Documentation:Modules/v4l2

2011-12-10T01:31:39Z

Josn: corrected typo or old info: 'vlc:quit' -> 'vlc://quit'

{{Module|name=v4l2|type=Access|first_version=0.9.0|os=Linux|description=Video for Linux 2 input}}
{{Module|name=v4l2|type=Access Demux|first_version=0.9.0|os=Linux|description=Video for Linux 2 input}}

== Options ==

{{Option
|name=v4l2-caching
|value=integer
|description=Caching in ms
}}

=== Video input ===
{{Option
|name=v4l2-dev
|value=string
|default="/dev/video0"
|description=Primary device name
}}
{{Option
|name=v4l2-standard
|value=integer
|default=0
|description=Video standard
}}
{{Option
|name=v4l2-chroma
|value=string
|default=""
|description=Force use of a specific video chroma (Use MJPG here to use a webcam's MJPEG stream)
}}
{{Option
|name=v4l2-input
|value=integer
|default=0
|description=Card input to use for video
}}
{{Option
|name=v4l2-audio-input
|value=integer
|default=0
|description=Card input to use for audio
}}
{{Option
|name=v4l2-io
|value=integer
|default=0
|description=IO method
}}
{{Option
|name=v4l2-width
|value=integer
|default=0
|description=Prefered video width (if non zero)
}}
{{Option
|name=v4l2-height
|value=integer
|default=0
|description=Prefered video height (if non zero)
}}
{{Option
|name=v4l2-fps
|value=float
|default=0
|description=Frames per second (if non zero)
}}

=== Audio input ===
These options do not apply to audio streams in compressed data.
{{Option
|name=v4l2-adev
|value=string
|default=""
|description=Audio input device
}}
{{Option
|name=v4l2-audio-method
|value=integer
|default=3
|description=Allowed audio input methods (bitmask: 1 for OSS, 2 for ALSA)
}}
{{Option
|name=v4l2-stereo
|default=enabled
|description=Capture audio in stereo
}}
{{Option
|name=v4l2-samplerate
|value=integer
|default=48000
|description=Audio input sample rate in Hz
}}

=== Tuner ===
{{Option
|name=v4l2-tuner
|value=integer
|default=0
|description=Tuner to use
}}
{{Option
|name=v4l2-tuner-frequency
|value=integer
|default=-1
|description=Tuner frequency in Hz or MHz depending on the underlying v4l2 driver
}}
{{Option
|name=v4l2-tuner-audio-mode
|value=integer
|default=-1
|description=Tuner audio mode
}}

=== Controls ===
These controls will be used only if they are supported by the v4l2 driver.
{{Option
|name=v4l2-controls-reset
|default=disabled
|description=Reset all the v4l2 controls
}}
{{Option
|name=v4l2-brightness
|value=integer
|default=-1
|description=Brightness
}}
{{Option
|name=v4l2-contrast
|value=integer
|default=-1
|description=Contrast
}}
{{Option
|name=v4l2-saturation
|value=integer
|default=-1
|description=Saturation
}}
{{Option
|name=v4l2-hue
|value=integer
|default=-1
|description=Hue
}}
{{Option
|name=v4l2-black-level
|value=integer
|default=-1
|description=Black level
}}
{{Option
|name=v4l2-auto-white-balance
|value=integer
|default=-1
|description=Auto white balance
}}
{{Option
|name=v4l2-do-white-balance
|value=integer
|default=-1
|description=Do white balance
}}
{{Option
|name=v4l2-red-balance
|value=integer
|default=-1
|description=Red balance
}}
{{Option
|name=v4l2-blue-balance
|value=integer
|default=-1
|description=Blue balance
}}
{{Option
|name=v4l2-gamma
|value=integer
|default=-1
|description=Gamma
}}
{{Option
|name=v4l2-exposure
|value=integer
|default=-1
|description=Exposure
}}
{{Option
|name=v4l2-autogain
|value=integer
|default=-1
|description=Auto gain
}}
{{Option
|name=v4l2-gain
|value=integer
|default=-1
|description=Gain
}}
{{Option
|name=v4l2-hflip
|value=integer
|default=-1
|description=Flip the image horizontaly
}}
{{Option
|name=v4l2-vflip
|value=integer
|default=-1
|description=Flip the image verticaly
}}
{{Option
|name=v4l2-hcenter
|value=integer
|default=-1
|description=Horizontal center
}}
{{Option
|name=v4l2-vcenter
|value=integer
|default=-1
|description=Vertical center
}}
{{Option
|name=v4l2-audio-volume
|value=integer
|default=-1
|description=Audio volume
}}
{{Option
|name=v4l2-audio-balance
|value=integer
|default=-1
|description=Audio balance
}}
{{Option
|name=v4l2-audio-mute
|default=disabled
|description=Audio mute
}}
{{Option
|name=v4l2-audio-bass
|value=integer
|default=-1
|description=Audio bass
}}
{{Option
|name=v4l2-audio-treble
|value=integer
|default=-1
|description=Audio treble
}}
{{Option
|name=v4l2-audio-loudness
|value=integer
|default=-1
|description=Audio loudness
}}
{{Option
|name=v4l2-set-ctrls
|value=string
|default=""
|description=Set any other control listed in the debug output using a comma seperated list in curly braces such as {video_bitrate=6000000,audio_crc=0,stream_type=3}
}}

== Example ==

Open a video device with default settings:
% '''vlc v4l2:///dev/video0:width=640:height=480'''

Get information about a video device's capabilities:
% '''vlc -vvv --color v4l2:///dev/video0 --run-time 1 vlc://quit -I dummy -V dummy -A dummy

Command line for Hauppauge PVR 250 to get France 2 (at ECP) and encode as MPEG2 and stream using UDP multicast:
% '''vlc -I dummy -vvv 'v4l2c://:audio-method=0:controls-reset:set-ctrls={video_bitrate_mode=1,video_bitrate=4000000,video_peak_bitrate=4000000}:width=720:height=576:tuner=0:tuner-frequency=478550' --sout "#std{access=udp{ttl=12},mux=ts,url=239.255.1.1}"'''
Note: v4l2c is an alias used to force VLC to use the v4l2 module in it's Access variant without probing the Access Demux version first (the c stands for compressed).

== See also ==
* [[Documentation:Modules/v4l]]
* [[Documentation:Modules/dshow]]

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VideoLAN Wiki - User contributions [en]

Documentation:Modules/v4l2