Head's up for those that build Sigil from source

[DiapDealer]

Originally Posted by KevinH

Could the Windows build for both avif and jxl plugins be turning off something Windows needs in libjxl or libavif?

When they built, I just assumed they were OK. They seem fine for "normal" sized images. And others seem to be experiencing much better performance than I am on their windows machines with this monster epub. My ancient Windows 10 laptop was slow, but both it and my Windows VM handle that epub better than this much newer Windows 11 machine with gaming graphics and tons of ram/cpu. *Shrug*

Originally Posted by KevinH

It is wild that turning off the gpu acceleration actually speeds things up!

I know. That makes no sense to me!

[DiapDealer]

I've seen several reports that jxl is engineered for high-efficiency encoding and decoding directly on the CPU across mobile and desktop devices without needing specialized hardware support. In fact: Disabling hardware acceleration in Chrome forces the browser to rely on software rendering through the CPU rather than offloading tasks to the GPU. If a GPU driver is buggy, outdated, or poorly optimized for a specific image rasterization path, falling back to CPU software rendering can eliminate lag or stutter.

This has definitely been my experience with the huge jxl images (as well as avif) on multiple Windows machines. A tired Windows 10 laptop, a beefy Windows 11 gaming desktop, a Windows 11 qemu vm on a stout Linux host, and a newer high-end Windows 11 mini-pc.

The speedup on jxls when disabling gpu hardware acceleration still doesn't make sense since Preview is converting them on the fly to jpg (95%). The only explanation is that large jpgs benefit from using software rendering in chrome on Windows as well.

I believe I'm going to start disabling WebEngine's GPU acceleration by default on Windows from now on.

[KevinH]

I also thought about that. I think Calibre disables it as well fwiw.

[DiapDealer]

My Windows 11 Mini-PC holds its own with the monster-sized images fairly well (after disabling acceleration, excluding all of Sigil's binaries/folders from antivirus, and telling Windows to optimize performance for Sigil and QtWebEngineProcess), so I think I'm ready to put this test case to bed. If you want to use monster-sized avifs in your epubs on Windows, be prepared for some fairly sluggish Sigil performance regardless of your hardware.

[KevinH]

Curious... How do you actually tell Windows to optimize performance for Sigil and QtWebEngineProcess? Is this akin to changing scheduling priority for specific processes on Linux?

[DiapDealer]

Originally Posted by KevinH

Curious... How do you actually tell Windows to optimize performance for Sigil and QtWebEngineProcess? Is this akin to changing scheduling priority for specific processes on Linux?

It's mostly a graphics thing. You can let Windows decide how to handle things, or you can choose a power saving option or a high performance option.

[KevinH]

FYI, disabling the GPU on my arm64 M2 Max using Sigil preferences and restarting Sigil, sped up loading avif slightly. So it is not just a Windows thing.