Expense vs. Quality in Scanning Choice
Displaying video on a screen is primarily handled through one of two types of scanning methods: Progressive or Interlaced.
Both technologies read individual lines of a frame of video from top to bottom. The main difference between the two is that the progressive method scans every line, while interlaced scanning only reads every other line. This reduces bandwidth and size requirements for video broadcasting, etc, but also reduces the quality at lower frame rates. Blurring and sync issues can occur at these lower frame rates that may not be noticeable at higher frame rates.
As you can imagine, the progressive scan method produces a higher quality video frame every time, because it is using every line of the recorded image. This can, however, increase bandwidth and storage requirements significantly (double), making it a real question of quality vs. expense when deciding which technology to focus on.
In the CCTV Security Camera world, interlaced scanning at high frames-per-second is often the way to go in order to keep storage and bandwidth costs down. Many video capture cards support it, and as long as you can justify the slight quality reduction for your specific application, it’s probably the way to go.
For projects and solutions where high quality video is required, such as law enforcement, banking, casinos, etc, using progressive scan technology and investing in the proper hardware is advisable. Progressive scan is also a good idea if you are recording at frame rates below 15FPS.