[FFmpeg-devel] [PATCH 1/1] avformat/movenc: use modern iTunes copyright atom
michael at niedermayer.cc
Fri Mar 30 03:39:13 EEST 2018
On Thu, Mar 29, 2018 at 10:12:50PM +0300, Timo Teras wrote:
> On Thu, 29 Mar 2018 20:29:44 +0200
> Michael Niedermayer <michael at niedermayer.cc> wrote:
> > On Wed, Mar 28, 2018 at 07:02:48PM +0300, Timo Teräs wrote:
> > > iTunes currently uses the 'cprt' atom to store the copyright notice
> > > and this patch fixes compatibility with majority of software that
> > > supports the 'ilst' atom. Other software and documentation using
> > > this:
> > > - AtomicParseley encodes and parses only 'cprt'
> > > - Most players recognize only 'cprt'
> > > - https://sno.phy.queensu.ca/~phil/exiftool/TagNames/QuickTime.html
> > > documents both tag types
> > > - http://mutagen.readthedocs.io/en/latest/api/mp4.html documents
> > > only 'cprt'
> > >
> > > ffmpeg mov reader properly parses the 'cprt' tag inside 'ilst' tag
> > > and functions correctly with streams produced with this commit.
> > >
> > > Since 'cprt' seems to be the current correct atom, it is used by
> > > default. "-movflags legacy_copyright" option is added to revert
> > > back to the old atom type in case that is needed.
> > >
> > > Signed-off-by: Timo Teräs <timo.teras at iki.fi>
> > > ---
> > > If the legacy option is not needed, I'm happy to resend patch just
> > > changing the atom types.
> > why dont you store both ?
> > the old should do no harm or am i missing something ?
> > and it avoids the need for the user parameter (which few will find if
> > they run in a file that doesnt work)
> AFAIK, 'cprt' is the canonical tag and always has been for iTunes list.
> I tried to look where the current ffmpeg atom came from, but did not
> find anything conclusive. It might be copy paste error on ffmpeg from
> other container variants, and others who supports it in iTunes list is
> to support ffmpeg generated .movs.
git log points to
This commit added both cpy and cprt, that makes your hypothesis not
fit very well
did you ask the author, who added this ? Maybe he remembers where it
It would be better to understand where it came from before its changed
If it was a typo or something like that, i agree that it should be
removed/replaced. I was assuming it come from some official
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
"Nothing to hide" only works if the folks in power share the values of
you and everyone you know entirely and always will -- Tom Scott
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