[FFmpeg-devel] [PATCH v2] avcodec/itut35: always check the provider code and country code together

[Maryla Ustarroz]

On Mon, Aug 4, 2025 at 1:08 AM Michael Niedermayer
<michael at niedermayer.cc> wrote:
>
> Hi Maryla
>
> On Wed, Jun 25, 2025 at 05:55:45PM +0200, Maryla Ustarroz-Calonge via ffmpeg-devel wrote:
> > Date: Wed, 25 Jun 2025 17:55:45 +0200
> > From: Maryla Ustarroz-Calonge <maryla at google.com>
> > To: ffmpeg-devel at ffmpeg.org
> > Subject: [PATCH v2] avcodec/itut35: always check the provider code and country code together
> >
> > From: Maryla <maryla at google.com>
> >
> > ITU-T T.35 provider codes are attributed by national bodies and it's
> > possible to have collisions across countries. This is why the country code
> > must always be checked as well.
> >
> > Use if statements rather than nested switches which would be unreadable.
> >
>
> > Rename some of the constants to match the corresponding organization.
>
> Renaming should be a seperate patch
>
>
> > Add a constant for AOM.
> > Write all constants with 4 hex digits to make it clear that they are 2-byte ids.
> >
>
> > The code for V-Nova should be 0x5000 instead of 0x0050 according to the
> > UK Register of Manufacturer Codes https://www.cix.co.uk/~bpechey/H221/h221code.htm
> > but I have been unable to find any reference for what code should be used for
> > LCEVC, and the author of the original change has not replied to my emails.
>
> this should be a seperate patch
>
> in general, please split this up a bit to make it easier to review
>
This was informational, I did not change the code.

> [...]
>
> > diff --git a/libavcodec/libdav1d.c b/libavcodec/libdav1d.c
> > index f4cbc927b5..a1158a23c4 100644
> > --- a/libavcodec/libdav1d.c
> > +++ b/libavcodec/libdav1d.c
> > @@ -386,6 +386,80 @@ static int libdav1d_receive_frame_internal(AVCodecContext *c, Dav1dPicture *p)
> >      return res;
> >  }
> >
> > +static int parse_itut_t35_metadata(Libdav1dContext *dav1d, Dav1dPicture *p,
> > +                                   const Dav1dITUTT35 *itut_t35, AVCodecContext *c,
> > +                                   AVFrame *frame) {
> > +    GetByteContext gb;
> > +    int provider_code, country_code;
> > +    int res;
>
> please split the factorization of code from changes to the code.
> That way the changes are clearer vissible in the patch
>
>
> thx
>

Thank you for the review. I resent this patch split into three parts.

> [...]
>
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
> Some people wanted to paint the bikeshed green, some blue and some pink.
> People argued and fought, when they finally agreed, only rust was left.
> _______________________________________________
> 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".