convert mp3 2 avi with ffmpeg - http://www.crimulus.com/2010/01/21/linux-bash-script-convert-mp3-to-avi-with-static-image-command-line/

mp32avi.sh

#!/bin/bash

FFMPEG=`which ffmpeg`
if [ "$FFMPEG" = "" ] ; then
  echo "Please install ffmpeg.";
  exit 0;
fi
if [ $# != 3 ] ; then
  echo "Usage: $0 <image_file> <mp3_file> <output_file.avi>";
  exit 0;
fi
if [ ! -f $1 ] ; then
  echo "Source image '$1' not found.";
  exit 0;
fi
if [ -f $3 ] ; then
  echo "Output file '$3' exists.  Overwrite? (y/n)";
  read CONFIRM
  if [ "$CONFIRM" == "y" ] ; then
    echo "Overwriting '$3'"
  else
    if [ "$CONFIRM" == "Y" ] ; then
      echo "Overwriting '$3'"
    else
      echo "Operation canceled.";
      exit 0;
    fi
  fi
fi
TIME=`$FFMPEG -i $2 |& grep 'Duration' | awk '{ print $2; }' | sed -e 's/,//g'`
$FFMPEG -loop 1 -i $1 -i $2 -acodec copy -y -t $TIME $3