video tech final

Principles ofVideo technology

KGV BTEC MEDIA

There are 3 main standards in use around the world.

• P A L N T S C S E C A M

• Each one is incompatible with the other.

• For example, a recording made in the France could not be played on an American VCR or DVD player.

• If you or your clients view video tapes or DVD's that are from other regions, you must first convert the tape or disc to or from the foreign television standard.

• The system used in America & Canada is called "NTSC". Western Europe and Australia use a system called "PAL", and Eastern Europe and France use "SECAM". Without standards conversion, it is impossible to view a video program that is recorded in a foreign country without first converting it..

Television Standards: Analogue Systems

Frames - all the lines of definition

Fields - the lines which are shown at any one time

Horizontal resolution is limited by bandwidth; different places established different limits

Interlacing - The system whereby only half of the lines are seen at a time (eg 1080i)

Progressive - the system whereby all the lines are seen at once (eg 1080p)


Television Standards: Component and Composite Video Signals

What do ‘component’ and ‘composite’ mean?

Three cables, each with RCA plugs at both ends, are often used to carry YPbPr analog component video

In home applications, the composite video signal is typically connected using an RCA jack (phono plug), normally yellow. It is often accompanied with red and white connectors for right and left audio channels respectively. BNC connectors and higher quality coaxial cable are often used in professional television studios and post-production applications. BNC Connectors were also used for composite video connections on early home VCRs, often accompanied by either phono connector(s) or a 5-pin DIN connector for audio.

In Europe, SCART connections are often used instead of RCA jacks (and to a lesser extent, S-Video), so where available, RGB is used instead of composite video with computers, video game consoles, and DVD players.

On consumer products a yellow RCA connector is typically used for composite video.

Both ANALOGUE systems


ANALOGUE OPTIONS

DVI - Digital Video Interface

HDMI - High Definition Multimedia Interface


What’s best - DVI or Composite or HDMI?

VGA - Video Graphics Array

(Analogue)


HDMI DVI

Digital

Up to 1920*1200

Audio (8 channels)

BluRay support

Analogue or digital

Up to 1920*1200

No audio

No BluRay support

Television Standards: High Definition

To put the 720 or 1080 lines into perspective, televisions of the past had 480 lines. Since more lines means a better picture then that alone shows why the HDTV has a nicer picture than an analog TV.

More lines is nice but don't forget about the 'p' and 'i' in the 720p, 1080i and 1080p. The letter is an abbreviation for the type of scan the TV uses -- 'p' stands for progressive and 'i' stands for interlaced.

Progressive scan is better than interlaced because it processes the images twice as fast. This faster scan rate produces better clarity and color in the on-screen picture.

The difference between 720p and 1080i is minimal but the TV industry is using 720p more than 1080i. So, buying a 720p HDTV is recommended over a 1080i HDTV.

As far as 1080p, there is no doubt that 1080p is the best resolution on the market. However, there is little to no difference in picture quality between a 1080p and 720p at the 32" and below screen size.

Television Standards: Aspect Ratio

More info here

• 1.33:1 A standard television set; roughly equivalent to 4:3.

• 1.37:1 Referred to as the academy aspect ratio. The standard for films shot before the mid-1950s.

• 1.66:1 A bit wider than a standard TV, but not by much.

• 1.78:1 The dimensions of a widescreen television set; roughly equivalent to 16:9.

• 1.85:1 Popular aspect ratio for many movies.

• 2.35: Another popular aspect ratio for movies.Pan and Scan versus Widescreen


We can change aspect ratio using an ANAMORPHIC lens which

basically squeezes the image.

Broadcast Systems: Terrestrial, Digital,

Satellite

Terrestrial TVSometimes called Broadcast Television

Usually sent as radio signals from an antennae; needs a tuner (a TV) with an arial to receive.

Terrestrial TV in HK – ATV and TVB

Limited in how far it can broadcast

Satellite TV

Signal is broadcast then directed by a parabolic mirror (a satellite dish.)

Requires a satellite receiver

Can be analogue or digital (Analogue is on the way out.)

Can broadcast over vast distances but coverage can be patchy

Signal can be affected by weather

Cable TVTV signal received through cables.

Can be coaxial cables (bad!) for analogue or optical fibre cables (good!) for digital.

Can also transmit phone, internet, radio.

For a better (digital) signal, additional hardware – a set-top box – is needed. Most TVs can receive analogue cable

without anything additional.

Digital TV

Generally, the transmission of digital rather than analogue television signals.

Now comes in two basic types – SDTV (standard def) and HDTV (hi-def.)

Can be received via arial, cable, satellite or internet

Can be encrypted.

Can be interactive; enables such things as video on demand.

Internet TV

Also called Online TV or catch-up TV

Programmes transmitted via internet, usually by traditional broadcasters.

Only requires internet access

Not everything is available everywhere, but in theory location is no longer an issue

Example: BBC iPlayer

Some links

Intro of satellite etc

The basics of digital television

Digital Recording

LOOK HERE!

CAMERAS http://student.lg.esf.edu.hk/mod/resource/view.php?

id=2034

Digital Editing: File Size and Compression

There are many, many file types in film, photography, sound editing and so on, and it helps to know how they

differ.Three key points to be aware of:

SIZE: The bigger they are, the slower they are and the harder to store

COMPATIBILITY: Not all files are compatible with all hardware / software

QUALITY: The smaller they are, the worse the quality


You might often find yourself changing the size of a file or converting it to another format – this often involves

COMPRESSION

Two types of compression – LOSSLESS and LOSSY

Lossless compression means you can compress and uncompress WITHOUT losing any of the

quality of your image, sound, film.


Example – sound files

Torrenting an album of MP3 files

– 171 MB

Torrenting an album of WAV files

– 766 MB

NOTE – don’t torrent stuff.


So, do you want MP3 or WAV?

MP3 is a LOSSY format. It discards quality in order to save space. (Though it actually removes parts you’re unlikely to

miss. It’s very clever.)

WAV is often uncompressed. No or very little of the original sound recording is discarded. It will be better

quality, and much larger, than MP3.

But what do you want to do? Do you want to put a million songs on your iPod? Use MP3. Are you going to play a

song through massive speakers in, for example,assembly? Use WAV.

Digital Editing: File Types

Photography

RAW – Uncompressed – best quality, massive size. Used for archiving.

TIFF – Big, high quality; good for editing.

JPG – Small, compressed. Extremely vesatile, good for home use.

GIF - Very compressed, low quality, good for web use.

More information here

Digital Editing: File Types

Film

The different types of formats are technically referred to as “container formats.” The differences between them lie in whether or not they compress the video and audio data they contain, and if so, how they go about compression. Some containers are more sophisticated than others and allow for storing extra data such as subtitles, metadata

(information describing the file), and even multiple audio and video streams (useful for having a multi-language file).

More information here

Digital Editing: File TypesAVI - "Audio Video Interlace" - Introduced in 1992 by Microsoft, supports multiple

steaming audio and video feeds.

MOV - QuickTime Movie File - Released in 1991, popular Apple format that supports live streaming.

RM - "RealMedia" - Multimedia format by RealNetworks which is mostly used to watch streaming content over the web.

3GP - Mobile Phone Format - Developed by the Third Generation Partnership Project (3GPP), it is a format used for recording and viewing on most modern cell phones.

WMV - "Windows Media Video" - Approved in 2006, WMV is a codec that has seen wide-scale adoption in not only streaming web content, but physical media such as HD DVD

and Blu-ray discs as well.

MPG/MPEG - Developed by the "Moving Pictures Experts Group," this format has gone through several revisions - the first of which being MPEG-1, a compression standard that

is the most widely used in the world.

MP4 - "MPEG-4 Part 14" - Based on Apple's MOV container, this format allows for subtitles as well as some MPEG features.

Digital Editing: Hardware

As a home user, you basically need a decent computer, and practically all desktop and laptop computers are now

capable of storing and editing film and media files.

If buying a computer to edit media on, you need to think about processor speed, screen size, and graphics/audio

capability.

Desktop computers are generally better (and, for the same specs, cheaper) than laptops. Screen is bigger, stability is

better and plugging and unplugging peripherals is less messy.

Digital Editing: Hardware

Professionals will probably need, or use, additional hardware.

Capture decks

Multiple monitors

Digital Editing: Software

The most obvious software consideration is probably the platform you want to use. Mac and PC are the most

obvious. PC users tend to use Adobe software (Premiere Pro) while Mac users have Final Cut Pro. They are both

very good!

These are NON LINEAR and NON DESTRUCTIVE editing applications.

video tech final

Technology

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broadcast television

digital analogue

video tapes

video program

analogue systems

composite video signals

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