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doc/indevs: apply misc fixes to the v4l2 documentation

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Reviewed-by: Giorgio Vazzana <mywing81@gmail.com>
This commit is contained in:
Stefano Sabatini 2013-01-31 12:53:50 +01:00
parent 514216d8a9
commit a842dc632e
1 changed files with 10 additions and 7 deletions
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doc/indevs.texi
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@ -583,10 +583,16 @@ command:
ffmpeg -f sndio -i /dev/audio0 /tmp/oss.wav
@end example
@section video4linux2
@section video4linux2, v4l2
Video4Linux2 input video device.
"v4l2" can be used as alias for "video4linux2".
If FFmpeg is built with v4l-utils support (by using the
@code{--enable-libv4l2} configure option), the device will always rely
on libv4l2.
The name of the device to grab is a file device node, usually Linux
systems tend to automatically create such nodes when the device
(e.g. an USB webcam) is plugged into the system, and has a name of the
@ -599,8 +605,6 @@ supported using @command{-list_formats all} for Video4Linux2 devices.
Some devices, like TV cards, support one or more standards. It is possible
to list all the supported standards using @command{-list_standards all}.
Some usage examples of the video4linux2 devices with ffmpeg and ffplay:
The time base for the timestamps is 1 microsecond. Depending on the kernel
version and configuration, the timestamps may be derived from the real time
clock (origin at the Unix Epoch) or the monotonic clock (origin usually at
@ -608,8 +612,8 @@ boot time, unaffected by NTP or manual changes to the clock). The
@option{-timestamps abs} or @option{-ts abs} option can be used to force
conversion into the real time clock.
Note that if FFmpeg is build with v4l-utils support ("--enable-libv4l2"
option), it will always be used.
Some usage examples of the video4linux2 devices with @command{ffmpeg}
and @command{ffplay}:
@example
# Grab and show the input of a video4linux2 device.
ffplay -f video4linux2 -framerate 30 -video_size hd720 /dev/video0
@ -619,8 +623,7 @@ framerate and size as previously set.
ffmpeg -f video4linux2 -input_format mjpeg -i /dev/video0 out.mpeg
@end example
"v4l" and "v4l2" can be used as aliases for the respective "video4linux" and
"video4linux2".
For more information about Video4Linux, check @url{http://linuxtv.org/}.
@section vfwcap