This article seeks to throw some light on the problem by looking at the options available to us in India. Whether you're completely new to this non-linear business or an old hand, hopefully there's something in here for you.

Non-linear editing - infinitely more flexibile.
First of all, what is non-linear editing? To the computer savvy, it's easy to explain. Non-linear editing allows you to manipulate video and audio - picture and sound - like text in a word-processor. You can cut a portion here, paste it there, add a little to the start, reduce a few frames at the end, move whole segments from here to there... you get the picture! What does this mean to you as a filmmaker? Infinitely more flexibility, that's what. But back to definitions. Non-linear means that you do not have to edit the first shot first, the second shot next and the third shot after that. You can simply go about your edit in any order that you wish. Now, I know what you film editors out there are thinking. You've had this flexibility since the beginning of time. Right! It's the video people who'll stand in awe. But wait, there's something here for you film types as well. No more physical labour. No more time spent cutting with a scissors and joining with cement or tape. No more lost frames on the cutting room floor. No more... you get the picture too? Great!

Geting Started
Let's assume that you are going to cut a film on a non-linear editing system and we will go through each of the steps involved. First, you would need to log your footage. Instead of doing this on paper as you or your assistants normally would have, you do this on the computer. Either on the non-linear editing system itself or on a low cost logging software running in your office, you would enter the start and end timecodes of each of your shots and name or number the shots. If you have conscientious assistants, they might even enter such additional data as type of shot (CU, MCU, LS, etc.), location (Hero's House Ext, Hotel Lobby, Gorai Beach, etc.) or any other data that is relevant.

This data is used to digitise the required footage from the videotape onto the computer's hard disk. Now, it's this hard disk which is the miracle worker that makes this whole wonderful technology possible. The hard disk is a random access medium, which means that unlike videotape, you can jump from any one spot on the disk to any other in a very, very short period of time. This really means that any required frame of picture or sound on the hard disk can be accessed instantly on demand.

Virtual edits
There is one key additional point that will open the door to your understanding of this technology. All the edits made on a non-linear system are virtual edits. Eh? Whatwazaaat? When you make an edit from shot three to shot seven, the computer does not copy or move the two shots to another place on the hard disk one after the other to play back to you. It simply remembers your edit decisions and seamlessly plays the third shot, then jumps to playing the seventh shot at the precise frame without a glitch. To give you a metaphor, it's as if you were reading aloud, the first sentence on this page and you jumped to the tenth sentence without a pause. A listener might well imagine that the tenth sentence actually followed the first on the printed page!

What is online and what is offline?
So now that's out of the way and we can go on to the next big muddle: What is online and what is offline. The definitions are in fact easy here. The path to the application of those definitions is what lies beyond the quicksand. Online is anything that you would use as the final output of your programme. And offline is anything that you use only as a guide to the edit, which you finally replicate in the online studio or in the case of film, on the negative. The offline system in this case is expected to produce an edit decision list or EDL, which can be fed through a floppy disk into the online edit controller. For film edits, a negative cut list that references the negative edge numbers is generated.

So what's the muddle here? Just that one man's roof is another man's floor. Depending on your application, you may well be satisfied with picture quality that someone else would sneer at. Or you may be the kind of person for whom even 35 mm film is low resolution. For the majority of us who do work for television, online quality would be what we can broadcast with no compromise in the picture quality that reaches the viewer's home.

Video Compression
We need to digress a little here to discuss another important topic: Video Compression. A normal frame of PAL broadcast quality video when converted to digital form occupies about 810 Kilobytes of data. At 25 frames each second, that's about 20 Megabytes of data for each second of video. To put these huge numbers into perspective, a 31/2" floppy disk will hold little more than one frame of video and your average office computer's hard disk will hold about less than a minute's worth. And the problem here is not just having large enough hard disks, it's also finding a hard disk that's fast enough to read so much data each second, for a sustained duration. Suffice to say that such hard disks are very, very expensive and you wouldn't have all these non-linear systems on the market if there weren't some other way.

Obviously, someone has found a solution to this problem. And yes, you've guessed it, the answer lies in video compression. With devilishly fast purpose-built circuits on a chip, there are ways to reduce the amount of data that you need to represent each frame. And the more cleverly you compress a frame, the better the picture quality for a given frame size. Most of the compression methods in use throw away picture data in areas of low detail while preserving as much as possible in areas of high detail. At a compression level of around 1:8, the human eye becomes unable to distinguish any loss of information. Compression ratios of this level or better appear essentially loss-less to most people.

As a matter of fact, one school of thought is that where compressed data would suffice, it's a waste of storage and transmission space to use uncompressed data at all. Like it or not, compression is now a fact of life whether in long distance telephone lines, studio to transmitter video/audio links, satellite broadcasting, or most of the new digital video and audio tape formats.

The question is, how much compression can we accept for a broadcast picture? And can we set measurable standards for the quality of compressed pictures. Alas, that is something that we can't do. The reason is simple. Since compression usually reduces data in areas of the picture with little detail, it's going to fool even the best test instruments! And while the compression ratio - assuming we can get an honest and accurate estimate - will give us a rough idea of the picture quality we can expect, the efficiency of the compression process used would also play a very big part. So finally, we're left with only one way to decide if the picture quality is good enough: use our own dear eyes and our own precious judgement. But hey, that's not so bad! It's exactly what we media people pride ourselves on being so good at.

Evaluating a non-linear editing system - suitability to the task
With that we've about covered all the theory we need. Whew! Now, we can get down to brass tacks - what to look for when evaluating a non-linear editing system.

The first thing you should look for in a system is its suitability to the task. If you think that sounds like the kind of down-to-earth advice that is as applicable when buying a car or a fax machine, you're dead right. Who am I to transcend the pearls of conventional wisdom.

Examine your intended application thoroughly. Would you be using your editing system to edit feature films, advertising commercials, documentaries, music videos, corporate films, training films, television serials or, what is most likely, several of the above? And if your delivery format is only video, would you prefer to use the output of the non-linear system itself or would you be doing an online edit elsewhere? Do you need to work on film projects at all? Let's examine each of these questions in detail.

If you ever need to cut on film, you've already narrowed your choices quite a bit. And if you actually need to edit your final sound track within your non-linear system (as is most likely for feature films and documentaries), you're pretty much looking at only a couple of possibilities here. Further, some systems' support for film cut lists is relatively new and which of us is going to volunteer our negatives for the test!

If your work is all video, you got a bit more choice out there. But not if you also consider what kind of programmes you're editing. Some systems are aimed at the not-so-experienced - and consequently, the not-so-demanding - semi-professional editor. Others are aimed squarely at professional film and video editors. And while each of these products offers the tools required to make every single cut perfect, some do the job better - and that's putting it mildly - than others. So the best way to figure out which system is the best for you is of course, to simply use it on a job.

One additional factor to keep in mind is that while good tools do go a long way in helping the creative filmmaker, a bit of innovation and planning can get you excellent results from every one of the systems out there.

Evaluating a non-linear editing system - availability and support
The second thing that you should look for when buying a system is availability and support. Non-linear systems are computer based and hence require a serious amount of handholding at the start. Don't be scared off by these words. Just about anyone and everyone can - and should - adapt to computers, but you'll sure appreciate that little additional help in the beginning. If the system you plan to buy has a technically and financially sound organisation behind it right here in India, think of that as a big plus. And look at the larger picture as well. Is the manufacturer doing well internationally? Is the company likely to be around five years from now?

Evaluating a non-linear editing system - conceptual editing model
The next item to consider is the conceptual editing model of the system. To the editor, this is probably the most important factor influencing his purchase. There are two main categories of machines: those that imitate the physical edit suite and those that evolve their own editing methodology.

As you probably know, in the conventional video edit suite we have a source VCR, a record VCR and an edit controller. To make an edit, we need to set In and Out points for the source and the record machines, i.e., four edit points in all. Most edit controllers let you set the In and Out points on either the source or the record and only the In point on the other. The controller calculates the fourth edit point. This is called three point editing. An advanced edit controller allows the additional flexibility of setting any three of the edit points rather than necessarily two In's and one Out. Also, controllers will assume that your current tape position is the In point if one is not explicitly set. This feature is called park and edit.

Some non-linear editing systems use this editing model. Being computers, they allow perfect three point editing and in most cases, also park and edit. This makes it extremely easy for the editor to learn the system. This is also a time-tested and reliable editing model that allows you as much accuracy in making edits as you wish. And needless to say, I heartily recommend systems that follow this method.

An alternative method, popular with computer based systems, is to have a clip editor where you mark the In and Out points for a particular shot. You can then carry the marked clip to the correct spot in the edit using the mouse.

A third editing method is storyboard editing. Here you arrange all the shots to be edited in order on the screen after setting their individual In and Out points ( and lo and behold, you have your first cut. And first cut it had better be, because you'll have to be a sorcerer to get a perfect edit by this method alone. The idea is that you trim the different shots in the edit after putting it together in this fashion to arrive at the final version.

Evaluating a non-linear editing system - trimming
Which conveniently brings us to a very, very important area of editing: trimming. When looking at a system, see how well and how accurately it allows you to trim shots. Preferably, you should also be able to slip and slide shots to alter the sync with the sound. Usually, systems have a trim mode that allows you to accomplish these actions. When you use effects such as dissolves or wipes between shots, some systems may not let you trim any more, so watch out.

Evaluating a non-linear editing system - effects
If you are into online editing, then effects are an area of great importance to you. I can only cover this area briefly since a comprehensive look would be beyond the scope of this article.

Many systems still expect you to live through the ordeal of rendering for achieving even a simple dissolve or a wipe. More and more of today's systems, however, offer most or all their effects in real-time. On the rest, you have to define the parameters of your effect and allow the computer some time to calculate and store the effect as a new clip. Even on systems with real-time effects, if you want any more than two pictures to appear at a time, you must first render or build to disk, the first two pictures. Being digital, you might assume that the image would not suffer any degradation in the rendering process. Be warned however, that this is true of only some systems. In others, there is a positive generation loss with every layer!

Some of the effects you could expect in a non-linear system are fades, dissolves, wipes with borders or soft edges or both, chroma, luma and matte keys, colour correction, titles, 2-D DVEs and 3-D DVEs. Some systems also allow you to add in third part effects developed by independent vendors. The variety of such effects available in the market is incredible and could add a whole new world of wonder to your music videos!

Long live non-linear!
Most of today's non-linear editing systems are computer based and therefore tend to improve over time. But some improve much faster than others and some get stuck in a rut so its a good idea to look at what new features have been added to the latest version of a system's software to see in what direction things are moving. Companies that have an organised method of collecting user input and suggestions tend to move in the right directions faster. If a company has different models with varying levels of functionality, then do confirm that their systems are upgradable. Also, check if yesterday's models can be brought up to today's levels. This should give you a good idea if the model you buy today will remain current some time in the future.

Talking about the future, I should warn you about a pitfall here too. Computer companies are notorious for putting out what is called vapourware (rather than software!). The essence of vapourware is promises, promises and more promises with deliveries scheduled for tomorrow. Remember tomorrow, that famous day which never comes! Well, to get the point, don't pay too much heed to promised features. Believe only what you see today and compare models based on features that are available here and now.

Well, that brings me to the end of my meandering advice. Whichever non-linear system you choose, you can be sure you're going to enter a wonderful world of creativity and freedom such as you've never seen before.

Long live non-linear!