[FFmpeg-devel] [PATCH] avformat: add option to parse/store ID3 PRIV tags in metadata.

wm4 nfxjfg at googlemail.com
Wed Jan 17 21:38:50 EET 2018


On Wed, 17 Jan 2018 11:10:26 -0800
Richard Shaffer <rshaffer at tunein.com> wrote:

> [...]
> I'm also not sure if an option for compatibility is needed. It's
> > probably fine to prefix the name with something (maybe "id3v2_priv."?),
> > and always export it.
> >  
> 
> I guess my thought was that users of ffmpeg/ffprobe might have some
> scripting or programming around the metadata API, such as dumping metadata
> with -f ffmetadata and then mapping it to a stream later. In those cases,
> this change might suddenly cause behavior that they weren't expecting.

That's probably a lost cause. The "metadata" the FFmpeg API is full of
container specific things and rather arbitrary. I don't think it
matters to invent and export a few new keys.

What needs to be assured is that the entry names can't clash with
generic tag names (there's a list in avformat.h), which is why I
suggested adding a prefix to the name.

Although if metadata entries are very long (like big binary blobs)
there might be a problem. I don't know what's the use of those priv
tags though.

> Maybe that would be mitigated to some degree if we could also map
> 'id3v2_priv' back to PRIV tags on output. That would actually address a use
> case that I have and would be super from my standpoint. I'll work on
> implementing that. Please let me know if you have additional thoughts.

Probably makes sense.


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