Articles and whitepapers

VCRs, DVDs and PVRs for High-End Installations (1/3/2004)

By Ewan Smith

The market for video systems is developing at a rapid pace. R&D departments are producing new products all the time, different media formats have emerged, and while the jury is still out on the eventual winner, the relentless progress of technology continues.

Choosing a high-end video system presents its own unique considerations. Issues concerning media type and suitability, whether removable or fixed, storage capacity and formats, uses and compatibility, support and upgrades, need to be addressed. So just how do we make the right choice?

The terminology

While different types of video systems are available, some definition of terms might be useful. VCR (Video Cassette Recorder) is one with which everyone is familiar, whereas DVD (Digital Video Disc or Digital Versatile Disc - depending on which camp you come from) and PVR (Personal Video Recorder) are relatively new terms.

When DVD technology first appeared in households, users were simply popping DVD discs into their DVD players to watch movies - an alternative to the then-conventional VCR. But just as compact disc technology evolved so that users could record and erase and re-record data onto CDs, the same is now true of DVDs. But with so many different formats, such as DVD+R, DVD+RW, DVD-RAM, DVD-R, DVD-RW, DVD-ROM, how do users know which DVD format is compatible with their existing systems, and why are there so many different formats for DVDs?

The crucial difference among the standards is based on which manufacturers adhere to which standards. Similar to the old VHS/Beta tape wars when VCRs first hit the markets, different manufacturers support different standards.

DVD+R and DVD+RW

Philips, Sony, Hewlett-Packard, Dell, Ricoh, Yamaha and others support DVD+R and DVD+RW formats.

DVD+R is a recordable DVD format similar to CD-R. A DVD+R can only record data once and then the data becomes permanent on the disc. The disc cannot be recorded onto a second time.

DVD+RW is a re-recordable format similar to CD-RW. The data on a DVD+RW disc can be erased and recorded over numerous times without damaging the medium. Most commercial DVD-ROM players can read DVDs created by a +R/+RW device.

DVD-R and DVD-RW

Panasonic, Toshiba, Apple Computer, Hitachi, NEC, Pioneer, Samsung and Sharp support these formats. The DVD Forum also supports these formats.

DVD-R is a recordable DVD format similar to CD-R and DVD+R. A DVD-R can only record data once and then the data becomes permanent on the disc. The disc cannot be recorded onto a second time. There also are two additional standards for DVD-R disks: DVD-RG for general use, and DVD-RA for authoring, which is used for mastering DVD video or data and is not typically available to the general public.

DVD-RW is a re-recordable format similar to CD-RW or DVD+RW. The data on a DVD-RW disc can be erased and recorded over numerous times without damaging the medium. Most commercial DVD-ROM players can read DVDs created by an -R/-RW device.

DVD-RAM

DVD-RAM discs can be recorded and erased repeatedly but are only compatible with devices manufactured by the companies that support the DVD-RAM format. DVD-RAM discs are typically housed in cartridges.

DVD-ROM

DVD-ROM was the first DVD standard to hit the market and is a read-only format. The video or game content is burned onto the DVD once, and the DVD will run on any DVD-ROM-equipped device.

PVR

The personal video recorder is a generic term for a device that is similar to a VCR but records television data in digital format as opposed to the VCR's analogue format. VCRs use analogue tapes to record and play programmes broadcast over television, but PVRs encode video data in MPEG-1 or MPEG-2 formats and store the data on a hard drive. PVRs have all of the same functionality of VCRs (recording, playback, fast forwarding, rewinding, pausing) plus the ability to instantly jump to any part of the program without having to rewind or fast-forward the data stream.

A PVR is essentially made up of two elements: the device that stores the hardware elements, such as the hard disk drive, power supply and buses, and the software in the form of a subscription service that provides programming information and the ability to encode the data streams. Two common PVR systems are TiVo and ReplayTV. A PVR is also referred to as a hard disk recorder (HDR), digital video recorder (DVR), personal video station (PVS), or a personal TV receiver (PTR).

Sky+ - the UK's first integrated Personal Television Recorder and Service

It could be argued that the latest Sky+ receivers are a type of PVR since the user subscribes to Sky, has the ability to save the programme onto hard disk, and this functionality is only available to subscribers with the appropriate hardware.

High-end systems

High-end systems are characterised by their ability to take full advantage of the high-quality video and audio content embedded in the source media, and also to read any of the available formats presented to the player. Such systems may well include the Silver Disk Engine developed by Linn, which will read any of the industry-standard formats mentioned above as well as the newer SACD and DVD-Audio formats for surround sound.

Based on the Silver Disk Engine, the Linn Unidisk SC player can decode and play almost every available quality commercial disc format

Most, if not all DVDs shipped now will have a minimum of Dolby Digital 5.1 surround and wide-screen representation. The movie channels in Sky+ also transmit in Dolby Digital 5.1 for greater viewing pleasure. The audio and video components of these sources need to be fed to a surround sound processor and plasma/TFT/monitor respectively. In many devices, the player and sound processor circuitry are combined in one unit, allowing for a smaller footprint. This works very well and allows for an upgrade path should the user choose to expand into a range of separates. Indeed certain units, such as the Linn Classik Movie Di, will also serve as a starting point for a multiroom media centre.

Multiroom systems

Multiroom systems have their own unique requirements in terms of distribution and feedback. A video switcher can handle switching of the video component, or alternatively, this can be fed into a TV/FM/DSS distribution system where the video and audio elements are combined. When opting for the former, account must be taken of the need to separately distribute/switch the audio component. This can lead to problems with running many lengths of speaker cable, and the choices here are numerous. A way of overcoming this is to choose a system that will convert and transmit both audio and video components over a Cat5e or Cat6 network cable and reconvert them back at the far end. High-end multiroom solutions tend to favour this approach, resulting in less cabling.

Back panel of the Linn Kisto multichannel AV system controller

It is important to note that music delivered over a standard computer data network will likely be compressed, resulting in a sound quality which is far from the original. Using a balanced audio configuration with the same network cable will ensure accurate musical reproduction. The difference is quite simply awesome. IEEE1394 (alternatively known as i.LINK or FireWire) is also worth a mention here. It is the new industry standard interface for the secure digital transmission of high-resolution audio from DVD-Audio and SACD sources. Some products already have this capability, and in future, expect to see more devices developed with this functionality incorporated.

The feedback system chosen will allow the user to interrogate what source is being selected, where it has to be displayed and then action these commands. This functionality is absolutely essential when dealing with a number of sources, and in particular when using a hard disk video or music server. Can you imagine trying to locate one particular feature from even a modest number of programs without some indication of where you are actually looking? Fortunately, modern wall outlets from a few select manufacturers such as Linn and Opus to name but two, allow the user to make this choice with ease.

Summary

The benefits of choosing the right video system should result in a solution that exceeds expectations in terms of video and audio quality, enjoyment and involvement in the whole entertainment experience. A high-end system will be capable of accepting and integrating with many sources, such as VCR, DVD, Sky+, PC, digital camera, video camera, Playstation, X-Box and a network connection. Market developments are likely to see more network-enabled devices allowing for standardised connectivity and communication between devices.

Our advice to someone considering purchasing/installing a high-end video system is nothing new. Consider and prioritise your options in the following order:

1. Source.
2. Control.
3. Playback.

No matter how good your control and playback systems are, they will only be as good as the source, which is delivering information to them. A high-quality source will always perform better with lesser-quality control and playback systems than a poorer-quality source can deliver with a higher-quality control and playback.

Reference: www.webopedia.com

Ewan Smith is the Technology Consultant for Intelligent Home Systems Ltd - planner, designer, installer and manager of whole-home media centres, home cinemas, digital media systems, high-end multi-room audio/video, intelligent lighting, data/telephone networks and home automation systems.

ihs@easylivin.co.uk
Telephone 01771 624832