The 2012 London Olympics really brought home to me just just what a huge technological jump in digital media has happened during the previous few years. There has been major progress in digital compression and transmission.
With analogue television transmission nearly becoming extinct, digital televisions promise of delivering more for less has become a reality. Now, how did we arrive at this stage and what does the future hold for digital multimedia?
Before the digital switchover, analogue television was resource hungry in terms of the total amount of bandwidth needed to carry just one station. This is generally between 6 – 8 MHz based on the kind of video standard being used. This restricted the amount of channels which might be transmitted, since there’s a finite amount of spectrum that should be shared with other services such as radio cellular and two way communications.
Exactly what the digital standards of ATSC (North America) and DVB (Rest of the World) supplied was the capability to reuse the existing analogue spectrum better. This meant a typical 8 MHz carrier useful for analogue broadcast may be converted to dvb t (Digital Video – Terrestrial) making it possible to carry 9 standard definition channels or 3 HD channels plus one SD station for the same amount of bandwidth.
It would have required to achieve this with the old analogue standard. Digital television doesn’t suffer from ghosting or other artifacts which troubled analogue systems and is quite a bit clearer along with squeezing more channels into less space. Being digital additionally allows other features like electronic program guide, enhanced digital sound and subtitle support to be comprised.
Televisions can be purchased together with the electronic decoder integrated and a separate set top box can be used by older televisions. As technology advances, we shall also find improvements in the compression techniques used, which means more content for digital media it has enabled 3D broadcasts for some events including the Olympics.
