niceify.sh

#!/bin/sh

#                     [s4s] PUBLIC LICENSE
#                   Version 1, December 2022
#
# Everyone is permitted to copy and distribute verbatim or modified
# copies of this license document, and changing it is allowed as long
# as the name is changed.
#
#                     [s4s] PUBLIC LICENSE
#   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
#
#  0. You can do whatever is eric, ebin, or nice
#  1. The definitions of `eric', `ebin', and `nice' are up to you
#  2. :^)
#
#  niceify.sh, version 0.22
#

usage() {
    printf "Usage: %s [ -n frame_num ] [ -f fps ] [ -o outfile ] -i infile\n" "$0"
    printf "       Defaults: 36 frames, 24 fps, written to nice.webm\n"
    exit
}

confirm () {
    read RESPONSE

    case "${RESPONSE}" in
        y*|Y*)
            return
            ;;
        *)
            printf "Aborting\n"
            exit
            ;;
    esac
}

FRAME_NUM=36
FPS=24
OUT_FILE="nice.webm"
IN_FILE="nice.png"

while getopts "n:f:o:i:" o
do
    case "${o}" in
        n)
            FRAME_NUM=$((${OPTARG}+0))
            ;;
        f)
            FPS=$((${OPTARG}+0))
            ;;
        o)
            OUT_FILE="${OPTARG}"
            ;;
        i)
            IN_FILE="${OPTARG}"
            ;;
        *)
            usage
            ;;
    esac
done

shift $((${OPTIND}-1))


if [ "${#}" != "0" ]
then
    usage
fi

if [ ${FRAME_NUM} -lt 1 ]
then
    printf "Fatal: frame number must be > 0 (got '%d')\n" "${FRAME_NUM}"
    usage
fi

if [ ${FPS} -lt 1 ]
then
    printf "Fatal: fps '%d' is not supported\n" "${FPS}"
    usage
fi

if [ ! -e  "${IN_FILE}" ]
then
    printf "Fatal: input file '%s' does not exist\n" "${IN_FILE}"
    usage
fi

if which vpxenc >/dev/null 2>&1
then
    :
else
    printf "Fatal: no vpxenc found\n"
fi

if which png2yuv >/dev/null 2>&1
then
    :
else
    printf "Fatal: no png2yuv found\n"
fi

if [ -e "${OUT_FILE}" ]
then
    printf "\nFile %s exists. Overwrite? [y/N] " "${OUT_FILE}"
    confirm
fi

printf "Converting %s to %s at %d FPS and %d frames\n" \
       "${IN_FILE}" "${OUT_FILE}" "${FPS}" "${FRAME_NUM}"

TEMP_DIR=$(mktemp -d)

for IDX in $(seq 1 "${FRAME_NUM}")
do
    HUE=$(($(($((${IDX}*200))/${FRAME_NUM}))+100))
    if convert "${IN_FILE}" -modulate "100,100,${HUE}" \
               "${TEMP_DIR}/mod.png" >/dev/null 2>&1
    then
        :
    else
        printf "Fatal: Some kind of problem creating temporary files\n"
        rm -rf "${TEMP_DIR}"
        exit 1
    fi

    if convert "${TEMP_DIR}/mod.png" -background "#f0e0d6" -flatten \
               "${TEMP_DIR}/nice_${IDX}.png" >/dev/null 2>&1
    then
        printf "Frame %s/%s\n" "${IDX}" "${FRAME_NUM}"
    else
        printf "Fatal: Some kind of problem creating temporary files\n"
        rm -rf "${TEMP_DIR}"
        exit 1
    fi
done

printf "png -> yuv ... "
if png2yuv -I p -f "${FPS}" -b 1 -n "${FRAME_NUM}" -j \
           "${TEMP_DIR}/nice_%d.png" > "${TEMP_DIR}/nice.yuv" 2>/dev/null
then
    printf "complete\n"
else
    printf "Fatal: some kind of problem with png2yuv\n"
    rm -rf "${TEMP_DIR}"
    exit 1
fi

printf "yuv -> webm ... "
if vpxenc --good --cpu-used=0 --auto-alt-ref=1 --lag-in-frames=16 \
          --end-usage=vbr --passes=2 --threads=2 --target-bitrate=3000 \
          -o "${OUT_FILE}" "${TEMP_DIR}/nice.yuv" >/dev/null 2>&1
then
    printf "complete\n"
else
    printf "Fatal: some kind of problem with vpxenc"
    rm -rf "${TEMP_DIR}"
    exit 1
fi

rm -rf "${TEMP_DIR}"