pan-scan

#!/bin/sh

# pan scan

# script usage
usage ()
{
# if argument passed to function echo it
[ -z "${1}" ] || echo "! ${1}"
# display help
echo "\
# pan scan image

$(basename "$0") -i infile.(png|jpg|jpeg) -d (000) -p (l|r|u|d) -o outfile.mp4
-i = infile.(png|jpg|jpeg)
-d = duration : from 1-999
-p = position : left, right, up, down
-o = outfile.mp4 : optional agument # default is infile-name-pan-date-time"
exit 2
}

# error messages
NOTFILE_ERR='not a file'
INVALID_OPT_ERR='Invalid option:'
REQ_ARG_ERR='requires an argument'
WRONG_ARGS_ERR='wrong number of arguments passed to script'
NOT_MEDIA_FILE_ERR='is not a media file'

# if script is run arguments pass and check the options with getopts,
# else display script usage and exit
[ $# -gt 0 ] || usage "${WRONG_ARGS_ERR}"

# duration regex match [1-9]
dur_regex='^[0-9]\{1,2\}$'
position_regex='^[a-z]\{1\}$'

# getopts and check if input a file
while getopts ':i:d:p:o:h' opt
do
  case ${opt} in
     i) infile="${OPTARG}"
	[ -f "${infile}" ] || usage "${infile} ${NOTFILE_ERR}";;
     d) dur="${OPTARG}"
        expr "${dur}" : "${dur_regex}" 1>/dev/null || usage "${dur} ${WRONG_ARGS_ERR}";;
     p) position="${OPTARG}"
        expr "${position}" : "${position_regex}" 1>/dev/null || usage "${position} ${WRONG_ARGS_ERR}";;
     o) outfile="${OPTARG}";;
     h) usage;;
     \?) usage "${INVALID_OPT_ERR} ${OPTARG}" 1>&2;;
     :) usage "${INVALID_OPT_ERR} ${OPTARG} ${REQ_ARG_ERR}" 1>&2;;
  esac
done
shift $((OPTIND-1))

# infile, infile name and extension
infile_nopath="${infile##*/}"
infile_name="${infile_nopath%.*}"

# file command check input file mime type
filetype="$(file --mime-type -b "${infile}")"

# image mimetypes
png_mime='image/png'
jpg_mime='image/jpeg'

# check if tile is null
if [ -z "${infile}" ]; then
   : # tile variable not set : = pass
else
# ffprobe get image height
   imgsize="$(ffprobe -v error -select_streams v:0 -show_entries stream=height,width -of csv=s=x:p=0  "${infile}")"
   img_w=$(echo "${imgsize}" | awk -F'x' '{print $1}')
   img_h=$(echo "${imgsize}" | awk -F'x' '{print $2}')
fi

# pan
left="scale=w=-2:h=3*${img_h},crop=w=3*${img_w}/1.05:h=3*${img_h}/1.05:x=t*(in_w-out_w)/${dur},scale=w=${img_w}:h=${img_h},setsar=1" \
right="scale=w=-2:h=3*${img_h},crop=w=3*${img_w}/1.05:h=3*${img_h}/1.05:x=(in_w-out_w)-t*(in_w-out_w)/${dur},scale=w=${img_w}:h=${img_h},setsar=1" \
up="scale=w=-2:h=3*${img_h},crop=w=3*${img_w}/1.2:h=3*${img_h}/1.2:y=t*(in_h-out_h)/${dur},scale=w=${img_w}:h=${img_h},setsar=1" \
down="scale=w=-2:h=3*${img_h},crop=w=3*${img_w}/1.2:h=3*${img_h}/1.2:y=(in_h-out_h)-t*(in_h-out_h)/${dur},scale=w=${img_w}:h=${img_h},setsar=1" \

# outfile file recording destination
outfile_default="${infile_name}-pan-$(date +"%Y-%m-%d-%H-%M-%S").mp4"

# check the files mime type is a image
case "${filetype}" in
    ${png_mime}|${jpg_mime});;
    *) { echo "${infile} ${NOT_MEDIA_FILE_ERR}" && usage; };;
esac

### zoom function
pan_func () {
  ffmpeg \
  -hide_banner \
  -stats -v panic \
  -r 30 \
  -y -loop 1 \
  -i "${infile}" -ss 0 -t "${dur}" \
  -filter_complex \
  "${1}" \
  -y -shortest \
  -c:v libx264 -crf 18 -profile:v high \
  -r 30 -pix_fmt yuv420p \
  -movflags +faststart -f mp4 \
  "${outfile:=${outfile_default}}"
}

# check zoom and position
case "${position}" in
     l) pan_func "${left}";;
     r) pan_func "${right}" "${infile}";;
     u) pan_func "${up}" "${infile}";;
     d) pan_func "${down}" "${infile}";;
     *) usage "${infile} ${NOT_MEDIA_FILE_ERR}";;
esac