Why would video files not open in OpenCV (both C & C++ APIs)?

Question

I am swapping from EmguCV to OpenCV so that I can try some of the OpenCV functions that are not yet wrapped by EmguCV. However I\'m failing to load my simple test video file, wh

Answer 1

It appears that, following advice from @tobias-senst on another answer, I needed to build OpenCV on my local machine rather than rely on the DLLs that are provided with the standard distribution. It has been a headache to get OpenCV to build locally (see here, here, and here) but now that I reference to a copy of OpenCV 2.4.6 that was built on this machine I can open the video files.

I have no idea why this works, why it is not mentioned in the requirements, why others are not more frequently having this problem, nor what is failing with the default deployment, but at least I have it fixed.