MPEG 1/2 program/system stream multiplexer
see also :
mpeg2enc - mp2enc - lavplay - lav2yuv - lav2wav - yuvscaler
[-v|--verbose num] [-b|--video-buffer
[-R|--run-in num] [-V|--vbr]
-o|--output output_pathname_pattern input_file...
add an example, a script, a trick and tips
no example yet ...
... Feel free to add your own example above to help other Linux-lovers !
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
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.
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.
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
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
multiplexed are supported).
7 - SVCD Stills stream.
8 - DVD (with NAV sectors). Don’t get too excited. This is
very minimal mux format. It includes empty versions of the
VOBU start sectors DVD VOB’s include. This is enough to
hardware players to play the stream but is a long way from full
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.
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.
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.
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.
Multiplex limit. Multiplex only the specified number of seconds.
Useful for tuning and debugging.
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.
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
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
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
Force variable bit rate multiplexing even if selected profile
defaults to constant-bit-rate.
Force constant bit rate multiplexing even if selected profile
defaults to variable bit-rate.
This option specifies the sector size of the output stream in
This option specifies the number of packets per pack in the
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).
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
A system header is generated in every pack rather than just in
general function letters
This mandatory option sets the pattern for the name(s) of output
An integer format code (e.g. %d) in the name is replaced by the
number of the file generated (see printf(3)).
Set verbosity level to num:
0 - warnings and errors only,
1 - information as well,
2 - really verbose.
Display a synopsis of the command syntax.
should handle MPEG(5.1) audio.
mp2enc , lavrec, lavplay ,
lav2yuv , lav2wav ,
This man page
was written by Andrew Stevens.
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