[FFmpeg-devel] [PATCH v6 2/4] avfilter/vf_framerate: if metadata lavfi.scd.mafd exists, we'll use it first

[lance.lmwang at gmail.com]

On Fri, May 15, 2020 at 10:27:35AM +0200, Paul B Mahol wrote:
> On 5/15/20, lance.lmwang at gmail.com <lance.lmwang at gmail.com> wrote:
> > On Thu, May 14, 2020 at 09:00:21PM +0200, Marton Balint wrote:
> >>
> >>
> >> On Thu, 14 May 2020, Marton Balint wrote:
> >>
> >> >
> >> >
> >> > On Thu, 14 May 2020, Nicolas George wrote:
> >> >
> >> > > Marton Balint (12020-05-14):
> >> > > > I am not a huge fan of this patch, mafd refers to a score
> >> > > > between this
> >> > frame
> >> > > > and the previous frame, we cannot ensure that there were no
> >> > > > additional
> >> > frame
> >> > > > processing between scdet and this filter which may have duplicated
> >> > > > or
> >> > > > removed frames. So I'd rather not add this feature.
> >> > >
> >> > > It can only happen if the user has put filters in the middle. I move
> >> > > we
> >> > > trust users who insert such obscure filters to do what they want to,
> >> > > or
> >> > > to fix their issues if they have some.
> >> >
> >> > Fine, I am not blocking this if null pointer deref issues are fixed.
> >> >
> >> > I think we can also assume that if the metadata exists, it will contain
> >> > a valid number, so I suggest this code:
> >> >
> >> >         e_mafd = av_dict_get(next->metadata, "lavfi.scd.mafd", NULL,
> >> > AV_DICT_MATCH_CASE);
> >> >         if (e_mafd) {
> >> >             mafd = strtod(e_mafd->value, NULL);
> >> >         } else {
> >> >             s->sad(crnt->data[0], crnt->linesize[0], next->data[0],
> >> > next->linesize[0], crnt->width, crnt->height, &sad);
> >> >             emms_c();
> >> >             mafd = (double)sad * 100.0 / (crnt->width * crnt->height) /
> >> > (1 << s->bitdepth);
> >> >         }
> >>
> >> Why this patch was committed without a recent review???
> >
> > Sorry, I consider it's reviewed old patchset, but it seems it's incomplete.
> 
> Also it uses scd for metadata filter name, which is bad. It should use
> full filter name.

Sorry, in fact I intentionally did not use the filter name. At that time, I considered
that there may be different filters for scene detection, but for filters that use the metadata,
the processing method should be the same. So I didn't use the filter name.


> 
> >
> >>
> >> Thanks,
> >> Marton
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> >
> > --
> > Thanks,
> > Limin Wang
> > _______________________________________________
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-- 
Thanks,
Limin Wang