[FFmpeg-devel] [PATCH 13/18] h264_sei: parse the picture timing SEIs correctly

[Anton Khirnov]

Quoting James Almer (2020-03-23 17:20:56)
> On 3/23/2020 1:17 PM, Anton Khirnov wrote:
> > Quoting Kieran Kunhya (2020-03-22 05:24:35)
> >> On Fri, 13 Mar 2020 at 10:32, Anton Khirnov <anton at khirnov.net> wrote:
> >>
> >>> Those SEIs refer to the currently active SPS. However, since the SEI
> >>> NALUs precede the coded picture data in the bitstream, the active SPS is
> >>> in general not known when we are decoding the SEI.
> >>>
> >>
> >> The spec disagrees with this statement (7.4.1.2.1 Order of sequence and
> >> picture parameter set RBSPs and their activation). There are reasonably
> >> clear rules about SPS activation.
> >> (Whether real world bitstreams comply is a different issue of course).
> > 
> > I don't think you read that section carefully enough. What it says (in
> > my interpretation) is that an SPS can be activated only by:
> > - buffering period SEI
> 
> Looking at our Buffering Period SEI parsing code, it doesn't look like
> we're activating the SPS it references, for that matter.

Right, but then against we're not really using it for anything so it
probably doesn't matter.

-- 
Anton Khirnov