The Digital Television Revolution

The 2012 London Olympics truly brought home to me just what a huge technological dive in digital media has actually taken place throughout the last couple of years. There has actually been considerable advances in digital compression and transmission. This year, in addition to hd broadcast, that made its look in the 2008 Beijing games, 3D tv was also contributed to the line up, providing more channels and options. With analogue tv broadcast nearly becoming extinct, digital tvs assure of providing more for less has actually come true. Now, how did we get to this point and what does the future hold for digital multimedia? Prior to the digital switchover, analogue tv was resource starving in regards to the quantity of bandwidth needed to bring a single channel. This is generally in between 6 - 8 MHz depending upon the kind of video requirement being used. This restricted the variety of channels which might be transferred, since there is a limited quantity of spectrum that need to be shown other services such as mobile, radio and 2 way interactions.

What the digital requirements of ATSC (North America) and DVB (Rest of the World) offered was the capability to recycle the existing analogue spectrum more effectively. This suggested a common 8 MHz provider used for analogue broadcast might be transformed to DVB-T (Digital Video - Terrestrial) making it possible to bring 9 basic meaning channels or 3 HD channels plus one SD channel for the exact same quantity of bandwidth.

It would have needed in excess of 70 MHz of frequency spectrum to attain this with the old analogue requirement. In addition to squeezing more channels into less area, digital tv is much clearer and does not experience ghosting or other artifacts which bothered analogue systems. Being digital also permits other functions like enhanced digital sound, electronic program guide and subtitle assistance to be included. Tvs are offered with the digital decoder incorporated and older tvs can use a different set top box. As technology advances, we will also see enhancements in the compression strategies used, which means a lot more content for digital media, currently this has actually allowed 3D broadcasts for some occasions such as the Olympics.

The Future

Ultimately as fiber to the home is released worldwide, the all IP made it possible for set leading box will change the DVB requirement, since the IP set leading box has an unique benefit over digital broadcast innovations, particularly multicast sign up with demands. Unlike DVB-T or DVB-S, IP multicast permits the receiver to send out a sign up with message to the network for the wanted channel then if the demand succeeds the broadcast is routed to the receiver, only the bandwidth for the asked for channel is used. With the DVB requirement, all readily available channels are being relayed all at once, and the channel count is restricted by the limited quantity of channel bandwidth no matter the compression methods being used. The IP set leading box can support both selective multicast (one to many) and as needed unicast (one to one) broadcast, this permits practically endless quantity of content. Nevertheless, unlike DVB, IP set leading boxes need to stress over latency and QOS, since there is traffic contention with both domestic broadband and IP Telephony. An improperly executed IPTV release can act like analogue tv in an over subscribed provider network, unless the proper traffic management remains in place.


Today HD is considered superior content by most operators and is charged at a greater rate than SD (Standard Definition). Nevertheless, in time this will change as people update their tvs to HD designs. Today there are 2 requirements for digital HD broadcast, 720p and 1080i. The 'p' means progressive and the 'i' means interlaced. In 720p broadcast, the photo is made from 720 horizontal scan lines and a vertical resolution of 1280 pixels, which has the benefit that a person frame represents a complete image.

In 1080i broadcast, the image is made from 2 540 horizontal scan images which when integrated make 1080 lines. The vertical resolution becomes 1920 pixels. Most modern-day tvs support playback of 1080p, which is certainly better than 1080i particularly in quick moving series where movement blur can be experienced. Nevertheless, on modern-day tvs the distinction is hardly noticeable. At first the general public uptake of HD was sluggish, the receivers were pricey and the offered content was restricted. HD tv has actually truly been an advancement instead of an innovative change for the majority of us and this is also real of digital tv in general. As digital switchover continues around the world and customers change their tvs, digital will become the new requirement. Nevertheless, it is regrettable that technology will not help to enhance the content.