[FFmpeg-devel] [PATCH 2/2] avcodec/jpeg2000dec: jpeg2000 has its own lowres option

[Tomas Härdin]

lör 2023-06-24 klockan 19:54 +0200 skrev Paul B Mahol:
> On Sat, Jun 24, 2023 at 12:53 PM Tomas Härdin <git at haerdin.se> wrote:
> 
> > lör 2023-06-10 klockan 20:31 +0200 skrev Michael Niedermayer:
> > > jpeg2000 overrides the global lowres variable with a lowres field
> > > called reduction_factor
> > > ffmpeg -lowres X causes the reduction_factor to be set
> > > ffplay -lowres X causes both lowres and the reduction_factor to
> > > be
> > > set
> > > ossfuss sets only lowres
> > 
> > Why does jpeg2000dec have its own -lowres? Does lavc reset it
> > somewhere
> > to where the decoder can't make use of the avctx-level setting?
> > 
> > 
> Libav removed lowres from avctx, but same was not done here.
> 
> IMHO lowres is codec-specific thing and only codecs supporting it
> should
> have private option to change it.

Enough codecs support lowres that marking support for it in codec caps
may be worthwhile. Something to consider for the future.

/Tomas