[FFmpeg-devel] [PATCH v1 2/5] avcodec/v210enc: make 8bit and 10bit function consistent

[Limin Wang]

On Wed, Aug 28, 2019 at 08:36:14PM +0200, Carl Eugen Hoyos wrote:
> Am Mi., 28. Aug. 2019 um 17:46 Uhr schrieb <lance.lmwang at gmail.com>:
> >
> > From: Limin Wang <lance.lmwang at gmail.com>
> >
> > Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> > ---
> >  libavcodec/v210enc.c | 7 +------
> >  1 file changed, 1 insertion(+), 6 deletions(-)
> >
> > diff --git a/libavcodec/v210enc.c b/libavcodec/v210enc.c
> > index 1b840b2..69a2efe 100644
> > --- a/libavcodec/v210enc.c
> > +++ b/libavcodec/v210enc.c
> > @@ -43,12 +43,7 @@ static void v210_planar_pack_8_c(const uint8_t *y, const uint8_t *u,
> >      uint32_t val;
> >      int i;
> >
> > -    /* unroll this to match the assembly */
> > -    for (i = 0; i < width - 11; i += 12) {
> > -        WRITE_PIXELS(u, y, v, 8);
> > -        WRITE_PIXELS(y, u, y, 8);
> > -        WRITE_PIXELS(v, y, u, 8);
> > -        WRITE_PIXELS(y, v, y, 8);
> > +    for (i = 0; i < width - 5; i += 6) {
> >          WRITE_PIXELS(u, y, v, 8);
> >          WRITE_PIXELS(y, u, y, 8);
> >          WRITE_PIXELS(v, y, u, 8);
> 
> Doesn't this have a performance impact?

I think it's compiler job for the optimization.

However I have done quick benchmark with ff_v210enc_init_x86 is
removed(to trigger the c function), below is the testing result:

./ffmpeg -benchmark -y -f lavfi -i smptehdbars -sws_flags +accurate_rnd+bitexact -vf \
scale=720x576,format=yuv422p -c:v v210  -frames 1000  -f framecrc -
master:
frame= 1000 fps=754 q=-0.0 Lsize=      57kB time=00:00:40.00 bitrate=  11.6kbits/s speed=30.2x
bench: utime=1.299s stime=0.013s rtime=1.326s
bench: maxrss=16244736kB

patch applied:
frame= 1000 fps=756 q=-0.0 Lsize=      57kB time=00:00:40.00 bitrate=  11.6kbits/s speed=30.2x
bench: utime=1.300s stime=0.013s rtime=1.323s
bench: maxrss=16166912kB


Thanks,
Limin

> 
> Carl Eugen
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