Question

使用这个url我在下面编写的代码将onpreviewframe数据编码为mp4视频，我用一个线程很好地完成了这项工作，但似乎它无法正常工作。

private void initCodec() {
    String root =  Environment.getExternalStorageDirectory().toString();
    File myDir = new File(root + "/Vocalist");
    if(!myDir.exists()) {
        myDir.mkdirs();
    }
    try {
        File file = new File (myDir, "myVideo.mp4");
        if(file.exists()){
            file.delete();
        }
        fos = new FileOutputStream(file, false);
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    }try {
        mMediaCodec = MediaCodec.createEncoderByType("video/avc");
    }
    catch (Exception e){

    }
    MediaFormat mediaFormat = MediaFormat.createVideoFormat("video/avc",
            320,
            240);
    mediaFormat.setInteger(MediaFormat.KEY_BIT_RATE, 500000);
    mediaFormat.setInteger(MediaFormat.KEY_FRAME_RATE, 15);
    mediaFormat.setInteger(MediaFormat.KEY_COLOR_FORMAT,
            MediaCodecInfo.CodecCapabilities.COLOR_FormatYUV420Planar);
    mediaFormat.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, 5);
    mMediaCodec.configure(mediaFormat,
            null,
            null,
            MediaCodec.CONFIGURE_FLAG_ENCODE);
    mMediaCodec.start();
    inputBuffers = mMediaCodec.getInputBuffers();
    outputBuffers = mMediaCodec.getOutputBuffers();

}

 private synchronized void encode(byte[] dataInput)
{
    byte[] data = dataInput;
    inputBuffers = mMediaCodec.getInputBuffers();// here changes
    outputBuffers = mMediaCodec.getOutputBuffers();

    int inputBufferIndex = mMediaCodec.dequeueInputBuffer(-1);

    if (inputBufferIndex >= 0) {
        ByteBuffer inputBuffer = inputBuffers[inputBufferIndex];
        inputBuffer.clear();
        inputBuffer.put(data);
        mMediaCodec.queueInputBuffer(inputBufferIndex, 0, data.length, 0, 0);
    } else {
        return;
    }

    MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();
    int outputBufferIndex = mMediaCodec.dequeueOutputBuffer(bufferInfo, 0);
    Log.i("tag", "outputBufferIndex-->" + outputBufferIndex);
    do {
        if (outputBufferIndex >= 0) {
            ByteBuffer outBuffer = outputBuffers[outputBufferIndex];
            System.out.println("buffer info-->" + bufferInfo.offset + "--"
                    + bufferInfo.size + "--" + bufferInfo.flags + "--"
                    + bufferInfo.presentationTimeUs);
            byte[] outData = new byte[bufferInfo.size];
            outBuffer.get(outData);
            try {
                if (bufferInfo.offset != 0) {
                    fos.write(outData, bufferInfo.offset, outData.length
                            - bufferInfo.offset);
                } else {
                    fos.write(outData, 0, outData.length);
                }
                fos.flush();
                Log.i("camera", "out data -- > " + outData.length);
                mMediaCodec.releaseOutputBuffer(outputBufferIndex, false);
                outputBufferIndex = mMediaCodec.dequeueOutputBuffer(bufferInfo,
                        0);
            } catch (IOException e) {
                e.printStackTrace();
            }
        } else if (outputBufferIndex == MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED) {
            outputBuffers = mMediaCodec.getOutputBuffers();
        } else if (outputBufferIndex == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {
            MediaFormat format = mMediaCodec.getOutputFormat();
        }
    } while (outputBufferIndex >= 0);
}

public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {

        if (mHolder.getSurface() == null) {
            return;
        }

        try {

            initCodec();
            mCamera.setPreviewDisplay(mHolder);
            mCamera.setPreviewCallback(new Camera.PreviewCallback() {
                @Override
                public void onPreviewFrame(final byte[] bytes, Camera camera) {
                    if (recording == true) {
                        if(mThread.isAlive())
                            encode(bytes);

                    }
                }
            });






        } catch (Exception e) {
            Log.d("TAG", "Error starting camera preview: " + e.getMessage());
        }
    }
}
  public void newOpenCamera() {
    if (mThread == null) {
        mThread = new CameraHandlerThread();
    }

    synchronized (mThread) {
        mThread.openCamera();
    }
}

private static void oldOpenCamera() {
    try {
        c = Camera.open(1);
        Camera.Parameters parameters = c.getParameters();
        parameters.set("orientation", "portrait");
        parameters.setJpegQuality(100);
        parameters.setPreviewFormat(ImageFormat.NV21);
        parameters.setPreviewSize(320, 240);
        c.setParameters(parameters);
    }
    catch (RuntimeException e) {
        Log.e("camera", "failed to open front camera");
    }
}

public CameraHandlerThread mThread = null;
public static class CameraHandlerThread extends HandlerThread {
    Handler mHandler = null;


    CameraHandlerThread() {
        super("CameraHandlerThread");
        start();
        mHandler = new Handler(getLooper());
    }

    synchronized void notifyCameraOpened() {
        notify();

    }

    public void openCamera() {
        mHandler.post(new Runnable() {
            @Override
            public void run() {
                oldOpenCamera();
                notifyCameraOpened();
            }
        });
    }
}

我将预览帧数据转换为视频但在第一个第二个视频播放后播放不顺畅。我该怎么办？

Answer 1

首先，您没有使用框架转发计时信息：

mMediaCodec.queueInputBuffer(inputBufferIndex, 0, data.length, 0, 0)

因此，当您将缓冲区出列时，BufferInfo.presentationTimeUs将始终为零。

其次，您似乎没有使用MediaMuxer，这意味着您只是将原始H.264流写入文件。这不是“.mp4”;它根本不包括时间信息。许多视频播放器甚至不知道如何处理普通的H.264。

使用相机的帧定时将文件包装为.mp4，可以产生更好的效果。

您的代码结构似乎假设它可以提供一帧输入并获得一帧输出，但情况并非总是如此。您希望保持输入完整，并在输出可用时将其耗尽。

您可以在bigflake和Grafika上找到更多信息和示例代码。

mediacodec不能顺利运作

1 个答案: