[FFmpeg-devel] Support of udta fields handled by libquicktime

al al at dneg.com
Fri Jul 6 15:15:07 CEST 2012


Hi,

I`ve been using the ffmpeg api to write out .mov`s with the prores encoder,
internally we use libquicktime for our other movs.

It appears libquicktime uses different identifiers for various udta fields, this
means if I try and set the comment field in ffmpeg when I generate the mov, it`s
not visible to libquicktime.

This this intended or just missing functionality, I`m guessing the spec for this
stuff is a bit flexible.

In movenc.c ffmpeg does the following:-

         } else if (mov->mode == MODE_MOV) { // the title field breaks gtkpod
with mp4 and my suspicion is that stuff is not valid in mp4
            mov_write_metadata(s, pb_buf, "\251ART", "artist");
            mov_write_metadata(s, pb_buf, "\251nam", "title");
            mov_write_metadata(s, pb_buf, "\251aut", "author");
            mov_write_metadata(s, pb_buf, "\251alb", "album");
            mov_write_metadata(s, pb_buf, "\251day", "date");
            mov_write_metadata(s, pb_buf, "\251swr", "encoder");
            mov_write_metadata(s, pb_buf, "\251des", "comment");
            mov_write_metadata(s, pb_buf, "\251gen", "genre");
            mov_write_metadata(s, pb_buf, "\251cpy", "copyright");
        } else {

It seems libquicktime is looking for "\251cmt" for the comment field not 
"\251des", I think quite a few of these fields don`t matchup.

Is support likely to be added to make this support libquicktime or am I best off
patching my own copy to support this ?

cheers




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