[FFmpeg-user] Write QuickTime tags

[Kieran O Leary]

Hi Andrius,


On Mon, Jul 10, 2017 at 5:05 PM, <aegoreev at gmail.com> wrote:

>
> Some of these tags such as 'keywords' and 'rating.user' are not being
> recognized by another software (I was checking results in mediainfo and
> exiftool) and some of them I was able to write using a different key(name)
> e.g. 'date' instead of 'creationdate'.
>
> I am wondering if there is any good documentation available on the web on
> what
> QuickTime tags ffmpeg is available to write.
>

It looks like your best bet is to go to the source code itself.
https://github.com/FFmpeg/FFmpeg/blob/master/libavformat/movenc.c#L3304

There's some other sections in there for other  profiles too:
https://github.com/FFmpeg/FFmpeg/blob/master/libavformat/movenc.c#L3520

As for 'keywords', it looks like mediainfo is capable of displaying it just
fine:
https://github.com/MediaArea/MediaInfoLib/blob/080212c30baea3f85602eaf61aa8feaedb983971/Source/MediaInfo/Multiple/File_Mpeg4.cpp#L2585

but i do not see 'keywords' on the ffmpeg encoding list. It might be not be
that difficult to add support for these tags.
ffmpeg seems to be able to decode these tags just fine though -
https://github.com/FFmpeg/FFmpeg/blob/master/libavformat/mov.c#L333


Best,

Kieran.