v4l2loopback-ctl1
Control v4l2 loopback devices
Usage
v4l2loopback-ctl [OPTIONS]
v4l2loopback-ctl add
[OPTIONS]
[<outputdevice>
[<capturedevice>]]
v4l2loopback-ctl delete
<device>
v4l2loopback-ctl list
[OPTIONS]
v4l2loopback-ctl query
[OPTIONS]
<device>
v4l2loopback-ctl set-fps
<device>
<fps>
v4l2loopback-ctl get-fps
<device>
v4l2loopback-ctl set-caps
<device>
<caps>
v4l2loopback-ctl get-caps
<device>
v4l2loopback-ctl set-timeout-image
[OPTIONS]
<device>
<image>
Overview
Manage v4l2 loopback devices.
The general invocation uses a verb (like 'add' or 'delete') that defines an action to be executed. Each verb has their own options and arguments.
Options
-h, -?, --help: print this help and exit
-v, --version: print version and exit
Verbs and their arguments
v4l2loopback-ctl add [OPTIONS] [<outputdevice> [<capturedevice>]]:
|
create/add a new loopback-device |
|
|
buffers to queue |
|
maximum allowed frame height |
|
pretty name for the device |
-o <num>, --max-openers <num> maximum allowed concurrent openers
|
verbose mode (print properties of device after successfully creating it) |
|---|---|
|
maximum allowed frame width |
|
whether to announce OUTPUT/CAPTURE capabilities exclusively |
|
minimum allowed frame width |
|
minimum allowed frame height |
-?,
|
print this help and exit |
<outputdevice>
|
if given, create a specific device (otherwise just create a free one). |
|
either specify a device name (e.g. '/dev/video1') or a device number ('1'). |
|
<capturedevice>
|
if given, use separate output & capture devices (otherwise they are the same). |
v4l2loopback-ctl delete <device>:
-
delete/remove an unused loopback device
- <device>
-
can be given one more more times (to delete multiple devices at once). either specify a device name (e.g. '/dev/video1') or a device number ('1').
v4l2loopback-ctl list [OPTIONS]:
|
list all available loopback-devices |
|
|
escape control-characters in (device) names |
|
print this help and exit |
v4l2loopback-ctl query [OPTIONS] <device>:
-
query information about a loopback device
-e,--escape-
escape control-characters in (device) names
-h,--help-
print this help and exit
- <device>
-
can be given one more more times (to query multiple devices at once). either specify a device name (e.g. '/dev/video1') or a device number ('1').
v4l2loopback-ctl set-fps <device> <fps>:
|
set the default framerate for a loopback device |
|
<device>
|
either specify a device name (e.g. '/dev/video1') or a device number ('1'). |
<fps>
|
frames per second, either as integer ('30') or fraction ('50/2'). |
v4l2loopback-ctl get-fps <device>:
-
query the framerate of a loopback device
v4l2loopback-ctl set-caps <device> <caps>:
-
set format/dimension/framerate of a loopback device
- <device>
-
either specify a device name (e.g. '/dev/video1') or a device number ('1').
- <caps>
-
format specification as '<fourcc>:<width>x<height>@<fps>' (e.g. 'UYVY:1024x768@60/1') unset the current caps with the special value 'any'
v4l2loopback-ctl get-caps <device>:
-
get current format/dimension/framerate of a loopback device
v4l2loopback-ctl set-timeout-image [OPTIONS] <device> <image>:
-
set a fallback image to be used if a video producer does not send new frames in time.
- <flags>
-
any of the following flags may be present
-h,--help-
print this help and exit
-t<timeout>,--timeout<timeout>-
timeout (in ms)
-v,--verbose-
raise verbosity (print what is being done)
- <device>
-
either specify a device name (e.g. '/dev/video1') or a device number ('1').
- <image>
-
image file
Releases
8 releases since Debian 7 (Wheezy); the text changed 7 times.