The religious debate over HD formats appears to be a thing of the past. Format converters-which let a production company that has standardized on 1080i or 720p work with material captured/stored as either-are now available in almost every piece of production equipment, including cameras. But what happens if your client asks you to produce a remote HD project that will include live SD sources?
The newest trend in HD switchers designed to produce live events is the option of internal video scalars and/or format converters that enable an operator working a live HD event, sports or entertainment, to switch SD or HD material, 1080i or 720p, and have it all look the same, or almost the same, on the final on-screen output. With this new feature, the switcher does all of the conversion without the operator (or viewer) ever knowing its happening.
Facilitated in both hardware and software, this is important when working on an HD show where a producer might want to incorporate a graphics or still image stored in an SD format, or a camera feed sent via microwave link, and wants to make the transition from an SD source to HD look natural. It operates much like a routing switcher tie line, which for years has helped facilities automatically convert signals from analog to digital.
Snell & Wilcox's "Format Fusion" technology was the first to show the feature, on its Kahuna switcher at last year's NAB. Grass Valley has announced that its Kayak HD switchers will offer a "MatchDef" feature this year, and Ross Video's Synergy MD switchers can include "Smart Conversion" as well. All of these switchers also support the variety of SD (525 for NTSC and 625 for PAL countries) and HD formats (including 1080/24p, 720p, and 1080/60i).
Sony keeps this upconversion process external to the switcher frame. The company’s MVS-8000 switcher includes an internal video matrix to create tie lines to route SD signals to a small bank of upconverters. These HD signals are then re entered into the switcher frame and routed to the selected source button. This allows processing of selected signals to take place seamlessly, without any TD intervention.
Yet users should be aware that any time you perform an up-or down-conversion live, there’s at least a one-frame delay in order to make it happen. A single frame is not noticeable to the average viewer, but when you add that delay to other single-frame delays in the signal path, say, though a frame sync to lock an input to your facility, and then through a DVE channel, that three-frame delay will cause your audio to move ahead of your video elements, resulting in lip-sync errors that audiences can clearly see.
It is important to keep in mind that this format conversion is being done inside the production switcher and is therefore unavailable in its converted form to other areas in your facility-a system benefit in going with dedicated outboard format converters. The technology is really valuable when lots of pre-production planning is not possible and last-minute inserts are anticipated. It’s also a helpful feature if you own a mobile production truck or production facility that caters to a variety of clients that all use different HD formats.