How to improve performance of AVIF encode times (single frame at a time)

[kevinmershon]

I've created an issue along this topic at strukturag/libheif#1458 but wanted to specifically reference the encode example here as I am unsure if I'm doing things correctly.

I have a persistent flow of screenshots from a screen capture process and want to take screenshots and encode them to AVIF single frames as quickly as possible. Right now working with libheif and libheif-sharp with the AOM encoder the fastest I can get it to encode (based on the encoder sample in this repo) is about 3.5-10 seconds per frame. This is awfully slow.

By comparison, in C# with a regular CanvasRenderTarget I can encode a full desktop screenshot in 15-25ms. On MacOS I can encode jpegs around 7ms and AVIF around 25ms. I feel like I have to be missing something with the way I'm setting things up.

Notably, it is specifically the call to context.EncodeImage that takes so long, if that is at all helpful.