v4l2.md 1.9 KB
title: Video4Linux 2 (V4L2) breadcrumbs:
- title: Media --- {% include header.md %}
A tool to manage video input devices (mainly webcams).
Setup
- Install:
apt install v4l-utils
Usage
- Show video devices:
- List devices:
v4l2-ctl --list-devices - Show brief device info:
v4l2-ctl [-d <dev>] --info - Show extended device info:
v4l2-ctl [-d <dev>] --all - Show device formats:
v4l2-ctl [-d <dev>] --info --list-formats - If no device is specified, it defaults to
/dev/video0. - Certain devices show up as multiple
/dev/video*files. Typically there's one video capture device and one metadata capture device. Use the command above to find out.
- List devices:
- Modify video device properties:
- Show properties with min, max and current values:
v4l2-ctl [-d <dev>] --all - Different webcams come with different properties and property names.
- Change a property (non-permanent):
v4l2-ctl [-d <dev>] -c <property>=<value> - Properties may be modified while the device is in use.
- As property changes are not permanent, you may want to set them in a script or something.
- Higher exposure may lead to reduced frame rate. To make it brighter you may increase the gain instead.
- Focus and white balance can typically be left at auto. Brightness, contrast and saturation should typically be left at default.
- Logitech C920 and similar:
- Disable auto focus:
focus_auto=0 - Disable auto exposure:
exposure_auto=1 - Set exposure manually (after auto is disabled):
exposure_absolute=250 - Set gain:
gain=250 - Disable auto white balance:
white_balance_temperature_auto=0 - Set white balance manually (after auto is disabled):
white_balance_temperature=4000 - Set brightness, contrast and saturation (generally not needed):
brightness=128,contrast=128,saturation=128
- Disable auto focus:
- Show properties with min, max and current values:
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