Andrew, testing here looks good with Cinelerra-GG on Fedora 29/30 on a desktop and a laptop.

0.5.0 brings large improvements in speed on SSSE3 CPU (up to 40% speedup), new speed improvements on AVX-2 (for 4-7%) and ARM64 (up to 10%) and ARM32. It introduces some VSX, SSE2 and SSE4 optimizations.

The speed up with Cinelerra is very good with this version. What I see on my laptop is:

Stream1_AV1_4K_8.5mbps.webm 0.4.0 about 22 fps 0.5.0 Full Speed at 25 fps !!

Stream2_AV1_4K_22.7mbps.webm 0.4.0 about 16 fps 0.5.0 Full Speed at 25 fps !!

Stream3_AV1_4K_13.9mbps.webm 0.4.0 about 14 fps 0.5.0 Full Speed at 25 fps !!