[FFmpeg-devel] [PATCH] avfilter/vf_w3fdif: 255 * 256 * 128 -> max

[lance.lmwang at gmail.com]

On Tue, Aug 11, 2020 at 05:41:58PM +0200, Paul B Mahol wrote:
> On 8/11/20, lance.lmwang at gmail.com <lance.lmwang at gmail.com> wrote:
> > On Tue, Aug 11, 2020 at 05:24:06PM +0200, Paul B Mahol wrote:
> >> NAK
> >>
> >> On 8/11/20, lance.lmwang at gmail.com <lance.lmwang at gmail.com> wrote:
> >> > From: Limin Wang <lance.lmwang at gmail.com>
> >> >
> >> > max is initialized to ((1 << depth) - 1) * 256 * 128 before.
> >> >
> >> > Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> >> > ---
> >> >  libavfilter/vf_w3fdif.c | 2 +-
> >> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >> >
> >> > diff --git a/libavfilter/vf_w3fdif.c b/libavfilter/vf_w3fdif.c
> >> > index 5d64dbd..0f9efbf 100644
> >> > --- a/libavfilter/vf_w3fdif.c
> >> > +++ b/libavfilter/vf_w3fdif.c
> >> > @@ -163,7 +163,7 @@ static void filter_scale(uint8_t *out_pixel, const
> >> > int32_t *work_pixel, int line
> >> >      int j;
> >> >
> >> >      for (j = 0; j < linesize; j++, out_pixel++, work_pixel++)
> >> > -        *out_pixel = av_clip(*work_pixel, 0, 255 * 256 * 128) >> 15;
> >> > +        *out_pixel = av_clip(*work_pixel, 0, max) >> 15;
> >> >  }
> >> >
> >> >  static void filter16_simple_low(int32_t *work_line,
> >> > --
> >> > 1.8.3.1
> >> >
> >> > _______________________________________________
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> >> >
> >> > To unsubscribe, visit link above, or email
> >> > ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".
> >>
> >>
> >> Change is pointless and give no real benefits.
> >
> > 1. max is input as parameter and calculated already, why use it is
> > pointless?
> > 2. keep 8 bit and 16bit with same code so that we can remove the duplicate
> > code
> > later.
> 
> Code is not duplicated at all. Different types are used.
> You can off course use macros if you are really bored but regressions
> in performance are unacceptable.
> Your patch also ruin performance.

I haven't do performance testing for the filter have 8bit x86 asm code, please
ignore it if it'll impact the performance. 

> 
> >
> > --
> > Thanks,
> > Limin Wang
> > _______________________________________________
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> > ffmpeg-devel at ffmpeg.org
> > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> >
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> > ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".
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-- 
Thanks,
Limin Wang