method to get internal storage audio file duration in seconds

public String gettotaltimestorage(String filePath) {
    // load data file
    Log.d("time=================>","time=================>");
    MediaMetadataRetriever metaRetriever = new MediaMetadataRetriever();
    metaRetriever.setDataSource(YourACTIVITY.this, Uri.parse(filePath));
    Log.d("time=================>","time=================>");
    String out = "";
    // get mp3 info

    // convert duration to minute:seconds
    String duration =
            metaRetriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION);
    Log.d("time=================>", duration);
    long dur = Long.parseLong(duration);
    String seconds = String.valueOf((dur % 60000) / 1000);
    Log.d("seconds===========>", seconds);
    // close object
    metaRetriever.release();
    return  seconds;

}