i dont know if that has a specific term, but it generally revolves around the render queue. different players/renderers handle what happens when the render queue isnt ready to play.

MadVR (a popular upscaling renderer for MPCHC) for example has an option to pause render queue till full.

ome player may have it setup as always play each frame which causes random slowdowns/speedups, other might implement it as drop frames to always be time synced correctly.