[Ffmpeg-devel] MMX/MMX2 and SSE optimizations for H.264 decoding

[Rich Felker]

On Thu, Sep 22, 2005 at 10:47:51AM -0700, Loren Merritt wrote:
> On Thu, 22 Sep 2005, Romain Dolbeau wrote:
> >Loren Merritt wrote:
> >
> >>we have:
> >>put_h264_qpel_16_mc*_altivec
> >>put_h264_chroma_mc8_altivec
> >>
> >>we do not have equivalents of:
> >>put_h264_qpel_8_mc*_mmx2
> >>put_h264_qpel_4_mc*_mmx2
> >>h264_*_loop_filter_*_mmx2
> >>ff_h264_idct_add_mmx2
> >
> >The additional question is, are we going to be bitten by
> >Amdahl's Law ? i.e. are these important enought during
> >the decoding process to justify optimizing them ?
> 
> idct is not so important (iirc 3% total speedup when I mmxed it).
> qpel_4 matters only on videos that use 4x4 motion partitions.
> qpel_8 and loop_filter are important.

IMO loop filter is irrelevant because everyone who cares about
performance disables it. :)

Rich