[FFmpeg-devel] [PATCH 1/2] fftools/cmdutils: make the default swscale flags identical for simple and complex filter graph

[Linjie Fu]

On Sun, Aug 1, 2021 at 10:13 PM Gyan Doshi <ffmpeg at gyani.pro> wrote:

>
>
> On 2021-08-01 19:19, Linjie Fu wrote:
> > On Sun, Aug 1, 2021 at 9:25 PM Nicolas George <george at nsup.org> wrote:
> >
> >> Linjie Fu (12021-08-01):
> >>> From: Linjie Fu <linjie.justin.fu at gmail.com>
> >>>
> >>> Currently the default swscale flags for simple filter graph is bicubic,
> >>> however for complex filter graph it uses bilinear as decleared in scale
> >>> filter.
> >> Why does ffmpeg set a default different from swscale?
> >>
> > Checked swscale, it uses bicubic by default.
> > Scale filter sets the flags to bilinear if sws_scale_opt is not
> initialized
> > by sws_dict.
> >
> > We should use the same default flags for both simple and complex filter
> > graphs, either from swscale, or from scale filter.
> > If prefer to keep it identical with swscale, we may modify the flags in
> the
> > scale filter.
>
> Keeping bicubic the default is best.
>
> You'll need to update the refs for all the failed FATE tests.


Got the point, bicubic seems more reasonable if taking FATE tests into
account.
Let's wait for more comments, and maybe do some code clean too for
libswscale
as Nicolas has pointed out.

- linjie