Android 视频分离和合成(MediaMuxer和MediaExtractor)

原文:https://blog.csdn.net/zhi184816/article/details/52514138#commentsedit

另外导入的项目的时候,需要将工程input.mp4导入sd卡中,放在根目录里,由代码可以知道。 

理论上来,我们可以利用的视频的分离和合成可以做很多事,比如裁剪视频大小,拼凑视频,对一段视频加入背景等。

MediaExtractor

MediaExtractor facilitates extraction of demuxed, typically encoded, media data from a data source.

其实就是将视频多信道的分离出来,比如声音和图像分隔出来,可以做到二次合成。 
1.实例对象 
2.setDateSource();//本地或者远程 
3.获取想追踪的TrackIndex; 
4.对TrackIndex的信道ByteBuffer数据进行处理

接下来讲一个mp4文件进行处理,分隔出audio信道和video信道


private void exactorMedia() {
    FileOutputStream videoOutputStream = null;
    FileOutputStream audioOutputStream = null;
    try {
        //分离的视频文件
        File videoFile = new File(SDCARD_PATH, "output_video.mp4");
        //分离的音频文件
        File audioFile = new File(SDCARD_PATH, "output_audio");
        videoOutputStream = new FileOutputStream(videoFile);
        audioOutputStream = new FileOutputStream(audioFile);
        //源文件
        mediaExtractor.setDataSource(SDCARD_PATH + "/input.mp4");
        //信道总数
        int trackCount = mediaExtractor.getTrackCount();
        int audioTrackIndex = -1;
        int videoTrackIndex = -1;
        for (int i = 0; i < trackCount; i++) {
            MediaFormat trackFormat = mediaExtractor.getTrackFormat(i);
            String mineType = trackFormat.getString(MediaFormat.KEY_MIME);
            //视频信道
            if (mineType.startsWith("video/")) {
                videoTrackIndex = i;
            }
            //音频信道
            if (mineType.startsWith("audio/")) {
                audioTrackIndex = i;
            }
        }

        ByteBuffer byteBuffer = ByteBuffer.allocate(500 * 1024);
        //切换到视频信道
        mediaExtractor.selectTrack(videoTrackIndex);
        while (true) {
            int readSampleCount = mediaExtractor.readSampleData(byteBuffer, 0);
            if (readSampleCount < 0) {
                break;
            }
            //保存视频信道信息
            byte[] buffer = new byte[readSampleCount];
            byteBuffer.get(buffer);
            videoOutputStream.write(buffer);
            byteBuffer.clear();
            mediaExtractor.advance();
        }
        //切换到音频信道
        mediaExtractor.selectTrack(audioTrackIndex);
        while (true) {
            int readSampleCount = mediaExtractor.readSampleData(byteBuffer, 0);
            if (readSampleCount < 0) {
                break;
            }
            //保存音频信息
            byte[] buffer = new byte[readSampleCount];
            byteBuffer.get(buffer);
            audioOutputStream.write(buffer);
            byteBuffer.clear();
            mediaExtractor.advance();
        }

    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        mediaExtractor.release();
        try {
            videoOutputStream.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

但是我们注意分离出的两个文件大小其实是不相等的。

inputSize:243104
audioSize:40720
videoSize:199555

MediaMuxer

上面是分离视频的,下面是合成视频。将所有的信道的信息合成一个视频 
下面的例子基本涵盖所有的使用情况

MediaMuxer和MediaExtractor使用的例子

分离视频的纯视频

输入视频是input.mp4 ,分离保存的视频output_video;


private void muxerMedia() {
    mediaExtractor = new MediaExtractor();
    int videoIndex = -1;
    try {
        mediaExtractor.setDataSource(SDCARD_PATH + "/input.mp4");
        int trackCount = mediaExtractor.getTrackCount();
        for (int i = 0; i < trackCount; i++) {
            MediaFormat trackFormat = mediaExtractor.getTrackFormat(i);
            String mimeType = trackFormat.getString(MediaFormat.KEY_MIME);
            // 取出视频的信号
            if (mimeType.startsWith("video/")) {
                videoIndex = i;
            }
        }
        //切换道视频信号的信道
        mediaExtractor.selectTrack(videoIndex);
        MediaFormat trackFormat = mediaExtractor.getTrackFormat(videoIndex);
        mediaMuxer = new MediaMuxer(SDCARD_PATH + "/output_video.mp4", MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4);
        //追踪此信道
        int trackIndex = mediaMuxer.addTrack(trackFormat);
        ByteBuffer byteBuffer = ByteBuffer.allocate(1024 * 500);
        MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();
        mediaMuxer.start();
        long videoSampleTime;
        //获取每帧的之间的时间
        {   
            mediaExtractor.readSampleData(byteBuffer, 0);
            //skip first I frame
            if (mediaExtractor.getSampleFlags() == MediaExtractor.SAMPLE_FLAG_SYNC)
                mediaExtractor.advance();
            mediaExtractor.readSampleData(byteBuffer, 0);
            long firstVideoPTS = mediaExtractor.getSampleTime();
            mediaExtractor.advance();
            mediaExtractor.readSampleData(byteBuffer, 0);
            long SecondVideoPTS = mediaExtractor.getSampleTime();
            videoSampleTime = Math.abs(SecondVideoPTS - firstVideoPTS);
            Log.d("fuck", "videoSampleTime is " + videoSampleTime);
        }
        //重新切换此信道,不然上面跳过了3帧,造成前面的帧数模糊
        mediaExtractor.unselectTrack(videoIndex);
        mediaExtractor.selectTrack(videoIndex);
        while (true) {
            //读取帧之间的数据
            int readSampleSize = mediaExtractor.readSampleData(byteBuffer, 0);
            if (readSampleSize < 0) {
                break;
            }
            mediaExtractor.advance();
            bufferInfo.size = readSampleSize;
            bufferInfo.offset = 0;
            bufferInfo.flags = mediaExtractor.getSampleFlags();
            bufferInfo.presentationTimeUs += videoSampleTime;
            //写入帧的数据
            mediaMuxer.writeSampleData(trackIndex, byteBuffer, bufferInfo);
        }
        //release
        mediaMuxer.stop();
        mediaExtractor.release();
        mediaMuxer.release();

        Log.e("TAG", "finish");
    } catch (IOException e) {
        e.printStackTrace();
    }
}

这里比上面文件的要大,因为保存了一些信道信息等,而且是可以播放。

分离视频的纯音频

输入视频是input.mp4,输出的音频为output_audio;

private void muxerAudio() {
    mediaExtractor = new MediaExtractor();
    int audioIndex = -1;
    try {
        mediaExtractor.setDataSource(SDCARD_PATH + "/input.mp4");
        int trackCount = mediaExtractor.getTrackCount();
        for (int i = 0; i < trackCount; i++) {
            MediaFormat trackFormat = mediaExtractor.getTrackFormat(i);
            if (trackFormat.getString(MediaFormat.KEY_MIME).startsWith("audio/")) {
                audioIndex = i;
            }
        }
        mediaExtractor.selectTrack(audioIndex);
        MediaFormat trackFormat = mediaExtractor.getTrackFormat(audioIndex);
        mediaMuxer = new MediaMuxer(SDCARD_PATH + "/output_audios", MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4);
        int writeAudioIndex = mediaMuxer.addTrack(trackFormat);
        mediaMuxer.start();
        ByteBuffer byteBuffer = ByteBuffer.allocate(500 * 1024);
        MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();

        long stampTime = 0;
        //获取帧之间的间隔时间
        {
            mediaExtractor.readSampleData(byteBuffer, 0);
            if (mediaExtractor.getSampleFlags() == MediaExtractor.SAMPLE_FLAG_SYNC) {
                mediaExtractor.advance();
            }
            mediaExtractor.readSampleData(byteBuffer, 0);
            long secondTime = mediaExtractor.getSampleTime();
            mediaExtractor.advance();
            mediaExtractor.readSampleData(byteBuffer, 0);
            long thirdTime = mediaExtractor.getSampleTime();
            stampTime = Math.abs(thirdTime - secondTime);
            Log.e("fuck", stampTime + "");
        }

        mediaExtractor.unselectTrack(audioIndex);
        mediaExtractor.selectTrack(audioIndex);
        while (true) {
            int readSampleSize = mediaExtractor.readSampleData(byteBuffer, 0);
            if (readSampleSize < 0) {
                break;
            }
            mediaExtractor.advance();

            bufferInfo.size = readSampleSize;
            bufferInfo.flags = mediaExtractor.getSampleFlags();
            bufferInfo.offset = 0;
            bufferInfo.presentationTimeUs += stampTime;

            mediaMuxer.writeSampleData(writeAudioIndex, byteBuffer, bufferInfo);
        }
        mediaMuxer.stop();
        mediaMuxer.release();
        mediaExtractor.release();
        Log.e("fuck", "finish");
    } catch (IOException e) {
        e.printStackTrace();
    }
}

基本原理和上面差不多,只是我们这次选中音频的信道

合成视频

将上面分离出的output_video和分离出output_audio合成原来完整的视频 
输入视频output_video,输入音频是output_audio,合成视频output

private void combineVideo() {
    try {
        MediaExtractor videoExtractor = new MediaExtractor();
        videoExtractor.setDataSource(SDCARD_PATH + "/output_video");
        MediaFormat videoFormat = null;
        int videoTrackIndex = -1;
        int videoTrackCount = videoExtractor.getTrackCount();
        for (int i = 0; i < videoTrackCount; i++) {
            videoFormat = videoExtractor.getTrackFormat(i);
            String mimeType = videoFormat.getString(MediaFormat.KEY_MIME);
            if (mimeType.startsWith("video/")) {
                videoTrackIndex = i;
                break;
            }
        }

        MediaExtractor audioExtractor = new MediaExtractor();
        audioExtractor.setDataSource(SDCARD_PATH + "/output_audio");
        MediaFormat audioFormat = null;
        int audioTrackIndex = -1;
        int audioTrackCount = audioExtractor.getTrackCount();
        for (int i = 0; i < audioTrackCount; i++) {
            audioFormat = audioExtractor.getTrackFormat(i);
            String mimeType = audioFormat.getString(MediaFormat.KEY_MIME);
            if (mimeType.startsWith("audio/")) {
                audioTrackIndex = i;
                break;
            }
        }

        videoExtractor.selectTrack(videoTrackIndex);
        audioExtractor.selectTrack(audioTrackIndex);

        MediaCodec.BufferInfo videoBufferInfo = new MediaCodec.BufferInfo();
        MediaCodec.BufferInfo audioBufferInfo = new MediaCodec.BufferInfo();

        MediaMuxer mediaMuxer = new MediaMuxer(SDCARD_PATH + "/output", MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4);
        int writeVideoTrackIndex = mediaMuxer.addTrack(videoFormat);
        int writeAudioTrackIndex = mediaMuxer.addTrack(audioFormat);
        mediaMuxer.start();

        ByteBuffer byteBuffer = ByteBuffer.allocate(500 * 1024);
        long sampleTime = 0;
        {
            videoExtractor.readSampleData(byteBuffer, 0);
            if (videoExtractor.getSampleFlags() == MediaExtractor.SAMPLE_FLAG_SYNC) {
                videoExtractor.advance();
            }
            videoExtractor.readSampleData(byteBuffer, 0);
            long secondTime = videoExtractor.getSampleTime();
            videoExtractor.advance();
            long thirdTime = videoExtractor.getSampleTime();
            sampleTime = Math.abs(thirdTime - secondTime);
        }
        videoExtractor.unselectTrack(videoTrackIndex);
        videoExtractor.selectTrack(videoTrackIndex);

        while (true) {
            int readVideoSampleSize = videoExtractor.readSampleData(byteBuffer, 0);
            if (readVideoSampleSize < 0) {
                break;
            }
            videoBufferInfo.size = readVideoSampleSize;
            videoBufferInfo.presentationTimeUs += sampleTime;
            videoBufferInfo.offset = 0;
            videoBufferInfo.flags = videoExtractor.getSampleFlags();
                mediaMuxer.writeSampleData(writeVideoTrackIndex, byteBuffer, videoBufferInfo);
            videoExtractor.advance();
        }

        while (true) {
            int readAudioSampleSize = audioExtractor.readSampleData(byteBuffer, 0);
            if (readAudioSampleSize < 0) {
                break;
            }

            audioBufferInfo.size = readAudioSampleSize;
            audioBufferInfo.presentationTimeUs += sampleTime;
            audioBufferInfo.offset = 0;
            audioBufferInfo.flags = videoExtractor.getSampleFlags();
            mediaMuxer.writeSampleData(writeAudioTrackIndex, byteBuffer, audioBufferInfo);
            audioExtractor.advance();
        }

        mediaMuxer.stop();
        mediaMuxer.release();
        videoExtractor.release();
        audioExtractor.release();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

完整例子见 MediaExtractor和MediaMuxer的Demo

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