[FFmpeg-user] Trying to add metadata media_type to mp4

Kieran O Leary kieran.o.leary at gmail.com
Fri Jul 14 18:11:21 EEST 2017

Hi both,

On Fri, Jul 14, 2017 at 2:32 PM, Andrey Goreev <aegoreev at gmail.com> wrote:

> I am pretty sure there was a large table with All the media types listed
> here: https://developer.apple.com/library/content/
> documentation/QuickTime/QTFF/Metadata/Metadata.html

That was the spec I mentioned. I can't find it there.

> I am not able to locate it from my phone right now though.
> There is also one on exiftool webpage.

Thanks, yes, that's really useful!

On Fri, Jul 14, 2017 at 3:53 PM, Karen Norton <nortok00 at gmail.com> wrote:

> Thanks for the speedy reply!! Is it just me or is getting info on writing
> metadata tags proving to be a challenge?

Yeah it seems so. I'm thinking of adding some info to the ffmpeg
documentation when I have a chance.

> I'm having a hard time finding
> comprehensive metadata documentation by media and container type (ex: I
> know mkv allows for custom tags but mp4 doesn't). I checked out that
> webpage you sent Andrey but wasn't able to find all of the flags and their
> parameters. I will look at it again. If there is a page listing everything
> that would be great.
> You are correct Kieran... media_type is an integer. Thanks. I should have
> thought to try that first although I wouldn't have thought to go to "10".

To be honest I would never have even guessed that it was an INT if I hadn't
looked at the source code. My experience with using -metadata is that your
usually pass a string.

> Most likely just 0 and 1. Thanks for sending those github pages!! That gave
> me what I needed for this flag.
> I came across this page (ttps://thediveo-e.blogspot.
> ca/2016/06/adventures-in-ffmpeg-meta-data-writing.html) with a limited set
> of flags which is what I've been going by but it doesn't have media_type. I
> discovered this flag via a gui program I have that converts mkv to mp4 and
> it has built in tagging. You can select "Movie", "Music", "TV Show" and a
> few others. I assumed this was a string field but obviously they have the
> selections mapped to integers as in "1" = Movie, etc.
I guess the integer is nice as it can allow for a stricter adherence to a
controlled vocabulary. But it adds an extra layer of complexity as that
table of entries must be easily available. As Andrey wrote, exiftool has a
good vocab here too for media_type/stik

> Given metadata is the cornerstone by which we live our lives I'm surprised
> I'm having such a hard time finding information. I just assumed there would
> be a metadata bible out there for media. :-) I'm keeping my own document of
> all the sites I find info on in hopes of piecing everything together. :-)

Can you send that on please? I work in a moving image archive so I am
interested in metadata resources.


Kieran O'Leary

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