identify abrupt frame changes in a video The frames of live streams or videos, in general, do not flow smoothly. A sports game would have multiple cameras recording the game and hence, there will be camera switches in the stream. I am detecting objects and tracking them as long as possible. When there are full changes in the video stream, I wish to reset object tracking and do a full detection.

I am looking for methods to efficiently identify when a camera switch (or anything of that kind) happens.

What algorithms are available to efficiently identify abrupt changes in a video?
Easiest is to capture video with an h.264 encoder, which uses key frames to identify switches. (It’s a bit more complicated, h264 will handle situations where frames come alternatively fro two different source, for example), but extracting that information from a video stream is easier than doing it yourself). 

Source code for decoders is available, and a decoder will also give you useful information about movement, and things that become covered or uncovered.