[FFmpeg-devel] yuv420_bgr24_mmxext conversion taking significant time

Lauri Kasanen cand at gmx.com
Tue Jun 11 09:02:23 EEST 2019

On Mon, 10 Jun 2019 17:42:00 -0700
Adrian Tong <adriantong1024 at gmail.com> wrote:

> I have been trying to implement yuv420_to_bgr24 using SSE2 instruction. I
> ran into the case where the output of C implemented yuv420_to_bgr24 has
> slightly different resulting bgr24 image from MMX implemented
> yuv420_to_bgr24. Is this expected behavior ?

Yes, some of the MMX implementations choose speed over accuracy, I ran
to that myself when doing PPC versions. For a SSE version, if an
accurate version is fast enough, please try to match the C version.
Otherwise try to match MMX.

- Lauri

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