You can zoom in the video image in both live video and archive view modes by stretching the image with two fingers.
Note
If the camera isn't a PTZ camera, you can also zoom in by double-tapping the screen. Video will be zoomed in to x3 size.
You cannot make the video smaller than its original size. You can zoom in up to x5 size.
To select the part of the frame that you want to view, move your finger over the video viewing area.