Images can not be converted to AVIF format

[Codes301]

Distribution

Linux Mint 22.2

Package version

3.4.7

Frequency

Always

Bug description

Trying to convert an image to .avif via "Convert Format..." results in this error.

Could not Perform the Operation
Could not encode the image: Usage Error: NULL argument received

I've tried a jpg and a few other .png images to convert to .avif, which results in the same error output.
I've noticed that this issue also occurs when I try using gThumb version 3:3.12.6-1.

Steps to reproduce

1. Open image with Pix
2. select option "Convert Format..."

Expected behavior

Image depending on saving preference would take some seconds to convert the image to the desired format chosen. In this case .avif

Additional information

No response

[Not-Sure-Whats-Going-On]

Using a fresh install with Mint 22.3 and pix 3.4.10, I also get this error. I can import an avif image OK, but if, for instance, I crop it and try re-export using either Save, or Save As I get the same error message as above.

Could not Perform the Operation
Could not encode the image: Usage Error: NULL argument received

Saving to other image formats like jpg or png works as expected.