[FFmpeg-devel] H.264: Partially inline CABAC residual decode

[Michael Niedermayer]

On Fri, Jan 14, 2011 at 03:13:42PM -0800, Jason Garrett-Glaser wrote:
> On Fri, Jan 14, 2011 at 3:13 PM, Jason Garrett-Glaser <jason at x264.com> wrote:
> > This is a port of a technique originally used in x264 (and later
> > ported to ffvp8). ?It inlines the CBF portion of residual coding,
> > which improves performance by allowing more constant propagation and
> > because a huge number of residual blocks terminate on the CBF check.
> >
> > Timing for CABAC mb decode:
> > Before: 6861 +/- 15 clocks
> > After: 6779 +/- 9 clocks
> >
> > Jason
> >
> 
> Forgot the patch...


[...]

>   */
>  int ff_h264_decode_mb_cabac(H264Context *h) {
> +    START_TIMER;
>      MpegEncContext * const s = &h->s;
>      int mb_xy;
>      int mb_type, partition_count, cbp = 0;
> @@ -1716,6 +1720,6 @@
>          h->ref_count[0] >>= 1;
>          h->ref_count[1] >>= 1;
>      }
> -
> +STOP_TIMER("test");
>      return 0;
>  }

that doesnt belong in here

otherwise if moving that around is faster lgtm of course


[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Complexity theory is the science of finding the exact solution to an
approximation. Benchmarking OTOH is finding an approximation of the exact
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