On 12/21/2012 07:38:52 PM, Mike Isely wrote:
On Thu, 20 Dec 2012, Helmut Jarausch wrote:
> On 12/19/2012 04:40:08 PM, Mike Isely wrote:
>
> Hi Mike,
>
> that was my testing all the time.
>
> Now, I've traced xawtv step for step.
> The single control which is needed by my device to even produce a
single byte
> of output on /dev/video0 is
>
> v4l2-ctl -s "pal"
>
> i.e. setting the video standard to PAL.
Oh, of course. I'm getting slow. The driver tries to pick a default
video standard based on the hardware it has encountered but that is an
imperfect process at best. But it's also true that any app which
uses a
V4L2 device really has the responsibility to set the correct video
standard to be used, which is what xawtv did for you there.
I tend to miss this because my area is NTSC and the driver tends to
start in that mode automatically for me.
Last time I've been using my PVRUSB2 (one or two years ago)
this wasn't necessary. And neither VLC nor MPLAYER2 are able
to read /dev/video0 unless I issue that control in advance.
>
> Is there any means to set this without v4l2-ctl ?
Yes, there is a sysfs way to do this...
>
> Here, I do not have
> /sys/class/pvrusb2/sn-8039400/ctl_video_standard
I believe there was a change a while back which eliminated that
particular control (because the underlying V4L feature I believe went
away). However you can achieve the same effect with another control.
IIRC, it's ctl_video_standard_mask_active. I can e-mail additional
detail about that, if you haven't already figured it out.
Yes please, because
echo "PAL" >
/sys/class/pvrusb2/sn-8039400/ctl_video_standard_mask_active/cur_val
gave echo: write error: invalid argument
and cat
/sys/class/pvrusb2/sn-8039400/ctl_video_standard_mask_active/cur_val
showed a null string.
After issueing v4l2-ctl -s "pal"
the same command gives
PAL-B PAL-B1 PAL-G PAL-H PAL-I PAL-D PAL-D1 PAL-K
Thanks and Merry Christmas,
Helmut.
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