Ubuntu Manpage: mplex - MPEG 1/2 program/system stream multiplexer

Provided by: mjpegtools_2.1.0+debian-6build1_amd64

NAME

       mplex - MPEG 1/2 program/system stream multiplexer

SYNOPSIS

       mplex  [-f|--format  format_code]  [-i|--vdr-index]  index_pathname [-v|--verbose num] [-b|--video-buffer
       video_buffer_size_kB[, video_buffer_size_kB...]] [-L|--lpcm-params params[, params...]] [-r|--mux-bitrate
       muxed_bitrate_kbps]   [-l|--mux-limit   num]   [-O|--sync-offset   num[ms|s|mpt]]  [-d|--subpicture-delay
       [ms|s|mpt|c][:stream-id][,delay[:stream-id]] [-R|--run-in num]  [-V|--vbr]  [-C|--cbr]  [-s|--sector-size
       sector_size_B]      [-p|--packets-per-pack      num]     [-h|--system-headers]     [-S|--max-segment-size
       output_filesize_limit_MB] [-M|--split-segment]

       [-?|--help] -o|--output output_pathname_pattern input_file...

DESCRIPTION

       Mplex is a general-purpose audio/video multiplexer for MPEG-1/MPEG-2.  It accepts one  or  more  MPEG-1/2
       video  stream,  MPEG layer I/II/III, DTS, AC3 and LPCM audio streams and multiplexes them into a combined
       program/system stream according to the constraints specified.  Many different types of  output  structure
       are  supported  along  with  presets for standard VCD and SVCD streams.  These latter can be burned to CD
       using tools such as vcdimager(1) and played in stand-alone players.

       It is also capable of automatically splitting the output stream into chunks of a  specified  size  either
       independently or at sequence end/start points in the input video stream.

GENERAL FUNCTION LETTERS

       -o|--output output_filename_pattern
              This mandatory option sets the pattern for the name(s) of output files.

              An  integer format code (e.g. %d) in the name is replaced by the number of the file generated (see
              printf(3)).

       -v|--verbose num
              Set verbosity level to num:
               0 - warnings and errors only,
               1 - information as well,
               2 - really verbose.

       -?|--help
              Display a synopsis of the command syntax.

FUNCTION LETTERS

-f|--format format_code
This command allows one of a number of convenient preset output formats or generic MPEG1 or MPEG2
output to be selected. For the generic formats other function letters can be used to control many
aspects of the multiplexed stream. For VCD/SVCD/DVD compliant output the corresponding formats
must be used as the standards require the multiplexer to enforce a variety of special constraints
on the structure of the output stream.

0 - Generic MPEG1. A simple general-purpose MPEG1 format primarily suitable for software
decoders. Buffer sizes and VBR must be specified. Bit-rate can be auto-detected.
1 - VCD. Standard VCD. Overrides other option settings.
2 - User VCD. VCD format but buffer size, bit rate and VBR can be set manually.
3 - Generic MPEG2. Like 0 except MPEG2.
4 - SVCD. Standard SVCD. Overrides other option settings.
5 - User-rate SVCD. SVCD format but buffer size bit rate and VBR can be set.
6 - VCD Stills stream (mixed mode with hi-res and standard-res image streams multiplexed
are supported).
7 - SVCD Stills stream.
8 - DVD (with NAV sectors). Don't get too excited. This is really a
very minimal mux format. It includes empty versions of the peculiar
VOBU start sectors DVD VOB's include. This is enough to persuade some
hardware players to play the stream but is a long way from full DVD authoring.
9 - DVD. As above but without the empty VOBU sectors.

-W|--workarounds workaround_flag [,workaround_flag...]
A comma-seperated list of flags that set special work-arounds for what are suspected to be parser
Bugs in widely used players. No workarounds are (currently) implemented but history suggests this
may change quickly ;-) -i|--vdr-index index_pathname This tells mplex to generate an index file
for the output in the format used by the 'vdr' (video disk recorder package). Useful if you want
to write output into vdr's recordings directory for playback on your video recorder PC. This
probably only useful in combination with -f 9.

-r|--mux-bitrate num
The total (non VBR) / peak (VBR) bit-rate of the output stream in k Bits/sec. If unspecified and
not set by a preset it is automatically calculated from the input stream.

-b|--video-buffer numlist
A comma-seperateed list of video decoder buffer sizes in KB for the video streams (given in the
order the video streams appear on the command line). The default is 46KB the (tiny) size
specified for VCD. The size to use for SVCD is the (more reasonable) 230KB. If you are encoding
for a half-decent software decoder it makes sense to push this up to 500K or more.

-L|--lpcm-params
samples_per_sec:channels:bits_per_sample
[, samples_per_sec:channels:bits_per_sample
...]
A comma-seperated list of paramter sets for the lpcm audio streams (given in the order the lpcm
streams appear on the command line). Each parameter set comprises the sampling rate in Hz, the
number of channels, and the number of bits per sample seperated by colons. For example, the
default 48kHz two-channel 16-bit audio would be specified as 48000:2:16.

Note: these parameters are necessary because mplex expects raw LPCM audio data without any
headers. That is: for each sample point a group of 16,20, or 24 bit amplitude values, one for
each channel. Amplitude values are signed with the constituent bytes in big-endian (most
significant bytes first) order. For 20 bit samples I am not sure but what documentation I have
suggests such samples are padded at the lsb end so that they byte-align at the most significant
bits.

-l|--mux-limit num
Multiplex limit. Multiplex only the specified number of seconds. Useful for tuning and
debugging.

-O|--sync-offset num[ms|s|mpt|c]
Set the presentation timestamp offset of video stream w.r.t. audio stream (video-audio) in mSec.
This flag is used to produce a stream with synchronised audio/video when one stream started
before/after the other. This is common when transcoding as the synchronisation information is
typically lost during the (seperate) decoding/encoding of audio and video.

By appending 's', 'ms' or 'mpt' the offset can given in seconds, milliseconds or MPEG clock ticks
(1/90000th of a second) respectively. If no suffix is given milliseconds are assumed.

-d|--subpicture-delay num[ms|s|mpt|c][:stream-id][,delay[:stream-id]]
Specify offset of timestamps (video-subpicture) in msec sec, mpt or clock-ticks. If no suffix is
given milliseconds are assumed.

The intention of the adding subtitle support was to enable mplex to mux all streams necessary for
a DVD so that the mpeg2 stream created can be used directly for further dvd creation. Currently
only ps1 streams (like created by tcextract) are supported

Valid subtitle stream are in a range of 32-63 (including). You may want to specify each stream
you mplex, use "," to delimit each stream.

Example: If you want to mux one video, one audio and two subtitle streams having delays of 500 and
1000 ms, the first shall have id 32, the second is 33 (Subtitle streams 0 and 1):

$ mplex -f 8 -o my_mpeg.mpeg -d 500:32,1000:33 video_in.mpv audio_in.m2a subtitle_0.ps1
subtitle_1.ps1

-R|--run-in num
Set a non-default run-in (the time data is preloaded into buffers before decoding is scheduled) at
the start of each sequence in video frame intervals. By default a run-in matching the specified
size of the video and audio buffers in the decoder and the type of multiplexing (constant or
variable bit-rate) is selected automatically.

-V|--vbr
Force variable bit rate multiplexing even if selected profile defaults to constant-bit-rate.

-C||-cbr
Force constant bit rate multiplexing even if selected profile defaults to variable bit-rate.

-s|--sector-size num
This option specifies the sector size of the output stream in bytes.

-p|--packets-per-pack num
This option specifies the number of packets per pack in the output stream.

-S|--max-segment-size num
This option specifies the maximum size of output files in MBytes (2^10) When the limit is reached
a new file is started. The default is (0) unlimited.

Note: This option is not for splitting a long video across multiple VCD's or SVCD's.

It simply splits a single long sequence into in a way that prevents bits of a video GOP(group of
pictures) or audio frame being split between chunks. This is fine for formats like that used for
DVDs where all stream parameters appear every GOP. However, for VCD / SVCD it won't work as the
players expect each file to start a new MPEG sequence.

For VCD / SVCD a different technique is used. If mplex encounters a sequence break (sequence end
followed by start) in the input video stream it starts a new output stream and file at the
sequence start. Thus to split a long video across VCD's/SVCD's you have to get the MPEG video
encoder to introduce sequence splits at the right points (see mpeg2enc(1) for details of how to do
this).

-M|--ignore-seqend-markers
This flag makes mplex ignore sequence end markers embedded in the first video stream instead of
switching to a new output file. This is sometimes useful splitting a long stream in files based
on a -S limit that doesn't need a run-in/run-out like (S)VCD.

-h|--system-headers
A system header is generated in every pack rather than just in the first.

DIAGNOSTIC OUTPUT

       When  multiplexing  using mplex you may get warning or error messages complaining about buffer underflow.
       This means that the bit-rate you have specified is simply too low to permit the video  and  audio  to  be
       played  back  without  skipping.   The  fix  is  to  either reduce the data-rate of the input material or
       increased the output stream bit-rate.

BUGS

       The multiplexer should handle MPEG(5.1) audio.

AUTHOR

       This man page was written by Andrew Stevens.
       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