From a615c697d8e2b4cf5be22d23aa210d896d365702 Mon Sep 17 00:00:00 2001
From: Manuel Bugallo
Setting -verbose setting, will cause -distort to attempt to output the internal coefficients, and the -fx equivalent to the distortion, for expert study, -and debugging purposes. This many not be available for all distorts.
+and debugging purposes. This may not be available for all distorts.You can alternatively specify a special "-define distort:viewport={geometry_string}" setting which will