What web interface ? I have never used a substream. I view everything via
Blue Iris.
The H.264 and H.265 are similar in there video compression. In very simple terms, and Iframe is a complete full frame / picture, with all the data, pixels and color information. The next frame after the Iframe just contains the information that has changed, the Iframe and the change data is used to reconstruct the second frame, Each frame after that uses the previous frame to build the new frame. The problem is that this is not perfect, Fast moving object, cars, People turning there head can cause fuzzyness or tails or items that seem to appear out of nowhere. So you need another Iframe to start the process over again. If the Iframes are too far apart the video looks like crap. If they are too close together you waste space. The general recommendation is for the Iframe to be the same as the FPS, so you get one Iframe per second. For real static images, then an iframe no more than every 2 seconds , twice the FPS.
On the kitchen camera it appears to be using 5 to 10 time more space/data then the other cameras. I know nothing about these cameras, I would look for doing a hard reset on the camera, Normally you take the camera down, open it up, push a button or short two pins. look at the documentation.
