Generating an MPG movie with mpeg_encode

The following description is for MPEG-1 software encoder mpeg_encode that can be downloaded as source code from its homepage.

Creating links

Usually, too few pictures will be available to create a movie with a standard MPEG frame rate. Therefore, additional still pictures have to be inserted. Further on, mpeg_encode is easiest with consecutive numbered frames. The following script creates five links for each picture f1.10.pnm,f1.20.pnm,...,f1.110.pnm.

#! /bin/sh
NAME=f1
a=0
for i in 10 20 30 40 50 60 70 80 90 100 110
do
  echo $i
  ln -s -f ../$NAME.$i.pnm links/l$NAME.$a.pnm 
  a=`expr $a + 1`
  ln -s ../$NAME.$i.pnm links/l$NAME.$a.pnm 
  a=`expr $a + 1`
  ln -s ../$NAME.$i.pnm links/l$NAME.$a.pnm 
  a=`expr $a + 1`
  ln -s ../$NAME.$i.pnm links/l$NAME.$a.pnm 
  a=`expr $a + 1`
  ln -s ../$NAME.$i.pnm links/l$NAME.$a.pnm 
  a=`expr $a + 1`
  ln -s ../$NAME.$i.pnm links/l$NAME.$a.pnm 
  a=`expr $a + 1`
done

Encoding

Creating a movie with the command mpeg_encode movie_params.txt requires a file movie_params.txt that could look like:

PATTERN                 IBBPBBPBBP
OUTPUT                  MovieName.mpg

BASE_FILE_FORMAT        PNM
INPUT_CONVERT           *   
GOP_SIZE                40   
SLICES_PER_FRAME        1

INPUT_DIR               links

INPUT
lf1.*.pnm               [0-54]
END_INPUT

PIXEL                   HALF   
RANGE                   10

PSEARCH_ALG             LOGARITHMIC
BSEARCH_ALG             CROSS2

IQSCALE                 4   
PQSCALE                 6   
BQSCALE                 8   

REFERENCE_FRAME         DECODED
FORCE_ENCODE_LAST_FRAME

The 54 apparently corresponds to the last frame in links and needs to be individually adjusted like the OUTPUT file. The other parameters are set to relatively low compression but high quality, which will usually be appropriate for scientific purposes. A documentation of all parameters is available online.

-- RalfDeiterding - 01 Feb 2005