Looking at directions to challenge patents on LCEVC

Posted Mar 14, 2025 8:22 UTC (Fri) by farnz (subscriber, #17727)
In reply to: Looking at directions to challenge patents on LCEVC by rolexhamster
Parent article: GStreamer 1.26.0 released

The missing bit from AV1 bitstream format is a quality extension layer; it can increase resolution (so base layer gets you 1280x720, extension layer + base layer gets you 1920x1080), and it can increase frame rate (base layer gets you 15 fps, extensions give you 30 fps or 60 fps), or a combination of the two, but not keep resolution and frame rate the same but increase picture quality.

With that, you could get very similar effects with more memory in the decoder - you decode extensions and base in parallel, and keep all the decoded pictures around. If you keep getting extensions, you keep using them. If you can't decode the extension layer due to packet loss, fall back to base layer until you can decode the extension layer. Then, you "just" need the encoder to be intelligent about the extension layer such that you can switch the extension layer off and on quickly on a frame-by-frame basis.