1:lavplay
From Linux Man Pages
lavplay - Playback and edit MJPEG video
lavplay [options] lavfile1 [lavfile2 ... lavfileN]
Contents |
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-cap-
ture 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. Dis-
abling 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.
-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 origi-
nal 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.
RELATED
mjpegtools(1), lavrec(1), glav(1)