[ivtv-devel] input signal detection

Hans Verkuil hverkuil at xs4all.nl
Fri Jul 18 23:31:24 CEST 2008

On Friday 18 July 2008 23:20:39 Boris Dores wrote:
>   Hi guys,
>   Is there a way with version 0.10.6 to ask the saa711x chip if it
> has detected an input signal (I mean in a C/C++ program, not with
> "v4l2-ctl --log-status") ? I need this to determine if the cable
> set-top box must be powered on (with an LIRC transmitter) before
> recording.
>   In 0.4.4, I used "ioctl( fd, IVTV_IOC_G_DECODER_REG, &saa7115_reg
> )" and interpreted the result just as it was done in "ivtvctl -I".
>   The same can probably be done in 0.10.6, but "ivtvctl
> --list-registers" (which seemed the logical place to look, right ?)
> fails whatever the parameters are (but I'm not sure what they should
> be actually).
>   Thanks.

The V4L2 ioctl VIDIOC_G_TUNER has a signal field that is 65535 when a 
signal is present. I guess that's what you want.



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