Android音視頻開(kāi)發(fā)-入門(mén)(四):使用 MediaExtractor 和 MediaMuxer API 解析和封裝 mp4 文件

好時(shí)光

春分已過(guò),下個(gè)時(shí)節(jié)就是清明了,送上古人小詩(shī)一首:

詠柳

【作者】賀知章 【朝代】唐

碧玉妝成一樹(shù)高,萬(wàn)條垂下綠絲絳。

不知細(xì)葉誰(shuí)裁出,二月春風(fēng)似剪刀。

MediaExtractor 抽取視頻不含音頻

 /**
     * 抽?。╨y.mp4)的視頻文件不含音頻
     */
    @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR2)
    @RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)
    private void extracMedia() {
        MediaExtractor mMediaExtractor = new MediaExtractor();
        try {
            mMediaExtractor.setDataSource(MEDIA_VIDEO_PATH);
            //獲取通道的個(gè)數(shù)
            int trackCount = mMediaExtractor.getTrackCount();
            int videoIndex = -1;
            for (int i = 0; i < trackCount; i++) {
                //這個(gè)trackFormat可不得了可以獲取視頻的寬高,視頻的通道(音頻視頻),獲取視頻的長(zhǎng)。有的人用這個(gè)獲取幀率我試過(guò),有的手機(jī)行有的
                //不行,會(huì)報(bào)錯(cuò)。這是個(gè)坑,所以還是另求方式
                MediaFormat trackFormat = mMediaExtractor.getTrackFormat(i);
                String typeMimb = trackFormat.getString(MediaFormat.KEY_MIME);
                if (typeMimb.startsWith("video/")) {
                    //這就獲取了音頻的信號(hào)通道了
                    videoIndex = i;
                    break;
                }
            }
            //設(shè)置音頻通道信號(hào)
            mMediaExtractor.selectTrack(videoIndex);
            //再次拿到這個(gè)視頻通道的format
            MediaFormat trackFormat = mMediaExtractor.getTrackFormat(videoIndex);
            //初始化視頻合成器
            MediaMuxer mediaMuxer = new MediaMuxer(BASE_PATH + "/out_ly.mp4", MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4);
            //添加給合成器的通道
            mediaMuxer.addTrack(trackFormat);
            ByteBuffer allocate = ByteBuffer.allocate(500 * 1024);

            mediaMuxer.start();
            //獲取視頻的幀率
            long videoSametime = 0;
            mMediaExtractor.readSampleData(allocate, 0);
            //跳過(guò)I幀,要P幀(視頻是由個(gè)別I幀和很多P幀組成)
            if (mMediaExtractor.getSampleFlags() == MediaExtractor.SAMPLE_FLAG_SYNC) {
                mMediaExtractor.advance();
            }
            mMediaExtractor.readSampleData(allocate, 0);
            long firstTime = mMediaExtractor.getSampleTime();
            //下一幀
            mMediaExtractor.advance();

            mMediaExtractor.readSampleData(allocate, 0);
            long senondTime = mMediaExtractor.getSampleTime();
            videoSametime = Math.abs(senondTime - firstTime);
            //重新設(shè)置通道讀取文件
            mMediaExtractor.unselectTrack(videoIndex);
            mMediaExtractor.selectTrack(videoIndex);
            MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();
            while (true) {
                int readSamSize = mMediaExtractor.readSampleData(allocate, 0);
                if (readSamSize < 0) {
                    break;
                }
                mMediaExtractor.advance();
                bufferInfo.flags = mMediaExtractor.getSampleFlags();
                bufferInfo.size = readSamSize;
                bufferInfo.offset = 0;
                bufferInfo.presentationTimeUs += videoSametime;
                mediaMuxer.writeSampleData(videoIndex, allocate, bufferInfo);
            }
            mediaMuxer.stop();
            mediaMuxer.release();
            mMediaExtractor.release();
            Log.e("av", "success!");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

MediaExtractor 抽取音頻不含視頻

@TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR2)
    @RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)
    private void extracAudio() {
        MediaExtractor mediaExtractor = new MediaExtractor();
        try {
            mediaExtractor.setDataSource(AUDIO_VIDEO_PATH);
            int trackCount = mediaExtractor.getTrackCount();
            int audioIndex = -1;
            for (int i = 0; i < trackCount; i++) {
                MediaFormat trackFormat = mediaExtractor.getTrackFormat(i);
                String type = trackFormat.getString(MediaFormat.KEY_MIME);
                if (type.startsWith("audio/")) {
                    audioIndex = i;
                }
            }
            mediaExtractor.selectTrack(audioIndex);
            MediaFormat trackFormat = mediaExtractor.getTrackFormat(audioIndex);
            MediaMuxer mediaMuxer = new MediaMuxer(BASE_PATH + "/out_eat", MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4);
            int writeAudio = mediaMuxer.addTrack(trackFormat);
            mediaMuxer.start();
            ByteBuffer buffer = ByteBuffer.allocate(1024 * 500);
            MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();
            long sampleTime = 0;
            mediaExtractor.readSampleData(buffer, 0);
            if (mediaExtractor.getSampleFlags() == MediaExtractor.SAMPLE_FLAG_SYNC) {
                mediaExtractor.advance();
            }
            mediaExtractor.readSampleData(buffer, 0);
            long firstTime = mediaExtractor.getSampleTime();
            mediaExtractor.advance();
//            mediaExtractor.readSampleData(buffer, 0);
            long secondeTime = mediaExtractor.getSampleTime();
            sampleTime = Math.abs(secondeTime - firstTime);

            mediaExtractor.unselectTrack(audioIndex);
            mediaExtractor.selectTrack(audioIndex);
            while (true) {
                int readSize = mediaExtractor.readSampleData(buffer, 0);
                if (readSize < 0) {
                    break;
                }
//                mediaExtractor.readSampleData(buffer, 0);
                mediaExtractor.advance();
                bufferInfo.size = readSize;
                bufferInfo.flags = mediaExtractor.getSampleFlags();
                bufferInfo.offset = 0;
                bufferInfo.presentationTimeUs = +sampleTime;
                mediaMuxer.writeSampleData(writeAudio, buffer, bufferInfo);
            }
            mediaMuxer.stop();
            mediaMuxer.release();
            mediaExtractor.release();
            Log.e("av", "success");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

MediaExtractor 抽取視頻音頻文件,然后利用MediaMuxer合成

 @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR2)
    @RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)
    private void combineVideo() {
        //用生成的out_ly.map4 和音頻out_eat 合成一個(gè)新的eat_ly.mp4
        try {
            MediaExtractor videoExtractor = new MediaExtractor();
            videoExtractor.setDataSource(BASE_PATH + "/out_ly.mp4");
            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(BASE_PATH + "/out_eat");
            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(BASE_PATH + "/eat_ly.mp4", 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);



            long stampTimeAudio = 0;
            ByteBuffer byteBufferAudio = ByteBuffer.allocate(500 * 1024);
            //獲取幀之間的間隔時(shí)間
            {
                audioExtractor.readSampleData(byteBufferAudio, 0);
                if (audioExtractor.getSampleFlags() == MediaExtractor.SAMPLE_FLAG_SYNC) {
                    audioExtractor.advance();
                }
                audioExtractor.readSampleData(byteBufferAudio, 0);
                long secondTime = audioExtractor.getSampleTime();
                audioExtractor.advance();
                long thirdTime = audioExtractor.getSampleTime();
                stampTimeAudio = Math.abs(thirdTime - secondTime);
                Log.e("fuck", stampTimeAudio + "");
            }

            audioExtractor.unselectTrack(audioTrackIndex);
            audioExtractor.selectTrack(audioTrackIndex);



            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(byteBufferAudio, 0);
                if (readAudioSampleSize < 0) {
                    break;
                }

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

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

以上代碼全部測(cè)試通過(guò),歡迎交流?。?!

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