But, as far as I can see: - if any other codec will actually be changing frame size, it is already handled in wg_transform_set_output_format() without recreating the transform, it just should not consider caps / formats with different size compatible (and there is transform flag for that); - if any other actual change requires transform recreation, then it can be checked in SetInputType, but it seems not directly related to what I am trying to fix here, that will probably need some case / tests to confirm what actually supposed to happen, maybe SetInputType will just fail?
Regarding requiring it to be quick, I guess this case I am concerning here is exactly the example, when the game wants just to loop the video (and calling probably unneeded SetInputType / SetOutputType)?