Vision Mixer

Intro
(Also known as a Vision Switcher or Production Switcher)
A tool to mix multiple video sources to create one output. They can also be used to add special effects such as Luminance and Chroma Keying, (Also known as Green/Blue Screen) as well as providing other effects like custom transitions such as, Mix (Fades between sources) and Wipe (Wipes one Video Source over another)

History
Vision Mixers were first used to mix live video as well as editing taped video. This method was known as Linear Video Editing. Now they are seldom used to edit video as Non-Linear Editing (Editing on computers) is now used.

Usage
Vision Mixers are now used primarily in the Television industry for "Live To Air" broadcasts, as well as in Corporate shows, Rock Concerts and Worship. They are used in non-TV industry with large screens/projectors so the audience can get a close up view of what's happening on stage, and this also allows Pre-Recorded Video to be displayed, as well as presentations of photo's etcetera. They are also used in Houses of Worship (and some concerts) to Key Lyrics over video. Meaning the audience can "Sing Along."

Operation
Vision Mixers fall into two seperate catagories:
Vision Mixers:

The video source is selected on the A bus (Top) and another is selected on the B bus (Bottom) to change between the two you would move the "Cross Fader" up to output the selected channel on bus A or down to output selected channel on bus B

Vision Switchers:

A video source is selected (on most mixers this will light Green) and then the "Cut" or "Take" button is pressed and this source is outputted. (On most switchers the outputting feed glows Red) to select another feed, the operator would press the button with the channel number he/she wishes to output, it would then glow Green, then after the Cut/Take button is pressed, it would glow Red and the feed would be outputting.

Basic Setup
The Mixer would have two or more video sources in the inputs, these are primarily:

• Video Cameras
• Computers/Media Servers
• DVD Players
• VCR Players
• VTR Recorders/Players
• Test Paten Genorators-If not built into console
• Robotic Cameras
• In our case often X-Boxes

Outputs are primarily:

• Projectors
• Screens
• Preview Monitors
• Computers/Media Servers
• Media Streamers
• DVD/VCR Recorders
• VTRs
• Broadcast Trasmitters

When setting up Vision Mixing equipment one must take into consideration variables such as Aspect Ratio, Resolution, High Definition/Standard Definition.

Popular Mixers
The most popular low end mixers would be:
The Edirol V-4
A legendary low end mixer, also available in 8 channel version, that costs under $1000
The products homepage is here
Panasonic WJ-MX50
Although more expensive than the Edirol V4 this mixer includes an on board audio mixer. And accepts composite video inputs.

This product is no longer listed on the Panasonic website.

Mid Range Mixers
These include:
Panasonic
TriCaster
Sony
Philips
Grass Valley
Videonics

High End Mixers

Ross Video QMD X
Sony MVS 8000