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

Gyan Doshi ffmpeg at gyani.pro
Sun Feb 19 10:13:55 EET 2023

Any further comments?

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.)
> Regards,
> Gyan
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