Editing Vision mixer

{{Short description|Device for selecting and compositing of live video sources}}

[[File:CurrentNew.jpg|thumb|[[Ross Video]] Vision 4 at [[Current TV]]]]
[[File:Snell Kahuna vision mixer.jpg|thumb|Kahuna video switcher made by [[Snell Limited]] company presented at [[International Broadcasting Convention|IBC]] 2010]]

A '''vision mixer''' is a device used to select between different live [[video]] sources and, in some cases, [[compositing]] live video sources together to create [[visual effect]]s.

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#Television|technical director]].

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 cut]]s (switching directly between two input signals), mixers can also generate a variety of other [[film transition|transitions]], from simple [[dissolve (film)|dissolves]] to [[wipe (transition)|pattern wipes]]. Additionally, most vision mixers can perform [[keying (graphics)|keying]] operations (called [[matte (filmmaking)|mattes]] in this context) and generate color signals. Vision mixers may include [[digital video effects]] (DVE) and still store functionality. Most vision mixers are targeted at the professional market, with analog models having [[component video]] connections and digital ones using [[serial digital interface]] (SDI) or [[SMPTE 2110]]. They are used in [[live television]], such as [[outside broadcasting]], with [[video tape recording]] (VTR) and [[video server]]s for [[linear video editing]], even though the use of vision mixers in video editing has been largely supplanted by computer-based [[non-linear editing system]]s.<ref>{{citation |last1=Ellis |first1=John |last2=Hall |first2=Nick |date=2017 |title=ADAPT |doi=10.17637/rh.c.3925603.v1}}</ref>

While professional analog mixers work with component video inputs. Consumer video switchers may use [[composite video]] or [[S-Video]]. These are often used for [[VJ (video performance artist)|VJing]], presentations, and small multi-camera productions.

== Operation ==
[[Image:Sony BVS-3200CP vision mixer.jpg|thumb|A Sony BVS-3200CP vision mixer]]
[[File:Broadcast Switcher in Rack Mounted Configuration.jpg|thumb|A Blackmagic Design ATEM 1 M/E broadcast switcher (fourth from top of rack), rack-mounted with other equipment in a typical live production environment. Many switchers are separated into two devices: one that does the bulk of video processing (pictured here), and a control surface used by the [[Technical director#Television|technical director]].]]

The most basic part of a vision mixer is a ''bus'', which is a signal path consisting of multiple video inputs that feed 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 select A/B or flip-flop modes. Both the preview and program buses usually have their own [[video monitors]] displaying the video selected.

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 [[dissolve (filmmaking)|dissolves]] (similar to an [[audio crossfade]]) and pattern wipes.

A third bus used for [[compositing]] is the ''key bus''. A mixer may have more than one key bus, but often they share only one set of buttons. Here, one signal can be selected for keying over the program bus. The [[digital on-screen graphic]] image that will be seen in the program is called the ''fill'', while the mask used to ''cut'' the key's translucence is called the ''source''. This source, e.g. [[chrominance]], [[Luminance (video)|luminance]], pattern or split and can be selected in the keying section of the mixer. Usually, a key is turned on and off the same way a transition is. For this, the transition section can be switched from program mode to key mode.

These three main buses together form the basic mixer section called program/preset (P/P). Bigger production mixers may have a number of additional sections of this type, which are called mix/effects (M/E) 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 the ''[[clean feed (TV)|clean feed]]''. After the DSK is one last stage that overrides any signal with black, usually called ''fade to black'' or ''FTB''.

== Setup ==
[[Image:Video switcher rear.jpg|thumb|Rear connection panel of a Sony DVS-7000 vision mixer main unit. Some of the [[BNC connector]]s accept source inputs, while others output video from the various buses and aux channels. The [[D-subminiature]] ports interface with other equipment such as the [[Chroma key|keyer]], [[Tally light|tally]], and control panel.]]

Since vision mixers combine various video signals such as VTRs and [[professional video camera]]s, all these sources must be in proper [[synchronization]] with one another. In professional analog facilities, all the equipment is [[genlock]]ed with [[black and burst]] or [[Tri Level Sync|tri-level sync]] from a [[video-signal generator]]. The signals that cannot be synchronized (either because they originate outside the facility or because the particular equipment doesn't accept external sync) must go through a [[frame synchronizer (video)|frame synchronizer]]. Some vision mixers have internal frame synchronizers or they can be a separate piece of equipment, such as a [[time base corrector]]. If the mixer is used for video editing, the editing console (which usually controls the vision mixer remotely) must also be synchronized. 

Most larger vision mixers divide the control panel from the actual hardware that performs the mixer functions because of noise, cooling and cable length considerations. With such mixers, the control panel is located in the [[production control room]], while the main unit, to which all cables are connected, is often located in a machine room alongside the other hardware.

== Manufacturers ==
{{div col|colwidth=20em}}
* Analog Way (manufacturer)<ref>[http://www.analogway.com «Analog Way»]</ref>
* [[Barco (manufacturer)]]
* [[Blackmagic Design]]: ATEM<ref>[https://www.blackmagicdesign.com/products Products], Blackmagic Design</ref>
* Broadcast Pix<ref>[http://www.broadcastpix.com Broadcast Pix - Integrated Live Production Tools]</ref>
* Datavideo<ref>{{cite web |url=https://www.datavideo.com/us/category/switchers |title=Datavideo Switchers |access-date=2025-05-24}}</ref>
* [[EVS Broadcast Equipment]]: Dyvi<ref>[http://www.evs.com/emea/product/dyvi IT based mixers]</ref>
* [[FOR-A]]
* [[Grass Valley (company)|Grass Valley]]
* Guramex<ref>[http://www.guramex.com «GURAMEX»]</ref>
* [[Kramer Electronics, Ltd.|Kramer Electronics Ltd.]]
* [[NewTek]] ([[Video Toaster]] and [[TriCaster]], bought by [[Vizrt]])
* [[Panasonic]]
* [[Philips]] ([[Broadcast Television Systems Inc.]], broadcast division bought by [[Thomson SA]] and later integrated into Grass Valley)
* [[Roland Corporation]]
* [[Ross Video]]
* [[Snell Limited|Snell]] (former, bought by Grass Valley)
* [[Sony]]
{{div col end}}<!--[[User:Kvng/RTH]]-->

== See also ==
* [[Audio router]]
* [[Mixing console]]
* [[Patch panel]]
* [[Video router]]

== References ==
{{Reflist}}

===Sources===
{{Refbegin}}
* {{cite web | title=Tools of the trade | work=renewedvision.com | url=http://www.renewedvision.com/support.php?item=tools | access-date=May 10, 2007 | archive-url=https://web.archive.org/web/20120207052144/http://www.renewedvision.com/support.php?item=tools | archive-date=February 7, 2012 | url-status=dead | df=mdy-all }}
* {{cite web | title=Ampex Production Switcher | work=CSU-Pueblo Television Production Handbook | url=http://faculty.colostate-pueblo.edu/samuel.ebersole/handbook/switcher.html | access-date=February 28, 2005 | archive-url=https://web.archive.org/web/20120415031459/http://faculty.colostate-pueblo.edu/samuel.ebersole/handbook/switcher.html | archive-date=April 15, 2012 | url-status=dead | df=mdy-all }}
* {{cite book | author=SRT (Hrsg.) | title=Ausbildungshandbuch audiovisuelle Medienberufe, Band 2 | edition=2nd | location=Heidelberg | publisher=Hüthig | year=2000 | isbn=3-7785-2809-2}}
* Luff, John: "[http://broadcastengineering.com/mag/broadcasting_production_switchers_2/ Production switchers] ". ''Broadcast Engineering'', November 1, 2002
* Moore, Jeff: "[https://web.archive.org/web/20070430061226/http://www.rossvideo.com/synergy/switchers.html Production Switcher Primer] ". ''Ross Video Production Switcher Primer''.
* VideoSolutions group "[https://web.archive.org/web/20110717232416/http://www.vsgp.com/index.php?option=com_content&view=category&layout=blog&id=34&Itemid=53%2F ODYSSEY Mixers Family ] ".
* Monarch Innovative technology pvt ltd"[https://web.archive.org/web/20100209004024/http://www.monarchinnovative.com/twister.php?parent_item=1&childitem=1&childdivtagid=xtraMenu1] ".
*[http://www.thameside.tv/product_PDFs/DVS-7000Series.pdf thameside.tv Sony Vision Mixer DVS-7000]
{{Refend}}

== External links ==
{{commons category|Video consoles}}
* [https://doi.org/10.17637/rh.6159563.v1 Outsite Broadcast Director setting up their vision mixer for an upcoming sports OB]
* [https://doi.org/10.17637/rh.5987878.v1 Outside broadcast director using vision mixer during recreation of 1970s sports coverage]
* [http://www.oldvcr.com Video equipment collection]

{{Film Editing}}

{{DEFAULTSORT:Vision Mixer}}
[[Category:Television terminology]]
[[Category:Television technology]]
[[Category:Television occupations]]
[[Category:Film and video technology]]

[[ja:スイッチャー (映像製作)]]