Low Complexity Enhancement Video Coding (LCEVC)

[SolidComp]

Hi all – Can anyone explain how LCEVC works? It's supposed to leverage an existing codec (e.g. H.264 or VP9) and adds an "enhancement layer". The end result is something like a 28% data savings. I've read a few things about it, but I don't understand where the trick is, the secret sauce. How can adding a layer to an existing encode save data?

Here's a recent test comparing H.264 to LCEVC using H.264 as the base layer.

Thanks.

[skal]

Looking at the slide #10 here: https://www.itu.int/en/ITU-T/Worksho...esentation.pdf
it seems the base layer is now coded at half the resolution (instead of full). The extra enhancement layer is then coded more efficiently. Hence the global gain.