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.
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:
An audio-only avi file will be created, containing
only the requested audio stream. Don't forget -lameopts,
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.
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 for 3-pass encoding:
rm 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
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:
-vop scale=widht:height. Its quality can be set with the
-sws option. If it's not specified, MEncoder will use 0:
fast bilinear.
MEncoder can handle input streams in two ways: encode or
copy them. This section is about copying.
Video stream (option -ovc copy): 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 -oac copy): straightforward.
It is possible to take an external audio file (MP3, Vorbis) and mux it
into the output stream. Use the -audiofile <filename>
option for this.
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 -ni option won't be needed for them
anymore.
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:
mjpeg - 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: -lavcopts vcodec=msmpeg4
An example, with MJPEG compression: mencoder -dvd 2 -o title2.avi -ovc lavc
-lavcopts vcodec=mjpeg -oac copy
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:
MEncoder decodes 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 -mf option can be found below in the
global Options section and in the man page.
Creating a DivX4 file from all the JPEG files in the current dir: mencoder \*.jpg -mf on:w=800:h=600:fps=25 -ovc divx4
-o output.avi
Creating a DivX4 file from some JPEG files in the current dir: mencoder frame001.jpg,frame002.jpg -mf on:w=800:h=600:fps=25
-ovc divx4 -o output.avi
Creating a Motion JPEG (MJPEG) file from all the JPEG files in the current dir: mencoder \*.jpg -mf on:w=800:h=600:fps=25 -ovc copy
-o output.avi
Creating an uncompressed file from all the PNG files in the current dir: mencoder \*.png -mf on:w=800:h=600:fps=25:type=png -ovc raw
-o output.avi
Creating a Motion PNG (MPNG) file from all the PNG files in the current dir: mencoder \*.png -mf on:w=800:h=600:fps=25:type=png -ovc copy
-o output.avi
Creating a Motion TGA (MTGA) file from all the TGA files in the current dir: mencoder \*.tga -mf on:w=800:h=600:fps=25:type=tga -ovc copy
-o output.avi
MEncoder 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
-vobsub and -vobsubid options.
You specify the basename (i.e without the .idx or
.sub extension) of the output files with -vobsubout
and the index for this subtitle in the resulting files with
-vobsuboutindex.
If the input is not from a DVD you should use -ifo 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 -vobsubid 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.
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.