#!/bin/sh
# See LICENSE file for copyright and license details.

set -e

usage () {
	printf 'usage %s: [-t time] [-y] in-file out-file\n' "$0" >&2
	exit 1
}

ffmpeg_flag_y=
ss=10

while getopts t:y flag; do
	case "$flag" in
	t)
		ss="${OPTARG}";;
	y)
		ffmpeg_flag_y=-y;;
	?)
		usage;;
	esac
done
shift $(( ${OPTIND} - 1 ))

if test ! $# = 2; then
	usage
fi

in_file="$1"
if test -z "${in_file}"; then
	usage
fi

out_file="$2"
if test -z "${out_file}"; then
	usage
fi

ffmpeg -i "${in_file}" -ss "${ss}" -update 1 -frames:v 1 -c:v png -f image2pipe - | \
	ffmpeg -f image2pipe -i - -i "${in_file}" -map 0:v:0 -map 1:a:0 -c:v png ${ffmpeg_flag_y} -- "${out_file}"