android - 设置mediacodec的演示时间

Question

我使用波纹管代码将原始数据编码为h264以创建视频,并且编码得非常好,但视频播放速度太快.似乎演示时间存在问题.当记录开始时,我设置"tstart"的值,并为每个帧计算当前时间与tstart的差异,并将其传递给queueinputbuffer但没有任何改变.哪个部分有问题？我知道在android 4.3中我可以将表面传递给mediacodec,但我想支持android 4.1.提前致谢.

 public void onPreviewFrame(final byte[] bytes, Camera camera) {
                    if (recording == true) {
                        long time = System.nanoTime();
                        time -= tstart;
                        if(mThread.isAlive()&&recording == true) {
                            encode(bytes, time );

                        }

                    }
 }

private synchronized void encode(byte[] dataInput,long time)
{
    byte[] data=new byte[dataInput.length];
    NV21toYUV420Planar(dataInput,data,640,480);

    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);
        time/=1000;
        mMediaCodec.queueInputBuffer(inputBufferIndex, 0, data.length, time, 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];
            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);
}

Answer 1

您的问题是您没有将输出帧写入实际存储任何时间戳的容器中.您正在编写一个简单的H264文件,该文件仅包含原始编码帧,没有索引,没有时间戳,没有音频,没有别的.

为了获得文件的正确时间戳,您需要使用MediaMuxer(出现在4.3中)或类似的第三方库(例如libavformat或类似的)将编码的数据包写入文件.输出数据包的时间戳在bufferInfo.presentationTime,并且在该if (outputBufferIndex >= 0) {子句中,您根本不使用它 - 您基本上丢弃了时间戳.