Safire is a 10 bit SDI digital chroma keyer which produces exceptional digital linear chroma keying for the creation of realistic virtual images making it ideal for any live chroma keying or virtual set production - whether it's news, weather, sports programming, chat shows, current affairs, game shows, election broadcasts or drama.

Well-known for being the easiest chroma keyer to set up and operate, many side-by-side evaluations have been won on this ease of use.

Safire also has features you won't find anywhere else - whether it's the special processing to perfect that picture or the unequalled features for sports graphics.

It will save you rack space too. As a 100mm x 266mm board it forms part of a modular system resulting in easy integration with any of Crystal Vision's interface products - including the video delays so essential in a virtual system.

It's no surprise then that Safire is used by broadcasters and sports graphics providers across the world.

What is chroma keying?

Chroma keying is used to combine a virtual object (Background) with a real image (Foreground) by replacing a real colour (usually blue or green) with a virtual input.

In a typical chroma key the Foreground subject is shot against a well lit uniformly coloured backdrop.

A Suppressed Foreground signal is produced in which the backdrop colour is removed and the signal is used to create a key to remove an area from the Background video that is identical in size to the Foreground subject.

The Suppressed Foreground is inserted into the backdrop 'hole', then masks can be added to remove any unwanted Foreground or Background and any fine-tuning can be applied.

Setting up is easy!

For those that need it, a full range of fine-tuning tools is available. A flexible output bus allows the main and auxiliary outputs to monitor each stage of the keying process, allowing you to look at the various internal signals individually and make any changes.

While blue and green are the traditional chroma keying colours, Safire gives you the flexibility to key on any colour just by selecting it with a cursor. Best results are obtained from intense colours (with high chrominance) that do not occur in the Foreground subject. Safire has been used in many sports applications where keying has been required on the normal playing surface.

Linear chroma keying avoids the hard switch associated with non-linear keying and allows areas of the final picture to be a mixture of both Foreground and Background, permitting the use of transparent and reflective objects (such as spectacles, a glass of water and smoke) and resulting in more convincing edges.

Safire features both additive and multiplicative keying to suit all types of situations. Additive keying relies on careful attention to the lighting of both backdrops and Foreground objects, but is recommended for shadows and transparent objects.

The fill video may be selected from any one of three video sources: Foreground input, Suppressed Foreground or a single colour from a matte generator. Sophisticated downstream processing of the combined picture is available, allowing fades to the Foreground or Background and a final fade to black. The keyed signal may also be amplified, offset or inverted.

Overruling the chroma keying

By using the cursor-based auto setup you can quickly produce a usable chroma key which is suitable for most applications. Where conditions are more challenging, a range of tools are available to fine-tune your chroma key.

Safire offers two internal rectangular masks (Foreground and Background) and an External Key which can be combined with the chroma key for additional effects. These masks can be used to overrule the keying process.

It's not always possible to have a perfect backdrop for your chroma key. Instead you can be faced with imperfections such as uneven lighting or cables running across the set.

No problem. These unwanted areas of the Foreground can easily be removed by forcing the Background with a Foreground mask.

Similarly wanted areas of the Foreground can be forced with a Background mask. Used either together or independently, the Background and Foreground masks can be turned on or off, inverted and adjusted in position and size.

Then there's the flexible External Key. This should be used when a customised non-rectangular or moving shape is required and can force areas to be either Foreground or Background under the control of a key generated by a graphics system.

Force Background allows an External Key to override a chroma key and force part of the Background to appear in front of the subject in the area of the supplied External Key. A typical application in a virtual studio is to allow the presenter to go behind a virtual pillar or desk.

The External Key can also be extensively used for sports graphics applications.

Perfecting the picture

A comprehensive range of fine-tuning controls can be used to produce very realistic edges and shadows with a minimum of residual colour spill.

Enhance the colour sensitivity of the chroma key using the Hue, Acceptance Angle and Suppression Angle controls to determine the range of colours to be suppressed in the Foreground and reduce colour spill around the subject.

Improve the chroma key luminance by using the Max Clip, Min Clip, Y Suppression, Y Correction, Shadow Min and Shadow Enhance controls to produce a solid key.

The sophisticated shadow processing using the Shadow Min and Shadow Enhance tools allows the intensity of shadows to be precisely adjusted which also helps to create that realistic final effect.

Safire also includes a useful feature called Key Shrink. The realism of a chroma key is largely determined by how the keyer handles the boundary surround the Foreground image. As a result of the processing involved in extracting a key signal from the Foreground chrominance, there is a tendency for the key to 'spread', leaving a dark line at the edges of non-keyed Foreground objects such as a presenter. Key Shrink corrects this problem by allowing the operator to move the edges of the key signal by the required fraction of a pixel, eliminating the dark band around Foreground objects.

The best chroma keyer for sports graphics

Safire is used to high acclaim across a whole range of sports and in a diverse range of applications from keying logos on to a pitch to virtual advertising.

It's the flexibility of the External Key that makes Safire ideal for inserting graphics on to sporting surfaces during live events. The result is three unique and very special features: Force Foreground, Force FB and Luma Keying.

With Force Foreground the External Key is used to restrict the chroma keying to the area that contains the sports graphics by forcing Foreground everywhere else in the picture.

A typical application may be sports where players on grass are keyed over a sponsor's logo which is made to appear as if painted on the grass. The grab cursor is placed on the green grass and the resulting chroma key removes the green and replaces it with the Background. Outside of ghe graphics area the Foreground is forced to allow the grass to appear in the composite output. Both the final key and External Key are automatically inverted to allow the graphic to be controlled by fade operations.

Force FB is an inspired feature that uses the different levels of a single External Key input to force Foreground and Background in different areas of a picture, allowing a chroma keyed subject to move in front of a selected Background object while at the same time displaying a graphic keyed over the Background.

There are three luminance levels in the External Key and each level applies a different effect.

The black in the External Key forces full Foreground, while the white forces full Background.

Chroma keying is restricted to the grey area in the External Key, with the shade of grey determining the intensity of the effect - the darker the shade the more dominant the Foreground becomes (Linear Force Foreground), while the paler the shade the more dominant the Background becomes (Linear Force Background).

Using Force FB a single chroma keyer could be used to chroma key a logo on to a pitch behind the players and linear key a scoreboard in front of the crowd at the same time.

Safire also includes special features for keying graphics on to snow or ice for winter sports programming - otherwise known as Luma Keying.

In this self-key mode Safire will key on the Foreground luminance instead of the colour, with the key extracted from the Foreground on the basis of brightness.

When keying on black or white you can set the level above which the key will be full amplitude (using Max Clip) and below which the key will be zero (using Min Clip). Keying on grey provides a very selective self-key that only places the Foreground subject in front of the Background when the Foreground subject has a specific luminance value.

The key generated from the luminance can be combined with an External Key and also with the internal masks, making this type of keying as flexible as chroma keying.

Use it as a linear keyer

Owning Safire brings the further benefit of giving you a product that can double as an extremely flexible linear keyer, for those occasions when you need this functionality.

When used in this way, captions, logos, scoreboards and other graphics can be keyed over an HD or SD video source.

There are two ways of generating the key. The external key mode uses the luminance of a key signal to cut a hole in the Background programme, while in self-key mode the luminance of the Foreground graphic is used to generate the key - useful if you don't want to use a dedicated key input.

Fill video is then inserted into the hole, usually the Foreground signal or a colour produced by the internal matte generator. The ability to select either additive or multiplicative linear keying allows you to choose a method to suit the graphics you're working with, while the internal masks can be used to overrule the key signal and force areas of the picture to Foreground or Background.

You can mix between the Foreground and Background inputs, fade the key in and out (either manually or as a timed transition), and fade to black on the main output. You can also amplify, offset or invert the key signal.

Use it as a basic mixer

For applications where you're not using the chroma key functionality, Safire can be used as a basic two input mixer. It can perform a mix or wipe between two video sources or between one video source and a colour produced by the internal matte generator.

The mix control combines two signals by performing an alpha blend, where as the front image becomes transparent you see more of the other image through it - until the first image disappears completely. The internal wipe pattern generator features a number of simple wipes: horizontal, vertical, horizontal blind, vertical blind, left corner, right corner, cross and box.

Using the Safire Controller, the mix or wipe can be controlled manually with the T-Bar or by setting an auto-transition triggered from the EFFECT button.

Controlling your chroma keyer

How would you choose to control Safire - control panel or PC software?

Those that select the first option will discover that the Safire Controller is a pleasure to operate. Not only does it look good, this stylish 2U dedicated control panel is also instinctively easy-to-use, with the physical controls making it ideal for live use.

It's easy to perform adjustments thanks to the large, clear display which provides extensive information on one screen, including a full set of selections for most controls.

There's no need to navigate through layers of menus - all the menus can be reached by a single button press. The main keying functions are all available on quick access keys, while direct function buttons allow extremely easy T-bar transitions of the 'live use' fades, allowing fades to Foreground, Background, External Key and black. LEDs indicate the state of the main keyer settings and are independent of the current menu.

The control panel allows a complete set up to be easily transferred from one board to another - allowing you to use a second chroma keyer as a preview keyer, and then move the settings to the main keyer when ready.

One Safire Controller can operate up to seven chroma keyers.

Alternatively use your PC. The Windows-based Statesman PC software can be used both to monitor the current state of the boards - either by examining control values and virtual LED settings or by setting alarms - and for the real-time control of boards.

Safire has a specially designed GUI, with sliders, dials, trackerballs, buttons, checkboxes and radio buttons allowing easy selection of options with a simple click of the mouse. Control your chroma keyer from anywhere - Statesman will plug into your Ethernet network using industry standard CAT5 cables.

All features are available on Statesman (including the recall of up to 40 presets) and PC control is ideal for those who do not expect to adjust the chroma keyer live on air.

Both the Safire Controller and Statesman allow recall of setups from GPIs. In addition the Safire Controller has a GPI input which can be used to choose which chroma keyer is being controlled. Instant memory recall of setups by GPI allows switching between cameras with their own individual settings and makes Safire ideal for live use.

Frames and rear modules

Safire is a space-saving single height 100mm x 266mm module housed in Crystal Vision's standard frames, which are available in four different sizes to suit all applications - large or small. 24 chroma keyers will fit in 4U, 12 in 2U, six in 1U and two in a desk top box.

Safire can be used with either the RM01 or RM18 rear modules which fit on to the back of the frames. The single slot high RM01 gives three inputs (Foreground, Background and External Key), two main outputs and an auxiliary output. The two slot high RM18 should be used when an additional auxiliary output and a Background loop-through are required.

Safire is one of two chroma keyers from Crystal Vision - with the alternative being the Safire HD 2 chroma keyer which works with both SD and HD.