PPMTOMPEG(1)PPMTOMPEG(1)NAMEppmtompeg - encodes MPEG-1 bitstreams
SYNOPSISppmtompeg [ options ] parameter-file
DESCRIPTIONppmtompeg 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 statis
tics 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 esti
mate 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 use
ful 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 num
bered 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 informa
tion 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 sum
mary, 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 direc
tory. 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 'stdin'.
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, foot
ball.002.ppm, ..., football.009.ppm, foot
ball.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, foot
ball.005.ppm, football.009.ppm, foot
ball.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 for
mats (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 sys
tem, 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 file
name (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 {EXHAUS
TIVE, TWOLEVEL, SUBSAMPLE, LOGARITH
MIC}. 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 compres
sion. 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 vec
tors, 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 com
puting 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 pro
cessor 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 param
eter 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 suf
fix ".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 -com
bine_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, fol
lowed by a listing, one machine per line, then "END_PARAL
LEL". 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 ppmtompeg (you may need to give
the complete path if you've built for different architec
tures). 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 exe
cutables and parameter files. This INCLUDES the parameter
file given as an argument to the original call to ppmtom
peg. 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 per
fectly 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, kev
ing@cs.berkeley.edu
Ketan Patel - University of California, Berkeley, kpa
tel@cs.berkeley.edu
Dan Wallach - University of California, Berkeley, dwal
lach@cs.berkeley.edu
Darryl Brown - University of California, Berkeley, dar
ryl@cs.berkeley.edu
Eugene Hung - University of California, Berkeley,
eyhung@cs.berkeley.edu
Steve Smoot - University of California, Berkeley,
smoot@cs.berkeley.edu
1 February 1995 PPMTOMPEG(1)
