VIDEO CAMERA 1997

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EDITING SUPPLEMENT

 

HEAD

THE GENERATION GAME

 

INTRO

It doesn’t matter how much time and effort you put into your video movies, the final production can still end up looking a mess, if your copying procedures aren’t up to scratch

 

COPY

Over the past fifteen years virtually all of the difficulties associated with editing and transferring camcorder footage to a VHS cassette have been eliminated, except one! That’s the sometimes catastrophic drop in quality that occurs when video material is copied from one deck to another, using domestic analogue equipment. The good news is that one day we’ll all be using digital camcorders and VCRs, able to make near perfect ‘clones’ of an original recording, but for the time being most of us are stuck with analogue kit, so we’d better learn to make the most of it.

 

But why does this reduction in picture quality occur, and is there anything that can be done about it? Picture quality means different things to different people, and there’s no simple technical definition. It’s a highly subjective matter; for some it’s the amount of fine detail in a video image that really counts. For others vibrant, natural-looking colours are more important. However, whilst we can all recognise quite large deficiencies in detail and colour, the eye is actually far more sensitive to something else, and that’s noise.

 

Noise is video enemy number one, and the primary cause of the quality reduction during the copying and editing process. Noise occurs across the frequency spectrum, but it has the most drastic impact on the higher frequency components of a video signal, affecting both colour fidelity and resolution. In short, the more noise there is within the limited bandwidth of a video signal, the less room there is available for picture information.

 

The effects of noise are immediately obvious on copies or edit masters made using low-band equipment (8mm or VHS-C to VHS). Edges and straight lines look whiskery, colours become fuzzy and fine detail is lost, replaced by a distinct texture or ‘grain’. Things really start to suffer on third generation recordings -- i.e. a copy of a copy -- when noise begins to have an impact on the recording’s synchronisation pulses. The top of the frame can start to ‘tear’, colours become unstable, and the picture starts to look increasingly ‘grainy’ as though it’s being viewed through a gauze screen. Fourth generation copies are generally so unstable as to be unwatchable.

 

Where does all this noise come from, and what can be done to get rid of it? Unfortunately noise is an integral component of all analogue recording systems, and one of the main reasons there’s been such an enthusiast shift towards digital technology in recent years; (noise is far less significant where information is represented by numbers, rather than waveforms of constantly varying amplitude or frequency). Noise is generated at all stages of recording and playback, even cables and the conductive tracks on circuit boards create noise, but the greatest contribution comes from the magnetic tape, and electronic components in the video processing circuitry.

 

Clearly you can’t do much about the amount of noise your camcorder and VCR generates internally, apart from replacing them with better specified models, but you can make a difference by your choice of tape and connecting leads and using good quality post production equipment.

 

Tape noise is by far the worst offender, so it makes good sense to use the best high-grade, low-noise tape you can lay your hands on; this is crucially important for the original recording! ‘Pro’ or ‘Master’ formulations cost on a little more but they can make a huge difference to the look of final tape. A lot of tosh is spouted about connecting leads, but the fact remains that poorly-made leads and connectors can introduce additional noise into a system. You don’t have to spend a fortune on gold plated leads and oxygen-free copper cables for video applications, but it makes sense to avoid the cheapo stuff, which can quickly develop intermittent contacts through corrosion or by being a poor fit.

 

Cross-format editing and copying is another consideration. The drop in quality is most apparent on low-band edits or copies; third generation material is usually only just watchable. Things improve considerably with high-band (Hi8 or S-VHS-C) master recordings. The amount of additional noise generated during copying will be about the same, but its effects are less significant, because you’re starting out with more detail and sharper colours. Second generation VHS recordings from a high-band master can look as good as a 8mm or VHS-C original. By the third generation there is a marked increase in noise, equivalent to a second generation low-band copy.

 

The best results are obtained by mastering on Hi8 or S-VHS-C, editing to Super VHS VCR. Third generation VHS copies taken from the S-VHS edit master can look almost as good as low-band originals.

 

The ultimate system would be all digital, with the potential for third, fourth or fifth generation copies to be almost indistinguishable from the original. A lot of enthusiasts and semi-pro users are early converts to the format, and it’s the only way to go if you’re looking for near broadcast picture quality, at a fraction of the cost of professional equipment. Unfortunately DVC is brought down to earth with a bump as soon as it’s transferred to analogue S-VHS or VHS, but the lower noise levels on DVC recordings mean subsequent analogue copies will still look cleaner than equivalent multi-generation copies of Hi8 or S-VHS-C originals.

 

At the moment the cheapest digital camcorders cost £1800, and the one and only DVC VCR sells for £3,500; digital post production equipment is still very thin on the ground, and very expensive.  It’s clearly a luxury few can afford right now, nevertheless it is a new technology and prices are coming down; we’d guess that within a decade concerns about copy and edit quality will have been consigned to the cutting room floor of history...

 

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Ó R. Maybury 1997 1601

 


 

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