[FFmpeg-devel] [PATCH v2] swscale/output: Altivec-optimize float yuv2plane1

[Lauri Kasanen]

On Mon, 17 Dec 2018 01:03:36 +0100
Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:

> 2018-12-16 10:06 GMT+01:00, Lauri Kasanen <cand at gmx.com>:
> > This function wouldn't benefit from VSX instructions, so I put it
> > under altivec.
> >
> > ./ffmpeg_g -f rawvideo -pix_fmt rgb24 -s hd1080 -i /dev/zero -pix_fmt
> > grayf32le \
> > -f null -vframes 100 -v error -nostats -
> >
> > 3743 UNITS in planar1,   65495 runs,     41 skips
> >
> > -cpuflags 0
> >
> > 23511 UNITS in planar1,   65530 runs,      6 skips
> >
> > grayf32be
> >
> > 4647 UNITS in planar1,   65449 runs,     87 skips
> >
> > -cpuflags 0
> >
> > 28608 UNITS in planar1,   65530 runs,      6 skips
> >
> > The native speedup is 6.28133, and the bswapping one 6.15623.
> 
> > Fate passes
> 
> I wonder a little how, given that grayf32 already breaks fate as-is...

Are the tests for it disabled? fate.ffmpeg.org reports 100% success for
many platforms.

> Note that this function / this pix_fmt currently has no real use-case
> afaict.

Is there a list of which pix fmts are useful? Of course I don't want to
waste both my and reviewers' time, if the format is considered for
removal or otherwise broken.

- Lauri