Niklas Haas authored Feb 01, 2021 and Jean-Baptiste Kempf committed Feb 06, 2021

The current playback loop triggers a repaint on any single event,
including spammy events such as SDL_MOUSEMOTION.

Fix this by only repainting on SDL_WINDOWEVENT_EXPOSED, which is defined
as the event sent when the window was damaged and needs to be repainted,
as well as on new frames.

Fixes videolan/dav1d#356