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XVidCap - Record X11 screen portions to video
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]
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/
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.
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.
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.
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