[FFmpeg-devel] [PATCH v6 0/1] avformat: add Software Defined Radio support

Kieran Kunhya kierank at obe.tv
Sat Jul 1 23:42:14 EEST 2023


>
> If we look at DAB or DVB in a more fundamental way, they have no need
> for mpegts.
> Should this (apparently unneeded) design decission in DAB/DVB dictate
> design on our side when it has not previously ?
>

What planet do you live on, of course they need MPEG-TS? How do you have
multiple programs in a mux and associated data for EPG?
Literally the whole point of Digital TV was that we could put more channels
in the space that one analogue channel took.
There are no other containers that support multiple programs.

For the rest of MPEG-TS justification I point you to:
https://www.obe.tv/why-does-mpeg-ts-still-exist/


> If so, what design ?
>

This is purely a flaw in FFmpeg that protocol/demux are joined up into the
same library. Also an assumption (coming from things like AVI and probably
reasonable at the time) that there is only going to be one layer of demux,
whereas in modern codecs (HEIF, LC-EVC, Dolby E etc) there can be many
layers of demux required.

Your logic is flawed, you base your assumption that everyone else is wrong
when it's in fact FFmpeg that's in the wrong by mixing transport and
container into the same library.


> > As for purely AM/FM, I'm not quire sure what the right level for
> > that is though.
>
> >
> > In any case, I disagree with the procedure of stating to push the patch
> if
> > there's no objections, when there has been numerous objections from
> > essentially most of the active community already.
>
> The objections have been unclear, are they against SDR, against the
> implementation.
> I took the liberty to be pushy here to get this more clear. And i will
> continue to do this until i get clear responses. Because otherwise
> iam just stuck as i dont know how to correct the design and code.
>

They are against SDR as this violates layering. FFmpeg doesn't handle the
physical layer, third party libs do upstream (e.g hardware capture).
Again, should we implement WiFi SDR in FFmpeg? Should we implement a
userspace TCP stack? Should we implement bitbanged Ethernet? All of these
things sit at a different layer to the data and transport layer that FFmpeg
sits in.

Regards,
Kieran Kunhya


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