The variety of formats and storage media for both video cameras and still cameras is vast. Digital photos and digital video are stored on digital storage cards such as SD cards, compact flash cards etc and are then stored on computer hard drives or up on The Cloud’.

Some software packages are designed to produce animations and slides. They organise data for presentations. They usually use templates or styles, which provide backgrounds, colours, textures, borders and fonts into which data is inserted. The software usually provides a selection of transitions or crossfades between screens, slides or animations and a variety of data presentation modes. The most frequently encountered version of this type of package is PowerPoint or Prezi.

VHS (Video Home System) video players are now obsolete and DVD (Digital Versatile Disc) are almost obsolete but you may ocassionally come across them. Video is now mostly recorded on memory cards or bigger hard drives.

Phones and tablets are increasingly being used to capture video and audio and are providing a reliable and cheap way to do it.

Monitor types include LCD (Liquid Crystal Display) LED (Light Emitting Diode) and plasma monitors, are most commonplace. Each of these types of monitor screen has benefits and drawbacks, but each is ideally suited to its purpose. LCD monitors are excellent flat panel for small monitor situations whereas plasma screens are excellent for large home theatre type or clubs and pubs displays. If, however, the presentation is intended for a large audience, a projector and screen combination or large LED wall displays are much better.   

Some projection screens can be used for both front and rear projection and others are designed only for front projection so the presentation requirements must be considered first when setting up a system.

Screens can be made from different fabrics which affect the quality of the images being projected. If a screen is going to be set up in a venue where there is a lot of ambient light, a high gain screen will be required. If the same screen were used in a low light venue, it would be too bright and distracting for the audience. A cinema would require a low gain screen as the venue is darkened for the show.

Screens are not always the traditional white. Grey screens are often used in a high ambient light situation. But a grey screen must be paired with a very bright projector to ensure a good white.

Projectors have many variations. A projector must be matched to the lighting conditions in the venue, the rigging point in the venue, the amount of uncontrolled ambient light in the venue and the screen being used in the venue. The amount of light a projector projects is measured in Lumens.

Projectors designed to be rigged very close to the screen are called short throw projectors. A short throw projector can be mounted on the top of the screen. They have a very wide angled lens to throw a wide beam.

Long throw projectors are used where the projector cannot be rigged close to the screen. Consider ‘Vivid’, the annual Sydney projection and light show. Projectors are often hundreds of metres away for the object they are projecting onto. They have a lens which projects a very tight beam of light.

A rear projector is set up behind the screen. It requires a screen suitable for this type of projection. Quite a useful technique when there are going to be people walking in front of the screen, or there is not enough room to set up a front projector.

Vision mixers and Vision Switchers are often different names for the same piece of equipment. Although Vision Mixers characteristically have the ‘T-Bar’ (Transition Bar) or swiping device which allows manual control of switching between sources, they usually have the option of a button for a ‘hard’ switch or the T-bar for a gradual switch. A vision mixer looks like a console.   

A Vision Switcher is often found installed in a venue and will only provide push button control of vision feeds, although higher end ones will have some additional options available for the speed of transitions. A vision switcher often just looks like a box with lots of buttons on it.

Some vision switchers are very simple, just a few buttons to push to select which feed is being projected to the ‘live feed’, also known as the ‘program’. High end Vision switchers have many complex functions, often more than a vision mixer.

A CCU (Camera Control Unit) is a common way of controlling camera functions in television production and large production events. The CCU grades the brightness and colour of camera pictures ensuring that each camera feed has the same colour and brightness level. It allows the camera operator to concentrate on focusing and framing the required content.

The RCA plug and jack is the most common connector type on consumer equipment for composite and component video, as well as for both digital and analogue audio.   

RCA jacks colour-coded yellow on a device are usually composite video inputs or outputs. Where there is a single RCA jack on the back panel, labelled ‘video’ or something similar, it is almost certainly composite.   

Component video is usually represented by three RCA connections colour-coded green (Y, or luminance), blue (Pb) and red (Pr). RGBHV will usually, though not always, be colour-coded red, green, blue, yellow (horizontal sync) and white (vertical sync).

The BNC plug and jack is the standard connector for most video signals on professional gear and is appearing increasingly on high-end consumer gear as well.   

It will be labelled similarly to the RCA, indicating composite video (one connection), Y/C s-video (two connections), Y/Pb/Pr (three connections), or one form or another of RGB.   

The most common confusion with BNCs, is that people often assume the female connector is a male; the problem is that both the male and female connectors have what looks like a pin in the centre.   On closer inspection, however, it is clear that a female BNC's ‘pin’ is actually a receptacle for the male pin.   A panel-mounted BNC will ALWAYS be female; a cable-mounted BNC will almost always be male.

The F-connector is the screw-on type connection used for most antenna and cable TV connections.   F-connectors are rarely used for anything other than RF; the one notable exception being that they were used as digital audio connectors on some laser disk players.

The 4-pin mini-DIN plug is the common s-video plug on consumer gear and is often considered a poor choice for video as it tends to unplug itself at the slightest urging.

An increasing number of devices are appearing with 15-pin connectors.   There are about as many names as pins for this connector, which is well known as the plug used with most PC computer monitors and consequently is often called a "VGA" plug. Since VGA is an RGBHV-type video signal, however, this usage is a bit confusing. This same plug is used not only for RGBHV, but also for RGBS, RGB sync-on-green, and Y/Pb/Pr Component video.   Because the plug can be used with so many different video standards, it's very important to know before using a 15-pin connector on a device, what sort of video it can put out or take in.

DVI Connectors come in a few types; the most important, in general, are DVI-I and DVI-D.   The difference between the two is that a DVI-I connector has extra pins at one end, which carry most of the analogue video signal.   A DVI-I cable can be used for either a digital or analogue signal, because it contains both the digital and analogue pins.   A DVI-D socket, however, which is designed to take a DVI-D plug, will not normally have anywhere for the analogue pins on a DVI-I plug to plug into.   It is therefore important when buying a cable to be sure that it will actually plug into the equipment it is intended for. 

SDI is the broadcast industry standard for digital video and the method it uses is similar to analogue component video. It is available in both standard definition and high definition.  SDI is useful as it not only handles video but can transmit 16 channels of audio.   

Category 5 cable (Cat 5) is a ‘twisted pair’ cable for computer networks.   Since 2001 most commonly used is the Category 5e specification (Cat 5e).  The cable standard provides performance of up to 100 MHz and is suitable for most varieties of Ethernet over twisted pair up to 1000BASE-T (Gigabit Ethernet). Cat 5 is also used to carry other signals such as telephony and video. Cat 6 is also available. It has four twisted wires and is capable of carrying a much greater band width.

There are a variety of different USB cables, each with an initial after its name.  They also come in mini and micro versions as well.  When using USB (Universal Serial Bus) peripherals the preferred cable length is up to 5 metres, before there is a chance of data loss and slowed down response speeds. Using a Cat5e extender over long distances or a passive cable extender for much shorter distances can assist with this problem.

There are times when a signal needs to be changed or a connector needs to be adapted so specific sources or equipment can be used. 

■  Scan conversion is when a high resolution is changed to a lower resolution. This may involve a data to video signal conversion. This will mean a loss in quality of the signal and can be done through a video mixer.

■  Scaling is taking a low resolution to a higher resolution. This includes a video signal to a data quality signal. There is no better video signal but is at data quality of output. This could include converting component to HDMI.

Adapters are used to change the connector type when they have the same signal characteristic and can also change the gender of a connector when required.

Watch the video 'Component to HDMI converter' to explore the equipment used to convert analogue video and audio to digital HDMI.

A pixel is a picture element or single illuminated point in an image. Each pixel has a colour and are combined to create a digital computer or television picture.

Watch the video 'What is a pixel?' to see how pixels are used to create an image.

The shape of the display device as an height to width ratio

■   4:3 - Video & PC

■   5:4 - PC

■   3:2 - 35mm Slide

■   16:9 - Widescreen & Digital TV

■   1.85:1 - Cinema

The distance between the projector lens and the screen.

Lens ratio is usually written on the lens and is calculated as PD = R x S

■   PD = Projection distance or throw

■   R = Lens ratio

■   S = Screen width

A good rule of thumb is use a ratio of 2:1, that the screen should be placed at a distance from the projector that is 2 times the width of the screen being used.

If the projector is ‘off axis’ keystone occurs and the image FOCUS is uneven and DISTORTION occurs

It is important to make sure the projector is set to its correct placement and is level. Use the keystone buttons on the projector or remote to correct any image distortion.

Watch the video 'Keystone correction' to see this function demonstrated.

Activity

Set up a prjector in the classroom which is slightly stage left. Each student will have a go at using the keystone button to correct the image.

Read through the following website and watch the embedded videos to learn about what a green screen is and how it is used.

Activtiy: Set up the vision equipment and use OBS software to play around with the green screen