You get it for free if you use CoreMedia (which is what WebKit does), but you can also use HW video decoding directly:

https://developer.apple.com/library/content/technotes/tn2267...

The VDADecoderCreate function will return an error if HW video decoding isn't available.

VDA framework was made obsolete in OS X.

Equivalent features are provided in the Video Toolbox framework from OS X 10.8 and later.

Firefox only supports 10.9 and later from now on, and no longer uses VDA.

Unlike VDA, when you create a decoder, you just get one. You then query if it's a hardware decoder or not, but the behaviour is fundamentally the same between SW and HW.

For some reasons, the VT frame gives us a software decoder most of the time for some users.

Until now, I had only ever seen Mac Pro (including 2013 trashcan model) to not provide hardware decoding support.

If you attempt to decode a video that is less than 144 pixels high, you always get a software decoder.

So, Safari on macOS uses private APIs that even programs outside the App Store can't use?

Not that. But safari is able to be per-configured to just work for apple's specific chosen hardware. So it is at an advantage in that respect.

Have anything you can cite to expand on this? That seems like an incredibly basic thing for native applications to not have access to on OS X. (note: not iOS)