[FFmpeg-devel] [RFC] AVDictionary2

[Michael Niedermayer]

Hi

On Wed, Apr 09, 2025 at 12:18:10AM +0200, Gerion Entrup wrote:
> Am Dienstag, 8. April 2025, 22:29:37 Mitteleuropäische Sommerzeit schrieb Michael Niedermayer:
> > On Tue, Apr 08, 2025 at 11:10:21AM -0500, Romain Beauxis wrote:
> > > Le mar. 8 avr. 2025 à 05:20, Michael Niedermayer
> > > <michael at niedermayer.cc> a écrit :
> >> [...]
> > > * Any interest in storing multiple values for the same key? This seems
> > > like a niche case but, as you pointed out in another thread, typically
> > > vorbis metadata do allow multiple key/values for the same field.
> > 
> > For a single key multiple values should not be stored
> > You can do
> > Author1=Eve
> > Author2=Adam
> > or
> > Author=Adam and Eve
> > 
> > But dont do
> > Author=Eve
> > Author=Adam
> > because if you do that and then you get later a
> > Author=Lilith
> > what does that mean? that its now 1 Author or 3 Authors
> > or 2 and if 2 then which 2 ?
> > 
> > Or said another way, you cant have multiple identical keys like that AND
> > allow updates.
> 
> AFAIK, Matroska also has Metadata that are explicitly a tree and can have the same key.
> A good example is the ACTOR tag: Most movies have more than one actor, the CHARACTER should be a subtag of ACTOR [1].

The AVDictionary2 API doesnt need to represent multiple actors the same way as
the matroska bitstream.

Also it changes nothing on the conflict between "multiple identical keys" and
updates


> Currently, FFmpeg just seem to ignore keys with multiple values and display the first.

Since 80b77e8e8d0630710ad6069133f397459015f139, we have some
support for multiple values in id3, this has the problem with updates
described above though

thx

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

If the United States is serious about tackling the national security threats 
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