tile-thumbnails

#!/bin/sh

#===============================================================================
# tile-thumbnails
# create an image with thumbnails from a video
#===============================================================================

# dependencies:
# ffmpeg ffprobe awk bc

#===============================================================================
# script usage
#===============================================================================

usage()
{
echo "\
# create an image with thumbnails from a video

$(basename "$0") -i input -s 00:00:00.000 -w 000 -t 0x0 -p 00 -m 00 -c color -f fontcolor -b boxcolor -x on -o output.png

-i input.(mp4|mkv|mov|m4v|webm)
-s seek into the video file                : default 00:00:05
-w thumbnail width                         : 160
-t tile layout format width x height : 4x3 : default 4x3
-p padding between images                  : default 7
-m margin                                  : default 2
-c color = https://ffmpeg.org/ffmpeg-utils.html#color-syntax : default black
-f fontcolor                               : default white
-b boxcolor                                : default black
-x on                                      : default off, display timestamps
-o output.png                              : optional argument 
# if option not provided defaults to input-name-tile-date-time.png"
exit 2
}


#===============================================================================
# error messages
#===============================================================================

INVALID_OPT_ERR='Invalid option:'
REQ_ARG_ERR='requires an argument'
WRONG_ARGS_ERR='wrong number of arguments passed to script'


#===============================================================================
# check the number of arguments passed to the script
#===============================================================================

[ $# -gt 0 ] || usage "${WRONG_ARGS_ERR}"


#===============================================================================
# getopts check the options passed to the script
#===============================================================================

while getopts ':i:s:w:t:p:m:c:b:f:x:o:h' opt
do
  case ${opt} in
     i) infile="${OPTARG}";;
     s) seek="${OPTARG}";;
     w) scale="${OPTARG}";;
     t) tile="${OPTARG}";;
     p) padding="${OPTARG}";;
     m) margin="${OPTARG}";;
     c) color="${OPTARG}";;
     f) fontcolor="${OPTARG}";;
     b) boxcolor="${OPTARG}";;
     x) timestamp="${OPTARG}";;
     o) outfile="${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))


#===============================================================================
# variables
#===============================================================================

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

# ffprobe get fps and duration
videostats=$(ffprobe \
-v error \
-select_streams v:0 \
-show_entries stream=r_frame_rate:format=duration \
-of default=noprint_wrappers=1 \
"${infile}")

# fps
fps=$(echo "${videostats}" | awk -F'[=//]' '/r_frame_rate/{print $2/$3}')

# duration
duration=$(echo "${videostats}" | awk -F'[=/.]' '/duration/{print $2}')

# check if tile is null
if [ -z "${tile}" ]; then
   : # tile variable not set : = pass
else
   # tile variable set
   # tile layout
   tile_w=$(echo "${tile}" | awk -F'x' '{print $1}')
   tile_h=$(echo "${tile}" | awk -F'x' '{print $2}')
   # title sum
   tile_sum=$(echo "${tile_w} * ${tile_h}" | bc)
fi

# defaults
seek_default='00:00:05'
scale_default='160'
tile_layout_default='4x3'
tile_default='12'
padding_default='7'
margin_default='2'
color_default='black'
fontcolor_default='white'
boxcolor_default='black'
timestamp_default='off'
pts_default='5'
pts=$(printf "%s %s\n" "${seek}" | awk '{
          start = $1
          if (start ~ /:/) {
            split(start, t, ":")
            seconds = (t[1] * 3600) + (t[2] * 60) + t[3] 
          }
          printf("%s\n"), seconds
}')

outfile_default="${infile_name}-tile-$(date +"%Y-%m-%d-%H-%M-%S").png"

# duration * fps / number of tiles
frames=$(echo "${duration} * ${fps} / ${tile_sum:=${tile_default}}" | bc)


#===============================================================================
# functions
#===============================================================================

# contact sheet - no timestamps
tilevideo () {
ffmpeg \
-hide_banner \
-stats -v panic \
-ss "${seek:=${seek_default}}" \
-i "${infile}" \
-frames 1 -vf "select=not(mod(n\,${frames})),scale=${scale:=${scale_default}}:-1,tile=${tile:=${tile_layout_default}}:padding=${padding:=${padding_default}}:margin=${margin:=${margin_default}}:color=${color:=${color_default}}" \
"${outfile:=${outfile_default}}"
}


# contact sheet - timestamps
timestamp () {
ffmpeg \
-hide_banner \
-stats -v panic \
-ss "${seek:=${seek_default}}" \
-i "${infile}" \
-frames 1 -vf "drawtext=text='%{pts\:hms\:${pts:=${pts_default}}}':x='(main_w-text_w)/2':y='(main_h-text_h)':fontcolor=${fontcolor:=${fontcolor_default}}:fontsize='(main_h/8)':boxcolor=${boxcolor:=${boxcolor_default}}:box=1,select=not(mod(n\,${frames})),scale=${scale:=${scale_default}}:-1,tile=${tile:=${tile_layout_default}}:padding=${padding:=${padding_default}}:margin=${margin:=${margin_default}}:color=${color:=${color_default}}" \
"${outfile:=${outfile_default}}"
}


#===============================================================================
# check option passed to script
#===============================================================================

if [ "${timestamp}" == on ]; then
    timestamp "${infile}" # -x on
elif [ ! -z "${fontcolor}" ]; then
    timestamp "${infile}" # -f 
elif [ ! -z "${boxcolor}" ]; then
    timestamp "${infile}" # -b
elif [ -z "${timestamp}" ]; then
    tilevideo "${infile}" # no timestamp
else
    tilevideo "${infile}" # no timestamp
fi