FOR-A's VPS-700 switcher began with one developer's simple question: “Couldn't we create fantastic images if independent DVEs are used for each input?” This became the key point and the initial concept for this digital video switcher.
Because the demand for SD-SDI switchers has not diminished in many regions, FOR-A began using a product concept based on SD-SDI input/output for a 1M/E, compact (2RU) chassis. A wide range of functions were incorporated in the standard configuration, such as six keyers, six chromakeyers, six powerful mask generators, six-channel DVEs, six trail stores and six border generators. The development also included adding multilayer support for optional configurations, which otherwise would only be available in large-size switchers, as well as capability for representing multilayer transitions.
Multilayer and multi-DVE
Despite being a 1M/E compact switcher, with the proper configuration, the VPS-700 can create multilayer, multi-DVE images that would normally only be possible with a large-size switcher. Multi-DVE capability means that up to a 38-DVE engine can be used when optional boards are installed. Also, with multilayer capability, there are 17 layers in each pre-combiner unit (DVE assignment and background matte to 16 channels) and eight layers in the M/E unit (PGM, PVW, four keyers and two DSKs) for a total of 25 layers (up to 40 pictures can be displayed simultaneously).
If a large-size switcher is used, complex images can be made by making a cascade connection of the M/E composition results. However, to clarify the concept of adding DVEs to each input, consider each input as a single layer, making this a layer-type switcher because of its capability to compose multilayering image with a combiner.
The layer system is based on keyers. Video and keys are sent to the combiner by each layer, and the background and priorities for each layer are determined and composed by the combiner. (See Figure 1.) An optional VPS-70DS (input DVE/pre-combiner) board can be added to the standard 1M/E configuration switcher functions for realizing the layer system functions.
The digital video switcher is capable of assigning DVEs to each input (up to 16 inputs), generating video and key signals, composition by setting the priority and transparency with a pre-combiner and returning these signals to the M/E. The returned signals are handled as cross point and keyer elements. Despite being a 1M/E switcher, the input DVE and pre-combiner functions enable the realizing of composition effects equivalent to multi-level M/E.
This switcher can accommodate up to two input DVE/pre-combiner VPS-70DS boards for enabling creation of complex images. However, it can also be used as a basic 1M/E compact switcher, when needed, without installing the boards. Then, when the user wants more advanced image creation, a VPS-70DS board can be added for realizing operation as a layer-type switcher with composite effects equivalent to a multilevel M/E switcher.
System configurations
In the standard system configuration, eight inputs and eight outputs (PGM1-2, PVW, Clean and four AUXs) are provided, and four keyers, two DSKs (with six CKs), six DVEs (2.5D), edge/shadow generator and other features are available. In its standard configuration, the system can be introduced into such production environments as cable TV stations, production creation and editing, live event recording and studio switchers. It can also be used as a base unit (L-shaped composite) that combines a broadcast with different types of information screens, such as regional information, emergency bulletins and weather forecasts.
Adding the optional VPS-70WARP, VPS-70DS, VPS-70SDI and VPS-70SDO boards enables the system to be used as a pre-combiner, to wipe effects as line DVEs and to create complex images for high-level presentations. For example, the VPS-700 combined with a switcher can be used as an external DVE capable of warp effects. Or the pre-combiner function can be used to realize multiple picture-in-picture effects without using a keyer for making more complex compositions of key composition base video.
Future development will focus on the tally unit and AUX control panel developed in the HANABI series and development of analog I/O board products that can be incorporated in the main unit. Because expansion slots are limited, it will be difficult to make a fully analog design for input/output, but an effort is underway to provide a method to enable effective use of existing equipment.
Ken Truong is technical manager for FOR-A.
