Broadcast and TV technicals

High definition TV
High definition video equipment {Hi Def in the film world, or HDTV to those with more of a television background} has been around a long time, and there are a number of competing formats. All offer substantial advantages over conventional (standard definition) broadcast video. HDTV broadcasts are now established in some countries, including the USA and Japan, though the numbers of viewers with HiDef screens is, as yet, quite small.

HDTV's excellent picture quality offers great potential, provided the means are in place to show the finished programme in its full glory - on a suitable large screen, or using a high definition video projection system, or by transfer to film for projection.

Hi Def production is now practical, if still relatively expensive. To date it remains a relatively rare choice in Europe. As trends in Japan and the USA towards high-definition production continue to strengthen, this may change over here in the near future.

The appeal for low-budget film makers planning an eventual transfer to film for distribution will be considerable. It would be no surprise were a number of businesses and organisations to want to use the new formats to make a splash at events, exhibitions or elsewhere, and traditional broadcasters will no doubt be examining both the cost and the quality developments closely.

There are a number of different technical routes under the HDTV umbrella. The two with early market dominance are:

Sony's HDCam (usually "1080i" - that is at a nominal 1920x 1080 resolution with interlaced frames, and 24 or 25 fps - but a number of variants are possible) ,

and Panasonic's DVCProHD (usually "720p" - that is, a nominal 1290x 720 resolution with progressive scan frames, and again typically 24 or 25 fps).

Both these formats downsample the nominal picture dimensions to manage data rates, and both use quite a lot of compression - nevertheless, the results can be excellent.

Sony's HDCAM SR goes a step further - full colour sampling (4:4:4 instead of a nominal 3:1:1; full screen resolution; apparently no compression - but as a result, more data to handle.)

Broadcast quality- digital:
A number of digital formats are at present available in the UK, including; Digital Betacam - 1/2" component from Sony, using 2:1 data compression. The dominant format. Digi Beta machines can play back earlier Betacam formats, so that archive footage can easily be incorporated into current production.

DVCPro 50 - Panasonic's full broadcast system, recording onto DV-width tapes. Excellent quality and value.

MPeg2 IMG - Sony broadcast mpeg 2 variant, recordable direct to optical disc on is XDCAM camcorders Has achieved considerable sales success in mainland Europe, if less so in the UK to date.

D5 - 1/2" component from Panasonic, does not use data compression. Originally Channel 4's required delivery format - now they accept D5 or Digi Beta. The strengths of D5 in editing and technical quality are offset by the lack of camera systems recording on this format, and it does not look likely to achieve wider market acceptance.

Digital S, also known as D9; 1/2" digital component from JVC, using low (3.3:1) compression and generating broadcast quality. High quality and low prices have yet to bring a breakthrough in the market, perhaps partly because of Sony’s clout, and the ability of Digi Beta and Beta SX machines to play back the vast amount of Betacam SP material which producers hold

Betacam SX - alternative digital format from Sony, offering lower quality and cost than Digital Betacam, and initially aimed at news organisations. Uses MPEG 2 compression. Offers choice of traditional or widescreen aspect ratios. To date few Beta SX edit suites have emerged - the source material has typically been mastered onto digital Betacam or D5.

Record to Disc and solid-state. Camcorders that bypass tape altogether and record directly onto hard disc or to f;lash drive cards are available, both at a pro level (see MPeg2 IMG / XD) and for the domestic market. Some think that this is the likely direction in the medium term. Others think this may take a long time to emerge as a mainstream shooting format.

Sometimes used for broadcast:

DVC Pro Close to broadcast quality at low cost from a 6mm tape using 6:1 data compression.( Full broadcast quality version DVC Pro 50 is also available.)

DV CAM: a competitor to DVCPro. Sony's record of success in broadcast video makes any format they back a contender, though their Betamax domestic system and DCC audio system both failed commercially. Neither DV Cam nor DVC Pro reach full broadcast standard, though both are much used for broadcast work.

DV (Digital Video) High-quality domestic standard, and the platform from which DVC Pro and DV Cam have been developed. DV camcorders are sometimes used for broadcast production when considerations of speed and ease of access take precedence over technical quality.

Other well-known digital formats include:D1 This was the original broadcast digital video system, and is still widely used for compositing graphics. Does not use data compression. D1 features excellent technical quality, but high prices, and has lost some ground to Digital Betacam

Broadcast quality - analogue:
Traditional analogue production systems are currently being replaced by digital systems, though organisations with large investments in analogue equipment will no doubt keep it running as long as possible. Of the main analogue systems, only Betacam SP retains a significant place in the production sector..

Betacam SP (component): Once dominant for broadcast both for production and as an edit format, and still widely used for promotional video programmes. Broadcast quality in its original "BVW" version, though to extend its dominance Sony introduced two lower cost variants, known as PVW and UVW.

Betacam was one of two early tape formats built on the "component" idea - recording separate "raw" streams of data to represent different components of the video signal (red, green and blue, or in Betacam's case, luminance, red minus luminance, blue minus luminance) rather than a single combined ("composite") stream, like PAL or NTSC. Component proved to give excellent data handling and picture quality, and is now used, in one or other variant, in most digital video systems.

Broadcast quality - film formats:
Film still has a significant share of the production market, both for TV and for promotional and training productions where projection to a large audience is necessary. Film gives the best results for large-screen projection, and offers very high quality as a source for video.

35mm: The standard format for cinema films and much TV advertising. Sometimes used for major public relations events, and presentations such as new car launches.

16mm / super 16 mm: Used for some TV drama and big-budget documentary. In the business world, a high-quality option when projection to a large audience is desired. Film is also often as the original recording medium with the results then transferred to computer disc or videotape for editing.

Sub-broadcast:

A number of formats are in widespread use which do not meet broadcast standards, but are cheaper. Recent years have seen steady improvements in lightweight domestic camcorders recording onto a variety of tape formats. These can be coupled to PCs (or Macs) to deliver a budget version of desktop video, though as yet this approach has attracted only a small part of the professional market. The most prominent domestic formats are:

DV (Digital Video) Domestic digital videotape, using small tapes and low compression ratios (6:1): offers spectacular improvement on VHS in quality. The quality is close to broadcast, and should not degrade in editing so long as repeated decompressing and recompressing of the video data is avoided. As low-cost DV production equipment (camcorders and edit machines) become more widely used, they may turn the whole video production world upside down.

VHS and S-VHS: VHS is the dominant format for domestic video, and offers reasonable playback quality from original recordings. As quality falls each time the original is copied, to edit or to make show copies, VHS is not much used for production except for home movies and weddings.

S-VHS offers an improvement on VHS, particularly in picture resolution, but is weak on colour handling in editing and has not been taken up professionally except where cost pressures are extreme; after editing, picture quality falls below the quality produced on high-band U-matic.

Digital 8: Sony hybrid format that records DV signals onto Hi- 8 tape. Little take-up for professional use.

Other contenders:
D-VHS Digital variant of VHS offering very high picture and sound quality, widescreen compatibility, and the ability to play back standard VHS tapes. Little take up to date.

DVD RECORDABLE A format that could be immensely significant; recordable DVD seems set to replace home VHS tape units, much as CD took over the mass market from tape and vinyl for audio. DVD recordable is also a strong computer format; this is an area of convergence in video and computing technology. Domestic camcorders which record direct to DVD are now on the market.

Historic note: formats we have loved.

D2 Digital composite - the colour signals are combined into a single signal, using the PAL colour system in the UK; this gives less good results than component when used for editing. This format looks likely to die out. D3 1/2" digital composite on portable cassettes; a strong early contender for location recording, and accepted and used by the BBC for the Barcelona Olympics. Looks likely to die out.

1"C format (composite): Ageing, high-quality tape standard, once the dominant workhorse for studio production and as the master or source tape for bulk duplication of VHS copies. Broadcast quality. Now more or less obsolete.

M11 (component): Similar to Betacam SP, and of equivalent quality, but never widely adopted and now little used. Broadcast quality.

Video 8mm, Hi-8: These formats are interesting because they use extremely small tapes, and tiny cassette players (not much bigger than a standard audio-cassette walkman) are available. They offer slightly higher quality than their VHS counterparts, but have not achieved wide acceptance except for camcorder use.

Video 8mm is mainly used as a domestic camcorder format, and partly because it allows for small, light camera kit with long recording times it achieved some success, at one time taking well over half of the camcorder market. There are many video 8 camcorders still in use.
Hi-8 is a later variant of video 8mm offering improved quality in a very compact form.

The U-matic family of formats, a 3/4" tape, cassette-based family first launched by Sony as a home recording and display format in the late 70s. These offer good playback quality, and were used for news gathering in the late 70s and early 80s. They are now mainly used for production where cost-saving is paramount; particularly for training programmes for internal audiences. Likely to disappear as cheap digital formats emerge

Some of these U-matic formats are frequently and wrongly described by their owners or proponents as "broadcast standard", although they fall way below EBU/ITC standards and are not normally allowable for UK broadcast. The main U-Matic formats in current use are:

U-matic SP and High Band U-matic(also known as BVU): still used in a few organisations for producing internal training videos, this was widely used for promotional films until the mid-80s and the spread of the Betacam formats.

Low Band U-matic: though this was mainly used as playback format, it as sometimes used for production. Likely to give way entirely to DV production and DVD distribution anytime soon ...