[FFmpeg-devel] [PATCH v2 7/7] avcodec: add AV_CODEC_FLAG_CLEAR

[Anton Khirnov]

Quoting Ronald S. Bultje (2023-12-07 02:44:36)
> Hi,
> 
> On Wed, Dec 6, 2023 at 3:23 AM Marton Balint <cus at passwd.hu> wrote:
> 
> > Signed-off-by: Marton Balint <cus at passwd.hu>
> > ---
> >  doc/APIchanges             |  3 +++
> >  doc/codecs.texi            | 14 ++++++++++++++
> >  libavcodec/avcodec.h       |  4 ++++
> >  libavcodec/decode.c        |  6 ++++++
> >  libavcodec/options_table.h |  1 +
> >  libavcodec/version.h       |  2 +-
> >  6 files changed, 29 insertions(+), 1 deletion(-)
> >
> > diff --git a/doc/APIchanges b/doc/APIchanges
> > index 416e2bec5e..f839504a64 100644
> > --- a/doc/APIchanges
> > +++ b/doc/APIchanges
> > @@ -2,6 +2,9 @@ The last version increases of all libraries were on
> > 2023-02-09
> >
> >  API changes, most recent first:
> >
> > +2023-12-xx - xxxxxxxxxxx - lavc 60.36.100 - avcodec.h
> > +  Add AV_CODEC_FLAG_CLEAR.
> > +
> >  2023-12-xx - xxxxxxxxxxx - lavu 58.33.100 - imgutils.h
> >    Add av_image_fill_color()
> >
> > diff --git a/doc/codecs.texi b/doc/codecs.texi
> > index 5b950b4560..0504a535f2 100644
> > --- a/doc/codecs.texi
> > +++ b/doc/codecs.texi
> > @@ -76,6 +76,20 @@ Apply interlaced motion estimation.
> >  Use closed gop.
> >  @item output_corrupt
> >  Output even potentially corrupted frames.
> > + at item clear
> > +Clear the contents of the video buffer before decoding the next picture
> > to it.
> > +
> > +Usually if only a part of a picture is affected by a decode error then the
> > +decoder (if it implements error concealment) tries to hide it by
> > interpolating
> > +pixels from neighbouring areas or in some cases from the previous frame.
> > Even
> > +without error concealment it is quite likely that the affected area will
> > +contain pixels from an earlier frame, due to frame pooling.
> >
> 
> No comment on the patch itself, but wouldn't our users (and the C standard
> itself) consider it a security issue to return stale

I don't see the security issue in returning previously-returned frame
data.

-- 
Anton Khirnov