VIDEO(1) | General Commands Manual | VIDEO(1) |
video
— record or
display images from
video(4)
video |
[-cdgqRv ]
[-a adaptor]
[-e encoding]
[-f file]
[-i input]
[-O output]
[-o output]
[-r rate]
[-s size]
[control[=value]] |
video
is a utility for reading, writing
and displaying streams of raw video frames. By default frames are read from
file and displayed via
Xv(3). The default
file is /dev/video. If the
-o
option is used frames are read from
file and written to output. If
the -i
option is used frames are read from
input and displayed via
Xv(3). If the
-O
option is used frames are read from
file, written to output and
displayed via Xv(3). The
acutance, brightness, contrast, gain, gamma, hue, saturation and white
balance temperature controls of file can also be
adjusted if file supports these controls.
The options are as follows:
-a
adaptor-c
-d
-e
encodinguyvy
’,
‘yuy2
’ and
‘yv12
’. The default is
‘yuy2
’ unless
file is being used and only supports
‘uyvy
’, in which case
‘uyvy
’ will be used by default.-f
file-g
-i
input-
’, frames will be read from
standard input.-O
output-
’, frames will be written to
standard output. In contrast to -o
, if this option
is used, video
will also display the frames via
Xv(3).-o
output-
’, frames will be written to
standard output.-q
-R
-r
rate-r
option is not specified, frames
will be read as quickly as possible. If reading from a
video(4) device, the
device's frame rate will be set to the frame rate the device supports that
is closest to rate. Frames will be read as quickly
as they are available from the device, but will be displayed and/or
written to output at the rate specified, unless the
-R
option is used.-s
sizex
’,
size is interpreted as only the width. If
‘x
’ is the first character of
size, the characters following
‘x
’ are interpreted as the height.
If only one of width or height is specified, the other will be calculated
using a 4:3 width:height ratio. For example, if given
‘-s 640
’
video
will use a size of
‘640x480
’. When reading from a
video(4) device and
displaying the frames on an
Xv(3) display, this option also
accepts two special strings, ‘half
’
and ‘full.
’ If either
‘half
’ or
‘full
’ are specified,
video
will read frames that are no larger than 2/3
the display width and 2/3 the display height. If
‘full
’ is specified,
video
will stretch the frame to the full size of
the display using Xv(3)
scaling. If video
is reading frames from a
video(4) device and the
frame size does not match a frame size the device supports,
video
will use the largest frame size supported by
the device that is smaller than the specified size.-v
video
will quit reading frames and exit
nicely if it receives any of the following signals: SIGHUP, SIGINT, SIGKILL,
SIGTERM, SIGPIPE.
video
responds to certain key presses
while it is displaying frames. The keypresses are as follows:
A
a
B
b
C
c
f
G
g
H
h
M
m
O
-O
option is used.o
-O
option is used.p
q
video
.r
S
s
W
w
The following command will read YUY2 encoded, 640 pixel wide and 480 pixel high video frames from /dev/video and display them using the default Xv(3) adaptor:
$ video
The following command will read YUY2 encoded, 640 pixel wide and 480 pixel high video frames from /dev/video and write them to video.raw at a rate of 15 frames per second:
$ video -r 15 -o
video.raw
The following command will read YUY2 encoded, 640 pixel wide and 480 pixel high video frames from /dev/video, write them to video.raw and display them using the default Xv(3) adaptor at a rate of 15 frames per second:
$ video -r 15 -O
video.raw
The following command will read YUY2 encoded, 640 pixel wide and 480 pixel high video frames from video.raw and display them on the default Xv(3) adaptor at a rate of 15 frames per second:
$ video -r 15 -i
video.raw
Note that with the first three commands, if /dev/video does not support 640x480 pixels sized frames, the largest frame size smaller than 640x480 will be used, and if /dev/video does not support yuy2 encoding, uyvy will be used.
August 5, 2020 | OpenBSD-6.8 |