Analogue or Digital Video

 

There are two main methods of turning the information from the image chip into the finished moving footage for display on a TV, Analogue and Digital.

All the early models of video camera and camcorder used analogue tape as the recording medium. In analogue systems the information from the chip is sent as a series of voltage signals to be written magnetically onto the tape - in exactly the same manner as a audio cassette recorder works. This methods allows a lot of electronic noise from the amplification circuits and the tape drive motors to be recorded too. A further drawback was that the tape surface could have imperfections within it and these would reduce the quality of the recorded signal. Such systems were termed 'Low-band' video and included VHS (Both full size and the compact VHS-C), and along with the 8mm format.

Later, the camcorder manufacturers used developments from commercial broadcast systems to offer the 'High-band' systems S-VHS / S-VHS-C and Hi8. Such formats separated the signal into two individual recorded information for the Chrominance (colour) and Luminance (brightness) components of the picture. This gave less colour smearing and a sharper overall picture although it did need to have a TV or computer fitted with a special socket and circuits to handle the picture information in this format. The tape normally had to be of improved quality too but surface imperfections could still degrade the picture.

Analogue has another drawback too - it is difficult for the user to make high quality copies as with each successive copy generation the voltage signal is reduced. If copies are ever needed then they should always be made using the original tape to ensure quality isn't reduced too much. Such 2nd or 3rd generation copies are usually easy to spot as the colours look washed out and the overall quality of the picture is fuzzy and ill-defined, these recordings are of little use to the paranormal investigator.

Hi-band systems however can produce excellent quality pictures and are nowadays camcorders using such systems are available often on the high street for less than £100 or £150 for models fitted with the IR Night vision technology. On internet auction sites some absolute bargains can be found from stores selling off old stock or users who have upgraded to digital camcorders. Provided one uses high quality tapes purpose made for High-band recording and is aware of the limiting factors then this is still a 1st class video tool for paranormal investigation work.

Digital camcorders have been around for about 10 years as consumer products - the 1st models to hit the stores had a massive price tag of well over £1000 but today digital camcorders can be found for less than £200 although IR night vision equipped models usually are a little more expensive.


In digital models the information from the image chip is sampled digitally thousands of times every second and output as a series of digital data to the recording media. To further reduce picture flaws the data from the chip is error checked by a microprocessor to ensure that the final data stream is error free before being written to the media.


The method also differs in another way too - it generates a vast amount of data and therefore some way of compressing the data is needed, to permit a decent amount of recording time per tape. Essentially, only one picture frame in every 25 (i.e. 1 per second) is fully written to the recording media - this is called a Key Frame. All subsequent images only have information about the changes to that Key Frame so areas that do not change are not recorded. The Key Frame compression technique also reduces tape flaw problems too, if the flaw falls on a Sub Frame data section then it may not affect the final image excessively.


There are a number of tape formats, the most common being miniDV (sometimes wrongly called DV). MiniDV tapes are small and that means the camcorder can often be small and easily portable. The tapes are readily available in many shops and supermarkets and cost less than £5 per tape.
Other consumer formats are MicroMV which uses and absolutely minute tape size, although it stills allows a full hour of recording to be made per tape. Digital 8 or D8 is a digital version of Hi8 and allows the user to playback previous Hi8 recordings on the same camcorder plus make digital recordings of new footage. In this format the tape speed is increased to allow greater quality, so the user can make 40 minute recordings on a 1 hour tape. There are some digital VHS-C (D-VHS-C) models still around but these should be generally avoided as they are now difficult to find tapes for and hard to interface with other items.

In the past 2 or 3 years we have seen the advent of DVD camcorders. These use smaller 8cm DVD discs and a slightly different form of compression technique to record the picture. They were originally promoted as 'Easy to use and View' - the disc simply being taken from the camcorder and placed into any DVD player to watch. These early models came in the inevitable variety of sub-formats such as DVD-R/RW, DVD+R/RW and DVD-RAM. All had compatibility problems and meant that these early models were not widely sold. However, DVD offers the investigator some distinct advantages too. The finished disc can be placed directly into a computer drive and the footage used without the often time-consuming step needed with tape systems to get the video data onto the computer. The discs, provided they are Re-Writable (RW) type can be used hundreds of times unlike tapes which are really only good for single use in evidential terms. A secondary advantage with these DVD camcorders is that the compression format (MPEG2) is not so easy to edit as yet by consumer software so computer assisted hoax video footage is also rarer at the moment with this system. The compression ratio is also usually selectable by the user so a disc can be last from around an hour to about 20 minutes depending on the picture quality required, obviously the higher quality / shorter times may be preferred by the investigator but even the lowest setting is still usually better than standard VHS tape footage. In the past couple of years many of the compatibility problems have been dealt with and any disc can usually be played in any home computer of fairly recent domestic DVD player - there are a few exceptions so one does still need to be aware.

Camcorders using solid state or internal hard discs are now becoming available too - these have some advantages for the paranormal investigator but also have some distinct problems of their own too. For the present those with Solid state memory either internally fitted or in the form of memory cards offer poor recording times and apart from their use in very small 'pocket' video cameras or in video-camera mobile phones their usefulness to the paranormal investigator is limited to perhaps making video 'sketches' of locations or short witness interviews.


Very recently, camcorders fitted with large internal hard drives have started to appear as consumer products. They allow very long continuous recordings to be made and remove the need to change tapes or discs - perhaps even for a whole investigation session. The compression technique is similar to that used for DVD and as with DVD this is variable allowing longer recording times to be made with a slight reduction in quality - again down to levels similar to standard VHS tape. At this sort of picture quality recording times up to 8 hours or more are possible.


The major downside of this system is that once the disc is full the user needs to download it to a computer before the disc can be re-used to make further recordings. If you do not have a computer to hand this may mean the camcorder is of no further use - a problem when away from base or on multi-night investigations unless one has a laptop available.


Evidentially, there may be other issues too - the footage from a tape or DVD camcorder can be retained on the original recording medium and so the investigator can show that no-post production techniques have used to 'create' anomalies. Sceptics may never be fully convinced but having the original recording is always a good safeguard. With these 'write to memory' systems the footage must be transferred to either a computer or via a computer be burned to a DVD etc. This is now a copy of the original and it becomes more difficult to demonstrate that any additional steps have taken place.


Digital video as with digital still needs to be carefully considered in terms of it's potential evidential value. Software and in-camera editing means that images can be easily altered either unwittingly or deliberately leading to the creation of false anomalies that some may then consider to be paranormal.

Some Useful Features

Camcorders often have a wide range of 'features' built-in by the manufacturer to make the products more saleable to the consumer. Most are little more than gimmicks and of little use the paranormal investigator, but one or two are of real benefit and if used correctly can increase the usefulness of the potential video evidence. It is these that we will look at here.

Solar-Terrestrial Data




CURRENT MOON

Para Entertainment




Pro Vocal Services

Video Services


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