On Mon, Jul 10, 2017 at 21:12:14 +0100, Kieran O Leary wrote: > > I am wondering if there is any good documentation available on the web on > > what QuickTime tags ffmpeg is available to write. [...] > > I also found this webpage: > > https://multimedia.cx/eggs/supplying-ffmpeg-with-metadata/ but it > > is not up to date either.
There's another list here, but the same conclusion is valid: https://wiki.multimedia.cx/index.php/FFmpeg_Metadata#QuickTime.2FMOV.2FMP4.2FM4A.2Fet_al. (Some of it is incorrect.) > It looks like your best bet is to go to the source code itself. I agree. > 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 Actually, if you look at that latter code location closely, you will see that those differentiations are between MOV, MP4 ("iTunes metadata") and 3GP - three very similar, but somewhat different formats. The most important observation is that the "mdta" atom, as mentioned in the Apple link given: https://developer.apple.com/library/content/documentation/QuickTime/QTFF/Metadata/Metadata.html#//apple_ref/doc/uid/TP40000939-CH1-SW43 is written only for "iTunes" (MP4, M4A I guess) files by default. To write it to MOV files as well, you need to specify -movflags +use_metadata_tags And indeed, in a quick test, I can add arbitrary metadata keys to MOV files. :-) (You need to find a different tool to check for sure, I guess. Does Apple have a refence MOV file checker?) I would need to double-check the source code to understand whether you have to specify the "com.apple.quicktime." prefix or not. > 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 apparently is capable of encoding *anything* to "mdta", see mov_write_mdta_keys_tag(). Moritz _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
