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

Loren Merritt lorenm
Thu Sep 22 19:47:51 CEST 2005

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.

--Loren Merritt

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