[gst-devel] Problem selecting input on tuner with v4l2src

Fredrik Persson frepe at bredband.net
Sun Apr 30 12:15:03 CEST 2006


I'm writing a small Python app where I use a Pinnacle USB tuner with v4l2src. 
The hardware have three different inputs; "Television", "Composite1" 
and "S-video". I found those using the command "v4l-info". That gave me this 

        channel                 : 0
        name                    : "Television"
        tuners                  : 1
        flags                   : 0x1 [TUNER]
        type                    : TV
        norm                    : 0
        channel                 : 1
        name                    : "Composite1"
        tuners                  : 0
        flags                   : 0x0 []
        type                    : CAMERA
        norm                    : 0
        channel                 : 2
        name                    : "S-Video"
        tuners                  : 0
        flags                   : 0x0 []
        type                    : CAMERA
        norm                    : 0

"gst-inspect v4l2src" gives me this:

  input               : input/output (channel) to switch to
                        flags: readable, writable
                        String. Default: null Current: null
  frequency           : frequency to tune to (in Hz)
                        flags: readable, writable
                        Unsigned Long. Range: 0 - 18446744073709551615 
Default: 0 Current: 0

So I assumed that "input" corresponds to the three input methods described 

This is what I did in python:

source = gst.element_factory_make("v4l2src",name="Pinnacle PCTV USB2.0")

... and then I build a pipeline using that source element. This does not work, 
I don't get the signal from the composite input. (And I know it's there, 
because when I run xawtv and select "Composite1", I can see the video 

So my question is; how do I make it so that the v4l2src element properly tells 
the v4l2 driver to select the composite (or S-video) input? (In python, 

Thank you in advance!

/Fredrik Persson

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