音视频合成

/**
     * 音频必须是aac,视频需要是H264或mpeg4
     */
    private void muxing(String audioFilePath,String videoFilePath) {


        String outputFile = "";

        try {

            File file = new File(Environment.getExternalStorageDirectory() + File.separator + "final.mp4");
            file.createNewFile();
            outputFile = file.getAbsolutePath();

            //创建视频分离器
            MediaExtractor videoExtractor = new MediaExtractor();
            videoExtractor.setDataSource(videoFilePath);

            //创建音频分离器
            MediaExtractor audioExtractor = new MediaExtractor();
            audioExtractor.setDataSource(audioFilePath);

            Log.d(TAG, "Video Extractor Track Count " + videoExtractor.getTrackCount());
            Log.d(TAG, "Audio Extractor Track Count " + audioExtractor.getTrackCount());
            //创建混音器
            MediaMuxer muxer = new MediaMuxer(outputFile, MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4);

            //选中轨道0
            videoExtractor.selectTrack(0);

            //-----------------
            //int trackCount = videoExtractor.getTrackCount();
            //MediaFormat trackFormat = videoExtractor.getTrackFormat(trackCount);
            //String mime = trackFormat.getString(MediaFormat.KEY_MIME);
            //Log.i(TAG,"video mime:" + mime);//mime=video/avc
            //-----------------
            //获取音频格式封装对象
            MediaFormat videoFormat = videoExtractor.getTrackFormat(0);
            int videoTrack = muxer.addTrack(videoFormat);

            //选中轨道0
            audioExtractor.selectTrack(0);

            //trackCount = audioExtractor.getTrackCount();
            //trackFormat = audioExtractor.getTrackFormat(trackCount);
            //mime = trackFormat.getString(MediaFormat.KEY_MIME);
            //Log.i(TAG,"audio mime:" + mime);//mime=audio/mp4a-latm

            //获取视频格式封装对象
            MediaFormat audioFormat = audioExtractor.getTrackFormat(0);

            //向混音器添加音轨
            int audioTrack = muxer.addTrack(audioFormat);

            Log.d(TAG, "Video Format " + videoFormat.toString());
            Log.d(TAG, "Audio Format " + audioFormat.toString());

            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();

            //将位置移动到0
            videoExtractor.seekTo(0, MediaExtractor.SEEK_TO_CLOSEST_SYNC);
            audioExtractor.seekTo(0, MediaExtractor.SEEK_TO_CLOSEST_SYNC);

            //开启混音器
            muxer.start();

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

                audioBufferInfo.offset = offset;
                //从分离器中读取数据包
                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();
                    //向混音器写入数据包
                    muxer.writeSampleData(audioTrack, audioBuf, audioBufferInfo);
                    //移到到下一个数据包
                    audioExtractor.advance();
                    //if(audioBufferInfo.presentationTimeUs > 5*1000*1000){
                    //    break;
                    //}
                    Log.d(TAG, "Frame (" + frameCount + ") Video PresentationTimeUs:" + videoBufferInfo.presentationTimeUs + " Flags:" + videoBufferInfo.flags + " Size(KB) " + videoBufferInfo.size / 1024);
                    Log.d(TAG, "Frame (" + frameCount + ") Audio PresentationTimeUs:" + audioBufferInfo.presentationTimeUs + " Flags:" + audioBufferInfo.flags + " Size(KB) " + audioBufferInfo.size / 1024);
                }
            }

            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++;

                    Log.d(TAG, "Frame (" + frameCount + ") Video PresentationTimeUs:" + videoBufferInfo.presentationTimeUs + " Flags:" + videoBufferInfo.flags + " Size(KB) " + videoBufferInfo.size / 1024);
                    Log.d(TAG, "Frame (" + frameCount + ") Audio PresentationTimeUs:" + audioBufferInfo.presentationTimeUs + " Flags:" + audioBufferInfo.flags + " Size(KB) " + audioBufferInfo.size / 1024);

                }
            }

            muxer.stop();
            muxer.release();
            audioExtractor.release();
            videoExtractor.release();

        } catch (IOException e) {
            Log.d(TAG, "Mixer Error 1 " + e.getMessage());
        } catch (Exception e) {
            Log.d(TAG, "Mixer Error 2 " + e.getMessage());
        }
    }