prettier test videos

230101/setup.sh

 #!/bin/busybox ash
 set -euo pipefail
 
-for i in 1 2 3; do rm "C0$i.svg" || true; rm "C0$i.mp4" || true; done
+rm C*.mp4 || true
 
-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_clip() {
+	local c0 c1 freq out
+	c0="$1"
+	c1="$2"
+	freq="$3"
+	out="$4"
 
-function render_svg() {
 	ffmpeg -hide_banner -vaapi_device /dev/dri/renderD128 \
-		-loop 1 -i "$1" \
-		-filter_complex "[0]format=nv12,hwupload[v];aevalsrc=sin($3*2*PI*t):s=48000[a]" \
+		-filter_complex "
+			gradients=s=1920x1080:c0=$c0:c1=$c1:d=4:x0=480:y0=540:x1=1440:y1=540,
+			format=nv12,hwupload[v];
+			aevalsrc=sin($freq*2*PI*t):s=48000[a]
+		" \
 		-map "[v]" -map "[a]" \
-		-c:v h264_vaapi -r 25 -t 4 -b:a 128000 "$2"
+		-c:v h264_vaapi -r 25 -t 4 \
+		-c:a aac -b:a 128000 \
+		"$out"
 }
 
-for i in 1 2 3; do render_svg "C0$i.svg" "C0$i.mp4" $(($i*40+400)); done
+render_clip '#0000FF' '#FF0000' 400 C01.mp4
+render_clip '#00FF00' '#0000FF' 440 C02.mp4
+render_clip '#FF0000' '#00FF00' 480 C03.mp4