nathan@0: #!/bin/bash
nathan@0: #
nathan@0: # requires: ...topnm, pnmscale, pnmcomp, ppmntsc, ppmtoy4m, mpeg2enc
nathan@0: #
nathan@0: 
nathan@0: # video format. pal or ntsc
nathan@0: FORMAT=pal
nathan@0: 
nathan@0: # target image width/height (taking into account visible screen area)
nathan@0: if [ "$FORMAT" = "ntsc" ]; then
nathan@0:   TW=600
nathan@0:   TH=420
nathan@0: else
nathan@0:   TW=632
nathan@0:   TH=512
nathan@0: fi
nathan@0: 
nathan@0: TMP=/tmp/image_convert.$$.pnm
nathan@0: IMG=$1
nathan@0: MPG=$2
nathan@0: 
nathan@0: DIR=`dirname "$MPG"`
nathan@0: if [ ! -d "$DIR" ]; then
nathan@0:   mkdir -p "$DIR"
nathan@0: fi
nathan@0: #
nathan@0: # get the file type and set the according converter to PNM
nathan@0: #
nathan@0: FILE_TYPE=`file -i -L -b "$IMG" 2>/dev/null | cut -f2 -d/`
nathan@0: case "$FILE_TYPE" in
nathan@0:   jpg | jpeg)
nathan@0:   TO_PNM=jpegtopnm
nathan@0:   ;;
nathan@0:   tiff)
nathan@0:   TO_PNM=tifftopnm
nathan@0:   ;;
nathan@0:   bmp | x-bmp)
nathan@0:   TO_PNM=bmptoppm
nathan@0:   ;;
nathan@0:   png | x-png)
nathan@0:   TO_PNM=pngtopnm
nathan@0:   ;;
nathan@0:   Netpbm | pnm | x-portable-pixmap)
nathan@0:   TO_PNM=cat
nathan@0:   ;;
nathan@0:   gif)
nathan@0:   TO_PNM=giftopnm
nathan@0:   ;;
nathan@0:   *)
nathan@0:   echo "filetype '$FILE_TYPE' is not supported"
nathan@0:   exit 1
nathan@0:   ;;
nathan@0: esac
nathan@0: #
nathan@0: # 'chroma subsampling mode' mjpegtools >= 1.8.0
nathan@0: #
nathan@0: SUBSAMPLINGMODE=""
nathan@40: if ppmtoy4m -h 2>&1 | egrep -q "'420mpeg2'"; then
nathan@0:     SUBSAMPLINGMODE="-S 420mpeg2"
nathan@0: fi
nathan@0: #
nathan@0: # extract the image size & compute scale value
nathan@0: #
nathan@0: LANG=C # get the decimal point right
nathan@0: $TO_PNM "$IMG" >$TMP 2>/dev/null
nathan@0: S=`pnmfile $TMP | awk '{ printf "%d %d ",$4,$6 }'`
nathan@0: S=`echo $S $TW $TH | awk '{ sw=$3/$1; sh=$4/$2; s=(sw<sh)?sw:sh; printf "%.4f\n",(s>1)?1.0:s; }'`
nathan@0: #
nathan@0: # now run the conversion
nathan@0: #
nathan@0: if [ "$FORMAT" = "ntsc" ]; then
nathan@0:   pnmscale $S $TMP | \
nathan@0:     pnmpad -black -width 704 -height 480 | \
nathan@0:     ppmntsc | \
nathan@0:     ppmtoy4m -v 0 -n 1 -r -F 30000:1001 $SUBSAMPLINGMODE | \
nathan@0:     mpeg2enc -f 7 -T 90 -F 4 -nn -a 2 -v 0 -o "$MPG"
nathan@0: else
nathan@0:   pnmscale $S $TMP | \
nathan@0:     pnmpad -black -width 704 -height 576 | \
nathan@0:     ppmntsc --pal | \
nathan@0:     ppmtoy4m -v 0 -n 1 -r -F 25:1 $SUBSAMPLINGMODE | \
nathan@0:     mpeg2enc -f 7 -T 90 -F 3 -np -a 2 -v 0 -o "$MPG"
nathan@0: fi
nathan@0: #
nathan@0: # cleanup
nathan@0: #
nathan@0: rm $TMP