Vision mixer
A vision mixer is a device used to select between several different live
In most of the world, both the equipment and its operator are called a vision mixer or video mixer; however, in the United States, the equipment is called a video switcher, production switcher or video production switcher, and its operator is known as a technical director (TD).
The role of the vision mixer for video is similar to what a mixing console does for audio. Typically a vision mixer would be found in a video production environment such as a production control room of a television studio, production truck or post-production facility.
Capabilities and usage
Besides hard cuts (
Older professional mixers worked with
Operation
The most basic part of a vision mixer is a bus, which is a signal path consisting of multiple video inputs that feeds a single output. On the panel, a bus is represented by a row of buttons; pressing one of those buttons selects the video signal in that bus. Older video mixers had two equivalent buses (called the A and B bus; such a mixer is known as an A/B mixer), and one of these buses could be selected as the main out (or program) bus. Most modern mixers, however, have one bus that is always the program bus, the second main bus being the preview (sometimes called preset) bus. These mixers are called flip-flop mixers, since the selected source of the preview and program buses can be exchanged. Some switchers allow the operator to switch between these two modes. Both the preview and program bus usually have their own
Another main feature of a vision mixer is the transition lever, also called a T-bar or Fader Bar. This lever, similar to an audio fader, is used to transition between two buses. Note that in a flip-flop mixer, the position of the main transition lever does not indicate which bus is active, since the program bus is always the active or hot bus. Instead of moving the lever by hand, a button (commonly labeled mix, auto or auto trans) can be used, which performs the transition over a user-defined period of time. Another button, usually labeled cut or take, swaps the preview signal to the program signal instantaneously. The type of transition used can be selected in the transition section. Common transitions include dissolves (similar to an audio cross fade) and pattern wipes.
A third bus used for
These three main buses together form the basic mixer section called Program/Preset or P/P. Bigger production mixers may have a number of additional sections of this type, which are called Mix/Effects (M/E for short) sections and numbered. Any M/E section can be selected as a source in the P/P stage, making the mixer operations much more versatile, since effects or keys can be composed offline in an M/E and then go live at the push of one button.
After the P/P section, there is another keying stage called the downstream keyer (DSK). It is mostly used for keying text or graphics and has its own cut and mix buttons. The signal before the DSK keyer is called
Modern vision mixers may also have additional functions, such as
Setup
Since vision mixers combine various video signals such as VTRs and
Manufacturers
- Analog Way (manufacturer) [2]
- Barco (manufacturer)
- Blackmagic Design: ATEM[3]
- Broadcast Pix[4]
- Datavideo
- EVS Broadcast Equipment: Dyvi [5]
- Focus Enhancements (Videonics, former)
- FOR-A
- Grass Valley
- Guramex[6]
- Kramer Electronics Ltd.
- TriCaster, bought by Vizrt)
- Panasonic
- Thomson SAand later integrated into Grass Valley)
- Roland Corporation
- Ross Video
- Snell (former, bought by Grass Valley)
- Sony
See also
References
- ^ «Analog Way»
- ^ Products, Blackmagic Design
- ^ Broadcast Pix - Integrated Live Production Tools
- ^ IT based mixers
- ^ «GURAMEX»
Sources
- "Tools of the trade". renewedvision.com. Archived from the original on February 7, 2012. Retrieved May 10, 2007.
- "Ampex Production Switcher". CSU-Pueblo Television Production Handbook. Archived from the original on April 15, 2012. Retrieved February 28, 2005.
- SRT (Hrsg.) (2000). Ausbildungshandbuch audiovisuelle Medienberufe, Band 2 (2nd ed.). Heidelberg: Hüthig. ISBN 3-7785-2809-2.
- Luff, John: "Production switchers ". Broadcast Engineering, November 1, 2002
- Moore, Jeff: "Production Switcher Primer ". Ross Video Production Switcher Primer.
- VideoSolutions group "ODYSSEY Mixers Family ".
- Monarch Innovative technology pvt ltd"[1] ".
- thameside.tv Sony Vision Mixer DVS-7000