Kadano
SVP can process 8bit YV12 only. NV12 can be converted from/to YV12 without losses.
Do you use OpenCL acceleration in SVP (SVP-Manager tray icon - GPU-acceleration)? It works more precize with colors and must help to avoid banding.
If your video 10bit depth then I recomend to use dithering in LAV Filters to convert video to 8bit with high quality and without visible banding artifacts.
I use these settings to watch 10bit movies with SVP.