Hello all, I'm hoping someone can help with understanding writing metadata to files using ffmpeg. The type of metadata I'm referencing is information such as movie/song title, artist, album, author, genre, show, etc.
I do all of my encoding to AVC/AAC in the mp4 container. I use these because it's pretty much guaranteed the file will play on all systems, browsers and media player software. I'm using version 4.1 of ffmpeg (windows). I have used ffmpeg hundreds of times to do this so my questions aren't about getting it to work.... my questions are around what can be written with ffmpeg because I can't seem to find definitive info about this. So here are my questions: 1. Is there an actual ffmpeg documentation page on this? I couldn't find anything. The only references I could find were from other sites such as: https://wiki.multimedia.cx/index.php/FFmpeg_Metadata#QuickTime.2FMOV.2FMP4.2FM4A.2Fet_al. and https://kdenlive.org/en/project/adding-meta-data-to-mp4-video/ 2. I quickly went through the mp4 standards document and couldn't find anything related to these specific keys (ex: "title", "episode_id", etc.) so I'm trying to understand whether these keys are defined by the mp4 standard or whether each software developer writes their own keys? 3. When I look at the websites mentioned in #1 they are different in so far as what is available for mp4 through ffmpeg. The wiki site references seventeen keys for mp4 but the kdenlive site references thirty that are available. I guess this goes back to finding out exactly what is available through ffmpeg. Also whether this is the full set available to mp4 as a standard. 4. Is there anyway to write in custom metadata? I read this is not possible with ffmpeg for mp4 but is possible with ffmpeg for matroska. I read that here: https://superuser.com/questions/1208273/add-new-and-non-defined-metadata-to-a-mp4-file. So this goes back to whether custom metadata is not available through the mp4 standard or whether it just hasn't been written for ffmpeg? I would like to write a custom key/field for TV shows for Episode Number (as in "episode_number" as a string). The reason I want this is because according to the kdenlive site sorting (episode_sort) is limited to 0-255 so when it comes to shows like Law & Order SVU which is already up to about 457 episodes the sorting key doesn't work. In this regard either episode_sort could be changed or a custom field added. Something like "title": Law & Order "show": Prescription For Death "episode_number": Episode 1 or Ep1 or 1 or One (any of these would be an acceptable input or as mentioned "episode_sort" is changed). As a side note this superuser page also references a different number of available keys than either the wiki site and the kdenlive site which goes back to finding a comprehensive list with definitions of the keys. Personally I would like to be able to write in custom fields but I would also like episode_sort updated to be useful for shows that go beyond 255 episodes. This means episode_sort could remain as a numeric value but something like "episode_number" would be alphanumeric so the user could write in the data however they want as in Ep1, Episode 1, 1 or One, etc. If there is somewhere else I should post this let me know or point me to the official documentation (not only for mp4 but all files types would be helpful). I googled and googled until my brain hurt but the only references I could find are the ones noted above (and others like this). Thanks. Karen _______________________________________________ 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".
