picture_transcode () {
    local VIDEO_SRC="$1"
    local VIDEO_DST="$2"
    local VIDEO_FPS="$3"
    local VIDEO_GEOMETRY="$4"
    local PICTURE_TIME="$5"
    local CURRENT_DIR=`pwd`
    local PICTURE_EXT=""
    local VIDEO_FRAME_HZ=""
    local MPEG_TO_ENC_N=""
    local PICTURE_X=""
    local PICTURE_Y=""
    local VIDEO_X=""
    local VIDEO_Y=""
    local PICTURE_MOVE_X=""
    local PICTURE_MOVE_Y=""
    local PICTURE_FRAMES=""
    local TEMPORARY=`tempfile`
    #
    touch $TEMPORARY
    #
    if   [ "$VIDEO_FPS" = "25" ]
    then
        MPEG_TO_ENC_N="p"
        PICTURE_FRAMES=$((25 * $PICTURE_TIME))
    else
        MPEG_TO_ENC_N="n"
        PICTURE_FRAMES=$((30 * $PICTURE_TIME))
    fi    
    #
    VIDEO_X=`echo $VIDEO_GEOMETRY | sed "s/x[0-9]*$//"`
    VIDEO_Y=`echo $VIDEO_GEOMETRY | sed "s/^[0-9]*x//"`
    #
    # Convert keeping the aspect ratio.
    #
    convert -scale $VIDEO_GEOMETRY $VIDEO_SRC $TEMPORARY.jpg
    #
    # Get geometry.
    #
    PICTURE_X=`identify $TEMPORARY.jpg | sed "s/^.* JPEG \([0-9]*\)x\([0-9]*\).*$/\1/"`
    PICTURE_Y=`identify $TEMPORARY.jpg | sed "s/^.* JPEG \([0-9]*\)x\([0-9]*\).*$/\2/"`
    #
    # Calculate pixel shift to get a centered image.
    #
    PICTURE_MOVE_X=$((($VIDEO_X - $PICTURE_X) / 2))
    PICTURE_MOVE_Y=$((($VIDEO_Y - $PICTURE_Y) / 2))
    #
    # Create a gray background
    #
    convert -geometry $VIDEO_GEOMETRY! \
            -fill gray \
            -colorize 100% \
            $VIDEO_SRC $TEMPORARY.bg.jpg
    #
    # Put the image on the center.
    #
    composite -geometry +$PICTURE_MOVE_X+$PICTURE_MOVE_Y \
              $TEMPORARY.jpg \
              $TEMPORARY.bg.jpg \
              $TEMPORARY.x.jpg
    #
    # Convert to a YUV4MPEG video.
    #
    jpeg2yuv -n $PICTURE_FRAMES -I p -f $VIDEO_FPS -j $TEMPORARY.x.jpg | \
             mpeg2enc -n $MPEG_TO_ENC_N -f 3 -b 200 -o $TEMPORARY.m2v
    #
    # Create a silent audio track of 1/30 s.
    #
    dd if="/dev/zero" bs=4 count=1600 | \
       toolame -b 128 -s 48 /dev/stdin $TEMPORARY.mp2
    #
    # Multiplex video and audio for DVD.
    #
    mplex -f 8 -V -o $VIDEO_DST \
                     $TEMPORARY.m2v \
                     $TEMPORARY.mp2
    #
    # Remove temporary files.
    #
    rm -f $TEMPORARY*
}