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

[Paul B Mahol]

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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>>
>>
>> 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.

>
> --
> Thanks,
> Limin Wang
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