Principles of Video Technology

By Diya Samtani

Television Standards

Analog SignalsThere are three systems of analog television:• Pal – used in Hong Kong• NTSC – used in Canada and USA• SECAM – used in EuropeEach system is incompatible with the other Frames – all the lines of definition Fields – how much information is shown on the screen at any given timeInterlace – only shows half the information at one time, split into odd and even numbers (the highest number is 1080i)Progressive – everything shown at once (e.g. 1080p). If it is progressive, the field and the frame will be the same

Example of Interlaced Video:

Television Standards

Analog SignalsWavelength – The distance from one wave to another.Frequency – The number of waves that pass a point each

second.Amplitude – The amount of energy measured in a sound wave.Widescreen Aspect Ratios • Aspect ratios are changeable using ANAMORPHIC which

squeezes the image. • The ratio stays the same all the way through.• Pan and scan helps keep the action in the middle of the

screen.• Pixel Aspect Ratio - This tool helps calculate the pixel aspect

ratio of video formats.

Television Standards

Analog SignalsThe analog signal can be split into a component signal or a composite signal.A component signal is when the signal is broken up into different bits, the sound then travels through the component.A composite signal is when everything is stored in one cable. The strengths of a component signal is that the color quality is much more noticeable then a component signal. The weakness of a component signal is that it does not give satisfactory video signal when being transferred

Component Signal Composite Signal

Television Standards

Digital Signals A digital signal is a constant waveform signal used in any form of digital communication. There are different cables used to transfer digital signals, each come with a few strengths and weaknesses.DVI Connector – DVI stands for Digital Visual Interface, it is used to maximize the picture quality of digital. Advantages • Analog or digital • Deliver signals discreetly together with synced information Disadvantages• No audio• No Blu-ray support

Television StandardsDigital SignalsHDMI Connecter – HDMI stands for High Definition Multimedia Interface, it is used for transferring encoded uncompressed numerical information. Advantages • They are popular because it is easy to use and includes a lot of functions• They are high definition and have high quality videos which make people

want to use HDMI’s more• HDMI’s carry video and audio in one cable which is much more convenient

then having a separate cable for each Disadvantages • HDMI’s can be quite expensive which is not good in a domestic market• In order to have an HDMI cable you need to have an HDMI player to get the

video to work

Broadcast Systems

Terrestrial TV (also known as broadcast systems) – Usually sent as radio signals from an antennae; needs a tuner with an areal to receive.

Advantages• Usually free• More channels • High image quality Disadvantages• Broadcasting is limited• A lot of interference• Limited color range

Broadcast Systems

Satellite TV – is when the signal is broadcasted then directed by a satellite dish.

Advantages • Analog or digital• Can broadcast over vast distances• High quality • Choice of programsDisadvantages • Requires a satellite receiver • Signal can be affected by bad weather• Installation required

Broadcast Systems

Cable TV – is a system providing television programs to consumers via radio frequency signals.

Advantages• Can be transmitted through phone, internet and radio• Better signal = additional hardware• On demand service• Bad weather doesn’t affect Disadvantages• TV signal received through cables• Expensive• Limited subscribers• Less channels

Broadcast SystemsDigital TV – Generally, the transmission of digital TV signals rather

then analog. There are two basic types:SDTV (Standard Definition Television) – is a digital format that

provides high quality images.HDTV (High Definition Television) – provides higher image quality

and offers a wide format.They can be received via areal cables, satellite or internet.Advantages • Can be encrypted• Can be interactive Disadvantages• Needs antennae upgrade for a strong digital signal• Needs new equipment, old – style analog TV sets can’t receive

digital signals

Broadcast Systems

Internet TV – Programs transmitted via internet, usually by traditional broadcasters.

Advantages• Only requires internet access• Can watch a program any time • Fewer ads • Disadvantages • Not everything is available everywhere• Students can watch under aged programs• Inaccurate advertising

Digital RecordingCamera Type: DSLRAdvantages• Excellent image quality• Changeable lens (huge advantage)• Cheap• Big sensor (much better image quality)• Hack able (can play around with it)Disadvantages • Not designed for filming• Doesn’t have certain features• Big sensor (slows it down)• Over heats quickly (after 7 minutes it turns off)• Lines of definition (neutral)

Digital Recording

Camera Type:CamcordersAdvantages• Easy to operate - straightforward• Designed for filming• Time saving• Easier storage• Cost effective Disadvantages• Quite limited functions • Not designed for photography

Digital RecordingCamerasISO • How fast or sensitive the light is to the film• The darker it is, the higher the number• The more sensitive the film is, the more noise is visibleAperture • The aperture is the size of the hole• The focus lens allows more light or less lightShutter Speed• The length of the time the image is exposed• Dark – long shutter speed• Bright – short shutter speedThese are the three things that affect exposure

Digital Editing

File, Size and CompressionFile – A collection of information that can be stored on the computer. There are many different file types that can store different information.Size – The bigger they are, the slower they are and the harder to store. Some files take quite some time to upload as the files are too big e.g. uploading a mov file to YouTube.Compatibility – Not all files are compatible with all hardware/software There are two types of compression: LOSSLESS – Every single bit of data that was in the file remains after the file is uncompressed.LOSSY – On the other hand, when the LOSSY files get uncompressed, only part of the information remains.

Digital Editing

Audio RecordingMP3 FileAdvantages• Can be played by many type of devices e.g. CD players and

iPods • High reliability• Mp3 files can be downloaded easily • Free or very cheap• Mp3 files are shared easily Disadvantages• Takes up quite a lot of storage space• The downloaded file may skip at unexpected areas

Digital Editing

Audio Recording WAV FileAdvantages• LOSELESS files• Can be easily edited and changed to your taste of music• High reliabilityDisadvantages • Limited to 4 gigabytes • Usually very large files• Limited space• Takes quite a bit of time to download

Digital EditingComparing Software Programs• Adobe Photoshop Elements – The advantages are its easy to use

and can be imported using many various ways. The disadvantage is that the program doesn’t have live chat.

• Photo Studio – The advantages are it has a lot of editing options and is organized. The disadvantage is it doesn’t have many ways to share the edited file.

• Pixelmator – The advantages are it is very easy to use and has a lot of output capabilities. The disadvantages are there aren't as much editing options as the other programs.

• Acom – The advantages are the program contains a lot of help and support and has a lot of output capabilities. The disadvantage is that there aren't many ways to organize the file.

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