VHS Video

The VHS Video format is still a widely used home cinema source, and has the advantage of being recordable. This is a guide to the VHS format, and details the features of both the software and the video recorders that are used to play them.
VHS VIDEO

 

INTRODUCTION

The most popular and most widely used video source format is the Video Home System (VHS). Most people have a video recorder (VCR) near their television and so makes the ideal Home Cinema source. Compared to the latest DVD Video discs, the video cassette may appear dated and ready for the scrap heap. However, although the picture quality of standard VHS tapes may not be up to DVD standards, the fact that you can record onto VHS with little loss of quality means that the video recorder is likely to retain its place beside DVD players rather than being replaced. Only when the "next generation" of recording formats, such as the DVD Re-Writable technology becomes cost competitive will the future of VHS look in doubt. But even then, with the extensive catalogue of pre-recorded tapes available, plus the continuing development of the VHS format, the humble video recorder is unlikely to vanish without a trace. Not for several years, anyway.

 
   

THE VHS FORMAT

VHS video is an analogue format where information is recorded onto a magnetic video tape, similar to that used in audio cassettes. Picture information is recorded onto the tape surface and sound information is encoded beside it on the edge of the tape. If you look inside a VCR you'll see a large silver barrel. This is the main 'head' of the machine that spins rapidly and reads the information on the tape as it passes. The recording and playback performance of this system can provide excellent sound and pictures, but it also creates a problem. Because the tape head is in contact with the actual tape, it is possible for the tape surface to wear down resulting in loss of picture and sound quality over a period of time. VHS is not the long term storage medium that it was hoped it would be.

A standard VHS video picture has a 240 line resolution, which means that there are 240 horizontal lines on every picture displayed on the screen. Sound information on video tapes can be either mono, stereo (hi-fi stereo or Dolby Stereo) or can be encoded with a dedicated Dolby Surround soundtrack for use with Dolby Pro-Logic equipment. Digital surround sound is not possible on VHS video due to the fact that VHS is an analogue format and because of the high amount of space needed on the tape to carry the digital surround information.

 
   
Recent developments of the VHS Video have given the format higher quality recording and playback capabilities:  
   
 

S-VHS

JVC originally created the VHS video format, and in 1989 the uprated S-VHS format was developed by JVC as the "next step" in VHS technology. The new format uses 400 horizontal lines of picture resolution - a big improvement over the 240 lines of standard VHS. Better picture and sound quality was promised, and the format delivered those promises. So why don't we all have S-VHS video recorders in our homes? The problem surrounded the fact that S-VHS was not backward-compatible with existing VHS tapes or players. Although S-VHS recorders could playback and record existing VHS tapes, the high quality S-VHS tapes can't be replayed on a standard VHS VCR. And prerecorded S-VHS tapes could only be played back on S-VHS machines. It was eventually Hollywood that prevented the adoption of S-VHS as a mass market format. The prospect of releasing two versions of every movie, one VHS and the other S-VHS, to retailers and rental outlets around the world was too much for the studios to handle. Without the backing of the major movie studios, the fate of S-VHS was sealed.

Today, S-VHS is widely used for home video editing with camcorder movies, and for high quality recording of television programmes for playback on the same S-VHS machine, but the absence of prerecorded S-VHS tapes the format can never be widely adopted.

   
 

D-VHS

Today we have the benefit of DVD, digital satellite and digital cable TV. With the benefits gained by the digital technology used in these new formats in terms of picture and sound quality, the humble VHS video format, with its 240 line resolution, looks rather old and dated. But the VHS format has also evolved into the digital domain in the form of D-VHS, the digital home recording format created by JVC in 1995.

But don't be fooled into thinking that D-VHS is simply a different version of the existing VHS format that records information as digital data - it is a much bigger leap forward, similar to the improvement that DVD-Video made over VHS. In many ways, D-VHS can actually be considered better than DVD-Video, and a quick look at the properties that make up D-VHS may even leave you with a feeling that DVD in its current form is looking a little dated.

Mechanically, a D-VHS video recording deck is identical to a high-quality VHS machine, except for the additional digital encoding/decoding hardware and extra tape heads for reading and writing the digital data. The tapes are also identical in appearance to standard VHS tapes, with the only difference being a couple of small indentations in the tape's casing that allows the VCR to identify the tape as D-VHS. The digital processing circuits use the MPEG-II/DVB format, which is also the technology behind set-top boxes for digital TV, so compatibility for home recording should be no problem.

Ah, did you spot it? "Home recording..." - a feature that in many respects is the only drawback of todays DVD-Video technology. D-VHS is a recordable format that can be used in place of a standard VHS recorder for top quality off-air television recordings and playback. Using dedicated D-VHS tapes, the versitility of digital technology allows these decks to greatly exceed the features of VHS. Where today's analogue VHS format is limited to a basic capacity of recording a single movie track and a stereo soundtrack, D-VHS can take any of todays picture and sound you care to throw at it, whether its 4:3 or anamorphic widescreen, or stereo, Dolby Digital or DTS 5.1. The recording speed can be adjusted to encode a variable amount of data - the slower tape speed with a high bitrate allows more data to be recorded which results in improved picture and sound quality, while increasing the speed and reducing the bitrate increases the storage capacity of the tape but brings the playback quality down towards existing VHS standards. In high quality mode, D-VHS can potentially achieve a staggering 1000 horizontal lines picture resolution - quite incredible if you consider the superb DVD-Video format with its 500 lines!

Take a standard D-VHS tape 300 minutes (5 hours) long. In standard mode you get 5 hours of playback with sound and picture quality superior to DVD-Video. Speed up the bitrate and the playback time decreases to around 3.5 hours, but the leap in quality is enormous. Alternatively, by slowing down the bitrate, an amazing 35 hours of recording is possible with sound and picture quality comparible to current VHS. By using a longer tape, VHS quality recording time can be increased to around 50 hours!

D-VHS players are now available, but it is yet to be seen whether it will replace the existing format, or whether it will become another high quality video recording and editing system. JVC say that D-VHS will not become the home editing format that S-VHS turned into, and also that it is not out to compete with DVD-Video. Considering the enormous versatility of its recording quality and range of features, there is no reason whyD-VHS and DVD couldn't exist side-by-side.

 


The JVC HM-DR10000 D-VHS Video Recorder

   

VHS VIDEO RECORDER

Most homes have a video recorder (VCR) under the television. People began to use the VCR as a Home Cinema source by simply connecting it to the stereo amplifier in their hi-fi system and listening to the sound through the stereo speakers placed either side of the television. This can still be done to greatly improve the sound quality when watching tapes or when routing the TV signal through the VCR, rather than using the television's own low powered speakers. Today, most people connect a VCR to an amplifier with a Dolby Pro-Logic decoder for four channel surround sound.

There are lots of features on a video recorder to look out for when using the VCR for recording and playback of television transmissions, but a few features are essential for home cinema use.

 


Sony SLV-F990 NICAM Video Recorder

 
   
 

NICAM Stereo or Hi-Fi Stereo

The VCR should be able to read and record stereo sound. Surround sound on VHS tapes are recorded as part of a stereo soundtrack. The sound passes through stereo phono interconnects to a Dolby Pro-Logic amplifier or processor in a stereo form.

   
 

Audio Outputs

The stereo VCR will have a pair of stereo phono outputs on the back (the same as any hi-fi source) to allow the VCR to be connected to an amplifier using two phono leads, one for the left channel and one for the right.

   
 

Euro A/V SCART Socket

SCART cables are used in the majority of homes for connecting the VCR to a television. The SCART lead provides a superior picture quality over the normal coaxial antenna lead, and also improved sound quality when listening to a soundtrack through a stereo television.

   
 

Composite Inputs / Outputs

The phono audio and video connections are found on most players - on the rear panel to send sound to an amplifier and pictures to a television, and on the front panel to receive sound and pictures from external sources such as camcorders, video games consoles or other video recorders.

   
 

S-Video Outputs

Mainly found on S-VHS video recorders, the S-Video outputs provide an excellent picture quality compared to SCART when connected to a television or projector that has an S-Video input.

   
 

Dolby Pro-Logic Decoder

A very small number of VCR's were produced with a built-in Dolby Pro-Logic decoder and a set of additional speakers. This is a simple way into home cinema but generally the sound quality can't really compare to even a low cost entry level separates home cinema system. With Pro-Logic appearing on everything from midi hi-fi systems to in-car CD players (its true! Look for the big Volvo's) I doubt you would find, or even need, a Pro-Logic VCR.

   
 

PAL/NTSC Playback

A VCR with this feature can play video tapes in both the PAL (UK) and NTSC (America) colour system. Not really needed if you only play PAL videos or if you record from the television, but is useful if you play tapes recorded in NTSC from America. Some VCR's allow you to view NTSC tapes on a standard PAL television, while some televisions allow you to change the picture settings to view NTSC tapes in their original form.

   
 

Jog Shuttle

A feature that allows you to play the video at a wide range of speeds from single frame advance to up to 30 times normal speed, in forward or reverse. The freeze frame feature allows you to stop the video at any point to look at details.

   
 

Head Count

A VCR will be described as having a certain number of 'heads'. A two head VCR has one head for playback and another for recording. The more common four head design has additional heads for erasing pre-recorded information before new information is recorded, and results in better overall performance. Some VCR's have six, or even eight, heads and these machines have additional heads for recording, erasing and playback to improve the sound and picture quality even further.