[FFmpeg-devel] [PATCH 1/1] avformat/movenc: use modern iTunes copyright atom

Timo Teras timo.teras at iki.fi
Fri Mar 30 04:10:26 EEST 2018

On Fri, 30 Mar 2018 03:54:59 +0300
Jan Ekström <jeebjp at gmail.com> wrote:

> On Fri, Mar 30, 2018 at 3:39 AM, Michael Niedermayer
> <michael at niedermayer.cc> wrote:
> >
> > 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
> > reference/software ...
> >  
> For the record, the current QTFF (aka MOV) specification still lists
> '©cpy' as the copyright statement international text field. The
> copyright sign at the beginning of the identifier is defined as:
> "All user data list entries whose type begins with the © character
> (ASCII 169) are defined to be international text. These list entries
> must contain a list of text strings with associated language codes. By
> storing multiple versions of the same text, a single user data text
> item can contain translations for different languages."
> Official ref:
> https://developer.apple.com/library/content/documentation/QuickTime/QTFF/QTFFChap2/qtff2.html#//apple_ref/doc/uid/TP40000939-CH204-BBCCFFGD
> 'cprt' is not mentioned in QTFF.
> Meanwhile, in ISOBMFF (aka MP4 aka 14496-12, available for free from
> http://standards.iso.org/ittf/PubliclyAvailableStandards/index.html )
> 'cprt' is defined.
> So with a quick look it seems like when writing in MOV mode one should
> still utilize '©cpy' while with MP4 one should utilize 'cprt'
> according to ISOBMFF.

Correct. And these modes are not touched in the patch, it changes
iTunes list writing which is not covered by any standard.

Do note that iTunes list is is not MOV format. It's Apple extension to
MP4. The MOV mode tag is written in mov_write_udta_tag() in the if
mov->mode == MODE_MOV block.

The commit bed4fc54c947b9e36d2103b400d438bfb4dd80dd pointed by Michael
shows the three code paths writing copyright tag in the different


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