如何使用Java将.webm转换为.mp4？

我想将视频从.webm转换为.mp4。我尝试过Java库JAVE（Java音频视频编码器）。这是我使用Jave的代码：

File source = new File("C:\\Development\\workspace\\java-project\\video.webm");
    File target = new File("C:\\Development\\workspace\\java-project\\video.mp4");

    Encoder encoder = new Encoder();
    AudioAttributes audio = new AudioAttributes();
    audio.setCodec("libmp3lame");
    audio.setBitRate(new Integer(64000));
    audio.setChannels(new Integer(1));
    audio.setSamplingRate(new Integer(22050));
    VideoAttributes video = new VideoAttributes();
    video.setCodec("mpeg4");
    video.setBitRate(new Integer(160000));
    video.setFrameRate(new Integer(15));
    video.setSize(new VideoSize(400, 300));
    EncodingAttributes attrs = new EncodingAttributes();
    attrs.setFormat("mp4");
    attrs.setAudioAttributes(audio);
    attrs.setVideoAttributes(video);
    try {
        encoder.encode(source, target, attrs);
    } catch (EncoderException e) {
        e.printStackTrace();
    }

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如果我像“source”一样使用video.avi或.flv，但使用的是.webm nothing，那么这个代码段就可以工作了！我做错了什么？我能做什么？

JAVE。您的ffmpeg安装是否支持WEBM文件？您是否尝试使用

audio.setCodec（AudioAttributes.DIRECT\u STREAM\u COPY）？是的，但是使用这个方法（audio.setCodec（AudioAttributes.DIRECT_STREAM_COPY）；）我做不到
import com.xuggle.mediatool.IMediaReader;
    import com.xuggle.mediatool.IMediaViewer;
    import com.xuggle.mediatool.IMediaWriter;
    import com.xuggle.mediatool.ToolFactory;


    public class XuggleApiTest {

         private static final String inputFilename = "filepath/filename.webm";
            private static final String outputFilename = "filepath/filename.mp4";
            public static void main(String[] args) {
                IMediaReader mediaReader = 
                       ToolFactory.makeReader(inputFilename);
                IMediaWriter mediaWriter = 
                       ToolFactory.makeWriter(outputFilename, mediaReader);
                mediaReader.addListener(mediaWriter);
                IMediaViewer mediaViewer = ToolFactory.makeViewer(true);
                 mediaReader.addListener(mediaViewer);
                while (mediaReader.readPacket() == null) ;

            }
    }