As it is not possible to remove a light created during the first video frame in YafaRay, a single call to [font=courier new]new YafarayRenderer[/font] has the consequence of adding new lights to the scene with each new frame which slows down the video rendering.
Using [font=courier new]finalize()[/font], Sweet Home 3D crashes by generating a .log file in the plug-in project folder.

With several calls to [font=courier new]new YafarayRenderer[/font] as for photos at points of view, a new scene is created with each video frame and the problem of removing lights does not arise.
The surprise is that the video rendering is no longer slowed down and is even faster than SunFlow.