Encoding with MEncoder
For the complete list of available MEncoder options
and examples, please see the man page. For a series of hands-on examples and
detailed guides on using several encoding parameters, read the
encoding-tips that were
collected from several mailing list threads on mplayer-users. Search the
archives
for a wealth of discussions about all aspects of and problems related to
encoding with MEncoder.
Encoding 2 or 3-pass MPEG-4 ("DivX")2-pass encoding
The name comes from the fact that this method encodes the file twice.
The first encoding (dubbed pass) creates some temporary files
(*.log) with a size of few megabytes, do not delete
them yet (you can delete the AVI). In the second pass, the 2-pass output
file is created, using the bitrate data from the temporary files. The
resulting file will have much better image quality. If this is the first
time you heard about this, you should consult some guides available on the
Net.
This example shows how to encode a DVD to a 2-pass MPEG-4 ("DivX") AVI.
Just two commands are needed:
rm frameno.avi
remove this file, which can come from a previous 3-pass encoding (it interferes
with current one)
mencoder -dvd 2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=1 -oac copy -o movie.avi
mencoder -dvd 2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=2 -oac copy -o movie.avi
3-pass encoding
This is an extension of 2-pass encoding, where the audio encoding takes
place in a separate pass. This method enables estimation of recommended
video bitrate in order to fit on a CD. Also, the audio is encoded only
once, unlike in 2-pass mode. The schematics:
Remove conflicting temporary file:
rm frameno.aviFirst pass:mencoder file/DVD -ovc frameno -oac mp3lame -lameopts vbr=3 -o frameno.avi
An audio-only avi file will be created, containing
only the requested audio stream. Don't forget
, if you need to set it. If you were encoding a
long movie, MEncoder prints the recommended
bitrate values for 650Mb, 700Mb, and 800Mb destination sizes, after this
pass finishes.
Second pass:
mencoder file/DVD -oac copy -ovc lavc -lavcopts vcodec=mpeg4:vpass=1:vbitrate=bitrate
This is the first pass of video encoding. Optionally specify the video
bitrate MEncoder printed at the end of the previous pass.
Third pass:
mencoder file/DVD -oac copy -pass 2 \
-ovc divx4 -divx4opts br=bitrate
This is the second pass of video encoding. Specify the same bitrate
as in the previous pass unless you really know what you are doing.
In this pass, audio from frameno.avi will be
inserted into the destination file...and it's all ready!
Example of 3-pass encodingrm frameno.avi
remove this file, which can come from a previous 3-pass encoding
(it interferes with current one)
mencoder -dvd 2 -ovc frameno -o frameno.avi -oac mp3lame -lameopts vbr=3
mencoder -dvd 2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=1 -oac copy -o movie.avi
mencoder -dvd 2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=2 -oac copy -o movie.avi
Encoding to MPEG formatMEncoder can create MPEG (MPEG-PS) format output
files. It's probably useful only with libavcodec's mpeg1video
codec, because players - except MPlayer - expect MPEG1
video, and MPEG1 layer 2 (MP2) audio streams in MPEG files.
this feature is not very useful right now, aside that it probably has many bugs,
but the more importantly because MEncoder currently cannot encode MPEG1 layer 2
(MP2) audio, which all other players expect in MPEG files.
To change MEncoder's output file format, use the option.
Example:
mencoder -of mpeg -ovc lavc -lavcopts vcodec=mpeg1video -oac copy other options media.avi -o output.mpg
Rescaling movies
Often the need to resize movie images' size emerges. Its reasons can be
many: decreasing file size, network bandwidth,etc. Most people even do
rescaling when converting DVDs or SVCDs to DivX AVI. This is bad.
Instead of even you doing so, read the Preserving aspect ratio
section.
The scaling process is handled by the scale video filter:
.
Its quality can be set with the option.
If it's not specified, MEncoder will use 0: fast
bilinear.
Usage:
mencoder input.mpg -ovc lavc -lavcopts vcodec=mpeg4 -vf scale=640:480-o output.aviStream copyingMEncoder can handle input streams in two ways:
encode or copy
them. This section is about copying.
Video stream (option ):
nice stuff can be done :) Like, putting (not converting!) FLI or VIVO or
MPEG1 video into an AVI file! Of course only
MPlayer can play such files :) And it probably
has no real life value at all. Rationally: video stream copying can be
useful for example when only the audio stream has to be encoded (like,
uncompressed PCM to MP3).
Audio stream (option ):
straightforward. It is possible to take an external audio file (MP3,
Vorbis) and mux it into the output stream. Use the
option
for this.
Fixing AVIs with broken index or interleaving
Easiest thing. We simply copy the video and audio streams, and
MEncoder generates the index. Of course this cannot fix possible bugs in
the video and/or audio streams. It also fixes files with broken interleaving,
thus the option won't be needed for them anymore.
Command:
mencoder -idx input.avi -ovc copy -oac copy -o output.aviAppending multiple AVI files
As a side-effect, the broken AVI fixer function enables MEncoder to append
2 (or more) AVI files:
Command:
cat 1.avi 2.avi | mencoder -noidx -ovc copy -oac copy -o output.avi -
This expects 1.avi and 2.avi to use
the same codecs, resolution, stream rate etc, and at least 1.avi
must not be broken. You may need to fix your input AVI files first, as described
above.
Encoding with the libavcodec codec family
libavcodec provides simple encoding to a lot
of interesting video and audio formats (currently its audio codecs are
unsupported). You can encode to the following codecs:
Codec nameDescriptionmjpeg
Motion JPEG
h263
H263
h263p
H263 Plus
mpeg4
ISO standard MPEG-4 (DivX 5, XVID compatible)
msmpeg4
pre-standard MPEG-4 variant by MS, v3 (aka DivX3)
msmpeg4v2
pre-standard MPEG-4 by MS, v2 (used in old asf files)
wmv1
Windows Media Video, version 1 (aka WMV7)
rv10
an old RealVideo codec
mpeg1video
MPEG1 video :)
huffyuv
lossless compression
The first column contains the codec names that should be passed after the
vcodec config, like:
An example, with MJPEG compression:
mencoder -dvd 2 -o title2.avi -ovc lavc -lavcopts vcodec=mjpeg -oac copyEncoding from multiple input image files (JPEGs,PNGs or TGAs)MEncoder is capable of creating movies from one
or more JPEG, PNG or TGA files. With simple framecopy it can create MJPEG
(Motion JPEG), MPNG (Motion PNG) or MTGA (Motion TGA) files.
Explanation of the process:MEncoderdecodes the input image(s) with
libjpeg (when decoding PNGs, it
will use libpng).
MEncoder then feeds the decoded image to the
chosen video compressor (DivX4, Xvid, ffmpeg msmpeg4, etc.).
Examples
The explanation of the option can be found below in
the man page.
Creating a DivX4 file from all the JPEG files in the current dir:
mencoder -mf on:w=800:h=600:fps=25 -ovc divx4 -o output.avi \*.jpg
Creating a DivX4 file from some JPEG files in the current dir:
mencoder -mf on:w=800:h=600:fps=25 -ovc divx4 -o output.avi frame001.jpg,frame002.jpg
Creating a Motion JPEG (MJPEG) file from all the JPEG files in the current
dir:
mencoder -mf on:w=800:h=600:fps=25 -ovc copy -o output.avi \*.jpg
Creating an uncompressed file from all the PNG files in the current dir:
mencoder -mf on:w=800:h=600:fps=25:type=png -ovc raw -o output.avi \*.png
Width must be integer multiple of 4, it's a limitation of the RAW RGB AVI format.
Creating a Motion PNG (MPNG) file from all the PNG files in the current
dir:
mencoder -mf on:w=800:h=600:fps=25:type=png -ovc copy -o output.avi \*.png
Creating a Motion TGA (MTGA) file from all the TGA files in the current
dir:
mencoder -mf on:w=800:h=600:fps=25:type=tga -ovc copy -o output.avi \*.tgaExtracting DVD subtitles to Vobsub fileMEncoder is capable of extracting subtitles from
a DVD into Vobsub fomat files. They consist of a pair of files ending in
.idx and .sub and are usually
packaged in a single .rar archive.
MPlayer can play these with the
and options.
You specify the basename (i.e without the .idx or
.sub extension) of the output files with
and the index for this subtitle in the
resulting files with .
If the input is not from a DVD you should use to
indicate the .ifo file needed to construct the
resulting .idx file.
If the input is not from a DVD and you do not have the
.ifo file you will need to use the
option to let it know what language id to put in
the .idx file.
Each run will append the running subtitle if the .idx
and .sub files already exist. So you should remove any
before starting.
Copying two subtitles from a DVD while doing 3-pass encoding
rm subtitles.idx subtitles.sub
mencoder -dvd 1 -vobsubout subtitles -vobsuboutindex 0 -sid 2 -o frameno.avi -ovc frameno
mencoder -dvd 1 -oac copy -ovc divx4 -pass 1
mencoder -dvd 1 -oac copy -ovc divx4 -pass 2 -vobsubout subtitles -vobsuboutindex 1 -sid 5Copying a french subtitle from an MPEG file
rm subtitles.idx subtitles.sub
mencoder movie.mpg -ifo movie.ifo -vobsubout subtitles -vobsuboutindex 0 -vobsuboutid fr -sid 1Preserving aspect ratio
DVDs and SVCDs (i.e. MPEG1/2) files contain an aspect ratio value, which
describes how should the player scale the video stream, so humans won't
have egg heads (ex.: 480x480 + 4:3 = 640x480). However when encoding to AVI
(DivX) files, you have be aware that AVI headers don't store this value.
Rescaling the movie is disgusting and time consuming, there must be a better
feature!
There is
MPEG4 has an unique feature: the video stream can contain its needed aspect
ratio. Yes, just like MPEG1/2 files (DVD, SVCD). Regretfully, there are
no video players outside which support this
attribute. Except MPlayer.
This feature can be used only with libavcodec's
mpeg4 codec. Keep in mind: although MPlayer
will correctly play the created file, other players will use the wrong aspect
ratio.
You seriously should crop the black bands over and below the movie image.
See the manpage about the usage of the cropdetect and
crop filters.
Usagemencoder sample-svcd.mpg -ovc lavc -lavcopts vcodec=mpeg4:aspect=16.0/9.0 -vf crop=714:548:0:14 -oac copy -o output.avi