OpenH264 DecodeFrameNoDelay output format

Question

I've used the OpenH264 turorial (https://github.com/cisco/openh264/wiki/UsageExampleForDecoder) to successfully decode an H264 frame, but I can't figure out from the tutorial what the output format is.

I'm using the "unsigned char *pDataResult[3];" (pData in the tutorial), and this gets populated, but I need to know the length in order to convert it to byte buffers to return it to java. I also need to know what is the ownership of this data (it seems to be owned by the decoder). This info isn't mentioned in the tutorial or docs as far as I can find.

unsigned char *pDataResult[3];
int iRet = pSvcDecoder->DecodeFrameNoDelay(pBuf, iSize, pDataResult, &sDstBufInfo);

The tutorial also lists an initializer, but gives "..." as the assignment.

//output: [0~2] for Y,U,V buffer for Decoding only
unsigned char *pData[3] =...;

Is the YUV data null terminated?

There is the SBufferInfo last parameter with TagSysMemBuffer:

typedef struct TagSysMemBuffer {
  int iWidth;                    ///< width of decoded pic for display
  int iHeight;                   ///< height of decoded pic for display
  int iFormat;                   ///< type is "EVideoFormatType"
  int iStride[2];                ///< stride of 2 component
} SSysMEMBuffer;

And the length is probably in there, but not clear exactly. Maybe it is "iWidth*iHeight" for each buffer?

Answer 1

pData is freed in decoder destructor with WelsFreeDynamicMemory in decoder.cpp, just as you supposed. Decoder itself assign nullptr's to channels, but it's fine to initialize pData with them as a good habit. You have iSize parameter as input, that is the byte buffers length you want.