In the world of video, things can get confusing with the terminology. At Life.Church, we use the switcher in such a way that all of the confusing technical terms are not necessary to run a service successfully. This article will list a few key terms and their definitions as a way to deepen your knowledge of video terminology.
This article is not very in-depth and will remain very simple.
The Program Bus - The top row of the larger buttons is what is 'live' or 'on air' - The output goes directly to the side projectors no matter what. The Program box is located in the top right corner of the multiviewer. To learn more, visit our article Ross Switcher : Program/Preview Explained.
The Preview Bus - Labeled on the switcher as the Preset row is the lower row of large buttons. Preview is an easier way to remember the row, as it is the 'preview' of the source coming next with the transition. The Preview box is located in the top left corner of the multiviewer. To learn more, visit our article Ross Switcher : Program/Preview Explained.
The Multiviewer - This allows you to view all incoming sources and most outputs as a way to verify what is being sent from the switcher. Each input and output has a label as well as a colored outline indicating the selected item. The 'switcher TV' is formally called a 'Multiviewer Output' of the switcher. To learn more, please visit our article Ross Switcher : Multiviewer TV.
For our purposes at Life.Church we rarely use the word key or any other technical form of the effect.
The LifeKids button uses a key to remove the black background and only display the small rectangle containing the LifeKids code. This process is a layer downstream of the program output, in other words it is on top of what the source being sent out to program.
The technical term for the way we use this key is a 'Downstream Key' or 'DSK'. We use what Ross refers to as a 'Self Key' instead of a 'Chroma' or 'Luma Key'. The Self Key has the ability to recognize the black background with little effort. For now, we this article will not go much deeper into details. To learn more, please visit our article Ross Switcher : LifeKids Code Best Practices.
The Bus - This term is often used interchangeably with the word crosspoint, although sometimes crosspoint is a little more specific. We refer to a row of buttons, such as the program, or live row, as the 'Program Bus'. These technical terms aren't needed, but as long as you reference which layer you are currently, the bottom row is always the 'Preview' row.
To learn more, please visit our article Ross Switcher : Program/Preview Explained.
The term 'signal' refers to the language of digital code being transmitted through the cable, which language is being transmitted and received. Cables don't care which language is being transmitted, but each end of the cable does care. The transmitter and receiver need to know what kind of signal they are working with, so they can translate it as it comes through.
In the video world, one of the most common signals is called 'SDI', which stands for 'Serial Digital Interface'.
The language is a serial transmission, transmitted digitally, all packaged in a specific way. There are many different forms of SDI (dialects), 3G SDI, HD-SDI, 3G HD-SDI, 12G, etc...
Another signal we use is 'HDMI'. A major difference between SDI and HDMI is, when using HDMI, the signal is split between multiple channel streams instead of a single constant stream down a single channel. SDI transmits one single channel.
The signal types refer to the signal, not the connector, meaning SDI is not a specific connector.
There can be compatibility conflicts between different signal types and connectors, especially when talking about high definition (HD) or 4K video.
Connectors are the connection points used at the end of a cable. In the world of video, we most often use a BNC connector. A BNC connector is metal connection piece with a single conductor pin in the middle for transmitting an SDI signal. The BNC connector secures into the port by rotating the connector clockwise, which locks it in place.
A Connector is not a signal type, as there are no BNC cables.
Other connector examples that you use often RF Coaxial Connector (the screw-on cable connector on a TV). There are more than ten different connectors when referring to USB; USB-A, USB-B, USB Mini A Male... It can get confusing pretty quickly.
HDMI can refer to the signal type, as well as the connector. There are, however, several different connectors that can be used with HDMI.
There can be a compatibility conflict between different signal types and connectors, especially when it comes to high definition or 4K video.