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). Currently it's in beta stage, and encodes only to DivX4 (1 or 2 passes) video, PCM/MP3/VBRMP3 audio. Also has stream copying abilities. In the future, there will be cropping, resizing filters, and other interesting stuff.

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-pass DivX4

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 :
    mencoder -dvd 2 -ovc divx4 -oac mp3lame -divx4opts br=1100 -o movie.avi -pass 1
    mencoder -dvd 2 -ovc divx4 -oac mp3lame -divx4opts br=1100 -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.

2.4.3.4. Fixing AVIs with broken index

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.

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 -ffourcc mjpg

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 !