Discussion
Image Flicker test
@void check this out when you get a chance, I'd like your second opinion because maybe I did something wrong?
I'm still going to use CVVDP for my lossy Webp vs lossy JXL comparison, at least for the photographic stuff, as every other image metric does worse IMHO.
- I think I figured out how to leverage animated webp for an image flicker test. It turns out there's a separate CLI tool dealing with animated webp called img2webp with lossless support.
Here's a bash script I wrote that will accept in.png and arbitrarily named .webp and .jxl files and splice them into a short 1 FPS flicker loop that also overlays the relevant filename as well.
#!/usr/bin/env bash
for f in in.png; do
ffmpeg -hide_banner -loglevel error -i "$f" \
-vf "format=rgb24,drawtext=text='$(basename "$f")':fontcolor=white:fontsize=12:box=1:[email protected]:boxborderw=8:x=20:y=20" \
-pix_fmt rgb24 png.png
done
for f in *.webp; do
ffmpeg -hide_banner -loglevel error -i "$f" \
-vf "format=rgb24,drawtext=text='$(basename "$f")':fontcolor=white:fontsize=12:box=1:[email protected]:boxborderw=8:x=(w-text_w)/2:y=20" \
-pix_fmt rgb24 webp.png
done
for f in *.jxl; do
ffmpeg -hide_banner -loglevel error -i "$f" \
-vf "format=rgb24,drawtext=text='$(basename "$f")':fontcolor=white:fontsize=12:box=1:[email protected]:boxborderw=8:x=w-text_w-20:y=20" \
-pix_fmt rgb24 jxl.png
done
img2webp -lossless -m 6 -loop 0 -d 1000 png.png webp.png jxl.png -o flicker.webp
rm -f png.png webp.png jxl.png
- While JXL achieves expected lower filesize in photographic content vs Webp, I've noticed some slight blurring in JXL. CVVDP does not seem to be able to capture this.
Do you see it as well? Not just in my OP animated webp but flipping through the raw .webp and .jxl files as well?
I'm still going to use CVVDP for my lossy Webp vs lossy JXL comparison, at least for the photographic stuff, as every other image metric does worse IMHO.
