Turning of webcam auto-focus

[Paul Smith]

Dear All,

To turn off the auto-focus feature of my webcam, I used the following command:

v4l2-ctl -c focus_auto=0

However, recently, the same command returns the following:

# v4l2-ctl -c focus_auto=0
unknown control 'focus_auto'
#

Any ideas?

Thanks in advance,

Paul

[Ed Greshko]

On 12/03/2021 04:34, Paul Smith wrote:
> Dear All,
>
> To turn off the auto-focus feature of my webcam, I used the following command:
>
> v4l2-ctl -c focus_auto=0
>
> However, recently, the same command returns the following:
>
> # v4l2-ctl -c focus_auto=0
> unknown control 'focus_auto'
> #
>
> Any ideas?

What does

v4l2-ctl -l

return?

Do you more than one /dev/videoX device?

[Paul Smith]

On Thu, Mar 11, 2021 at 9:14 PM Ed Greshko  wrote:
> > To turn off the auto-focus feature of my webcam, I used the following command:
> >
> > v4l2-ctl -c focus_auto=0
> >
> > However, recently, the same command returns the following:
> >
> > # v4l2-ctl -c focus_auto=0
> > unknown control 'focus_auto'
> > #
> >
> > Any ideas?
>
> What does
>
> v4l2-ctl -l
>
> return?
>
> Do you more than one /dev/videoX device?

Thanks, Ed.

---------------------------------------
#  v4l2-ctl -l
User Controls

keep_format 0x0098f900 (bool)   : default=0 value=0
              sustain_framerate 0x0098f901 (bool)   : default=0 value=0
                        timeout 0x0098f902 (int)    : min=0 max=100000
step=1 default=0 value=0
               timeout_image_io 0x0098f903 (bool)   : default=0 value=0
#
---------------------------------------

I have only one webcam. But I am using a virtual camera via OBS Studio.

Paulo

[Ed Greshko]

On 12/03/2021 05:24, Paul Smith wrote:
> #  v4l2-ctl -l
> User Controls
>                  keep_format 0x0098f900 (bool)   : default=0 value=0
>            sustain_framerate 0x0098f901 (bool)   : default=0 value=0
>                      timeout 0x0098f902 (int)    : min=0 max=100000
>
> step=1 default=0 value=0
>                 timeout_image_io 0x0098f903 (bool)   : default=0 value=0
> #
>
> I have only one webcam. But I am using a virtual camera via OBS Studio.

AFAIK, the v4l2-ctl command gets its information from the device and/or driver in use by the device.

Do you know if the loss of focus_auto happen recently?  If so, try booting to a previous kernel to see
if a kernel change may have triggered it.

FWIW, the webcam of my laptop has ceased working.  Old age.  And I only have a USB Capture HDMI
device on my desktop that does create both a /dev/video0 and /dev/video1.

[Roger Heflin]

You might try uvcdynctl that is what I have been using as it directly
talks to the webcam.

It will show the controls that exist and let you query and set them.

On Thu, Mar 11, 2021 at 4:14 PM Ed Greshko  wrote:
> On 12/03/2021 05:24, Paul Smith wrote:
> > #  v4l2-ctl -l
> > User Controls
> >                  keep_format 0x0098f900 (bool)   : default=0 value=0
> >            sustain_framerate 0x0098f901 (bool)   : default=0 value=0
> >                      timeout 0x0098f902 (int)    : min=0 max=100000
> >
> > step=1 default=0 value=0
> >                 timeout_image_io 0x0098f903 (bool)   : default=0 value=0
> > #
> >
> > I have only one webcam. But I am using a virtual camera via OBS Studio.
>
> AFAIK, the v4l2-ctl command gets its information from the device and/or driver in use by the device.
>
> Do you know if the loss of focus_auto happen recently?  If so, try booting to a previous kernel to see
> if a kernel change may have triggered it.
>
> FWIW, the webcam of my laptop has ceased working.  Old age.  And I only have a USB Capture HDMI
> device on my desktop that does create both a /dev/video0 and /dev/video1.
>
> --
> People who believe they don't make mistakes have already made one.
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[Roger Heflin]

On Thu, Mar 11, 2021 at 6:03 PM Roger Heflin  wrote:
> You might try uvcdynctl that is what I have been using as it directly
> talks to the webcam.
>
> It will show the controls that exist and let you query and set them.

uvcdynctrl that is.

guvcview will give you an interactive tool to test with and display it.

and you can often get settings set prior to going into an application
to stay, that is if the application does not reset the values.  And
you should be able to run uvcdynctrl while some apps are running and
change the settings while the app has it open.

[Ed Greshko]

On 12/03/2021 08:18, Roger Heflin wrote:
> On Thu, Mar 11, 2021 at 6:03 PM Roger Heflin  wrote:
> > You might try uvcdynctl that is what I have been using as it directly
> > talks to the webcam.
> >
> > It will show the controls that exist and let you query and set them.
>
> uvcdynctrl that is.

FWIW, uvcdynctrl seems to return much the same info as does v4l2-ctl.  At least for my capture device.

[egreshko@meimei ~]$ uvcdynctrl -c
Listing available controls for device video0:
   Brightness
   Contrast
   Saturation
   Hue

[egreshko@meimei ~]$ v4l2-ctl -l
                      brightness 0x00980900 (int)    : min=-100 max=100 step=1 default=0 value=0
                        contrast 0x00980901 (int)    : min=50 max=200 step=1 default=100 value=100
                      saturation 0x00980902 (int)    : min=0 max=200 step=1 default=100 value=100
                             hue 0x00980903 (int)    : min=-90 max=90 step=1 default=0 value=0

v4l2-ctl seems just a tad bit more user friendly since it returns the current value for the controls.

[Paul Smith]

On Fri, Mar 12, 2021 at 12:27 AM Ed Greshko  wrote:
> > > You might try uvcdynctl that is what I have been using as it directly
> > > talks to the webcam.
> > >
> > > It will show the controls that exist and let you query and set them.
> >
> > uvcdynctrl that is.
>
> FWIW, uvcdynctrl seems to return much the same info as does v4l2-ctl.  At least for my capture device.
>
> [egreshko@meimei ~]$ uvcdynctrl -c
> Listing available controls for device video0:
>    Brightness
>    Contrast
>    Saturation
>    Hue
>
> [egreshko@meimei ~]$ v4l2-ctl -l
>                       brightness 0x00980900 (int)    : min=-100 max=100 step=1 default=0 value=0
>                         contrast 0x00980901 (int)    : min=50 max=200 step=1 default=100 value=100
>                       saturation 0x00980902 (int)    : min=0 max=200 step=1 default=100 value=100
>                              hue 0x00980903 (int)    : min=-90 max=90 step=1 default=0 value=0
>
> v4l2-ctl seems just a tad bit more user friendly since it returns the current value for the controls.

Thanks, Roger. Ed's suspicion has turned out to be pointing to the
right direction:

------------------------------------
# v4l2-ctl --list-devices
OBS Virtual Camera (platform:v4l2loopback-000):
    /dev/video0

EasyCamera 5M: EasyCamera 5M (usb-0000:01:00.0-7):
    /dev/video1
    /dev/video2
    /dev/media0
#
------------------------------------

The default camera is taken to be the virtual one. Thus, running the command:

v4l2-ctl -d /dev/video1 -c focus_auto=0

went fine!

Paul