#!/bin/env bash
# usage: script.sh <input> [<output>]
if [ ! "$1" ]; then echo Specify an input.; exit; fi
if [ ! -e "$1" ]; then echo \"$1\" doesn\'t exist.; exit; fi
if [ "$2" ]; then output="${2%.*}.png"; else output="${1%.*}.png"; fi
if [ -e "$output" ]; then echo Output exists, specify another name.; exit; fi
size=$(echo "sqrt($(stat -c%s "$1")/8)+0.5/1" | bc)
cat "$1" /dev/zero - | ffmpeg -f rawvideo -s ${size}:${size} -pix_fmt rgba64be -i - -vframes 1 "$output"
echo Playback with\:
echo ffmpeg -i \"$output\" -f rawvideo - \| mpv -