[gst-devel] FM radio using v4lsrc

Alexey Chernov 4ernov at gmail.com
Wed Feb 17 21:36:09 CET 2010


В сообщении от Среда 17 февраля 2010 17:29:48 автор gstreamer-devel-
request at lists.sourceforge.net написал:

>you will probably have to use v4l2 interface directly, or link v4l2src !
>fakesink and set v4l2src into locked state at READY. The point is that
>there can't be any dataflow between v4l2src and fakesink. The 2nd part
>could be e.g. alsasrc ! wavenc ! filesink location="...". You will need
>to use the GstMixerInterface on alsasrc to ensure you record from the
>right source. I don't have an example for that.
Yeah, I just tried it today, pipeline went OK to READY and PLAYING state and 
noise was in speakers, but I found that it seems that /dev/videoX and 
/dev/radioX are separate tuners and incompatible even on ioctl level (i.e. 
even frequency is set in different formats). So, setting /dev/videoX as a 
device I cannot tune to any station, but on setting /dev/radioX as a device 
v4l2src cannot recognize it as a tuner.

I decided to create custom element for radio tuning using v4l2src code and 
radiobin mentioned above. This element communicates with /dev/radioX device 
using ioctl's and implements GstTuner interface (unnecessary methods just do 
nothing).

Stefan, perhaps  you have some information, don't I do a duplicate job writing 
it? Maybe, there're some way to get work FM radio using only v4l2src with 
/dev/videoX tuner? Or something other way? If not, maybe it would be sensible 
to include such an element, maybe on top of mine, to at least gst-plugins-bad, 
because I think it could be useful for someone else building FM radio 
application using GStreamer.

Thank you for support and information,
Alexey




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