[FFmpeg-devel] [PATCH 5/6] fftools: avradio support

[Michael Niedermayer]

On Thu, Jul 27, 2023 at 03:05:23PM +0200, Tomas Härdin wrote:
> ons 2023-07-26 klockan 12:37 +0200 skrev Michael Niedermayer:
> 
> > But what my goal after
> > having some fun with SDR is, is to
> > serve the end user. And here iam
> > trying to make it possible that "FFmpeg based" players and tools
> > can use SDR.
> 
> Which tools and players?

Thats a good question. I did not state that clearly probably

The idea really is any tool which is able to use an arbitrary
demuxer / input device.

all of our tools (ffplay, ffprobe, ffmpeg) work
but our doc/examples should work too

Also id like to say thanks for writing this mail without terse
attacks like some other replies i got.


> 
> > For FFmpeg using a C or C++ libraray for some parts of SDR like DAB
> > is something that makes sense and i plan to go that route. But beyond
> > that I simply do not understand how your suggestions would server
> > end users
> 
> End users are already served by existing programs like gqrx.

I disagree, let me explain

Let me first explain what i want to provide to the user (most of this
is already implemented, some needs more work)
the user starts her favorite player, be that vlc, ffplay, or whatever
chooses sdr as input device and thats all configuration she needs.
She can select a specific driver, gain and so but she doesnt have to
Now she only needs 2 buttons, seek forward and seek backward, in
ffplay thats the cursor keys. To select the station.
And she sees on the screen what station that is, what song title and
artist are playing as well as what is playing on any other FM station
in view (that works here already in europe, for the US if it doesnt work
i need a sample from dumpurl ...)
(for non interactive tools like ffmpeg she would have to select the
frequency she wants to listen to or all in view ...)

Now gqrx needs me to manually enter the frequency, the modulation the
device, then it still doesnt work (first one has to know why from multiple
rtlsdr lines some dont work) and once one is through this it still
doesnt work, all AGC methods dont work, i have to set the gain manually
for the station i want to listen to to have acceptable quality. I do know
but at this point we lost likely 90% of users already who dont realize that
the AGC sets a too high gain
Also gqrx doesnt tell me what iam listening to, the
name of the radio station?
the artist ?
the song name ?
nothing like this is shown
and if i want to switch to the next station i have to enter its frequency
or click on the location of the radio spectrum

gqrx is a tool a radio amateur like you will be happy with (and i
realize likely more powerfull tools would fit even better)

but i think the average user wants to listen to or record broadcast radio
and have as little to mess with and has the maximum information like
song names and titles available


> My point
> is rather about the sanity of our developers, and of downstream
> developers. The fact that you don't mention downstream projects by name
> tells me that you haven't asked them

The original plan of an input device should not affect anyone in
any way who doesnt want to use it. Its just another device.
libavradio could affect people because it could be an extra dependancy
an extra package and so on.
I will propose a patchset to libavradio that avoids this.

Thanks!

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No great genius has ever existed without some touch of madness. -- Aristotle
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