opengl: add blend deinterlace filter
--deinterlace-mode
selects a blend algorithm, but not a particular implementation.
--deinterlace-mode=blend
or equivalently ("deinterlace" is the default filter):
--deinterlace-filter=deinterlace --deinterlace-mode=blend
To run the OpenGL version (the mode is "auto"):
--deinterlace-filter=glblend
The module glblend only implements the "blend" algorithm, it can be passed explicitly:
--deinterlace-filter=glblend --deinterlace-mode=blend
To pass a list a modules, executed in order until one works:
--deinterlace-filter=glblend,deinterlace --deinterlace-mode=blend
Edited by Romain Vimont