NAME
lavplay - Playback and edit MJPEG video
SYNOPSIS
lavplay [options] lavfile1
[lavfile2 ... lavfileN]
DESCRIPTION
lavplay can be used to playback video in MJPEG format
(either quicktime or AVI) on a zoran video-capture device, such as
the Miro/Pinnacle DC10(+), the Iomega Buz or Linux Media Labs'
LML33, or in software mode (using SDL).
It also provides mechanisms for non-destructive editting video
using an interactive front-end such as glav(1). See
SEARCHING AND EDITING below for details.
OPTIONS
lavplay accepts the following options:
- -p/--playback [S|C|H]
- The playback mode to be used. 'S' means software-playback using
SDL. hardware-playback to the video-out of the zoran video-capture
device. Obviously, 'C' and 'H' only work on computers with zoran
video-capture devices.
- -Z/--full-screen
- Full-screen playback. This works if SDL- or onscreen-playback
is chosen.
- --size NxN
- Size of the video window (default: size of the input video)
when using software (SDL) or hardware onscreen playback
- -a/--audio num
- When play audio, 0 means never, or sum of
1: while playing forward,
2: while playing reverse,
4: even fast playing,
8: while pausing
(default: 7: forward/reverse/fast). If 8(pausing) was contained,
lavplay will be very noisy, but useful when you want to edit by
sound.
- -z/--zoom
- Zooms the video to fit the screen as good as possible.
- -x
- Exchange fields of an interlaced video. Try this if the video
looks weird. It shouldn't be necessary with stuff captured using
lavrec(1) but
could be needed for other sources.
- -s/--skip num
- Skip <num> seconds of video at the beginning.
- -x/--exchange-fields
- Invert field order (for videos which are recorded with wrong
field order interlacing settings)
- -F/--flicker
- Disable stills flicker reduction. This is useful if you want to
see stills exactly as they were recorded rather than flicker-free!
- -c/--synchronization [0|1]
- Enables (1) or disables (0) the use of sync corrections.
Basically, you almost certainly want this. Disabling is really
there for diagnostic purposes and not much else.
- -H/--H-offset num, -V/--V-offset
num
- Horizontal (-H) and vertical (-V) offset when using
hardware-playback. Offset plus width or height should be smaller
than or equal to the playback device's maximum allowed size (DC10+:
640x480 or 768x576, LML33/Marvel/Buz: 720x480/576).
- --s-x-offset num, --s-y-offset num
- Offset for the video window (from top left screen corner) when
using hardware onscreen playback in non-fullscreen mode.
- --display :x.x
- When using hardware fullsreen video playback (-pH), this
setting can be used to specify the video display (default: :0.0) to
use for video display.
- -q/--no-quit
- Makes lavplay stay alive at the end of the video (lavplay won't
quit). Use 'q<enter>' on the command line to quit (see below,
SEARCHING AND EDITING).
- -g/--gui-mode
- Enables GUI-mode. This is used by glav and Linux Video Studio.
It will output the current position in the video each frame, so
that the glav or LVS can keep track of where we are in the video
which is being played back.
- -P/--preserve-pathnames
- This is used by glav and Linux Video Studio. When editlists are
created the original pathnames for files are used and not the
canonicalised pathnames from the root directory. Useful if you've
got things like automounters active that make directories with the
same non-canonical name have different canonical names on different
machines.
- -U/--use-write
- Use the write() system call rather than the mmap() system call
for audio writing to the sound device. This may fix some audio
playback problems.
- -n/--mjpeg-buffers num
- Number of MJPEG-buffers. Default is 32. Try changing this
number if you have many lost frames.
- -v/--verbose num
- Verbosity level (0, 1 or 2)
ENVIRONMENT VARIABLES
The following environment variables
can be recognized by lavrec:
- LAV_VIDEO_DEV
- The video device. Default is /dev/video
- LAV_AUDIO_DEV
- The audio device. Default is /dev/dsp
SEARCHING AND EDITING
lavplay can do more than
simple plain playback. It is also intended to be controlled using
commands sent via stdin from a front-end like glav(1) or
similar, more sophisticated tools. The most significant aspect of
this functionality is the ability to create edit list files
giving the playback sequence of an editted version of the input
video. The edit list file can be read by any of the mjpegtools(1)
(including lavplay!) wherever an actual video file would be
acceptable. Such edit lists record only the original source file
and start and stop frames of the components of the editted video
editting rather than the video itself. As such editting leaves the
original files unchanged and requires only tiny amounts of
data-movement. The drawback is that for the edit list to work the
original files must remain unchanged, and that interactive play may
be jumpy due to the playback sequence "skipping about" between
different parts of the original video sequence.
If a stand-alone consolidated versions of editted video is
required it can be produced by running the lavtrans(1)
utility on the edit list.
Edit list files are plain text with a very simple syntax to
allow easy manual editting using a text-editor or writing of
scripted editting tools.
STDIN COMMANDS
The commands accepted on standard input sre
as follows (and can of course be entered directly by command-line
junkies):
- +, -
- Goes to next/previous frame. Only makes sense when the video is
paused.
- pN
- Sets playback speed to N (N=..., -1, 0, 1, ...)
- a[01]
- Enables/disables audio playback
- sN
- if N is a number, this means to go to frame N. if N is prefixed
by a + or -, this means to go N frames back- or forward.
- om editlist [N1 N2 [N3 N4]]
- Opens a movie or editlist. A second and third argument can
specify to only open a specific range of frames from this video
(N1=-1 means whole video). N3 and N4 can specify to show only a
specific range of frames from the frames which were just opened
(useful for trimming).
- w[as] file
- Save the current editlist (a) or the current selection (s) to a
file.
- q
- Quit lavplay.
- e[ou] N1 N2
- Cuts (u) or copies (o) frames N1-N2 from the current editlist
into an internal selection.
- ep
- Pastes the contents of the selection into the current position
in the editlist.
- em N1 N2 N3
- Moves frames N1-N2 to position N3 in the video.
- ed N1 N2
- Deletes frames N1-N2 from the editlist.
- ea video N1 N2 N3
- Adds frames N1-N2 of the video into position N3 within the
editlist. N1=-1 means to add the whole video.
- es N1 N2
- Sets the current viewable frames within the whole video to
N1-N2. This is useful for trimming.
BUGS
Editlists record absolute pathnames. This more or less
forces manual editting of the pathnames in them if it is desired to
move editlists and source video files.
lavplay really ought to make a decent job of detecting what
playback options are feasible (on-screen hardware, video-out port
hardware, software) and set the default playback mode
appropriately. Alas, it does not.
AUTHOR
This man page was written by Ronald Bultje.
If you have questions, remarks, problems or you just want to
contact the developers, the main mailing list for the MJPEG-tools
is:
For more info, see our website at
SEE ALSO
mjpegtools(1),
lavrec(1),
glav(1)