mpeg_encode
NAME
mpeg_encode - encodes MPEG-1 bitstreams
SYNOPSIS
mpeg_encode [ options ] parameter-file
DESCRIPTION
mpeg_encode produces an MPEG-1 video stream. param_file is
a parameter file which includes a list of input files and
other parameters. The file is described in detail below.
The -gop, -combine_gops, -frames, and -combine_frames
options are all exclusive. This man page is probably
incomplete. For complete usage, see the User's Guide.
OPTIONS
-stat stat_file : causes the encoder to append the
statistics to the file stat_file. In any case, the
statistics are output to stdout. The statistics use
the following abbreviations: bits per block (bpb),
bits per frame (bpf), seconds per frame (spf), and bits
per second (bps).
-quiet num_seconds : causes the program to not report
remaining time for at least num_seconds seconds. A
negative values tells the program not to report at all.
0 is the default (reports once after each frame). Note
that the time remaining is an estimate and does not
take into account time to read in frames.
-realquiet : causes the encoder to run silently, with the
only screen output being errors. Particularly useful
when reading input from stdin.
-no_frame_summary : prevents the program from printing a
summary line for each frame
-float_dct : forces the encoder to use a more accurate, yet
more computationally expensive version of the DCT.
-gop gop_num : causes the encoder to only encode the
numbered GOP (first GOP is 0). The parameter file is
the same as for normal usage. The output file will be
the normal output file with the suffix ".gop.<gop_num>"
No sequence info is output.
-combine_gops : causes the encoder to simply combine some
GOP files into a single MPEG stream. A sequence
header/ender are inserted. In this case, the parameter
file need only contain the YUV_SIZE value, an output
file, and perhaps a list of input GOP files (see
below).
-frames first_frame last_frame : causes the encoder to only
encode the frames from first_frame to last_frame,
inclusive. The parameter file is the same as for
normal usage. The output will be placed in separate
files, one per frame, with the file names being the
normal output file with the suffix ".frame.<frame num>"
No GOP header information is output. (Thus, the
parameter file need not include the GOP_SIZE value)
-combine_frames : causes the encoder to simply combine some
frames into a single MPEG stream. Sequence and GOP
headers are inserted appropriately. In this case, the
parameter file need only contain the YUV_SIZE value,
the GOP_SIZE value, an output file, and perhaps a list
of frame files (see below).
-nice : causes the program to run any remote processes
'nicely.' This is only relevant if the program is
using parallel encoding. (see 'man nice.')
-max_machines num_machines : causes the program to use no
more than num_machines machines as slaves for use in
parallel encoding.
-snr : print the signal-to-noise ratio. Prints SNR (Y U V)
and peak SNR (Y U V) for each frame. In summary,
prints averages of luminance only (Y). SNR is defined
as 10*log(variance of original/variance of error).
Peak SNR is defined as 20*log(255/RMSE). Note that the
encoder will run a little slower if you want it to
print the SNR.
-mse : computes the mean squared error per block. Also
automatically computes the quality of the images when
set, so there is no need to specify -snr then.
-bit_rate_info rate_file : prints bit rate information into
the file rate_file. Bit rate info is bits per frame,
and also bits per I-frame-to-I-frame.
-mv-histogram : prints histogram of motion vectors as part
of statistics. There are three histograms -- one for
P, forward B, and backward B vectors. Each histogram
is a 2-dimensional array, and there is one entry for
each vector in the search window.
PARAMETER FILE
The parameter file MUST contain the following lines (except
when using the -combine_gops or -combine_frames options):
PATTERN <pattern>
OUTPUT <output file>
INPUT_DIR <directory>
all input files must reside in this directory. If
you want to refer to the current directory, use
'.' (an empty INPUT_DIR value would refer to the
root directory). If input files will be coming in
from standard input, use
INPUT
This line must be followed by a list of the input
files (in display order) and then the line
END_INPUT
There are three types of lines between INPUT and
END_INPUT. First, a line may simply be the name
of an input file. Secondly, the line may be of
the form
<single_star_expr> [x-y]
single_star_expr can have a single '*' in it. It
is replaced by all the numbers between x and y
inclusive. So, for example, the line
tennis*.ppm [12-15]
is replaced by tennis12.ppm, tennis13.ppm,
tennis14.ppm, tennis15.ppm. Uniform zero-padding
occurs, as well. For example, the line
football.*.ppm [001-130]
is replaced by football.001.ppm, football.002.ppm,
..., football.009.ppm, football.010.ppm, ...,
football.130.ppm. The third type of line is:
<single_star_expr> [x-y+s]
Where the line is treated exactly as above, except
that we skip by s. Thus, the line
football.*.ppm [001-130+4]
is replaced by football.001.ppm, football.005.ppm,
football.009.ppm, football.013.ppm, etc.
BASE_FILE_FORMAT <YUV or PPM or PNM or JPEG or JMOVIE>
All the input files must be converted to YUV,
JPEG(v4), JMOVIE, PNM, or PPM format. This line
specifies which of the three formats (actually PPM
is a subset of PNM). The reason for having a
separate PPM option is for simplicity. If your
files are RAWBITS ppm files, then use the PPM
option rather than the PNM. Also, depending on
the system, file reads will go much faster with
the PPM option (as opposed to PNM).
INPUT_CONVERT <conversion command>
You must specify how to convert a file to the base
file format. In the conversion command, each '*'
is replaced by the filename (the items listed
between INPUT and END_INPUT). If no conversion is
necessary, then you would just say:
INPUT_CONVERT *
If you had a bunch of gif files, you might say:
INPUT_CONVERT giftoppm *
If you have a bunch of separate a.Y, a.U, and a.V
files, then you might say:
INPUT_CONVERT cat *.Y *.U *.V
Input conversion is not allowed with input
from stdin.
GOP_SIZE <n>
n is roughly the number of frames in a Group
of Pictures (roughly because a GOP must begin
with an I-frame)
SLICES_PER_FRAME <n>
n is roughly the number of slices per frame.
Note, at least one MPEG player may complain
if slices do not start at the left side of an
image. To ensure this does not happen, make
sure the number of rows is divisible by
SLICES_PER_FRAME.
PIXEL <FULL or HALF>
use half-pixel motion vectors, or only full-
pixel ones
RANGE <n>
use a search range of +/- n pixels
PSEARCH_ALG <algorithm>
algorithm must be one of {EXHAUSTIVE,
TWOLEVEL, SUBSAMPLE, LOGARITHMIC}. Tells
what kind of search procedure should be used
for P-frames. Exhaustive gives the best
compression, but logarithmic is the fastest.
You select the desired combination of speed
and compression. TWOLEVEL is an exhaustive
full-pixel search, followed by a local half-
pixel search around the best full-pixel
vector (the PIXEL option is ignored for this
search algorithm).
BSEARCH_ALG <algorithm>
algorithm must be one of {SIMPLE, CROSS2,
EXHAUSTIVE}. Tells what kind of search
procedure should be used for B-frames.
Simple means find best forward and backward
vectors, then interpolate. Cross2 means find
those two vectors, then see what backward
vector best matches the best forward vector,
and vice versa. Exhaustive does an n-squared
search and is EXTREMELY slow in relation to
the others (Cross2 is about twice as slow as
Simple).
IQSCALE <n>
use n as the qscale for I-frames
PQSCALE <n>
use n as the qscale for P-frames
BQSCALE <n>
use n as the qscale for B-frames
REFERENCE_FRAME <ORIGINAL or DECODED>
If ORIGINAL is specified, then the original
images are used when computing motion
vectors. To be more accurate, use DECODED,
in which the decoded images are used. This
should increase the quality of the image, but
will take a bit longer to encode.
The following lines are optional:
FORCE_I_ALIGN
This option is only relevant for
parallel execution (see below). It
forces each processor to encode a block
of N frames, where N must be a multiple
of the pattern length. Since the first
frame in any pattern is an I-frame, this
forces each block encoded by a processor
to begin with an I-frame.
foo
NOTES
If the BASE_FILE_FORMAT is YUV, then the parameter file must
contain:
YUV_SIZE <w>x<h>
where w = width, h = height (in pixels) of image, and
YUV_FORMAT <ABEKAS or PHILLIPS or UCB or EYUV or
pattern>.
See the file doc/INPUT.FORMAT for more information.
If the -combine-gops option is used, then only the YUV_SIZE
and OUTPUT values need be specified in the parameter file.
In addition, the parameter file may specify input GOP files
in the same manner as normal input files -- except instead
of using INPUT_DIR, INPUT, and END_INPUT, use GOP_INPUT_DIR,
GOP_INPUT, and GOP_END_INPUT. If no input GOP files are
specified, then the default is to use the output file name
with suffix ".gop.<gop_num>" starting from 0 as the input
files.
If the -combine-frames option is used, then only the
YUV_SIZE, GOP_SIZE, and OUTPUT values need be specified in
the parameter file. In addition, the parameter file may
specify input frame files in the same manner as normal input
files -- except instead of using INPUT_DIR, INPUT, and
END_INPUT, use FRAME_INPUT_DIR, FRAME_INPUT, and
FRAME_END_INPUT. If no input frame files are specified,
then the default is to use the output file name with suffix
".frame.<frame_num>" starting from 0 as the input files.
Any number of spaces and tabs may come between each option
and value. Lines beginning with '#' are ignored. Any other
lines are ignored except for those between INPUT and
END_INPUT. This allows you to use the same parameter file
for normal usage and for -combine_gops and -combine_frames.
The encoder is case-sensitive so, except for file names and
directories, everything should be in upper case.
The lines may appear in any order, except the following
exceptions. INPUT must appear before END_INPUT (also,
GOP_INPUT before GOP_END_INPUT and FRAME_INPUT before
FRAME_END_INPUT). All lines between INPUT and END_INPUT
must be the frames in play order.
The encoder is prepared to handle up to 16 B frames between
reference frames when encoding with input from stdin. To
increase this amount, change the constant B_FRAME_RUN in
frame.c and recompile.
PARALLEL OPERATION
The encoder may be run on multiple machines at once. To do
so, add a line "PARALLEL" in the parameter file, followed by
a listing, one machine per line, then "END_PARALLEL". Each
of the lines should be in one of two forms. If the machine
has access to the file server, then the line should be:
<machine> <user> <executable>
The executable is normally mpeg_encode (you may need to give
the complete path if you've built for different
architectures). If the machine is a remote machine, then
the line should be:
REMOTE <machine> <user> <executable> <parameter file>
Full paths should generally be used when describing
executables and parameter files. This INCLUDES the
parameter file given as an argument to the original call to
mpeg_encode. Also, .rhosts files on the appropriate
machines should have the appropriate information.
The encoder will use the original machine for the master and
I/O server processes, and uses the listed machines as slaves
to do the computation.
Optional lines are
RSH <remote shell command>
The encoder uses the remote shell command to start
processes on other machines. The default command
is 'rsh.' If your machine supports a different
command, specify it here.
PARALLEL_TEST_FRAMES <n>
n is the number of frames to encode initially on
each processor
PARALLEL_TIME_CHUNKS <t>
subsequently, each slave processor will be asked
to encode for approximately t seconds. Smaller
values of <t> increase communication, but improve
load balancing.
The default values for these two options are n = 3
frames and t = 30 seconds.
PARALLEL_PERFECT
If this line is present, then scheduling is done
on the assumption that work distribution will be
perfectly even -- meaning that each machine is
about the same speed. The frames will simply be
divided up evenly between the processors. This
has the advantage of very minimal scheduling
overhead, but is obviously wrong if machines have
varying speeds, or if the network load makes
performance uneven.
VERSION
This is version 1.5 it contins new features and bug fixes
from version 1.3.
BUGS
No known bugs, but if you find any, report them to mpeg-
bugs@plateau.cs.berkeley.edu.
AUTHORS
Kevin Gong - University of California, Berkeley,
keving@cs.berkeley.edu
Ketan Patel - University of California, Berkeley,
kpatel@cs.berkeley.edu
Dan Wallach - University of California, Berkeley,
dwallach@cs.berkeley.edu
Darryl Brown - University of California, Berkeley,
darryl@cs.berkeley.edu
Eugene Hung - University of California, Berkeley,
eyhung@cs.berkeley.edu
Steve Smoot - University of California, Berkeley,
smoot@cs.berkeley.edu