[FFmpeg-devel] [PATCH 5/5] libavcodec/jpeg2000dec.c: Remove log2_chroma check in pixel format selection

[Michael Niedermayer]

On Mon, Jun 22, 2020 at 12:14:39AM +0530, Gautam Ramakrishnan wrote:
> On Mon, Jun 22, 2020 at 12:12 AM <gautamramk at gmail.com> wrote:
> >
> > From: Gautam Ramakrishnan <gautamramk at gmail.com>
> >
> > The log2_chroma_wh is derived from the sample separations of the
> > codestream if the file is a j2k codestream. Not sure if sample
> > separation is same is subsampling and whether using sample
> > separation values from the codestream to determine pixel format.
> > ---
> >  libavcodec/jpeg2000dec.c | 2 --
> >  1 file changed, 2 deletions(-)
> >
> > diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c
> > index c8c89803ac..2b9659bf96 100644
> > --- a/libavcodec/jpeg2000dec.c
> > +++ b/libavcodec/jpeg2000dec.c
> > @@ -225,8 +225,6 @@ static int pix_fmt_match(enum AVPixelFormat pix_fmt, int components,
> >
> >      case 1:
> >          match = match && desc->comp[0].depth >= bpc &&
> > -                         (log2_chroma_wh >>  2 & 3) == 0 &&
> > -                         (log2_chroma_wh       & 3) == 0 &&
> >                           (desc->flags & AV_PIX_FMT_FLAG_PAL) == pal8 * AV_PIX_FMT_FLAG_PAL;
> >      }
> >      return match;
> > --
> > 2.17.1
> >
> This patch has to be discussed. I do not see any other formats having
> a check like this,

see pix_fmt_id in mjpegdec.c


> but that is probably because the pixel format is determined from the
> headers and not
> from the codestream.

If the removed check was wrong then i suspect more changes are needed
and just removing this alone will not be correct

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

There will always be a question for which you do not know the correct answer.
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