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|
#!/usr/bin/env zsh
# export a clip from a video as a gif
local callstr=$0
local hasgsic
[[ $(whence gifsicle) ]] && hasgsic=true
print_error() {
echo -e "\e[1;31merror:\e[0m $1\n"
}
usage() {
[[ -z $1 ]] || print_error $1
echo "Usage: $callstr [OPTIONS...] <infile> <outfile>"
echo "Create an animated gif from a video"
echo ""
echo -e " \e[1mdescription opt longform arg default val\e[0m"
echo " start time -s --start <time> 00:00:00"
echo " length in seconds -l --length <num> full length"
echo " gif fps -f --fps <num> 10"
echo " output pixel width -w --width <num> 480"
echo " use subtitles -b --sub [int] track 0, if enabled"
echo " (optionally specify track)"
echo " number of colours -c --colours <int> 256"
echo " dithering algorithm -d --dither <str> sierra2_4a"
echo "redraw only changed rectangle -r --rect"
[[ $hasgsic ]] && echo " optimise with gifsicle -o --optimise"
echo " print this help -h --help"
exit 1
}
# preface used to ensure unique inputs, just in case links exist. see below
local tmp_pref
rm_tmps() {
if [[ ${tmp_pref} ]]; then
rm -f ${tmp_pref}-palette.png
rm -f ${tmp_pref}-in
fi
}
abort() {
[[ -z $1 ]] || print_error $1
rm_tmps
exit 1
}
trap 'abort' SIGABRT SIGHUP SIGINT SIGQUIT SIGTERM
local start="00:00:00"
local length=""
local fps=10
local width=480
local subs=""
local strack=0
local gsic=""
local dithalg="sierra2_4a"
local colour_count=256
local rect=""
local timepat='^(([0-9][0-9]:){1,2}[0-9][0-9]|[0-9]+)(\.[0-9]+){0,1}$'
local numpat='^([1-9][0-9]*(\.[0-9]+){0,1}|0\.[0-9]*[1-9])$'
local intpat='^[1-9][0-9]*$'
local zintpat='^[0-9]+$'
local dithpat='^(none|bayer[0-5]|heckbert|floyd_steinberg|sierra2|sierra2_4a)$'
zparseopts -D -E -M -A args \
s: -start:=s \
l: -length:=l \
f: -fps:=f \
w: -width:=w \
b:: -sub::=b \
c: -colours:=c -colors:=c \
d: -dither:=d \
r -rect=r \
o -optimise=o -optimize=o \
h -help=h
local optarg
for opt in ${(@k)args}; do
unset optarg
[[ -z $args[$opt] ]] || optarg=$args[$opt]
case $opt in
-s)
[[ ! $(echo $optarg | grep -oE "$timepat") ]] \
&& usage "malformed start timestamp"
start="$optarg"
;;
-l)
[[ ! $(echo $optarg | grep -oE "$numpat") ]] \
&& usage "length must be a positive rational number"
length=(-t $optarg)
;;
-f)
[[ ! $(echo $optarg | grep -oE "$numpat") ]] \
&& usage "fps must be a positive rational number"
fps=$optarg
;;
-w)
[[ ! $(echo $optarg | grep -oE "$intpat") ]] \
&& usage "width must be a positive integer"
width=$optarg
;;
-b)
[[ ! -z $optarg ]] && [[ ! $(echo $optarg | grep -oE "$zintpat") ]] \
&& usage "sub track index must be a non-negative integer"
[[ -z $optarg ]] && strack=0 || start=$optarg
subs=true
;;
-c)
[[ ! $(echo $optarg | grep -oE "$intpat") ]] \
|| [[ $optarg -gt 256 || $optarg -lt 2 ]] \
&& usage "colour count must be an integer in the range 2-256"
colour_count=$optarg
;;
-d)
[[ ! $(echo $optarg | grep -oE "$dithpat") ]] \
&& usage "dithering algorithm must be one of none, bayer<0-5>, heckbert,\nfloyd_steinberg, sierra2, sierra2_4a"
dithalg=$optarg
[[ $(echo $optarg | grep -o bayer) ]] \
&& dithalg="bayer:bayer_scale=$(echo $optarg | grep -oE '[0-5]')"
;;
-o) gsic=true; [[ -z $hasgsic ]] && usage "gifsicle program not found" ;;
-r) rectmode=":diff_mode=rectangle" ;;
-h) usage ;;
esac
done
# check some error conditions
if [[ ${#@} -gt 2 ]]; then
for opt in $@; do
[[ $opt[1] == '-' ]] && usage "unrecognised option $opt"
done
usage "trailing file arguments detected"
fi
[[ ${#@} -eq 1 ]] && usage "no output file specified"
[[ ${#@} -eq 0 ]] && usage "no input file specified"
[[ $1 != "%d.png" ]] && [[ ! -f $1 ]] && usage "input file not found"
[[ ${2:e} != "gif" ]] && usage "output file must have a .gif file extension"
# make links
local tmp_pref_i
tmp_pref_i="${2:h}/make-gif"
while [[ -f "${tmp_pref_i}-palette.png" ]] || [[ -f "${tmp_pref_i}-in" ]]; do
tmp_pref_i="${tmp_pref_i}-1"
done
tmp_pref=${tmp_pref_i}
ln -s "${1:a}" "${tmp_pref}-in" \
|| abort "could not write to output dir"
# get output height using aspect ratio
local height
local as
height=-1
ffprobe -loglevel -8 -print_format json -show_streams "${tmp_pref}-in" \
| grep -m 1 display_aspect_ratio | grep -Eo '[0-9]+:[0-9]+' \
| IFS=':' read -A as
[[ -z $as ]] || [[ ${as[1]} -eq 0 ]] || [[ ${as[2]} -eq 0 ]] \
|| let "height = (${width} * ${as[2]}) / ${as[1]}"
# convenience var
local substr
[[ $subs ]] && substr="subtitles=${tmp_pref}-in:si=$strack,"
# convert
echo "pass 1..."
ffmpeg -loglevel 16 -y -ss "$start" ${length[@]} -i "${tmp_pref}-in" -copyts -filter_complex \
"${substr}setsar=1/1,fps=$fps,scale=${width}:${height}:flags=lanczos,palettegen=max_colors=${colour_count}" \
${tmp_pref}-palette.png
[[ $? -ne 0 ]] && fferr=true
[[ ! $fferr ]] && echo "pass 2..." && ffmpeg -loglevel 24 \
-ss $start ${length[@]} \
-i "${tmp_pref}-in" -i ${tmp_pref}-palette.png -copyts -filter_complex \
"${substr}setsar=1/1,fps=$fps,scale=${width}:${height}:flags=lanczos[x];[x][1:v]paletteuse=dither=${dithalg}${rectmode}" \
"$2"
[[ $? -ne 0 ]] && fferr=true
[[ $fferr ]] && abort
rm_tmps
# gifsicle
if [[ -f "$2" && $gsic ]]; then
echo "optimising..."
gifsicle --batch -O3 -i "$2"
fi
|
