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Surprised and disappointed to hear "bad-faith reading". I have seen AVIF tiling artifacts myself. Hand-waving them away by appealing to a metric that averages

by janwas 20d ago

Surprised and disappointed to hear "bad-faith reading". I have seen AVIF tiling artifacts myself. Hand-waving them away by appealing to a metric that averages across all image pixels is not convincing.

juliobbv 20d ago
Let's be productive: https://pengbins.github.io/aomanalyzer.io/ https://pengbins.github.io/aomanalyzer.io/ - Upload the problematic image to the AOM analyzer - Press 'L' to show tiles view - How many tiles (yellow rectangles) do you count? - Are artifacts actually at those tile borders? This takes 10 seconds.
computerbuster 20d ago
I was even more surprised & disappointed to see this dismissed as an ad for my company. Think about how fantastic JPEG XL would be for my company: an image codec with tons of fans and an extremely weak reference encoder? Sign me up. I'm writing this as someone who wants a better Internet. If you're sensitive to tiling artifacts, you must deeply dislike the way JPEG XL images look. Every block of a JPEG XL image is effectively a small tile, because there is no deblocking loop filter (I talk about this in the article). JPEG XL has two filters that are pretty much equivalents of what AVIF has, while AVIF has three; plus, tile boundaries are handled by the DLF. Your point doesn't really stand on two legs if it means to come to JPEG XL's defense here.
- eviks 20d ago
  > Every block of a JPEG XL image is effectively a small tile, Operative word here is "small", so it has different effect, thus doesn't imply same sensitivity trigger
  - juliobbv 20d ago
    By "small", it's meant in a relative sense. JXL's coded blocks can be as big as 64x64, and block boundaries can create visible seams. Example: https://juliobbv.com/pics/photo.jxl https://juliobbv.com/pics/photo.jxl These seams are especially noticeable in the background, and align with coded block edges. You can tell the encoder is trying to conceal them as best as it can, but this cannot be properly mitigated without a proper deblocking filter. For comparison, AV1 tiles normatively go through the deblocking filter.
- janwas 19d ago
  We can agree on wanting a better internet :) I participated in the design of those filters, so no, I do not deeply dislike the way they look. This gaslighting is not convincing. No matter how many filters AVIF has, I distinctly remember tile artifacts being particularly disturbing. More so than individual blocks, whose size and border effects differ; tiles are a straight line through the entire image. JPEG XL does not have this problem because the design and codestream enables parallel decoding (thanks to per-group offsets encoded in the 'TOC'), hence does not require separate tiles.

by janwas 20d ago

juliobbv 20d ago

Let's be productive: https://pengbins.github.io/aomanalyzer.io/ https://pengbins.github.io/aomanalyzer.io/ - Upload the problematic image to the AOM analyzer - Press 'L' to show tiles view - How many tiles (yellow rectangles) do you count? - Are artifacts actually at those tile borders? This takes 10 seconds.

computerbuster 20d ago

I was even more surprised & disappointed to see this dismissed as an ad for my company. Think about how fantastic JPEG XL would be for my company: an image codec with tons of fans and an extremely weak reference encoder? Sign me up. I'm writing this as someone who wants a better Internet. If you're sensitive to tiling artifacts, you must deeply dislike the way JPEG XL images look. Every block of a JPEG XL image is effectively a small tile, because there is no deblocking loop filter (I talk about this in the article). JPEG XL has two filters that are pretty much equivalents of what AVIF has, while AVIF has three; plus, tile boundaries are handled by the DLF. Your point doesn't really stand on two legs if it means to come to JPEG XL's defense here.

eviks 20d ago
> Every block of a JPEG XL image is effectively a small tile, Operative word here is "small", so it has different effect, thus doesn't imply same sensitivity trigger
- juliobbv 20d ago
  By "small", it's meant in a relative sense. JXL's coded blocks can be as big as 64x64, and block boundaries can create visible seams. Example: https://juliobbv.com/pics/photo.jxl https://juliobbv.com/pics/photo.jxl These seams are especially noticeable in the background, and align with coded block edges. You can tell the encoder is trying to conceal them as best as it can, but this cannot be properly mitigated without a proper deblocking filter. For comparison, AV1 tiles normatively go through the deblocking filter.
janwas 19d ago
We can agree on wanting a better internet :) I participated in the design of those filters, so no, I do not deeply dislike the way they look. This gaslighting is not convincing. No matter how many filters AVIF has, I distinctly remember tile artifacts being particularly disturbing. More so than individual blocks, whose size and border effects differ; tiles are a straight line through the entire image. JPEG XL does not have this problem because the design and codestream enables parallel decoding (thanks to per-group offsets encoded in the 'TOC'), hence does not require separate tiles.