How to fill 'extradata' field of AVCodecContext with SPS and PPS data?

Question

Here is the problem: When decoding H264 stream with ffmpeg, I can obtain raw data of SPS and PPS but I have no idea how to fill them into the extradata

Answer 1

The data you mentioned is a byte stream holding NAL units for SPS and PPS. extradata in turn expects a pointer to AVC decoder configuration record, which is the data you have with extra formatting.

See MPEG-4 Part 15 "Advanced Video Coding (AVC) file format" section 5.2.4.1 for details.

5.2.4.1.1 Syntax 

aligned(8) class AVCDecoderConfigurationRecord { 
   unsigned int(8) configurationVersion = 1; 
   unsigned int(8) AVCProfileIndication; 
   unsigned int(8) profile_compatibility; 
   unsigned int(8) AVCLevelIndication;  
   bit(6) reserved = ‘111111’b;
   unsigned int(2) lengthSizeMinusOne;  
   bit(3) reserved = ‘111’b;
   unsigned int(5) numOfSequenceParameterSets; 
   for (i=0; i< numOfSequenceParameterSets;  i++) { 
      unsigned int(16) sequenceParameterSetLength ; 
  bit(8*sequenceParameterSetLength) sequenceParameterSetNALUnit; 
 } 
   unsigned int(8) numOfPictureParameterSets; 
   for (i=0; i< numOfPictureParameterSets;  i++) { 
  unsigned int(16) pictureParameterSetLength; 
  bit(8*pictureParameterSetLength) pictureParameterSetNALUnit; 
 } 
}