mplex - Online in the Cloud

PROGRAM:

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.

Use mplex online using onworks.net services