lavplay(1) MJPEG tools manual lavplay(1)NAMElavplay - Playback and edit MJPEG video
SYNOPSISlavplay [options] lavfile1 [lavfile2 ... lavfileN]
DESCRIPTIONlavplay 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.
OPTIONSlavplay accepts the following options:
-p/--playback [S|C|H]
The playback mode to be used. 'S' means software-playback using
SDL.
'H' means hardware-playback on the monitor (on-screen). 'C'
means 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 con‐
tained, 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. Basi‐
cally, 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 set‐
ting 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 directo‐
ries 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 num‐
ber 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 EDITINGlavplay 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 "skip‐
ping 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:
mjpeg-users@lists.sourceforge.net
For more info, see our website at
http://mjpeg.sourceforge.net/
SEE ALSOmjpegtools(1), lavrec(1), glav(1)MJPEG Linux Square 6 December 2001 lavplay(1)
