topic Re: Decoding H.264 stream from memory, not file in Intel® Integrated Performance Primitives

Decoding H.264 stream from memory, not file

Chris1 — Fri, 30 Jan 2009 16:23:34 GMT

I need to decode an H.264 stream which is in a buffer in memory, i.e. I just want to supply a pointer and a buffer size. I had this working using the decoder supplied in the ipp-samples for IPP 5.3 but I had to override the H264AnnexBSplitter::Init method to get it to point to the appropriate place in memory since the examples only provide the facility for reading from a file.

Now, I've upgraded to 6.0-1 and it seems a lot harder to do. There is the class FileReader but that's not particularly easy to modify or override as it relies on other things like vm_mmap_create.

Is there a recommended simple way to do this or will I have to derive a class from DataReader (seems like quite a lot of work for such a simple, common task)?

Thanks...

Re: Decoding H.264 stream from memory, not file

Chao_Y_Intel — Mon, 02 Feb 2009 02:20:10 GMT

Writing a derive class from DataReader is one of the way. I also attached another sample code. This sample code read raw H.264 data to memory and
then decode the H.264 data.

Thanks,
Chao

Re: Decoding H.264 stream from memory, not file

Chris1 — Mon, 02 Feb 2009 12:46:55 GMT

Thanks for that. I've been playing with that code and I'm having problems getting it to work. You seem to not be using a splitter so does this work for streams that include audio?

I ask this because when I first implemented my decode, I did it in this way and I had the problem that after calling H264VideoDecoder::Init(...), when I call GetInfo, it returns "not initialised". I fixed this by using a splitter first.

Now the splitter has changed in IPP 6.0. I think I might have to derive from DataReader to get it to work but it's a shame there is no BufferReader class built in with the examples.

Thanks, Chris.