#!/bin/busybox ash
set -euo pipefail

for i in 1 2 3; do rm "C0$i.svg" || true; rm "C0$i.mp4" || true; done

function write_svg() {
	echo '<svg viewBox="0 0 1920 1080" width="1920" height="1080">'
	echo '  <rect fill="'"$1"'" x="0" y="0" width="1920" height="1080"/>'
	echo '</svg>'
}

write_svg blue  >C01.svg
write_svg green >C02.svg
write_svg red   >C03.svg

function render_svg() {
	ffmpeg -hide_banner -vaapi_device /dev/dri/renderD128 \
		-loop 1 -i "$1" \
		-filter_complex "[0]format=nv12,hwupload[v];aevalsrc=sin($3*2*PI*t):s=48000[a]" \
		-map "[v]" -map "[a]" \
		-c:v h264_vaapi -r 25 -t 4 -b:a 128000 "$2"
}

for i in 1 2 3; do render_svg "C0$i.svg" "C0$i.mp4" $(($i*40+400)); done