Implement browser NVR

Question

The simplest abstraction of NVR(Network Video Recorder) is like the follow:

1. The user specifies a path (such as: ~/recrods/) to store video records.
2. The NVR creates video files (such as: 1.mp4, 2.mp4) on the path.

Now we are going to implement a web-page NVR. Is it possible to do the similar things in the browser without popping up file selectors?