mediamuxer+MediaExtratoc+MediaCodec剪视频代码

以下是使用MediaExtractor、MediaMuxer和MediaCodec剪切视频的示例代码，其中包括了剪切视频的主要逻辑：

public void cutVideo(String srcVideoPath, String dstVideoPath, long startMs, long endMs) throws IOException {
    MediaExtractor extractor = new MediaExtractor();
    extractor.setDataSource(srcVideoPath);

    int trackCount = extractor.getTrackCount();
    int videoTrackIndex = -1;
    int audioTrackIndex = -1;

    // 获取视频轨道和音频轨道的索引
    for (int i = 0; i < trackCount; i++) {
        MediaFormat format = extractor.getTrackFormat(i);
        String mime = format.getString(MediaFormat.KEY_MIME);
        if (mime.startsWith("video/")) {
            videoTrackIndex = i;
        } else if (mime.startsWith("audio/")) {
            audioTrackIndex = i;
        }
    }

    // 获取视频轨道和音频轨道的格式
    MediaFormat videoFormat = extractor.getTrackFormat(videoTrackIndex);
    MediaFormat audioFormat = extractor.getTrackFormat(audioTrackIndex);

    // 创建包含需要剪切的时间段的新视频文件
    MediaMuxer muxer = new MediaMuxer(dstVideoPath, MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4);
    int dstVideoTrackIndex = muxer.addTrack(videoFormat);
    int dstAudioTrackIndex = muxer.addTrack(audioFormat);
    muxer.start();

    // 使用MediaCodec对源视频文件中的视频轨道进行编解码操作，并将解码后的数据写入新文件中
    MediaCodec videoDecoder = MediaCodec.createDecoderByType(videoFormat.getString(MediaFormat.KEY_MIME));
    videoDecoder.configure(videoFormat, null, null, 0);
    videoDecoder.start();

    MediaCodec.BufferInfo videoBufferInfo = new MediaCodec.BufferInfo();
    ByteBuffer[] videoInputBuffers = videoDecoder.getInputBuffers();
    ByteBuffer[] videoOutputBuffers = videoDecoder.getOutputBuffers();

    boolean videoInputDone = false;
    boolean videoOutputDone = false;

    while (!videoOutputDone) {
        if (!videoInputDone) {
            int inputBufferIndex = videoDecoder.dequeueInputBuffer(1000);
            if (inputBufferIndex >= 0) {
                ByteBuffer inputBuffer = videoInputBuffers[inputBufferIndex];
                int sampleSize = extractor.readSampleData(inputBuffer, 0);
                if (sampleSize < 0) {
                    videoDecoder.queueInputBuffer(inputBufferIndex, 0, 0, 0L, MediaCodec.BUFFER_FLAG_END_OF_STREAM);
                    videoInputDone = true;
                } else {
                    long presentationTimeUs = extractor.getSampleTime();
                    videoDecoder.queueInputBuffer(inputBufferIndex, 0, sampleSize, presentationTimeUs, 0);
                    extractor.advance();
                }
            }
        }

        int outputBufferIndex = videoDecoder.dequeueOutputBuffer(videoBufferInfo, 1000);
        if (outputBufferIndex >= 0) {
            ByteBuffer outputBuffer = videoOutputBuffers[outputBufferIndex];
            muxer.writeSampleData(dstVideoTrackIndex, outputBuffer, videoBufferInfo);
            videoDecoder.releaseOutputBuffer(outputBufferIndex, false);
        }

        if ((videoBufferInfo.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {
            videoOutputDone = true;
        }
    }
    videoDecoder.stop();
    videoDecoder.release();

    // 根据需要剪切的时间段，使用MediaExtractor定位到指定时间戳的数据位置，并使用MediaCodec对该时间段的视频数据进行编解码操作，并将解码后的数据写入新文件中
    extractor.seekTo(startMs, MediaExtractor.SEEK_TO_CLOSEST_SYNC);

    MediaCodec audioDecoder = MediaCodec.createDecoderByType(audioFormat.getString(MediaFormat.KEY_MIME));
    audioDecoder.configure(audioFormat, null, null, 0);
    audioDecoder.start();

    MediaCodec.BufferInfo audioBufferInfo = new MediaCodec.BufferInfo();
    ByteBuffer[] audioInputBuffers = audioDecoder.getInputBuffers();
    ByteBuffer[] audioOutputBuffers = audioDecoder.getOutputBuffers();

    boolean audioInputDone = false;
    boolean audioOutputDone = false;

    while (!audioOutputDone) {
        if (!audioInputDone) {
            int inputBufferIndex = audioDecoder.dequeueInputBuffer(1000);
            if (inputBufferIndex >= 0) {
                ByteBuffer inputBuffer = audioInputBuffers[inputBufferIndex];
                int sampleSize = extractor.readSampleData(inputBuffer, 0);
                if (sampleSize < 0) {
                    audioDecoder.queueInputBuffer(inputBufferIndex, 0, 0, 0L, MediaCodec.BUFFER_FLAG_END_OF_STREAM);
                    audioInputDone = true;
                } else {
                    long presentationTimeUs = extractor.getSampleTime();
                    if (presentationTimeUs < startMs) {
                        extractor.advance();
                    } else if (presentationTimeUs > endMs) {
                        audioInputDone = true;
                    } else {
                        audioDecoder.queueInputBuffer(inputBufferIndex, 0, sampleSize, presentationTimeUs, 0);
                        extractor.advance();
                    }
                }
            }
        }

        int outputBufferIndex = audioDecoder.dequeueOutputBuffer(audioBufferInfo, 1000);
        if (outputBufferIndex >= 0) {
            ByteBuffer outputBuffer = audioOutputBuffers[outputBufferIndex];
            muxer.writeSampleData(dstAudioTrackIndex, outputBuffer, audioBufferInfo);
            audioDecoder.releaseOutputBuffer(outputBufferIndex, false);
        }

        if ((audioBufferInfo.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {
            audioOutputDone = true;
        }
    }

    audioDecoder.stop();
    audioDecoder.release();

    muxer.stop();
    muxer.release();
    extractor.release();
}

请注意，这只是一个简单的示例代码，实际应用中还需要考虑更多细节问题，如异常处理、内存管理等等。