What is an avif file signature?

Question

I have searched it from here, here, here but none of them included the avif signature.

I want to determine whether a file is avif or not from bitstream. But document is too complex or cannot be accessed freely. How can I achieve this?

It will be better if answer includes the reason why it can be applied without false positive or false negative.

user_560784 · Answer

The file signature for avif file is ftypavif.

You can see a list of sample avif files here: https://github.com/link-u/avif-sample-images

To check file signatures yourself, download/find a file you want to check, then you can check via any hex viewer.

In Powershell on Windows, you can run this:

format-hex c:\yourfile.someextension