Digital Media

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Digital Television Broadcasting

All terrestrial broadcasts are now digital. Indeed it can’t even be called the box or the “tube” in the corner anymore. Here are links to useful sites:

Why Digital Like it or not it’s a digital world out there. Since the 1960s more devices are implemented with digital insides. Whether it be a toaster, washing machine, media player, telephone, radio or TV the reasons for using digital innards are obvious: once working the device performance doesn’t reduce with age, far more user adjustments can be made available, quantity and quality of facilities are higher, manual and automatic methods of upgrade or “fixes” can be performed, completely new functions are possible and often encouraged and, most crucially for the manufacturers, can be charged regularly for.

Whole new industries and feeder companies have appeared eg Blackberry. Whole new groups of users now choose the technology eg schools now email or text rather than send send the inevitably lost paper letter out.


Is Digital Good ? It can certainly be complicated, frustrating, if it goes slightly wrong may completely stop altogether, but in the main digital is now reliable. It’s here to stay. So I offer here a few more links to explanations if you want to know more.

Recording Digital Television With Old Analogue Equipment

Sadly some websites (including DirectDotGov) say that a new VCR must be purchased. This is not entirely true. The internal analogue tuner in your old trusty video cassette recorder won’t find any TV stations in the UK since digital switchover but nearly all will still record directly off an external digibox (costing at little as £20). Therefore allowing you to playback old cassette tapes on the same equipment.

The TiVo was the first all digital recorder on the UK market. It’s now so cheap to buy a digital recording device that price is not a barrier to most people. However some may find operating a disc recorder or PVR a struggle at first. I strongly advise that purchasers research the subject before buying a new device that is either too complicated or does not offer the desired features. And be prepared for a fair number of three-letter abbreviations.


Those wonderful consumer watchdogs are a good starting point:         Which Guide To PVRs 

Realise that there are now thousands of types out there:                       Frequency Cast DVRs

Ok so you really want to know more                                                     Wikipedia Megaguide To DVRs

Navigating Around Digital Television - EPGs

Electronic Programme Guides finally do what the printed codes of “VideoPlus+” or “Gem Star” in the newspapers started to do way back in the 1990’s: that is to connect your TV listings direct to those blasted timers on your recorder that only your grandson ever really knew how to operate ! Yes, thank God for EPGs:


I resort to one of many purely commercial explanations                        Guide Plus

The  Red Button

As well as new text services on digital transmissions many broadcasters give the opportunity to gather more information relating to their programmes. These are first accessed by pressing the first coloured button on the handset which is red. A variety of text, prerecorded and live sport subpages are then routed to your display.


Interactive Features                                                                                   Freeview Red Button

Audio

Cinema Systems At Home - Surround Sound

Again analogue is not good enough. Nor is digital NICAM. In the early days in order to sell expensive high definition TVs manufacturers boasted that their systems also delivered an almost cinema quality of audio experience with five, six or even seven channels. UK law requires broadcasters to transmit 10% of material with Audio Description now. So what is all this multi-channel audio noise all about:


Nigel Whitfield’s really brilliant helper for the semi-technically minded         Gone Digital

Setting Up Surround Sound                                                                                       10 Tips From Which?

How it works -introduction     {this link due to be replaced]                              Argos

How it works -more technical                                                                                    Webopedia

There’s a lot of cables -going wireless is possible but requires investment       Aspect TV

Interactivity

Development

Compared to the Nipkow’s 32 line systems of 1884 and the 240 line Baird and the 405 line Marconi-EMI systems of the mid-1930s all systems appearing later could be considered ‘high definition’. Around the world a great number of line and frequency standards have been implemented but for several decades broadcasters had settled with either 525 in the Americas and 625 lines in Europe and the Far East and it was pretty good analogue technology.

In the late 1980‘s the BBC, EBU and Japanese manufacturers developed new methods of higher definition capture, storage, editing, transmission and display but they realised that there needed see a way to persuade viewers and their parent companies to part with substantial amounts of money to if they were to upgrade to their 1250 line “High Definition” standard.

From 2007 onwards improvements of several technologies had become sufficiently cheap to persuade relatively conservative consumers that the time was coming for them to invest in new technology in their homes. These improvements were:


● Displays:

● Transmission:

● Dissemination:

● Airwaves:

● Home Storage:

● Surround Sound:


What Is HDTV

Standard Definition in Europe is 625 lines (x720 pixels) but only 576 lines are displayed.

According to  Sony description there is great significance in your TV shop’s HD claims:

    “HD Ready”   manufacturers only display 720 lines (x 1280 pixels)

    “Full HD”       manufacturers should display 1080 lines (x1920 pixels)


Further information:

Frequently Asked Questions                HDTV FAQs

Resolution may not be resolution:       Native Resolution

Hi-Tech Resolution                             Pixel Count

High Definition Television

Commercial 3D

Just a couple of years ago at the BBC I saw demonstrations of possible future mass producable 3D technologies. Some designs needed one to stand in an exact position relative to the display and some needed the viewer to wear special glasses. The advent of well written cinema offerings (see my Film Reviews page) has significantly boosted interest. The R&D departments of our Japanese friends have been honing the technologies needed. The results, as many of you may have seen, are stunningly good. As well as solving the challenges of display, storage and one day transmission a host of other features are built into the units now eg web browsing, video conferencing etc. You’ll notice that the display screen needs to be large for the experience to be effective so most offer built in five channel surround sound too. Here are links to some commercial home solutions (as at May 2010):

       Bravia

       Viera

       3D-TV

       Infinia

3D Television

Games consoles are also going in this wonderful direction too but I wonder how long it will be before we won’t need those darn glasses ?

Home Cinema 3D Movie Releases

Currently available are:                                                                   BluRay 3D Movies

Bulky Cathode Ray Tubes replaced by plasma and LED systems

Set Top Boxes became reliable, reprogrammable and cheap

Digital Versatile Disks became hireable and players became cheap

Broadcasters persuaded European governments to provide more channels

WORM DVDs & harddisk systems replaced tape

Yes investment in displays was more persuasive with more audio channels !

The Range Of Analogue Standards

After the very first theoretical 8x8 pixel system, in the first days of television transmission as we now know it, John logie Baird merely transmitted 30 lines of TV scanned from top to bottom. Eventually he progressed to 240 lines but there were many competing systems. The BBC started the first monochrome broadcasts of 405 lines, scanned horizontally and then called “High Defintion”, from 1936 to 1985. It’s not the HD we know today. Here is the superb Wiki History Of Television and you will see that there is no worldwide standard for Standard Definition so the name is a bit of a misnomer.


On 20th April 1964 the BBC launched BBC2 with 625 horizontal lines. On 1st July 1967 it was the first in Europe to transmit colour with a highly reliable PAL system.


All of this was analogue. The UK’s first digital terrestrial (ie not satellite) programming was provided by ONDigital set-top boxes. However the broadcast chain was unreliable and the company went bankrupt. In order for the public not to lose faith in the emerging technology BBC Research provided major input into the setting up of the Freeview  collaboration. The result has been a major success and all TV’s around the world can now decode the formats that it provides.

Standard Definition Television

What’s In A Name ?

So what about higher resolutions ? Two times 1080 lines is surely 2160. Yep but to make it sound sexy, instead of measuring vertically, they went full circle and started to measure horizontally again which is 4000 pixels. Which admittedly is a nice round figure. And twice again is 8000 pixels. K being the abbreviation of the Greek for Kilo meaning one thousand. Digital cameras happen to use 4096 pixels in an almost 2:1 aspect ratio.


DCI-4K v UHD ?

So of course these could be called Ultra High Definition or UHD ? No these above are the digital cinema formats now called DCI. Digital terrestrial TV has stolen the name UHD and UHD-2 to sell more TVs. It transmits in 16:9 aspect ratio so only needs 3840 or 7680 of the 4000 or 8000 pixels.

4K and 8K Cinema

Digital Tip

Can’t Get All Your Files On Your Memstick ?

The formatting of memsticks is a boring thing but if you can’t squeeze all you want onto one stick I suggest that you delete all the files and re-format it as it’s highly likely not to be using all the available space very wisely once it’s been used a few times.


There you go. No need to buy another - all that memory for free.

Digital Audio Broadcasting

Radio

Of course medium wave AM broadcasting started (2MT & 2LO) in 1922. This was followed by FM broadcasting in 1950’s. In 1974 a German manufacturer added a modest digital information stream at 1100 baud. Norway, then UK and Sweden were the first countries across the Digital Audio Broadcasting (MP2) line in 1995 -the system can cram more stations into a given frequency band. DAB+ (AAC) followed in 2007. Norway is currently the only country in the world not now offering any AM or FM analogue services.


Streaming

With the advent of the internet the download of audio files became possible. However livestreaming of broadcasts requires the “media player” to do a fair amount of processing at each end. Firstly the audio dynamic range is so high it needs to be compressed and then coded to reduce the inherently initial high bandwidth. Control protocols are required to signal how to unpack the coded data. Because the internet connection may be slower than necessary, intermittent or packets may take different paths on route the stream need to be re-assembled in the correct order - therefore a FIFO is required -only then it can be decoded. It is debatable who was the first to livestream in the 1990’s.


Who Is Livestreaming - Internet Radio Guides

See the following general guides:             (Further information subpage: ReceivingInternetRadio)

NOTE  Not all of these are sorted into genres or can be searched. All implant cookies.