如何获得作为摄像机输入的视频播放？

Question

i want to detect specific object from live ongoing video.so i implement frame extraction part(opencv, c++) as one part and other detection function(emgucv, c#) for other part. for integrating those part i added exe file of c++ project to c# project and that is working well. but now i want to test this project in offline. That mean i want to test this project by using video that saved in hard disk. before integration,c++ project could able to execute on both online and offline situations. but after integration that could execute only in online condition. please help me to solve this.

Answer 1

You can always try webcamera emulators like Magic Camera, Fake Webcam or whatever (just google it, there are a bunch of software all over the internet) – they would play a video file as if it was coming from your webcamera.

However, you might also want to think of re-organizing your software design so that it could accept both streams and file inputs – it should be very straightforward once you separate the processing logic from the capture logic.

Answer 2

A live video camera is basically an asynchronous source of image frames. Presumably you pass a callback function to the camera API, and that callback is triggered upon a new frame's availability? You can mimick this functionality in a fairly straightfoward fashion.

Write a function which opens your video file, and then runs in a loop... each iteration of the loop, it grabs a frame from the file, packages it up appropriately and then calls your callback function. It can then sleep for a few milliseconds, and then repeat the loop. Run this function in its own thread. From the point of view of the callback, it is no different from a live camera.