如何使用MediaMuxer合并音频和视频？

Question

我正在开发一个带有mp3音频文件和mp4视频文件(没有声音)的安卓应用程序。

现在，我想混合它们，并创建一个新的mp4视频文件(声音)。从Android4.3，谷歌建议使用MediaMuxer类混合流音频和视频。我试过很多次，但都没有成功。

以下是代码：

    private void muxing() {

    String outputFile = "";

    try {

        File file = new File(Environment.getExternalStorageDirectory() + "/final2.mp4");
        file.createNewFile();
        outputFile = file.getAbsolutePath();
        MediaExtractor videoExtractor = new MediaExtractor();
        videoExtractor.setDataSource(Environment.getExternalStorageDirectory().toString()+"/vd1.h264");
        MediaExtractor audioExtractor = new MediaExtractor();
        audioExtractor.setDataSource(Environment.getExternalStorageDirectory()+"/audioVideoDir/audio.m4a");
        MediaMuxer muxer = new MediaMuxer(outputFile, MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4);

        videoExtractor.selectTrack(0);
        MediaFormat videoFormat = videoExtractor.getTrackFormat(0);
        int videoTrack = muxer.addTrack(videoFormat);

        audioExtractor.selectTrack(0);
        MediaFormat audioFormat = audioExtractor.getTrackFormat(0);
        int audioTrack = muxer.addTrack(audioFormat);
        boolean sawEOS = false;
        int frameCount = 0;
        int offset = 100;
        int sampleSize = 256 * 1024;
        ByteBuffer videoBuf = ByteBuffer.allocate(sampleSize);
        ByteBuffer audioBuf = ByteBuffer.allocate(sampleSize);
        MediaCodec.BufferInfo videoBufferInfo = new MediaCodec.BufferInfo();
        MediaCodec.BufferInfo audioBufferInfo = new MediaCodec.BufferInfo();


        videoExtractor.seekTo(0, MediaExtractor.SEEK_TO_CLOSEST_SYNC);
        audioExtractor.seekTo(0, MediaExtractor.SEEK_TO_CLOSEST_SYNC);

        muxer.start();

        while (!sawEOS)
        {
            videoBufferInfo.offset = offset;
            videoBufferInfo.size = videoExtractor.readSampleData(videoBuf, offset);


            if (videoBufferInfo.size < 0 || audioBufferInfo.size < 0)
            {
               // Log.d(TAG, "saw input EOS.");
                sawEOS = true;
                videoBufferInfo.size = 0;

            }
            else
            {
                videoBufferInfo.presentationTimeUs = videoExtractor.getSampleTime();
                videoBufferInfo.flags = videoExtractor.getSampleFlags();
                muxer.writeSampleData(videoTrack, videoBuf, videoBufferInfo);
                videoExtractor.advance();


                frameCount++;

            }
        }

        Toast.makeText(getApplicationContext() , "frame:" + frameCount , Toast.LENGTH_SHORT).show();



        boolean sawEOS2 = false;
        int frameCount2 =0;
        while (!sawEOS2)
        {
            frameCount2++;

            audioBufferInfo.offset = offset;
            audioBufferInfo.size = audioExtractor.readSampleData(audioBuf, offset);

            if (videoBufferInfo.size < 0 || audioBufferInfo.size < 0)
            {
              //  Log.d(TAG, "saw input EOS.");
                sawEOS2 = true;
                audioBufferInfo.size = 0;
            }
            else
            {
                audioBufferInfo.presentationTimeUs = audioExtractor.getSampleTime();
                audioBufferInfo.flags = audioExtractor.getSampleFlags();
                muxer.writeSampleData(audioTrack, audioBuf, audioBufferInfo);
                audioExtractor.advance();

            }
        }

        Toast.makeText(getApplicationContext() , "frame:" + frameCount2 , Toast.LENGTH_SHORT).show();

        muxer.stop();
        muxer.release();


    } catch (IOException e) {

    } catch (Exception e) {

    }
}

我得到以下错误：

未知mime类型‘音频/mpeg’。12-09 11:58:33.569: A/MPEG4Writer(332)：frameworks/av/media/libstagefright/MPEG4Writer.cpp:2699 CHECK(！)

有什么解决办法来解决我与谷歌的MediaMuxer API的问题吗？就连我也试过使用ffmpeg，在将音频和视频合并在一起之后，视频不会在android设备的默认视频播放器中播放，但它会在Vlc播放器中加载。

FFMPEG紧随其后：https://github.com/WritingMinds/ffmpeg-android-java

Answer 1

尝试添加mp4视频文件。它为我工作。但是输出文件具有音频持续时间。