NAME
XVidCap - Record X11 screen portions to video
SYNOPSIS
xvidcap [-v] [ --mf | --sf ] [--file file name pattern |- ] [--fps
frames per second] [--cap_geometry geometry] [--rescale size
percentage] [--quality quality percentage] [--source x11|shm ]
[--time maximum duration in seconds] [--frames maximum frames]
[--start_no initial frame number] [--continue yes|no ] [--gui
yes|no ] [--auto] [--codec video codec] [--codec-help]
[--format output file format] [--format-help] [--audio yes|no ]
[--aucodec audio codec] [--aucodec-help] [--audio_in audio
capture device |- ] [--audio_bits audio bit rate] [--audio_rate
audio sample rate] [--audio_channels audio channels]
INTRODUCTION
xvidcap is a tool that captures movement on a selected area of an X11
screen to files. It can operate in two distinct modes: (1) single-frame
capture or (2) multi-frame capture. In single-frame capture mode
xvidcap takes a configurable number of screenshots per second and saves
them to individual files. In multi-frame capture mode xvidcap also
takes a number of screenshots per second, but encodes them to a single
video in real time. Audio capture is only available with multi-frame
formats.
Recording in single-frame capture mode may be more convenient if you
wish to preprocess the images before encoding, or if you need other
video codecs xvidcap does not support. Individual images can later be
encoded with tools like ffmpeg, mencoder, or transcode.
For help, feature requests, or bug-reports please turn to
http://www.sourceforge.net/projects/xvidcap/
OPTIONS
This program follows the usual GNU command line syntax, with long
options starting with two dashes (--). A summary of options is
included below.
-v Runs xvidcap in verbose mode. This will provide more information
about user settings, input and output codecs, performance and so
forth. Messages like ‘"missing XX milli secs .."’ while
capturing mean you are missing frames due to lack of ressources
(dropped frames). This results in a video that will play back
too quickly. Note though, that verbose mode slows down xvidcap
and may actually be causing frame drops. Try running without
verbose mode and watch the frame drop monitor.
--mf | --sf
xvidcap tries to be smart about what capture mode you want. If
you specify --file test.avi xvidcap will assume you want multi-
frame capture. You can explicitly specify capture mode on the
command line with this switch. If, for example, you have your
settings properly configured and saved with multi-frame capture
as the default mode, calling xvidcap --sf will start xvidcap in
single-frame capture mode with all stored settings. The default
is multi-frame capture.
--file file name pattern
File name or pattern to use for saving the captured frames. A
file name pattern contains printf()-like formatting (ref. man
printf) information to make the file name incrementable, e.g.
--file out-%02d.xwd. This is necessary for single-frame
capture. xvidcap will replace the first printf() format string
with the number of the frame currently captured. Thus, in the
example given, it will write to files out-00.xwd, out-01.xwd,
out-02.xwd, etc. The frame number to start with can be specified
with --start_no, see above.
Multi-frame capture does not need a file pattern. If you specify
one nonetheless like --file mymovie-%d.mpeg for example, xvidcap
will replace the format string with the number of the current
recording session (always starting the count from zero). This
will enable you to manually in-/decrement that number, or use
the autocontinue feature (ref. --continue below) effectively
creating a series of video files.
--fps frames per second
Specifies the number of frames to be captured per second. This
parameter accepts floating point values, which allows for very
low capture rates like e.g. --fps 0.5 to record one frame every
2 seconds. This is only possible in single-frame mode. Codecs
used for multi-frame modes usually only accept certain frame
rates as valid. Note that fractional frame rates for codecs like
MPEG1 which only accept very specific fractions are disabled in
this version due to an inconsistency with fractional timing
between xvidcap and libavcodec. Only integer frames rates will
be accepted here.
--cap_geometry geometry
Specify the geometry as for e. g. xterm, i. e. like this:
widthxheight+x-position+y-position
This overrides the default width and height of the capture
frame. Use the picker button of the GUI rather than this command
line option to adjust the frame size to a given window. Capture
sizes below 20 x 20 don’t seem to work well with most multi-
frame capture codecs.
--rescale size percentage
Rescale the output to a percentage of the original input. A
value of 25, e. g. makes the output size be 25 percent of the
original input area. Rescaling does not work with XWD output.
--quality quality percentage
Specify a value between 0 and 100 to define the quality
encoding. The default value is 90. Note that the effect of a
value below 100 has changed in version 1.1.5.
--source x11|shm
Enable or disable the usage of the X11 shared memory extension.
For shared memory support both client and server have to run on
the same host. If shared memory support is available, xvidcap
will use it by default. If your X server and client do not run
on the same machine, you need to disable it by passing --source
x11.
--time maximum duration in seconds
Specifies the maximum time to capture, a value of 0 will cause
xvidcap to capture until stopped interactively. For any other
value any recording session will stop automatically after the
specified number of seconds. This parameter conflicts with
--frames (see below). If both are given xvidcap will stop
capturing when either applies. The program accepts floating
point values, e.g. 2.5.
--frames maximum frames
Stops capturing after the specified number of frames are
captured. If 0 xvidcap will capture until stopped interactively,
ref. --time above.
--start_no initial frame number
Defines the start number which should be used for numbering
files. The default value is 0.This parameter is used for single-
frame capture only. The numbering of movie files for --continue
always starts at zero.
--continue yes|no
When multi-frame capture is selected, maximum recording time or
frames are specified, and the output filename is incrementable
(see --file below), xvidcap can automatically continue to
capture to a new file when one exceeds the maximum recording
time or number of frames. This will change the behaviour of
--time and --frames because recording will not stop at the
specified limits, but rather start a new video file. The feature
is esp. useful if you want to automatically split your recording
into chunks of e. g. five minutes. If no argument --continue is
given, xvidcap defaults to no. Because single-frame capture
needs an incrementable filename to count the individual frames,
this feature is disabled for single-frame capture.
--gui yes|no
Start xvidcap with or without control GUI overriding what’s in
the preferences file. Running without GUI will automatically
start a single capture session. It can be stopped by either
specifying one of --time or --frames, or by hitting CTRL-C.
--auto xvidcap supports automatic detection of parameters for output
format, video- and audio codec. If any of those settings are
saved as fixed values in the stored preferences, they can be
overriden by specifying the parameter auto to any of the
arguments --format, --codec, or --aucodec. This argument is a
shorthand for setting all three to automatic detection.
--codec video codec
Override preferences and automatic codec selection with the
explicitly specified codec.
--codec-help
List valid codecs.
--format output file format
Override preferences and automatic format selection with the
explicitly specified file format.
--format-help
List valid file formats.
AUDIO OPTIONS
The following options relate to audio capture which is available with
multi-frame output formats only. There audio streams can either be
captured from a compatible audio device (e.g. /dev/dsp) or from STDIN
(ref. --audio_in below).
--audio yes|no
Enable or disable audio capture using default parameters or
those saved to the preferences file. If supported this is
enabled by default for multi-frame capture.
--aucodec audio codec
Override preferences and automatic codec selection with the
explicitly specified audio codec.
--aucodec-help
List valid audio codecs.
--audio_in audio capture device|-
Capture audio from the specified device or from stdin. The
latter allows for dubbing a captured video using a command line
like the following. The default is /dev/dsp.
cat some.mp3 | xvidcap --audio_in -
--audio_bits audio bit rate
Set the desired bit rate. The default is 64000 bit. Note that
when using STDIN input the input file will be resampled as
needed.
--audio_rate audio sample rate
Set the desired sample rate. The default is 44100 Hz. Note that
when using STDIN input the input file will be resampled as
needed.
--audio_channels audio channels
Set the desired number of channels. The default is 2 for stereo.
Any value above 2 is probably only useful with STDIN input and a
5-channel AC audio input file or very good and rare recording
equipment.
AUTHORS
xvidcap was written by Rasca Gmelch and Karl H. Beckers.
This manual page was written by Karl H. Beckers
<karl.h.beckers@gmx.net> for the xvidcap project.
This translation was done by TRANSLATOR-CREDITS HERE!!!
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1 or
any later version published by the Free Software Foundation; with no
Invariant Sections, no Front-Cover Texts and no Back-Cover Texts.