Thanks to the PAL/NTSC standards, it's long been guaranteed that TV broadcasts, VHS cassettes or DVD videos will play on your TV. Introduced over 60 years ago, the development of these standards involved a curious mix technological constraints and political motivation. Indeed, technological advances increasingly render these standards obsolete, and the advent of multi-channel interactive broadcasts brings a need for more appropriate standards. The consumer's desire for increased content within a finite bandwidth (the physical limit of how much data can be transmitted without loss) conflicts with the consumers’ desire for increased quality. A new standard is therefore required to meet these conflicting goals – High Definition aims to provide this high quality content at reduced bandwidth requirements.

High Definition Television (HDTV) is being embraced by Japan and America but largely neglected in the rest of the world. As with the adoption of a “standard definition” standard 8 years after North America, Europe is once again lagging in the adoption of a ratified approach to HDTV. But with the BBC launching test transmissions in late 2004, Sky committed to the introduction of its HDTV broadcasts by 2006, and the European Broadcasting Union (EBU) releasing a proposition paper, it would seem that 2005 will be a year of growth in the European High Definition arena.

It's worth highlight at this point the distinction between the current "digital" broadcasts (DVB) and the entirely new set of standards created by HDTV. Current technology underpinning Digital Video Broadcasts allows for increased content with the addition of a set-top box. Based on the existing PAL broadcast standard, DVB uses MPEG2 compression to allow broadcasters to fit multiple channels on a single frequency. It remains based on the Standard Definition (SD) 576i50 standard - 576 interlaced lines on screen, refreshed every 50 seconds. Incidentally, this practice of interlacing was a solution to early technological constraints - TV tubes couldn't draw the entire picture quickly enough, resulting in the top half fading before the whole picture was shown. So rather than display an uneven picture, the screen was divided into alternate lines, with each each half being drawn alternately.

But the technology for an improved picture has long been available, and the High Definition standard embraces this technology. The EBU suggest a 720p50 standard be adopted bu European broadcasters until bandwidth requirements permit the broadcast of a 1080p50 picture. Curiously, the only current HD transmission in Europe, courtesy of Euro1080, broadcasts using an entirely different 1080i50 picture. Obviously the use of MPEG2 compression at these increased resolution rates would result in increased bandwidth requirements (hence the initial roll out of 720 lines), but the proposed universal HD standard also embraces new compression technology - H.264 in the MPEG4 standard. This compression technology results in picture quality to match the best available from MPEG2 at half the data rate. Resulting from the combined efforts of the International Telecommunication Union (ITC) and the ISO MPEG ( International Organization for the Standardization's Moving Picture Experts Group), this is a worldwide standard adopted by most broadcasters. However, at this stage it is not clear whether initial broadcasts will be based on the existing DVB compression (MPEG2).

HD broadcasts are only one part of what I see as 3 tranches to the delivery of High Definition: TV broadcasts, Distributed Media (films), and Home Movies (camcorders). Curiously, all 3 are at varying stages of development, with camcorders currently leading the way in the UK and Europe. The HDV format, the next generation of DV used in camcorders, was announced in September 2003 and has received backing from just about every leading manufacturer of video editing equipment. Those fortunate enough to have purchased a HDV camcorder in the UK are currently limited to playback opportunities. This is a direct result of inactivity in the two related tranches: content delivery. This rather odd scenario is best summed up by our article on Video Forum 2005.

In part two of this series on High Definition, we take a look at technology beyond High Definition Video, the next generation of miniDV. Part three looks at the format war between HD-DVD and Blu Ray, and the development of H.264.