Let’s face it: if I didn’t start with a title like that, there’s no way you’d read a story about waveform monitors. They’re boring! They’re not creative! They’re all the same! They’re not sexy. They’re not RED.
Scopes are important if you’re doing real work that gets duplicated, broadcast or color corrected. They can be used “creatively.” They can help you do better work. Without them, all that other cool gear is worthless.
So WHY are scopes the “Rodney Dangerfield” of the production and post production world? Some of it is probably fear of not understanding them. Some is probably that they don’t really seem to DO anything other than cost a lot of money. Some is probably because they have a lot of unrealized potential.
If you’ve read either of my color correction books, you know that the basis for my approach to color correction is that you have to be able to analyze your image before you can grade your image. Scopes are a big part of that. And you don’t need to understand ANYTHING about all that arcane terminology about blanking, sync pulses, burst, backporches, breezeways and millivolts.
I have preached often enough on the importance of scopes, so I’m going to leave that behind and do a little review of some of the choices out there for scopes. There are basically four types. There are all-inclusive scopes with built in displays. I’ve got a Tektronix WFM7120 that does standard and high def and displays waveforms, vectorscopes, jitter, gamut, audio phase and levels and more. There are also rasterizers. These are little 1 or 2 rack-unit-high instruments that get mounted in a rack and then display the data on a separate computer monitor. I also have one of these: an aging SD-only VideoTek VTM-300. There is also a new category of scopes that uses software, a spare computer and a video card to deliver an “external” scope. The data is displayed on the computer monitor of the computer on which the software is running, which is NOT the same computer as the “video feed” is coming from. I am running demos of two of these types of scopes: for the Mac – Scopebox – and for the PC – Hamlet’s VidScope and Adobe’s OnLocation. Finally there are the built-in scopes in the editing, color correction and compositing software you use.
Because I understand that most people don’t want to spend 10 times as much for their scopes as they did for their editing software (FCP $1200 compared to good Tek scopes at $12,000), I wanted to compare some of the choices that are out there that purport to do the same thing for a LOT less money.
I suppose it shows my bias to hold the Tektronix scope up as the gold standard. (If I had a Leader or OmniTek scope or some other brand, I’m assuming that it would give me a similar result.) But, prior to my “scope shootout” I double-checked the accuracy of my Tek scopes at an on-line post-house I do work with, looking at color corrected footage from one of my favorite colorists that was bound for broadcast. The Tek scopes were very accurate with great, fine detail. One of the differences between the manufacturers of scopes is that some of them, especially Tektronix, have patented certain displays, like the Diamond and Lightning displays. No other manufacturer can offer these methods of analyzing your signal. So before you buy, find out what exclusive displays each manufacturer brings to the table.
Some other advantage to the Tek scopes (and for most other manufacturers of “standalone” scopes, for that matter), include a crucial ability to customize the way that the data is presented. That includes being able to adjust the gain and position of the waveform and vectorscope as well as to include NTSC set-up or not. These scopes can also present numerous displays simultaneously in either “parade” mode (next to each other) or overlaid (superimposed on each other). The Tek scope is also capable of logging errors and identifying the timecodes at which the errors occurred. The WFM 7120 can display multiple tools either full-frame or with four different displays in quadrants on its face. All of which are easily customizable with dedicated buttons and not too much “delving into menus” for the commands you need. Obviously it can also save these views as presets which can be quickly and easily called up.
I’ve also used several “rasterizer” or “hybrid” scopes, including those by Tektronics and the above-mentioned VideoTek model. These scopes tend to have identical abilities and accuracy to the standalone scopes. Basically the difference boils down to one advantage and one disadvantage. The disadvantage is that the display of the “trace” – the part of the image that responds to the video signal – does not seem to be as finely detailed on the rasterizers as with standalone scopes. It seems much more “grainy” or “pixelated.” The advantage of the rasterizers is that they can be displayed on a nice big CRT or LCD monitor, which is great when you’ve been editing for 25 years and your eyes are a little less sharp than they used to be. However, in defense of my trusty WFM 7120, in addition to the built-in display, which measures about 4.25 inches high (about 6″ on the diagonal), is that it has a XGA output on the back of it to deliver the data to a bigger screen if I wanted to.
Some people I respect have been proposing the use of the new software-based scopes that take advantage of the relatively meager computing power of a “spare” computer that you may have lying around in combination with a video card for accepting the incoming video signal. These scopes can also display video data on “file-based” video, like QuickTimes and AVIs. I was really hopeful about these solutions because I hoped that their low price point would allow more people to use “external” scopes. My problem with “internal” scopes has never really been that they were “computer-based” but that the scopes that are a part of the software that you’re editing or color correcting or compositing with have two significant drawbacks: lack of CPU cycles and they aren’t downstream of the videocard.
Let’s address those two issues separately. It has long been known as a dirty little secret that the scopes that are a part of your editing application are giving you a basic idea of the incoming video signal. It’s fairly accurate, but all of the manufacturers know that their customers want the main power of their computer to be devoted to running the main application, and not powering the scopes, so instead of sampling and displaying all of the pixels and lines of video that are present, they only sample half or a quarter or even a sixteenth. This is not speculation on my part. It’s the truth as confirmed by several product managers who wished not to go on record about their software. But it’s industry-wide, and not limited to one editing application or another. Some editing applications actually experience a fair amount of “buginess” when realtime scopes are turned on. This is a primary reason why I advocate using standalone scopes. Why tax your system with this unnecessary drain on its power? Use real scopes to give you real information. Scopes like ScopeBox, VidScope and OnLocation can devote the full measure of the computer’s power to displaying the data.
The other issue is that if you’re looking at the scopes in Final Cut, Color, Premiere or Avid, you are NOT seeing anything that the video card or any outside elements may be having on your signal. Let’s say you don’t have your deck terminated properly. If you were looking at that deck through an external scope, you’d know that you had a problem. If your videocard or software output has been tweaked – intentionally or not – to deliver a revised signal, like increased gain or lowered chroma, you’ll never know it from the internal scopes. That’s simply a recipe for disaster.
Since this article is getting a little long, I’ll conclude with the shoot-out in the next article.
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