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The evolution of IP video has placed a lot of attention on the resolution of video, as measured in the growing number of pixels in a frame. But another variable, receiving less attention, is the number of frames captured per minute (fps). We inherited the idea of “full-frame-rate” video from the analog world, but increasing numbers of pixels (and more data!) have sometimes led to use of slower frame rates. We asked our Expert Panel: What is the value of “full-frame-rate” video? Absent specific compliance requirements, what might suffice as an acceptable frame rate (i.e., less than 30 frames per second [NTSC] or 25 frames per second [PAL])?
As with any variable related to a video surveillance of security system, the question of frame rate comes down to determining the needs of the application. As higher pixel counts (and limited storage and bandwidth resources) put downward pressure on frame rates, it’s important that integrators and end users manage the compromises well. After all, what good is a really clear image if it misses action that happened between frames?
Fredrik Nilsson,
General Manager, North America, Axis Communications
The more information you have in a video, the better is it for forensics purposes to figure out what happened after the fact. Following that theory, high frame rate should always be better than lower, right? Well, the surveillance industry has long accepted and talked in terms of 4 fps, 7.5 fps and 15 fps, which has stemmed from technical limitations and high costs, creating a real desire to have a lower frame rate. When looking at a certain storage capacity, of course, the user has to choose between retention time, frame rate, but also resolution and image quality. That being said, there will always be different scenarios and needs in different market segments. For instance, a casino has long required a full 30 fps, and looks at 60 fps as beneficial. In the future, as technology improves, it is possible that we could see 30 fps become the norm.