2.4. Encoding with MEncoder

2.4.1. Overview

MEncoder (MPlayer's Movie Encoder) is a simple movie encoder, designed to encode MPlayer-playable movies (AVI/DVD/VCD/VOB/MPG/MOV/VIV/FLI/RM/NUV/NET) to other MPlayer-playable formats (see below). It can encode with various codecs, like DivX4 (1 or 2 passes), libavcodec, PCM/MP3/VBRMP3 audio. Also has stream copying and video resizing abilities.

2.4.2. Compiling

You are ready. As you probably know, other encoding tools need the avifile library installed. MEncoder doesn't need it at all.

2.4.3. MEncoder features

Planned features :

2.4.3.1. Encoding 2 or 3-pass DivX4

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 DivX4 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 -divx4opts br=1100 -o movie.avi -pass 1
    mencoder -dvd 2 -divx4opts br=1100 -o movie.avi -pass 2

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 :

rm frameno.avi remove conflicting temporary file
mencoder <file/DVD> -ovc frameno -o frameno.avi First pass : 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.
mencoder <file/DVD> -oac copy -pass 1 -divx4opts br=<bitrate> Second pass : alias the first pass of DivX4 video encoding. Optionally specify the video bitrate MEncoder printed at the end of the previous pass.
mencoder <file/DVD> -oac copy -pass 2 -divx4opts br=<bitrate> Third pass : alias the second pass of DivX4 video encoding. Optionally specify the video bitrate MEncoder printed at the end of the previous pass. 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
    mencoder -dvd 2 -divx4opts br=1100 -oac copy -o movie.avi -pass 1
    mencoder -dvd 2 -divx4opts br=1100 -oac copy -o movie.avi -pass 2

2.4.3.2. Rescaling movies

Often the need to resize movie images' size emerges. Its reasons can be many, examples are decreasing output file size, encoding SVCDs to DivX. Ripped DVDs are mostly rescaled, for example a 4:3 DVD should be 640x480, especially when you want it to fit to 1 CD, and have good quality at the same time. SVCDs have 480x480 size, and their header contains the aspect ratio the player should use (Ex.: 480x480 + 4:3 = 640x480). However when encoding to AVI (DivX) files, you have be aware that AVI headers don't store this value. Thus, the only solution is rescaling.

MEncoder can scale input images if they come in YV12 format (for example: ffdivx, odivx drivers, or mpeg1/2). The output size is specified with the -x, and -y options. Furthermore, there are 3 rescaling filters in MEncoder, 0 : fast bilinear, 1 : bilinear, 2 : bicubic (best quality). They can be specified with the -sws option. If not specified, MEncoder will use 0 : fast bilinear.

Rescaling is very simple :
    mencoder sample-svcd.mpg -divx4opts br=1300 -x 640 -y 480 -sws 2 -o output.avi

2.4.3.3. Stream copying

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.

2.4.3.4. 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 -ni option won't be needed for them anymore.

Command : mencoder input.avi -ovc copy -oac copy -o output.avi

2.4.3.5. 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 :

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

2.4.4. Syntax

  mencoder [options] [input file] [options] ...

2.4.5. Available options

NOTE : for all available options, read the manpage !

-o filename specify output filename
-x width in pixels rescale output video to given pixels width
-y height in pixels rescale output video to given pixels height
-sws 0-2 type of scaling method
  0 - fast bilinear
  1 - bilinear
  2 - bicubic (best quality)
-ovc codecname Encode with the given codec (codec names are from codecs.conf). Examples:
  help - get list of available codecs
  copy - no encoding, just copy the stream (only from AVI/ASF now)
  divx4 - encode to DivX4
  lavc - encode with a codec from libavcodec
-oac codecname Encode with the given codec (codec names are from codecs.conf). Examples:
  help - get list of available codecs
  copy - no encoding, just copy the stream (only from AVI/ASF now)
  pcm - encode to uncompressed PCM
  mp3lame - encode to MP3 (using Lame)
-divx4opts If encoding to DivX4, you can specify its parameters here, like:
  -divx4opts br=1800:deinterlace:key=250
Common options: (for full list, check the manpage!)
  help - get help
  br=XXX - specify bitrate in kbit <4-16000> or bit <16001-24000000>
  q=XXXX - quality (1-fastest, 5-best - default 5)
  key=XXXX - keyframe interval
-lavcopts If encoding with libavcodec, you can specify its parameters here, like:
  -lavcopts vcodec=msmpeg4:vbitrate=1800:vhq:keyint=250
Common options: (for full list, check the manpage!)
  help - get help
  vcodec=XXX - select videocodec (for the full list, see the libavcodec section above)
  vbitrate=XXX - specify bitrate in kbit <4-16000> or bit <16001-24000000>
  vhq - high quality
  keyint=XXX - keyframe interval
-lameopts If encoding to MP3 with libmp3lame, you can specify its parameters here, like:
  -lameopts q=3
  -lameopts br=192:cbr
Common options: (for full list, check the manpage!)
  help - get help
  cbr - select CBR MP3 (default is VBR)
  br=XXX - specify bitrate in kbit <0-1024> (this is for CBR only!)
  q=XXXX - quality (0-highest, 9-fastest - default 0) (this is for VBR only!)

2.4.6. Examples

Using MEncoder is the easiest thing on Earth. See the following :

Encoding from DVD, title 2 :
    mencoder -dvd 2 -o title2.avi

The same, but with libavcodec family, MJPEG compression :
    mencoder -dvd 2 -o title2.avi -ovc lavc -lavcopts vcodec=mjpeg -ffourcc mjpg

Encoding from DVD, title 2, with rescaling :
    mencoder -dvd 2 -x 640 -y 480 -sws 2 -o title2.avi

Encoding from HTTP :
    mencoder http://mplayer.hq/example.avi -o example.avi

Encoding from a pipe :
    rar p test-SVCD.rar | mencoder -divx4opts br=800 -ofps 24 -pass 1 -- -

Encoding multiple *.vob files :
    cat *.vob | mencoder <options> -

Encoding from tuner (for tuner options see the TV input section !) :
    mencoder -tv on:driver=v4l:width=640:height=480 <options>

For all available options, check the MEncoder man page !