Is it possible to capture video from a DTT software?

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I'm planning to develop an app using Python that would take a frame from a video stream for processing it later (actually it will capture frames every X seconds) from a DTT receiver software. So the point is, how can I get that picture programmatically? Does it depend on the specific DTT software? Should I get a DTT card whose manufacturer provides an API? Does OpenCV allow to get that videostream from code?

Thanks!