#!/bin/bash
# TODO
# make pix_fmt a variable when svt supports more than 10bit/4:2:0
# stop avif mode fucking up png colors, if possible
# add selection menus for audio and subtitle streams
# script cannot handle input files with ' in the name

# Dependencies: ffmpeg 6.1+ built with libplacebo-7+ and libsvtav1-3.1+
# Usage: ./av1encode.sh [file] [start] [stop]
Input="$1"
StartTime="$2"
StopTime="$3"
Filters=()

encode() {
	TimeArgs=()
	if [[ "$StartTime" != "" && "$StopTime" != "" ]]; then
		TimeArgs=(-ss "$StartTime" -to "$StopTime")
	fi

	AudioOutput=()
	mapfile -t AudioProbe < <(ffprobe -v error -select_streams a:0 -show_entries stream=codec_name,channels -of default=noprint_wrappers=1:nokey=1 "$Input")
	if [[ ${AudioProbe[1]} != 2 ]]; then
		AudioOutput=(-c:a libopus -b:a 192k -ac 2)
	elif [[ ${AudioProbe[0]} == "flac" && ${AudioProbe[1]} == 2 ]]; then
		AudioOutput=(-c:a libopus -b:a 192k)
	else
		AudioOutput=(-c:a copy)
	fi

	SubsProbe=$(ffprobe -v error -select_streams s -show_entries stream=index -of csv=p=0 "$Input")
	if [[ $SubsProbe != "" ]]; then
		EscapedInput=$(printf "%q" "$Input")
		if [[ ${#Filters[@]} -eq 0 ]]; then
			Filters=(-vf subtitles="$EscapedInput")
		else
			string="${Filters[1]},subtitles=$EscapedInput"
			Filters=(-vf "$string")
		fi
	fi

	ffmpeg -hide_banner -i "$Input" "${TimeArgs[@]}" "${AudioOutput[@]}" "${Filters[@]}"\
		-c:v libsvtav1 -preset "$Preset" -crf "$CRF" -pix_fmt yuv420p10le -svtav1-params tune=1:enable-tf=0"$1""$2"\
		"${Input%.*}"_"$ffmpegaction"_preset"$Preset"_crf"$CRF"."$Ext"
	exit
}

quality() {
	printf "Enter an svt-av1 preset [0-12] or a script option [a, b, c]\nLower numbers mean higher visual quality, lower filesize and longer encoding time.\n"
	printf "a) Normal AV1 video (Preset 4, CRF 28, Variance Boost Off)\nb) Fast AV1 video (Preset 4, CRF 44, Variance Boost On)\nc) AVIF image (Preset 0, CRF 12)\n"
	Ext="mp4"
	useAvif=""
	varBoost=""
	while true; do
		read -r -p "#? " Preset
		if [[ $Preset == a ]]; then
			Preset=4
			CRF=28
		elif [[ $Preset == b ]]; then
			Preset=4
			CRF=44 # VMAF >95 at preset 4
			varBoost=":enable-variance-boost=1"
		elif [[ $Preset == c ]]; then
			Preset=0
			CRF=12
			Ext="avif"
			useAvif=":avif=1"
		elif [[ "$Preset" =~ ^[0-9]{,2}$ ]]; then
			printf "Enter a Constant Rate Factor (CRF) [1-63]"
			read -r -p "#? " CRF
		fi
		encode $useAvif $varBoost
	done
}

ffprobe -hide_banner -i "$1"
printf "Choose a scaling factor: \n"
select ffmpegaction in "scale1x" "dscale2x" "dscale4x" "scale2x" "scale4x" "exit"; do
		ExtraArgs="extra_opts=preset=high_quality:deband=no"
		case $ffmpegaction in
			scale1x)
				quality
				break
			;;
			dscale2x)
				Filters=(-vf libplacebo=w=iw/2:h=ih/2:"$ExtraArgs")
				quality
				break
			;;
			dscale4x)
				Filters=(-vf libplacebo=w=iw/4:h=ih/4:"$ExtraArgs")
				quality
				break
			;;
			scale2x)
				Filters=(-vf libplacebo=w=iw*2:h=ih*2:"$ExtraArgs")
				quality
				break
			;;
			scale4x)
				Filters=(-vf libplacebo=w=iw*4:h=ih*4:"$ExtraArgs")
				quality
				break
			;;
			exit)
				break
			;;
		esac
	done