mpeg_play
NAME
mpeg_play - plays mpeg-1 encoded bitstreams using X11
SYNOPSIS
mpeg_play [ -nob ] [ -nop ] [ -display display_name ] [ -
quality {on|off} ] [ -dither dither_option ] [ -loop ] [ -
eachstat ] [ -seek offset ] [ -start num ] [ -end num ] [ -
gamma gamma_correction_value ] [ -framerate num ] [ -
no_display ] [ -controls {on|off|none} ] [ -shmem_off ] [ -
l_range num ] [ -cr_range num ] [ -cb_range num ] [ -quiet ]
file_name
DESCRIPTION
mpeg_play decodes and displays mpeg-1 encoded bitstreams on
systems running X11. The player will create a new window,
display the bitstream, and exit. Any error messages or
notices are sent to stderr.
OPTIONS
-nob : causes the player to ignore and not display any B
frames.
-nop : causes the player to ignore and not display any P and
B frames.
-display display_name : causes the player to open the window
on the display display_name.
-quality {on|off} : forces player to choose output quality
over speed when on, and vice versa when off. When
quality is on, the player uses a computationally
expensive IDCT and also improves playback through
improved handling of half pixel motion vectors. The
default can be set to on if you compile mpeg_play with
the flag -DQUALITY.
-dither dither_option : selects from a variety of dither
options. The possible values are:
ordered - ordered dither.
ordered2 - a faster ordered dither. This is the
default.
mbordered - ordered dithering at the macroblock level.
Although there is a noticeable decrease in dither
quality, this is the fastest dither available.
fs4 - Floyd-Steinberg dithering with 4 error values
propagated.
fs2 - Floyd-Steinberg dithering with 2 error values
propagated.
fs2fast - Fast Floyd-Steinberg dithering with 2 error
values propagated.
hybrid - Hybrid dithering, a combination of ordered
dithering for the luminance channel and Floyd-
Steinberg 2 error dithering for the chrominance
channels. Errors are NOT propagated properly and
are dropped all together every two pixels in
either direction.
hybrid2 - Hybrid dithering as above, but with error
propagation among pixels.
2x2 - A dithering technique using a 2x2 pixel area for
each pixel. The image displayed is 4 times larger
than the original image encoded. Random error
terms are added to each pixel to break up contours
and gradients.
gray - Grayscale dithering. The image is dithered into
128 grayscales. Chrominance information is thrown
away.
gray256 - Grayscale dithering. The image is dithered
into 256 grayscales (requires private colormap).
Chrominance information is thrown away.
color - Full color display (only available on 16/24 bit
color displays).
color2 - Full color display with increased size (only
available on 16/24 bit color displays).
none - no dithering is done, no image is displayed.
Used to time decoding process.
mono - Floyd-Steinberg dithering for monochrome
displays.
threshold - Floyd-simple dithering for monochrome
displays.
ppm - Write a PPM file for each frame.
-loop : makes the player loop back to the beginning after
reaching the end.
-owncm : makes the player use a private colormap for the
window.
-step : requires the user to press return for each new
frame.
-seek offset : before playing the movie, seek to the given
offset in the file (useful for large movies). In this
case -end is redefined to give the number of frames to
play, and -start has no meaning. The offset should
point to a Sequence or (closed) GOP header, but data
will be discarded until one is found. The initial
sequence header will be parsed before the seek. The
skipped sections must not change the quantization
matrices or the results are undefined.
-start num : Waits to start display until this frame number
(previous frames are parsed).
-end num : ends display at this frame number (except when
-seek is used).
-gamma gamma_correction_param : specifies the amount of
gamma correction. Default is 1.0. Use higher values
if movie looks dark and hard to see.
-framerate num : sets the framerate of the playback to num
frames per second. A value of 0 indicates that the
stream should be played as fast as possible. The
default is to play at the rate specified in the stream
(if possible). Note this is merely a framerate
limiter, it will not discard frames to meet the rate.
-controls {on|off|none} : determines the initial interactive
X user interface control bar state (if available). The
value on (default) opens the control bar at
initialization and enters pause mode after displaying
the first frame. The value off leaves the control bar
initially hidden and begins playback without pausing
(similar to the old behavior). The control bar can be
toggled on and off at any time by clicking in the video
display window, unless the -controls none option is
specified, in which case the control bar is unavailable
and playback functions as though the player were built
without interactive controls (exactly the old
behavior).
-quiet : suppresses printing of frame numbers, timing
information, and most error messages.
-eachstat : causes statistics to be displayed after each
frame. Only valid when compiled with -DANALYSIS.
-shmem_off : turns shared memory off.
-l_range num_colors : sets the number of colors assigned to
the luminance component when dithering the image. The
product of l_range, cr_range and cb_range should be
less than the number of colors on the display.
-cr_range num_colors : sets the number of colors assigned to
the red component of the chrominance range when
dithering the image. The product of l_range, cr_range
and cb_range should be less than the number of colors
on the display.
-cb_range num_colors : sets the number of colors assigned to
the blue component of the chrominance range when
dithering the image. The product of l_range, cr_range
and cb_range should be less than the number of colors
on the display.
-no_display : dithers, but does not display, usually used
for testing and timing purposes.
NOTES
The player expects video streams only. It can handle
multiplexed MPEG streams (video+audio streams) by discarding
the audio.
Some streams do not end with the proper sequence end code
and will probably generate an "Improper sequence end code."
error when done playing.
This player can play XING data files. Be aware that XING
makes no use of temporal redundancy or motion vector
information. In other words, they do not use any P or B
frames in their streams. Instead, XING data is simply a
sequence of I frames. Since I frames take significantly
longer to decode, performance of the player using XING data
is not representative of the player's ability.
The player does not play MPEG-1 D-frame streams, but they
are a rarity.
If the player is compiled without the controlbar, then it
can play multiple streams in different windows.
VERSION
This is version 2.1a, containing some new features since
2.0, and several bug fixes. It is a major change since
version 1.0.
BUGS
The only known bug is that multiple mpeg_plays cannot seem
to be run simultaneously on a multiprocessor SPARC 20 or a
SparcCenter 2000E using shared memory (in particular: "On a
bi-processor Sparc 20/20 sparc-processor 2000E running
Solaris 2.3 or 2.4, it is not possible to run two concurrent
'mpeg_play -loop' on the same bitstream. One of the
mpeg_play dies when it loops." This may be a problem with
the X shared memory library and not our code.)
AUTHORS
Ketan Patel - University of California, Berkeley,
kpatel@cs.berkeley.edu
Brian Smith - University of California, Berkeley,
bsmith@cs.berkeley.edu
Henry Chi-To Ma - University of California, Berkeley,
cma@cs.berkeley.edu
Kim Man Liu - University of California, Berkeley,
kliu@cs.berkeley.edu
Steve Smoot - University of California, Berkeley,
smoot@cs.berkeley.edu
Eugene Hung - University of California, Berkeley,
eyhung@cs.berkeley.edu