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Hi.
I'm developing an aplication for
image recognizing under linux with v4l2. My program starts very good, everything
goes right. I detect the device, get and set the correct properties (at least i
think so) but when i try to tune the tuner (um.) with VIDIOC_S_FREQUENCY, it
doesn't work.
VIDIOC_G_FREQUENCY doesn't work
either.
Previously i have
made:
- Opened the
device "/dev/video0" with open
- Query
capabilities of the device VIDIOC_QUERYCAP
- supports capture
- supports read (this is what i am going to use)
- Query the
type of input VIDIOC_G_INPUT
- there are one tuner and 2 camera inputs.
- the current input is the tuner but for
security...
- Selected
the tuner input VIDIOC_S_INPUT
- Query the
format of the capture VIDIOC_G_FMT setting the type field to
V4L2_BUF_TYPE_CAPTURE
- Set the new
format of the capture VIDIOC_S_FMT
- Modifying the result previously got.
- Query again
the format (and it goes right)
- Query the
standard VIDIOC_G_STD
-PAL
- Query the
current tuner VIDIOC_G_TUNER
- Tuner with standar pal but the frequencies are 0 and -1
(tuner.rangelow, tuner.rangehigh)
...and then...
- Query the
frequency of the tuner VIDIOC_G_FREQUENCY (with the struct v4l2_frequency to
zero)
The end.
I can't make
VIDIOC_S_FREQUENCY.
Have i
jumped any step in the way?
Is there any
mistake?
I have read
the sample programs but no one uses the tuner.
I have tried
to read xawtv but i lose myself in so much code. What i need is a simple program
that tunes one channel, capture the image with read() and thats all. I don't
need sound.
Is there any
tutorial anywhere?
and the
simple program?
Thanks.
pd:
Sorry for my english. I have
been 6 years without practising it, and 6 years ago i was very bad too.
:)
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