How to get Sampling rate and frequency of music fi

问题:

I am developing audio player in android. So i want to add the details of the playing song i.e. Artist Name, Duration, Bit rate and sampling frequency. I can get Artist Name and duration of a music file by using MediaStore.Audio.Media library. But i am unable to get Bit rate and sampling frequency of the same file. So how can i get the same?

As i know, it can be done by using native library. But don't know how? So anyone can help me on this?

回答1:

You can approximate it by dividing the file size by the length of the audio in seconds, for instance, from a random AAC encoded M4A in my library:

File Size: 10.3MB (87013064 bits)
Length: 5:16 (316 Seconds)
Which gives: 87013064 bits / 316 seconds = 273426.147 bits/sec or ~273kbps
Actual Bitrate: 259kbps

Since most audio files have a known set of valid bitrate levels, you can use that to step the bit rate to the appropriate level for display.

回答2:

I know it's been resolved but i got much better way to get accurate answer

MediaExtractor mex = new MediaExtractor();
try {
    mex.setDataSource(path);// the adresss location of the sound on sdcard.
} catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}

MediaFormat mf = mex.getTrackFormat(0);

int bitRate = mf.getInteger(MediaFormat.KEY_BIT_RATE);
int sampleRate = mf.getInteger(MediaFormat.KEY_SAMPLE_RATE);

回答3:

MediaMetadataRetriever offers METADATA_KEY_DURATION which you can divide with the file size for bitrate.