[FFmpeg-devel] [PATCH 1/2 v3] lavf/isom: add Dolby Vision sample entry codes for HEVC and H.264

[Jan Ekström]

On Mon, Dec 17, 2018 at 10:57 PM Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
>
> 2018-12-17 21:52 GMT+01:00, Jan Ekström <jeebjp at gmail.com>:
> > On Mon, Dec 17, 2018 at 10:49 PM Carl Eugen Hoyos <ceffmpeg at gmail.com>
> > wrote:
> >>
> >> 2018-12-17 21:30 GMT+01:00, Jan Ekström <jeebjp at gmail.com>:
> >> > On Mon, Dec 17, 2018 at 10:23 PM Carl Eugen Hoyos <ceffmpeg at gmail.com>
> >> > wrote:
> >> >>
> >> >> 2018-12-17 21:17 GMT+01:00, Jan Ekström <jeebjp at gmail.com>:
> >> >> > On Mon, Dec 17, 2018 at 3:47 PM Carl Eugen Hoyos <ceffmpeg at gmail.com>
> >> >> > wrote:
> >> >> >>
> >> >> >> 2018-12-17 7:58 GMT+01:00, Jan Ekström <jeebjp at gmail.com>:
> >> >> >> > On Mon, Dec 17, 2018, 03:02 Carl Eugen Hoyos <ceffmpeg at gmail.com
> >> >> >> > wrote:
> >> >> >> >
> >> >> >> >> 2018-12-17 1:58 GMT+01:00, Jan Ekström <jeebjp at gmail.com>:
> >> >> >>
> >> >> >> >> > So as far as it's been possible to test this, that's been done
> >> >> >> >>
> >> >> >> >> Could you point me to a dva1 sample?
> >> >> >> >
> >> >> >> > I have not seen any dolby vision samples with avc in the wild.
> >> >> >> > You can ask Vittorio if he has some as he noted about
> >> >> >> > possibly being able to ask for some before.
> >> >> >>
> >> >> >> The patch is of course ok if Vittorio tested it with his samples.
> >> >> >>
> >> >> >> Thank you, Carl Eugen
> >> >> >
> >> >> > Unfortunately I have no idea what samples Vittorio does or does not
> >> >> > possess, he has only mentioned off-hand that he might able to get
> >> >> > hold
> >> >> > of some if required. And since you were the one requiring them, I
> >> >> > pointed you towards him.
> >> >> >
> >> >> > For myself, I am happy with the following points regarding this:
> >> >> > 1. The identifiers are registered at the MPEG-4 RA.
> >> >> > 2. There is a proper specification for these mappings that is
> >> >> > seemingly kept up-to-date.
> >> >> > 3. The mappings specification specifically notes that the only
> >> >> > difference between the AVC and HEVC identifiers are the semantics
> >> >> > mentioned in ISO/IEC 14496-15. We already have all of the identifiers
> >> >> > specified which these mappings are based upon, so those semantics
> >> >> > should not matter to us (and if they do, we have already broken those
> >> >> > constraints at this point).
> >> >> > 4. The mapping specification specifically notes that the given AVC
> >> >> > and
> >> >> > HEVC identifiers must also include the standard avcC and hvcC boxes
> >> >> > so
> >> >> > that they can be decoded normally without any additional custom code.
> >> >> > 5. We have samples for at least one of the four identifiers that
> >> >> > matches points 1 to 4.
> >> >> > 6. Android, Chromium, VLC among others have already implemented these
> >> >> > identifiers in the same way.
> >> >> >
> >> >> > Now, if you are not happy with these points, then please clearly
> >> >> > state
> >> >> > that you are blocking any and all additional identifier additions -
> >> >> > no
> >> >>
> >> >> > matter how specified - as long as there are no samples on hand for
> >> >> > them.
> >> >>
> >> >> I thought we had samples?
> >> >>
> >> >> Anyway, please mention ticket #7347.
> >> >
> >> > The sample last linked in that ticket was supposedly MPEG-TS for the
> >> > other HEVC identifier, not ISOBMFF.
> >>
> >> Why do you think so? Which sample did you test?
> >>
> >
> > From #7347
> >> Dobly Vision transport stream with codec tag "dvhe" can be found under:
> >> http://4kmedia.org/tag/dolby-vision/
> >
> > The site also notes that it's supposed to be a transport stream. I did
> > not look further.
>
> Then please allow me to once again suggest testing (at least if
> you trust neither me nor Igor).
>
> Carl Eugen

That was a quote FROM Igor's post
(https://trac.ffmpeg.org/ticket/7347#comment:12). If he and the site
mentioned it wrong then please just note that.

Jan