VP8编码Nexus 5返回空/ 0帧

Question

我试图将我的摄像头源编码到VP8。问题是：当我从输出缓冲器的帧，字节数组始终是不同的大小，但所有条目都为0

这里就是我抢框架和打印的代码：

while (true) { 
    try { 
     encoderIndex = mEncoder.dequeueOutputBuffer(encoderOutputInfo, timeOut); 
    } catch (Exception e) { 
     e.printStackTrace(); 
    } 
    switch (encoderIndex) { 
    case MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED: 
     // something 
     break; 
    case MediaCodec.INFO_OUTPUT_FORMAT_CHANGED: 
     // something else 
     break; 
    case MediaCodec.INFO_TRY_AGAIN_LATER: 
     // something completely different 
     break; 
    default: 
     // get encoded frame 
     byte[] frame = new byte[encoderOutputInfo.size]; 

     mEncoderOutputBuffers[encoderIndex].get(frame); 

     Log.v(tag, "got frame. size: " + frame.length); 
     Log.v(tag, "printing frame"); 
     Log.v(tag, printBytesAsBinary(frame)); 

     mEncoderOutputBuffers[encoderIndex].clear(); 

     // release encoder output buffer 
     mEncoder.releaseOutputBuffer(encoderIndex, false); 
} 

和Logcat打印：

02-07 11:48:19.014: V/GoogleEncoder(24883): got frame. size: 427 
02-07 11:48:19.014: V/GoogleEncoder(24883): printing frame 
02-07 11:48:19.014: V/GoogleEncoder(24883): 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 
02-07 11:48:20.544: V/GoogleEncoder(24883): got frame. size: 379 
02-07 11:48:20.544: V/GoogleEncoder(24883): printing frame 
02-07 11:48:20.544: V/GoogleEncoder(24883): 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 

任何人都已经有这个问题，并可以告诉我，我可能会做错什么？我已经尝试搞乱输出缓冲区（例如rewind（）），但似乎没有任何工作。

奇怪的是，编码工作在与的CyanogenMod 11的装置，这也是4.4（尝试上的S3）

Answer 1

MediaCodec不把ByteBuffer在正确的位置。您需要在通话后手动定位它dequeueOutputBuffer()：

int encoderStatus = encoder.dequeueOutputBuffer(info, TIMEOUT_USEC); 
... 
ByteBuffer encodedData = encoderOutputBuffers[encoderStatus]; 
encodedData.position(info.offset); 
encodedData.limit(info.offset + info.size); 

（见EncodeDecodeTest。）这是不一样的rewind()，虽然我有点惊讶，没有工作 - 我本来预期输出通常从缓冲区的开始处开始。

Android 4.3上的VP8存在一些已知问题，但您似乎没有碰到这些问题。

如果这不能解决您的问题，那么了解您正在使用的设备（Android和Cyanogen的S3），Android软件版本，以查看您使用的代码为configure()MediaCodec，以及使用了什么值。