Trying to process an mp4 file...

[tombrown86]

I'm at capture stage.. I get this error when trying to process from Video file.
I don't have this error when I use regular darknet so I wonder if it's to do with the saving jpg element?

FPS:0.0
Objects:

aeroplane: 56%
OpenCV Error: Unspecified error (could not find a writer for the specified extension) in imwrite_, file /build/opencv-2TNgni/opencv-3.1.0+dfsg1/modules/imgcodecs/src/loadsave.cpp, line 459
terminate called after throwing an instance of 'cv::Exception'
what(): /build/opencv-2TNgni/opencv-3.1.0+dfsg1/modules/imgcodecs/src/loadsave.cpp:459: error: (-2) could not find a writer for the specified extension in function imwrite_

[1] 2908 abort (core dumped) ./darknet detector demo cfg/coco.data fddb-face/yolo-face.cfg me.mp4