Video processing

When I discuss video processing with engineers, their specific needs are definitely varied. But one common factor does exist, which is that video processing typically gets lumped into two categories: one-time setup and operational. One-time setup is usually carried out during the plant commissioning or studio setup: Although there may be some presets as programs change throughout the week, there are typically few modifications after the initial configuration. The second category of video processing allows for operational control. Back in the good old days, this generally entailed simple stuff like proc amp controls.

But the move to digital has complicated processing functions. Going 100-percent digital simplifies matters (notice I said 100 percent); it is the mixed-mode transition era that makes operations so difficult. Let me give you a simple example using audio. 

In analog, there were many “plant standards,” which made it rough to move audio from plant to plant. In digital, it’s simple: Full scale is 0dBFS — not +10dB, not even +4dB; all 1s are defined at 0dBFS. The trick here is to always keep the audio in digital — right from the mixing board. The minute it hits analog again, the signal needs to go through analog-to-digital converters, which is where the nightmare begins; both levels and phasing are bound to get messed up. The same goes for NTSC and PAL composite video; someone’s fingers are typically on the input proc before the converter to “fix up” the video before conversion to digital.

So let’s zoom out a little into your future plant being 100 percent digital. Will you still need proc functions? Of course, technical directors will always want their show to look its best and will tweak a little here and there, but that is where it should stop. Once the show has been created, there is no reason to change it for standard television distribution, short of adding in some localized branding. The key is in the setup. Normalize as much as possible within your plant, and give operation people the chance to fix bad feeds when needed (which should not be often, except in live situations).

Keeping this consistency in plant digital video means that video processing (including timing) can increasingly be of the one-time-setup variety. Technology advances have eliminated the need for an engineer to adjust every process continually, enabling hands-free operation — and creating a clear paradigm shift (as shown in Figure 1) in plant design.

The server paradigm shift

Let’s look at this paradigm shift in more detail by using video playout servers as an example. Ingested video can be stored in many formats — 480i, 720p, 1080i. The trick here is to define at the output port what format is needed. Let’s say it is 720p. Video stored in 480i will be scaled, and color space changed, and pillar-boxed (or stretched) based on AFD codes and the user’s preset parameters — all automatic and hands-free. Software-based video processing running in real time on multiple CPUs in the video server make this conversion possible. In some cases, branding and multiviewer functions are also incorporated into servers.