[FFmpeg-devel] [RFC PATCH v5 2/3] libavcodec/j2kenc: Fix tag tree coding

[Gautam Ramakrishnan]

On Wed, Aug 26, 2020 at 4:04 AM Michael Niedermayer
<michael at niedermayer.cc> wrote:
>
> On Tue, Aug 25, 2020 at 07:25:44PM +0530, gautamramk at gmail.com wrote:
> > From: Gautam Ramakrishnan <gautamramk at gmail.com>
> >
> > The implementation of tag tree encoding was incorrect.
> > However, this error was not visible as the current j2k
> > encoder encodes only 1 layer.
> > This patch fixes tag tree coding for JPEG2000 such tag
> > tree coding would work for multi layer encoding.
>
> [...]
>
> > diff --git a/libavcodec/jpeg2000.c b/libavcodec/jpeg2000.c
> > index 26e09fbe38..2e26bc5b00 100644
> > --- a/libavcodec/jpeg2000.c
> > +++ b/libavcodec/jpeg2000.c
> > @@ -82,12 +82,13 @@ static Jpeg2000TgtNode *ff_jpeg2000_tag_tree_init(int w, int h)
> >      return res;
> >  }
> >
> > -void ff_tag_tree_zero(Jpeg2000TgtNode *t, int w, int h)
> > +void ff_tag_tree_zero(Jpeg2000TgtNode *t, int w, int h, int val)
> >  {
> >      int i, siz = ff_tag_tree_size(w, h);
> >
> >      for (i = 0; i < siz; i++) {
> > -        t[i].val = 0;
> > +        t[i].val = val;
> > +        t[i].temp_val = 0;
> >          t[i].vis = 0;
> >      }
> >  }
> > @@ -567,8 +568,8 @@ void ff_jpeg2000_reinit(Jpeg2000Component *comp, Jpeg2000CodingStyle *codsty)
> >              Jpeg2000Band *band = rlevel->band + bandno;
> >              for(precno = 0; precno < rlevel->num_precincts_x * rlevel->num_precincts_y; precno++) {
> >                  Jpeg2000Prec *prec = band->prec + precno;
> > -                ff_tag_tree_zero(prec->zerobits, prec->nb_codeblocks_width, prec->nb_codeblocks_height);
> > -                ff_tag_tree_zero(prec->cblkincl, prec->nb_codeblocks_width, prec->nb_codeblocks_height);
> > +                ff_tag_tree_zero(prec->zerobits, prec->nb_codeblocks_width, prec->nb_codeblocks_height, 0);
> > +                ff_tag_tree_zero(prec->cblkincl, prec->nb_codeblocks_width, prec->nb_codeblocks_height, 0);
>
> this looks a bit like a somewhat unlrelated bugfix thats spread over this and
> the next patch
> if so, that should be moved into a seperate patch
> the patches are already complex without an additional bugfix in them
>
This portion is a fix for what you pointed out yesterday saying that
the parent of a the
nodes are not getting set. I thought this would be an appropriate
patch to fix this. Do you
feel its better that this part is made separate though?
In my opinion, only this patch provides the bug fix and the next patch
just uses the fix.
Do correct me if I am wrong.
> thx
>
> [...]
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
> Whats the most studid thing your enemy could do ? Blow himself up
> Whats the most studid thing you could do ? Give up your rights and
> freedom because your enemy blew himself up.
>
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".



-- 
-------------
Gautam |