[FFmpeg-devel] Question about parallelizing h264 decoding

[Guillaume POIRIER]

Hi,

On 5/10/07, Guillaume Poirier <gpoirier at mplayerhq.hu> wrote:
> Hi,
>
> Le 10 mai 07 ? 17:01, Thorsten Jordan a ?crit :
>
> > since it seems that the performance of a single core is not enough for
> > full HDTV decoding, one obvious alternative is multithreading on SMP
> > systems.
> > I know that the current h264 decoder can't decode multithreaded, but i
> > want to discuss some ideas how this could be done.
> >
> > Two choices come to my mind:
> >
> > 1) decode slices in parallel - problematic, because intra-frame
> > references and many data dependencies, also because of difficult
> > parallelization of cabac decoding etc.
> >
> > 2) decode frames or even GOPs in parallel - this one i want to
> > discuss a
> > bit further.
>
> There's actually another way to perform multi-threaded H264 decoding:
> split different stages of the decoding process into different threads.
>
> Since CABAC is pretty CPU-hungry, You could start by putting cabac
> decoding in a separate thread.
>
> This certainly does not scale too well with core count, but it's
> probably the easiest thing to do IMHO.

Mmmm.... maybe it's not that much of a good idea... anyhow, I suggest
you read this thread, which covered a bit of these issues
http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/2006-November/018995.html

Guillaume
-- 
Rich, you're forgetting one thing here: *everybody* except you is
stupid.
    M?ns Rullg?rd