libheif evc: initial work for EVC

Initial work on EVC. No codec yet, just the basic box.

Oct 29 '24 10:10 bradh

I've redone the merge, adopting the new define. Looks like I need to do a bit more work though.

Nov 22 '24 21:11 bradh

Why did you close this PR? It is very good and just was not merged yet because we lack the EVC codec implementation. If you don't mind, I'd like to keep this open.

Jul 13 '25 20:07 farindk

I had hoped to use the xeve and xevd implementations for the codec, but they don't look like they are ready for production use. So I've moved on, and didn't really see how this was going to get to a usable state.

I am OK with re-opening though, in case someone else wants to continue the work.

Jul 14 '25 07:07 bradh

Right, the last commit to xeve/xevd was ten months ago and there are no alternative implementations. Not sure if that will ever take off. But with this PR, we are at least prepared, just in case.

Jul 14 '25 08:07 farindk