视频和音频同步问题

Question

我正在将帧保存为H264格式，并且将音频保存为aac格式。然后，我将这些格式串联起来，使用ffmpeg播放器在android中创建mp4格式，但是当我将音频和视频串联在一起时，音频返回的视频不在同步模式下播放，如何在同步模式下播放视频和音频？ H264视频格式是6秒，音频格式是8秒当我将这些连接起来时，它们会变成8秒，并且音频会变长并发生异步。

将音频录制为AAC格式

    recorder = new MediaRecorder();

    recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
    recorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4); 
    recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);    
    recorder.setAudioEncodingBitRate(48000);//48000
    recorder.setAudioSamplingRate(720);//16000
    recorder.setOutputFile(path2);
    try {
        recorder.prepare();
    } catch (IOException e) {
        e.printStackTrace();
    }
    recorder.start();

将视频保存为H264格式

        MediaFormat mediaFormat = MediaFormat.createVideoFormat("video/avc",
                1280,
                720);
        mediaFormat.setInteger(MediaFormat.KEY_COLOR_FORMAT,
                MediaCodecInfo.CodecCapabilities.COLOR_FormatYUV420Planar);
        mediaFormat.setInteger(MediaFormat.KEY_BIT_RATE, 6000000);
        mediaFormat.setInteger(MediaFormat.KEY_FRAME_RATE, 720); //video second

        mediaFormat.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, 5);
        try {
            mMediaCodec = MediaCodec.createEncoderByType("video/avc");
        } catch (IOException e) {
            e.printStackTrace();
        }
        mMediaCodec.configure(mediaFormat,
                null,
                null,
                MediaCodec.CONFIGURE_FLAG_ENCODE);

        mMediaCodec.start();

//Video format H264
private synchronized void encode(byte[] data) {

    ByteBuffer[]  inputBuffers = mMediaCodec.getInputBuffers();
    ByteBuffer[]  outputBuffers = mMediaCodec.getOutputBuffers();

    int inputBufferIndex = mMediaCodec.dequeueInputBuffer(-1);
    if (inputBufferIndex >= 0) {
        ByteBuffer inputBuffer = inputBuffers[inputBufferIndex];
        inputBuffer.capacity();
        inputBuffer.clear();
        inputBuffer.put(data);
        mMediaCodec.queueInputBuffer(inputBufferIndex, 0, data.length, 0, 0);

    } else {
        return;
    }

    MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();
    int outputBufferIndex = mMediaCodec.dequeueOutputBuffer(bufferInfo, 0);
    Log.i(TAG, "outputBufferIndex-->" + outputBufferIndex);
    do {
        if (outputBufferIndex >= 0) {
            ByteBuffer outBuffer = outputBuffers[outputBufferIndex];
            System.out.println("buffer info-->" + bufferInfo.offset + "--"
                    + bufferInfo.size + "--" + bufferInfo.flags + "--"
                    + bufferInfo.presentationTimeUs);
            byte[] outData = new byte[bufferInfo.size];
            outBuffer.get(outData);
            try {
                if (bufferInfo.offset != 0) {
                    fos.write(outData, bufferInfo.offset, outData.length
                            - bufferInfo.offset);
                } else {
                    fos.write(outData, 0, outData.length);
                }
                fos.flush();
                Log.i(TAG, "out data -- > " + outData.length);
                mMediaCodec.releaseOutputBuffer(outputBufferIndex, false);
                outputBufferIndex = mMediaCodec.dequeueOutputBuffer(bufferInfo,
                        0);
            } catch (IOException e) {
                e.printStackTrace();
            }
        } else if (outputBufferIndex == MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED) {
            outputBuffers = mMediaCodec.getOutputBuffers();
        } else if (outputBufferIndex == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {
            MediaFormat format = mMediaCodec.getOutputFormat();
        }
    } while (outputBufferIndex >= 0);
}

使用ffmpeg连接视频和音频

String[] cmd = {"-i", h264_video_path, "-i", aac_audio_path, "-c", "copy", "-map","0:v:0","-map","1:a:0", outpath_mp4};

    try {
                    //FFMPEG execute command
                    executeCommand(cmd);
                } catch (FFmpegCommandAlreadyRunningException e) {
                    e.printStackTrace();
                }