[FFmpeg-devel] [PATCH 7/8] avformat/mpegts: Fix for the DOVI video stream descriptor

[lance.lmwang at gmail.com]

On Thu, Oct 14, 2021 at 09:45:45AM -0400, quietvoid wrote:
> On Thu, Oct 14, 2021 at 9:36 AM <lance.lmwang at gmail.com> wrote:
> 
> > On Thu, Oct 14, 2021 at 09:18:16AM -0400, f tcChlisop0 wrote:
> > > On Thu, Oct 14, 2021 at 9:10 AM <lance.lmwang at gmail.com> wrote:
> > >
> > > > From: Limin Wang <lance.lmwang at gmail.com>
> > > >
> > > > By <<Dolby Vision Streams Within the MPEG-2 Transport Stream Format
> > v1.2>>
> > > >
> > > > Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> > > > ---
> > > >  libavformat/mpegts.c | 11 +++++++++--
> > > >  1 file changed, 9 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/libavformat/mpegts.c b/libavformat/mpegts.c
> > > > index 44d9298..774964d 100644
> > > > --- a/libavformat/mpegts.c
> > > > +++ b/libavformat/mpegts.c
> > > > @@ -2178,6 +2178,8 @@ int ff_parse_mpeg2_descriptor(AVFormatContext
> > *fc,
> > > > AVStream *st, int stream_type
> > > >              AVDOVIDecoderConfigurationRecord *dovi;
> > > >              size_t dovi_size;
> > > >              int ret;
> > > > +            int dependency_pid;
> > > > +
> > > >              if (desc_end - *pp < 4) // (8 + 8 + 7 + 6 + 1 + 1 + 1) / 8
> > > >                  return AVERROR_INVALIDDATA;
> > > >
> > > > @@ -2193,7 +2195,11 @@ int ff_parse_mpeg2_descriptor(AVFormatContext
> > *fc,
> > > > AVStream *st, int stream_type
> > > >              dovi->rpu_present_flag  = (buf >> 2) & 0x01;    // 1 bit
> > > >              dovi->el_present_flag   = (buf >> 1) & 0x01;    // 1 bit
> > > >              dovi->bl_present_flag   =  buf       & 0x01;    // 1 bit
> > > > -            if (desc_end - *pp >= 20) {  // 4 + 4 * 4
> > > > +            if (!dovi->bl_present_flag && desc_end - *pp >= 2) {
> > > > +                buf = get16(pp, desc_end);
> > > > +                dependency_pid = buf >> 3; // 13 bits
> > > > +            }
> > > > +            if (desc_end - *pp >= 1) {  // 8 bits
> > > >                  buf = get8(pp, desc_end);
> > > >                  dovi->dv_bl_signal_compatibility_id = (buf >> 4) &
> > 0x0f;
> > > > // 4 bits
> > > >              } else {
> > > > @@ -2210,12 +2216,13 @@ int ff_parse_mpeg2_descriptor(AVFormatContext
> > *fc,
> > > > AVStream *st, int stream_type
> > > >              }
> > > >
> > > >              av_log(fc, AV_LOG_TRACE, "DOVI, version: %d.%d, profile:
> > %d,
> > > > level: %d, "
> > > > -                   "rpu flag: %d, el flag: %d, bl flag: %d,
> > compatibility
> > > > id: %d\n",
> > > > +                   "rpu flag: %d, el flag: %d, bl flag: %d,
> > > > dependency_pid: %d, compatibility id: %d\n",
> > > >                     dovi->dv_version_major, dovi->dv_version_minor,
> > > >                     dovi->dv_profile, dovi->dv_level,
> > > >                     dovi->rpu_present_flag,
> > > >                     dovi->el_present_flag,
> > > >                     dovi->bl_present_flag,
> > > > +                   dependency_pid,
> > > >                     dovi->dv_bl_signal_compatibility_id);
> > > >          }
> > > >          break;
> > > > --
> > > > 1.8.3.1
> > > >
> > > > _______________________________________________
> > > > 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".
> > > >
> > >
> > > Hi, this is something I had fixed in this patchset:
> > > https://ffmpeg.org/pipermail/ffmpeg-devel/2021-September/286234.html
> > > However the dependency_pid is ignored, as it has no use presently.
> > >
> > > Which patch should take precedence?
> >
> > Sorry, I have noticed your patch before. By the quick review of your patch,
> > it's a lot function change and difficult to merge I think. I prefer to
> > fix the issue with existing code first instead of mixed function change.
> >
> 
> Okay, that makes sense.
> I will wait and rebase before resending for review then.
> 
> However I'm worried my patch will still result in ignoring dependency_pid,
> because it is not part of AVDOVIDecoderConfigurationRecord, unless it is
> added.

I failed to find your patchset in my email archive, so I reply it here for my comments:
-            if (ret < 0) {
-                av_free(dovi);
+            if ((ret = ff_isom_parse_dvcc_dvvc(fc, st, *pp, desc_len, 1)) < 0)
                 return ret;
-            }

I think it's wrong to use ff_isom_parse_dvcc_dvvc() here for mpegts
use DOVIVideoStreamDescriptor, ISOM use DOVIDecoderConfigurationRecord.
they're different syntax if you have checked the two specs. So your parsing isn't
follow the specs as dependency_pid is used by DOVIVideoStreamDescriptor.


> 
> >
> > > thanks, quietvoid
> > > _______________________________________________
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> > > 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".
> >
> > --
> > Thanks,
> > Limin Wang
> > _______________________________________________
> > 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".
> >
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-- 
Thanks,
Limin Wang