[FFmpeg-devel] [PATCH] avformat/flvenc: allow to write qualifying metadata as number

[Anton Khirnov]

Quoting Gyan Doshi (2023-02-19 09:13:55)
> On 2023-02-14 06:21 pm, Gyan Doshi wrote:
> >
> >
> > On 2023-02-14 03:35 pm, Anton Khirnov wrote:
> >> Quoting Gyan Doshi (2023-02-11 12:02:51)
> >>> The FLV format can store metadata as numbers which are used and handled
> >>> by many streaming platforms.
> >>>
> >>> Now, metadata values can be sent as AMF Number type if
> >>> 1) tag key starts with "num_"
> >>> 2) value is scanned and can be represented as a double.
> >>>
> >>> Written tag will have "num_" prefix removed if written as AMF Number.
> >> Using the normal metadata dict for structured data seems hacky to me.
> >> Wouldn't it be better to add a private dict-type muxer option for this?
> >
> > The numerical metadata, like other string meta in FLV can change 
> > during streaming, so it will be
> > reloaded and refreshed. Once you suggested to shift the loading 
> > metadata from file + reload options
> > to fftools, this was the way to identify such metadata, since format 
> > contexts and AVStream only support
> > one AVDictionary and entries will have to be commingled
> >
> > And this isn't really structured data. We are re-encoding how some of 
> > it is stored. It is still inputted
> > by the user as strings. The prefix is a cheap hack to clearly identify 
> > such keys.
> >
> > (The other option would be add AVDictionary value 'types' and all 
> > associated signalling and tooling,
> > which seems useful in the long run but overkill for this.)

We have way too many hacks already, because everbody's looking for a
quick solution and ignores longterm maintainability.
I don't think this patch should go in.

-- 
Anton Khirnov