How to use Android MediaCodec encode Camera data(YUV420sp)

问题

Thank you for your focus! I want to use Android MediaCodec APIs to encode the video frame which aquired from Camera, unfortunately, I have not success to do that! I still not familiar with the MediaCodec API。 The follow is my codes,I need your help to figure out what I should do.

1、The Camera setting:

Parameters parameters = mCamera.getParameters();
parameters.setPreviewFormat(ImageFormat.NV21);
parameters.setPreviewSize(320, 240);
mCamera.setParameters(parameters);

2、Set the encoder:

private void initCodec() {
    try {
        fos = new FileOutputStream(mVideoFile, false);
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    }
    mMediaCodec = MediaCodec.createEncoderByType("video/avc");
    MediaFormat mediaFormat = MediaFormat.createVideoFormat("video/avc",
            320,
            240);
    mediaFormat.setInteger(MediaFormat.KEY_BIT_RATE, 125000);
    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 void encode(byte[] data) {
    int inputBufferIndex = mMediaCodec.dequeueInputBuffer(0);
    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(TAG, "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);
}

I guess the problem occurred in the encoder method,the method will be used in the Camera Preview Callback ,like

initCodec();

//mCamera.setPreviewCallback(new MyPreviewCallback());
mCamera.setPreviewCallback(new PreviewCallback() {
    @Override
    public void onPreviewFrame(byte[] data, Camera camera) {
        encode(data);
    }
});

I just have no idea how to do it correctly with the MediaCodec API.Can you give me some advice or links about it?

Thank you!

回答1:

I have solved the problem.As follows：

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

    int inputBufferIndex = mMediaCodec.dequeueInputBuffer(-1);
    Log.i(TAG, "inputBufferIndex-->" + inputBufferIndex);
    //......

And next,you will find your encoded video color is not right, for more information,please go to here MediaCodec and Camera: colorspaces don't match

回答2:

The YUV420 formats output by the camera are incompatible with the formats accepted by the MediaCodec AVC encoder. In the best case, it's essentially NV12 vs. NV21 (U and V planes are reversed), requiring a manual reordering. In the worst case, as of Android 4.2, the encoder input format may be device-specific.

You're better off using MediaRecorder to connect the camera hardware to the encoder.

Update: It's now possible to pass the camera's Surface preview to MediaCodec, instead of using the YUV data in the ByteBuffer. This is faster and more portable. See the CameraToMpegTest sample here.

来源：https://stackoverflow.com/questions/17232477/how-to-use-android-mediacodec-encode-camera-datayuv420sp