Video Quality Vis- -vis Frames-Per-Second
The number of frames per second has nothing to do with the image quality. While 30 frames per second is real time in NTSC, it is made up of 30 individual snapshots of sort. So while a video recorded at 5 frames-per-second has 1/6th the number of images, it does not have 1/6th the quality; it merely has fewer snapshots (that is of course if everything else is equal – such as bitrate, resolution, etc.) Remember, it is nothing but a succession of still images.
So why is there a need to record in real time? After all human beings don’t move that quickly, or do they? We are not recording speeding cars. One answer is from a prosecutorial standpoint, what happened in between, if you are not looking at the whole picture. If you are recording in real-time, there is no room for hypothecations by the defense lawyers. Further, a more detailed picture can make it easier to identify sleight-of-hand movements. You are also going to find that older technologies have trouble with slow motion and smooth playback under those conditions, so higher frame rates tend to compensate for some of the shortfalls, but not all. In reality unless it’s mission critical applications 5 frames per second is more than enough to accomplish the task, which is what many bank and institutions use; some even less.
A still shot from a recording at 30 FPS will look the same as one at 5 FPS