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

[Carl Eugen Hoyos]

2018-12-17 22:02 GMT+01:00, Jan Ekström <jeebjp at gmail.com>:
> 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).

> 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.

Which reminds me that you could mention him too in
the commit message:
https://patchwork.ffmpeg.org/patch/10023/

Carl Eugen