Question

我想使用android mediamuxer混合视频（1分钟）和音频（10秒）。我希望音频重复播放直到视频结束。当我使用下面的代码时，音频仅播放10秒钟。有人知道如何解决这个问题吗？

 mediaMuxer.start();
        while ((sampleSize = videoExtra.readSampleData(videoBuffer, 0 )) != -1) {
            videoBufferInfo.offset = 0;
            videoBufferInfo.size = sampleSize;
            videoBufferInfo.presentationTimeUs = videoExtra.getSampleTime();
            videoBufferInfo.flags = videoExtra.getSampleFlags();
            mediaMuxer.writeSampleData(videoIndex, videoBuffer, videoBufferInfo);

            videoExtra.advance();
        }



        while ((audioSize = musicExtra.readSampleData(audioBuffer, 0)) != -1) {
            audioBufferInfo.offset = 0;
            audioBufferInfo.size = audioSize;
            audioBufferInfo.presentationTimeUs = musicExtra.getSampleTime();
            audioBufferInfo.flags = musicExtra.getSampleFlags();
            mediaMuxer.writeSampleData(audioIndex, audioBuffer, audioBufferInfo);
            musicExtra.advance();
        }
        musicExtra.seekTo(0, MediaExtractor.SEEK_TO_CLOSEST_SYNC);

        videoExtra.release();
        musicExtra.release();
        mediaMuxer.stop();
        mediaMuxer.release();

Answer 1

三个输入参数：

String videoPath，String audioPath，String outputPath

获取视频时长及其音轨索引：

    videoExtractor = new MediaExtractor();
    videoExtractor.setDataSource(videoPath);
    MediaFormat videoFormat = null;

    int videoTrackCount = videoExtractor.getTrackCount();
    //vedio max input size
    int frameMaxInputSize = 0;
    int frameRate = 0;
    long videoDuration = 0;

    for (int i = 0; i < videoTrackCount; i++) {
        videoFormat = videoExtractor.getTrackFormat(i);
        String mimeType = videoFormat.getString(MediaFormat.KEY_MIME);
        if (mimeType.startsWith("video/")) {
            /*
             * just use the first track
             */
            videoTrackIndex = i;
            frameMaxInputSize = videoFormat.getInteger(MediaFormat.KEY_MAX_INPUT_SIZE);
            frameRate = videoFormat.getInteger(MediaFormat.KEY_FRAME_RATE);
            videoDuration = videoFormat.getLong(MediaFormat.KEY_DURATION);
            break;
        }
    }

    if (videoTrackIndex  < 0 ) {
        Log.e(TAG, "Error input file:: No Vedio track");
        return;
    }

获取音频信息

    audioExtractor = new MediaExtractor();
    audioExtractor.setDataSource(audioPath);
    MediaFormat audioFormat = null;

    int audioTrackCount = audioExtractor.getTrackCount();
    audioExtractor = new MediaExtractor();
    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;
        }
    }

    if (audioTrackIndex  < 0 ) {
        Log.e(TAG, "Error input file:: No Audio track");
        return;
    }

写入视频数据：

    MediaCodec.BufferInfo videoBufferInfo = new MediaCodec.BufferInfo();
    mediaMuxer = new MediaMuxer(outputPath, MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4);
    int writeVideoTrackIndex = mediaMuxer.addTrack(videoFormat);
    int writeAudioTrackIndex = mediaMuxer.addTrack(audioFormat);
    mediaMuxer.start();

    ByteBuffer byteBuffer = ByteBuffer.allocate(frameMaxInputSize);
    videoExtractor.unselectTrack(videoTrackIndex);
    videoExtractor.selectTrack(videoTrackIndex);

    while (true) {
        int readVideoSampleSize = videoExtractor.readSampleData(byteBuffer, 0);
        if (readVideoSampleSize < 0) {
            videoExtractor.unselectTrack(videoTrackIndex);
            break;
        }
        long videoSampleTime = videoExtractor.getSampleTime();
        videoBufferInfo.size = readVideoSampleSize;
        videoBufferInfo.presentationTimeUs = videoSampleTime;
        //videoBufferInfo.presentationTimeUs += 1000 * 1000 / frameRate;
        videoBufferInfo.offset = 0;
        videoBufferInfo.flags = videoExtractor.getSampleFlags();
        mediaMuxer.writeSampleData(writeVideoTrackIndex, byteBuffer, videoBufferInfo);
        videoExtractor.advance();
    }

写入音频数据

    long audioPresentationTimeUs = 0;
    MediaCodec.BufferInfo audioBufferInfo = new MediaCodec.BufferInfo();
    audioExtractor.selectTrack(audioTrackIndex);
    /*
     * the last audio presentation time.
     */
    long lastEndAudioTimeUs = 0;
    while (true) {
        int readAudioSampleSize = audioExtractor.readSampleData(byteBuffer, 0);
        if (readAudioSampleSize < 0) {
            //if end of the stream, unselect
            audioExtractor.unselectTrack(audioTrackIndex);
            if (audioPresentationTimeUs >= videoDuration) {
                //if has reach the end of the video time ,just exit
                break;
            } else {
                //if not the end of the video time, just repeat.
                lastEndAudioTimeUs += audioPresentationTimeUs;
                audioExtractor.selectTrack(audioTrackIndex);
                continue;
            }
        }

        long audioSampleTime = audioExtractor.getSampleTime();
        audioBufferInfo.size = readAudioSampleSize;
        audioBufferInfo.presentationTimeUs = audioSampleTime + lastEndAudioTimeUs;
        if (audioBufferInfo.presentationTimeUs > videoDuration) {
            audioExtractor.unselectTrack(audioTrackIndex);
            break;
        }
        audioPresentationTimeUs = audioBufferInfo.presentationTimeUs;
        audioBufferInfo.offset = 0;
        audioBufferInfo.flags = audioExtractor.getSampleFlags();
        mediaMuxer.writeSampleData(writeAudioTrackIndex, byteBuffer, audioBufferInfo);
        audioExtractor.advance();
    }

释放资源。

   if (mediaMuxer != null) {
        try {
            mediaMuxer.stop();
            mediaMuxer.release();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    if (videoExtractor != null) {
        try {
            videoExtractor.release();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    if (audioExtractor != null) {
        try {
            audioExtractor.release();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

希望这会有所帮助！

如何使用Android MediaMuxer混合不同长度的音频和视频

1 个答案: