The new build works fine so far, Richard.
But it seems the graphics are much slower. During testing I saw much more stuttering in the video. Using turbo on the current published version I can get 570 FPS, while on this test build I can only get up to 180 FPS (1x video size, no filters). Without turbo, the FPS counter stays at 60-61 FPS (even using HQ3X). There was no difference in CPU utilization between builds.
Testing was done on a MacBook Air Late 2010. 1.86 GHz Intel Core2 Duo. NVIDIA GeForce 320M w/256MB VRAM. macOS 10.12.6.