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Selecting Input Channel for QCamera

  • Hi all,

    I am using a Hauppauge ImpactVCB model 558 video capture card to capture the output of several analogue cameras on Linux. This card has 4 input channels (3 RCA, 1 s-video). On Linux, the card shows up as a single /dev/videoX device and can be access using V4L2. The required channel can be selected using the "input" setting. I've tested it using mplayer and I see the expected image on two of the channels. So I know the card works. I've used the following command for this test:

    mplayer tv:// -tv driver=v4l2:norm=NTSC:device=/dev/video0:input=0

    Next I would like to capture the video using the QCamera class, so I can analyse the image using Qt. Qt detects the camera at /dev/video0 and correctly shows the image on the input channel 0. However I do not see an option in the class to select a different input channel. Is it possible to change such settings (input channel, NTSC vs PAL) of a camera using the QCamera class?

    Karol Krizka

  • Lifetime Qt Champion


    I might be wrong but I have a doubt about that.

    Out of curiosity, do you have the equivalent line for GStreame ?

  • @SGaist, I do not have an equivalent line for gstreamer. I looked at the output of gst-inspect v4l2src, but don't see the input property there. I can change the norm there though.

    I've ended up implementing the reading from the capture card using the V4L2 functions and converting the output to an QImage.

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