如何在Android中使用Java将音频从mp4提取到mp3? [英] How do I extractor audio to mp3 from mp4 using java in Android?

问题描述

我想在Android平台上将mp4视频转换为mp3音频文件吗? 我该怎么做? 实际上，我测试了一些JAR. 首先，使用JAAD lib进行测试.

I want convert mp4 video to mp3 audio file in Android platform? How can I do it? Actually I test some JAR. Firstly, the JAAD lib be used to test.

import java.io.File;
import java.io.RandomAccessFile;
import java.util.List;

import net.sourceforge.jaad.aac.Decoder;
import net.sourceforge.jaad.aac.SampleBuffer;
import net.sourceforge.jaad.mp4.MP4Container;
import net.sourceforge.jaad.mp4.api.AudioTrack;
import net.sourceforge.jaad.mp4.api.Frame;
import net.sourceforge.jaad.mp4.api.Movie;
import net.sourceforge.jaad.mp4.api.Track;
import net.sourceforge.jaad.util.wav.WaveFileWriter;

public class Main2 {
    public static void main(String[] args) {
    System.out.println("dfd");
    try {
        decodeMP4("C:/a/input.mp4","./out.wav");
    } catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    System.out.println("over");

}
private static void decodeMP4(String in, String out) throws Exception {
    WaveFileWriter wav = null;
    try {
        final MP4Container cont = new MP4Container(new RandomAccessFile(in, "r"));
        final Movie movie = cont.getMovie();
        final List<Track> tracks = movie.getTracks(AudioTrack.AudioCodec.AAC);
        if(tracks.isEmpty()) throw new Exception("movie does not contain any AAC track");
        final AudioTrack track = (AudioTrack) tracks.get(0);

        wav = new WaveFileWriter(new File(out), track.getSampleRate(), track.getChannelCount(), track.getSampleSize());

        final Decoder dec = new Decoder(track.getDecoderSpecificInfo());

        Frame frame;
        final SampleBuffer buf = new SampleBuffer();
        while(track.hasMoreFrames()) {
            frame = track.readNextFrame();
            dec.decodeFrame(frame.getData(), buf);
            wav.write(buf.getData());
        }
    }
    finally {
        if(wav!=null) wav.close();
    }
}
}

但是会引发错误

"java.lang.ClassCastException: net.sourceforge.jaad.mp4.boxes.impl.PixelAspectRatioBox cannot be cast to net.sourceforge.jaad.mp4.boxes.impl.sampleentries.codec.CodecSpecificBox
    at net.sourceforge.jaad.mp4.api.VideoTrack.<init>(VideoTrack.java:62)
    at net.sourceforge.jaad.mp4.api.Movie.createTrack(Movie.java:65)
    at net.sourceforge.jaad.mp4.api.Movie.<init>(Movie.java:46)
    at net.sourceforge.jaad.mp4.MP4Container.getMovie(MP4Container.java:134)
    at Main2.decodeMP4(Main2.java:30)
    at Main2.main(Main2.java:18)"

推荐答案

这个问题有点太复杂了.我知道如何执行. 这是从视频文件中提取音频数据的代码，但它是PCM数据，而不是mp3:

This question is a little too complex. I know how to implement it. here is the code to extract audio data from video file ,but it's PCM data ,not mp3:

 public class AudioFromVideo{
    private String audio,video;
    private MediaCodec amc;
    private MediaExtractor ame;
    private MediaFormat amf;
    private String amime;
    public AudioFromVideo(String srcVideo,String destAudio){
        this.audio=destAudio;
        this.video=srcVideo;
        ame=new MediaExtractor();
        init();
    }
    public void init(){
            try {
                ame.setDataSource(video);
                amf=ame.getTrackFormat(1);
                ame.selectTrack(1);
                amime=amf.getString(MediaFormat.KEY_MIME);
                amc=MediaCodec.createDecoderByType(amime);
                amc.configure(amf, null, null, 0);
                amc.start();
            } catch (IOException e) {
                e.printStackTrace();
            }
    }
    public void start(){
        new AudioService(amc,ame,audio).start();
    }
    private class AudioService extends Thread{
        private MediaCodec amc;
        private MediaExtractor ame;
        private ByteBuffer[] aInputBuffers,aOutputBuffers;
        private String destFile;
        @SuppressWarnings("deprecation")
        AudioService(MediaCodec amc,MediaExtractor ame,String destFile){
            this.amc=amc;
            this.ame=ame;
            this.destFile=destFile;
            aInputBuffers=amc.getInputBuffers();
            aOutputBuffers=amc.getOutputBuffers();
        }
        @SuppressWarnings("deprecation")
        public void run(){
            try {
                OutputStream os=new FileOutputStream(new File(destFile));
                long count=0;
                while(true){
                        int inputIndex=amc.dequeueInputBuffer(0);
                        if(inputIndex==-1){
                            continue;
                        }
                        int sampleSize=ame.readSampleData(aInputBuffers[inputIndex], 0);
                        if(sampleSize==-1)break;
                        long presentationTime=ame.getSampleTime();
                        int flag=ame.getSampleFlags();
                        ame.advance();
                        amc.queueInputBuffer(inputIndex, 0, sampleSize, presentationTime, flag);
                        BufferInfo info=new BufferInfo();
                        int outputIndex=amc.dequeueOutputBuffer(info, 0);
                        if (outputIndex >= 0) {
                            byte[] data=new byte[info.size];
                            aOutputBuffers[outputIndex].get(data, 0, data.length);
                            aOutputBuffers[outputIndex].clear();
                            os.write(data);
                            count+=data.length;
                            Log.i("write", ""+count);
                            amc.releaseOutputBuffer(outputIndex, false);
                        } else if (outputIndex == MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED) {
                            aOutputBuffers = amc.getOutputBuffers();
                        } else if (outputIndex == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {}
                }
                os.flush();
                os.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
}

例如，要从视频文件video.mp4中提取音频数据，并将提取的日期保存到文件audio.pcm中，请编写如下代码:

For example ,to extract audio data from Video file video.mp4,and save the extracted date into file audio.pcm,write code like this:

String videoPath=PATH+"/video.mp4";
String audioPath=PATH+"/audio.pcm";
new AudioFromVideo(video.audio).start();

如果您需要mp3数据，可以使用lame mp3 lib将PCM数据编码为MP3格式.我拥有所有代码.但是将它们全部粘贴到这里并不容易.

If you need mp3 data,you can use lame mp3 lib to encode PCM data to MP3 format.I have all the code. but it is not convinent to paste all of them here.

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