On Thu, Dec 6, 2018 at 1:56 PM Gyan Doshi <[email protected]> wrote:
> On 07-12-2018 12:10 AM, Karen Norton wrote: > > > > > My questions are about finding the full scope of keys that can be written > > with ffmpeg because the sites I reference give varying sets of keys. I > > would like to find a comprehensive list of keys for all files in general > > (video and audio) but for mp4 in particular. I would also like to know > > about writing custom tags/keys. Is this possible for mp4 in general but > > more importantly mp4 with ffmpeg. :-D > > The MP4 file format itself does not provide any restrictions on metadata > keys. The list in my SU answer lists all the iTunes tags that our muxer > currently supports. Custom global tags are possible if > > -movflags use_metadata_tags > > is added to the command. > > Then -metadata somekey=somevalue can be stored. I should update my > answer to reflect this. I can't test this but it's possible that Apple > applications may not read these or any other tags if this method is used. > > Thanks, > Gyan > _______________________________________________ > ffmpeg-user mailing list > [email protected] > http://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email > [email protected] with subject "unsubscribe". Thank you Gyan. This is exactly the information I was looking for. I was trying to understand whether the limitations were with the mp4 standard or the keys I found were defined by ffmpeg and you confirmed it isn't a limitation of the mp4 standard. I'm also so glad to know custom tags can be written because that directly contradicts the page I found on the superuser website. I understand that writing custom tags doesn't mean they will suddenly show up in software. Ex: If I added in a custom tag called "episode_number" I won't necessarily see it in software like mediainfo or itunes, etc. but it's good to know they can be written in case there is software that will display all tags including custom. Just a few more questions: 1. Where do I find your SU answer that you mention? Is there a link to see it? 2. To make sure I understand using that -movflags use_metadata_tags does this mean my command line would now be: ffmpeg -i input.mp4 -metadata media_type="10" -metadata show="Law & Order" -metadata season_number="1" -metadata title="Prescription For Death" -metadata episode_id="66209" -metadata episode_sort="1" -metadata:s:a:0 language=eng -movflags use_metadata_tags -metadata episode_number="Episode 1" -c:v libx264 --c:a aac output.mp4 3. Will custom tags display in ffprobe? 4. Can episode_sort be changed from Int8 to general number that allows more than 255 or maybe alphanumeric? As mentioned I can't use this for Law & Order Special Victims Unit and Law & Order because they are well over 255. Thanks also to Carl and Peter for your replies! Karen _______________________________________________ ffmpeg-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
