topic Re: NAL Units in Intel® Integrated Performance Primitives

NAL Units

bale — Tue, 29 Jan 2008 12:38:08 GMT

Hi All,

I searched the forum but could not find an answer to this question.

Can the H.264 encoder output NAL units (for an RTP stream) instead of whole frames?? If so, how??

If it is not possible, then is there some other functionality in the UMC to allow this??

Thanks,

Bale

Re: NAL Units

bale — Wed, 06 Feb 2008 15:21:06 GMT

From searching through the code for the H264 splitter, I see a protected function called:
GetNALUData(MediaData & p_data);

Has anyone used this function before? If it were a public function could I simply use the splitter on an encoded frame, cycle through the encoded frame and get outputted the NAL units without any undesired side-effects??

If this is possible, then how can I create an H.264 splitter that constructs using a MediaData object as opposed to a file on disk??

Help would be much appreciated!!!

Bale

Re: NAL Units

shyaki — Wed, 13 Feb 2008 18:08:53 GMT

check the usage of H264Splitter in umc_h264_dec_con

Re: NAL Units

bale — Thu, 14 Feb 2008 10:50:08 GMT

Hi,

Thanks for the reply. I looked at the code that you suggested. I think the following summarises what the H264Splitter does in the decoder:

1) Gets initialised with the filename of the H.264 file
2) In a loop, calls GetNextVideoData on the media data object. This (as far as I can tell) just takes as much data as it can get.

Unfortunately this does not give any indication as to what I want to do as it (1) gets initialised with a file as opposed to a stream, and (2) you cannot specifically ask it to only get a NAL unit, it just takes whatever is in the input MediaData object.

Basically, I need to be able to generate H.264 NAL units from raw video input. I firstly thought that the encoder would be able to output NAL units, but this does not seem to be the case. So I thought that perhaps a splitter could take an encoded stream and extract one NAL unit at a time (which would be less efficient, but would at least work).

Any other ideas??