Re: [FFmpeg-devel] [PATCH v1 3/6] swscale: Add explicit rgb24->yv12 conversion

From: Michael Niedermayer <michael@niedermayer.cc>
To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>
Subject: Re: [FFmpeg-devel] [PATCH v1 3/6] swscale: Add explicit rgb24->yv12 conversion
Date: Tue, 22 Aug 2023 20:03:15 +0200
Message-ID: <20230822180315.GF7802@pb2> (raw)
In-Reply-To: <tlf9eiljsn8jqrotcf1pbtho49m2k5ojg9@4ax.com>

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On Tue, Aug 22, 2023 at 03:24:17PM +0100, John Cox wrote:
> On Mon, 21 Aug 2023 21:15:37 +0200, you wrote:
[...]
> >> I can get to simple bilinear without adding so much complexity that I
> >> lose the speed I need - would that be OK?
> >
> >Not sure simple bilinear is 100% clearly defined
> >I think it could mean 3 things
> >
> >1 2 1
> >  C
> >1 2 1
> >
> >or
> >
> >  1
> >  C
> >  1
> >
> >  or
> >
> >1 2 1
> >
> >3 6 3
> >  C
> >3 6 3
> >
> >1 2 1
> >
> >I think the 6 and 12 tap cases would produce ok results teh 2 tap not
> >Also maybe there are more finetuned filters for this specific case, i dont
> >know / didnt look.
> >Testing these probably would not be a bad idea before implementation
> >
> >I think users in 2023 expect the default to be better than what the
> >existing code was doing by default
> >so feel free to replace the existing "identical" code too
> 
> I was thinking of 2-tap (in both X & Y) which is equivalent to
> SWS_FAST_BILINEAR in ffmpeg. In the case I'm looking at I need the speed
> more than I need the quality and I'm quite happy to gate them behind a
> test for SWS_FAST_BILINEAR.

ok but maybe you want to still fix/add the higher quality C version too?
it would be almost the same code, just a different mix of source samples
iam asking as you are already working on this

thx

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

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