get duration of audio file

问题

I have made a voice recorder app, and I want to show the duration of the recordings in a listview. I save the recordings like this:

MediaRecorder recorder = new MediaRecorder();
recorder.setOutputFormat(MediaRecorder.OutputFormat.DEFAULT);
recorder.setAudioEncoder(MediaRecorder.AudioEncoder.DEFAULT);
folder = new File(Environment.getExternalStorageDirectory()
            + File.separator + "Audio recordings");
String[] files = folder.list();
    int number = files.length + 1;
    String filename = "AudioSample" + number + ".mp3";
    File output = new File(Environment.getExternalStorageDirectory()
            + File.separator + "Audio recordings" + File.separator
            + filename);
    FileOutputStream writer = new FileOutputStream(output);
    FileDescriptor fd = writer.getFD();
    recorder.setOutputFile(fd);
    try {
        recorder.prepare();
        recorder.start();
    } catch (IllegalStateException e) {
        e.printStackTrace();
    } catch (IOException e) {
        Log.e(LOG_TAG, "prepare() failed");
        e.printStackTrace();
    }

How can I get the duration in seconds of this file?

Thanks in advance

---EDIT I got it working, I called MediaPlayer.getduration() inside the MediaPlayer.setOnPreparedListener() method so it returned 0.

回答1:

MediaMetadataRetriever is a lightweight and efficient way to do this. MediaPlayer is too heavy and could arise performance issue in high performance environment like scrolling, paging, listing, etc.

Furthermore, Error (100,0) could happen on MediaPlayer since it's a heavy and sometimes restart needs to be done again and again.

Uri uri = Uri.parse(pathStr);
MediaMetadataRetriever mmr = new MediaMetadataRetriever();
mmr.setDataSource(AppContext.getAppContext(),uri);
String durationStr = mmr.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION);
int millSecond = Integer.parseInt(durationStr);

回答2:

Either try this to get duration in milliseconds:

MediaPlayer mp = MediaPlayer.create(yourActivity, Uri.parse(pathofyourrecording));
int duration = mp.getDuration();

Or measure the time elapsed from recorder.start() till recorder.stop() in nanoseconds:

long startTime = System.nanoTime();    
// ... do recording ...    
long estimatedTime = System.nanoTime() - startTime;

回答3:

The quickest way to do is via MediaMetadataRetriever. However, there is a catch

if you use URI and context to set data source you might encounter bug https://code.google.com/p/android/issues/detail?id=35794

Solution is use absolute path of file to retrieve metadata of media file.

Below is the code snippet to do so

 private static String getDuration(File file) {
                MediaMetadataRetriever mediaMetadataRetriever = new MediaMetadataRetriever();
                mediaMetadataRetriever.setDataSource(file.getAbsolutePath());
                String durationStr = mediaMetadataRetriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION);
                return Utils.formateMilliSeccond(Long.parseLong(durationStr));
            }

Now you can convert millisecond to human readable format using either of below formats

     /**
         * Function to convert milliseconds time to
         * Timer Format
         * Hours:Minutes:Seconds
         */
        public static String formateMilliSeccond(long milliseconds) {
            String finalTimerString = "";
            String secondsString = "";

            // Convert total duration into time
            int hours = (int) (milliseconds / (1000 * 60 * 60));
            int minutes = (int) (milliseconds % (1000 * 60 * 60)) / (1000 * 60);
            int seconds = (int) ((milliseconds % (1000 * 60 * 60)) % (1000 * 60) / 1000);

            // Add hours if there
            if (hours > 0) {
                finalTimerString = hours + ":";
            }

            // Prepending 0 to seconds if it is one digit
            if (seconds < 10) {
                secondsString = "0" + seconds;
            } else {
                secondsString = "" + seconds;
            }

            finalTimerString = finalTimerString + minutes + ":" + secondsString;

    //      return  String.format("%02d Min, %02d Sec",
    //                TimeUnit.MILLISECONDS.toMinutes(milliseconds),
    //                TimeUnit.MILLISECONDS.toSeconds(milliseconds) -
    //                        TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(milliseconds)));

            // return timer string
            return finalTimerString;
        }

回答4:

Try use

long totalDuration = mediaPlayer.getDuration(); // to get total duration in milliseconds

long currentDuration = mediaPlayer.getCurrentPosition(); // to Gets the current playback position in milliseconds

Division on 1000 to convert to seconds.

Hope this helped you.

回答5:

After you write the file, open it up in a MediaPlayer, and call getDuration on it.

回答6:

Have you looked at Ringdroid?. It's pretty light weight and the integration is straight forward. It works well with VBR media files as well.

For your problem with getting the duration, you might want to do something like below using Ringdroid.

public class AudioUtils
{
    public static long getDuration(CheapSoundFile cheapSoundFile)
    {
        if( cheapSoundFile == null)
            return -1;
        int sampleRate = cheapSoundFile.getSampleRate();
        int samplesPerFrame = cheapSoundFile.getSamplesPerFrame();
        int frames = cheapSoundFile.getNumFrames();
        cheapSoundFile = null;
        return 1000 * ( frames * samplesPerFrame) / sampleRate;
    }

    public static long getDuration(String mediaPath)
    {
        if( mediaPath != null && mediaPath.length() > 0)
            try 
            {
                return getDuration(CheapSoundFile.create(mediaPath, null));
            }catch (FileNotFoundException e){} 
            catch (IOException e){}
        return -1;
    }
}

Hope that helps

回答7:

If the audio is from url, just wait for on prepared:

mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
        @Override
        public void onPrepared(MediaPlayer mp) {
             length = mp.getDuration();
        }
});

回答8:

It's simply. use RandomAccessFile Below is the code snippet to do so

 public static int getAudioInfo(File file) {
    try {
        byte header[] = new byte[12];
        RandomAccessFile randomAccessFile = new RandomAccessFile(file, "r");
        randomAccessFile.readFully(header, 0, 8);
        randomAccessFile.close();
        return (int) file.length() /1000;
    } catch (Exception e) {
        return 0;
    }
}

You can, of course, be more complete depending on your needs

来源：https://stackoverflow.com/questions/15394640/get-duration-of-audio-file