[FFmpeg-devel] [PATCH] Add HDR dynamic metadata struct (for SPMTE 2094-40) to libavutil.

[Jan Ekström]

On Tue, Dec 18, 2018 at 12:58 AM Vittorio Giovara
<vittorio.giovara at gmail.com> wrote:
>
> On Mon, Dec 17, 2018 at 5:53 PM Jan Ekström <jeebjp at gmail.com> wrote:
>
> > On Tue, Dec 18, 2018 at 12:41 AM Vittorio Giovara
> > <vittorio.giovara at gmail.com> wrote:
> > >
> > > I like
> > VeryLongJavaLikeNamingForFunctionsAndDataTypesAsWellAsEnumsOfCourse
> > > as much as the next guy, but this is overly too long and the related
> > > structure name (AVDynamicMetadataSMPTE2094_40) is inconsistent with the
> > > public type naming present in this project.
> > >
> > > If I may suggest, please use the following names:
> > > - AV_FRAME_DATA_DYNAMIC_HDR for frame data type: it is obviously
> > metadata,
> > > and the fact that is based on SMPTE2094-40 should not be hardcoded in the
> > > name
> > > - dynamic_hdr.h as header name: again the fact that it's metadata does
> > not
> > > be carried everywhere
> > > - AVDynamicHDR as structure name: short and to the point, and without
> > spec
> > > numbers or underscores
> > >
> >
> > I don't think SMPTE ST.2094-XX utilized the same fields?
> >
> > I think SMPTE ST.2094-40 is Samsung's dynamic metadata which is effect
> > usually called "HDR10+" ? Not just calling it AVDynamicHDR could come
> > up useful if we plan on adding support for SMPTE ST.2094-10 which is
> > one part of what's called "Dolby Vision" (even though it is just
> > dynamic metadata - because of course you have to stick everything
> > under a single marketing name).
> >
>
> It's still technically dynamic metadata but I get your point.
> It could maybe be stored in dynamic_hdr.h header, and call it
> AVDynamicHDRPlus to differenciate it from the future AVDolbyVisionHDR. What
> do you think?
>

The other alternative would have been to make sure that the structure
can take the values that are "essential" from those separate
specifications.

I do not have a heavy opinion one way or another (separate structure
per spec or single with all the required data), but just had to
mention it because it would have otherwise been a singular "dynamic
HDR metadata" entity while it unfortunately seems that these things
have splintered into multiple competing alternatives... (of which
Samsung's and Dolby's things seem to be those getting most use)

Jan