Using an External Preview Monitor

Have you ever finished the final cut of a video, burned it to Blu-ray or DVD and watched it on a big screen only to see a problem that sent you right back to your editing software? Maybe the color looked washed out or part of a title was off-screen? Using a preview monitor enables you to see these problems while you edit so you can fix them before you render out your video. 

Three’s Company Too

Many video editors are already using dual monitors to make the post-production process more manageable. So why would you need a third monitor? While most editing software allows you to full screen a monitor window on your computer, it covers your editing controls so you can't make changes while you're watching. This can slow down even the fastest of video editors.
When you open a project in your editing software, you typically have open a timeline, bins, and some assorted control panels as well as monitor windows. With all the space that utilizes on the screen, you're lucky if your program monitor displays at 960×540. That’s only 25 percent of the size of full HD. An external preview monitor allows you to see the detail of what you edit pixel for pixel. 


All digital image reproduction uses color profiles or color spaces to express color. These different color spaces allow for color to be mapped and converted to mathematical formulas. Different color spaces are used for different purposes. For example, digital projection in movie theaters uses the XYZ color space while HDTV uses the Rec. 709 color space. Since these color spaces use different methods to reproduce color, when you change from one color space to another in post production, you'll often see a shift in color. The colors seen in a shot or a graphic on your computer could look much different when mastered out for television or DVD. The easiest way to see this is with an external preview monitor. 

Staying in the Safe Zones

It's been a few years since digital broadcasting went nationwide, yet many people are still watching on analog television sets. Even if your video is streaming from a website like YouTube or Vimeo, your viewers may be watching it on an SDTV connected to a game console (XBOX 360) or a streaming media box (Roku) that has SD outputs. Monitoring your safe zones will ensure that nothing gets lost in the conversion.
Safe zones are overlaid lines that indicate where titles and action can be seen on the screen without fear of them being cut off. Typically, televisions don’t display the full picture, zooming in slightly. Video safe zones were established so editors would know what could be seen on the screen. This feature can be enabled in most editing software to be viewed in the monitoring window. One of the advantages of a professional preview monitor is that they have the ability to display the title and action safe markers usually via a switch on the front of the monitor. 


HDMI is an affordable, common connector type used in both professional and consumer video equipment.


Setting Up Your External Preview Monitor

When selecting a preview monitor there are several factors to consider: size, features, resolution and color reproduction. The last two are the most important. If you're editing in 1920×1080, you'll need a preview monitor that is 1920×1080. Additionally, a good preview monitor can reproduce at least 100 percent of the NTSC color space.
How you set up your external monitor is going to depend on your editing software, your computer, and the type of preview monitor you want to use. You’ll want to start by checking to see what types of external monitoring your editing software supports. This information is usually found in the documentation that came with the editing software.
Next you’re going to need a way to get a video signal from your computer to your video monitor. There are a number of types of signals and connector types to choose from depending on your budget and the types of videos you edit. If you're working in HD you're going to want to connect to your monitor digitally via HD-SDI or HDMI. [] 
Two images of a barn, one with off-balanced color
Closeup of SDI and HDMI slots
HD-SDI offers the ability to monitor uncompressed HD. This is the best way to view footage without color loss. It’s the standard for feature film and broadcast work, but video cards and interfaces with HD-SDI connections tend to cost several hundred dollars. This puts them out of the price range of many video editors.
HDMI is an affordable, common connector type used in both professional and consumer video equipment. Many computers already have an HDMI connector that you can use to attach an external monitor. Even if yours doesn’t, interfaces like Blackmagic Design's Intensity Shuttle and Matrox’s MX02 Mini are both candidates for a young producer. Many of these interfaces have the extra ability to capture video which can be a great bonus.
But what if your videos are only seen on DVD or in SD on the Web? Even if you shot in HD, you can edit in SD and use an SD preview monitor. Many of the video cards and interfaces that have HDMI connectors have SD connectors as well. You'll want to use component or S-video connectors to attach to your preview monitor. Avoid using a composite connection; composite video lacks the quality needed for accurate monitoring. You can buy a used professional SD preview monitor very inexpensively, and there are USB to SD video interfaces that cost less than $100.
If your computer doesn't already have the video output you need, you'll need to purchase a video card or video interface. There are several options to connect including PCI Express (inside your desktop), USB or Thunderbolt ports.
After your monitor is connected, you need to calibrate the color to ensure the brightness, and contrast are accurate. Most preview monitors are calibrated manually while some like the LaCie 324i or NEC MultiSync PA271W can be calibrated automatically. This convenient feature is something to consider when purchasing a preview monitor. 
Two images of a barn, one with off-balanced color
Professional color bars graphic
Monitors can be manually calibrated using color bars which are included in most editing software. The process is fairly simple and doesn't take very long. Apple has a useful guide to calibrating external preview monitors using color bars

Alternatives To a Professional Preview Monitor

Even if you don’t have the budget for a professional monitor, you can use a standard computer monitor to preview video from your editing software and get much of the same functionality. There will be some performance limitations, but the benefits still outweigh the total absence of a preview monitor.
Most computer monitors will only reproduce about 80 to 90 percent of the NTSC color space; whereas, many professional monitors can reproduce more than 110 percent of the NTSC color space. Despite the differences, you can calibrate the color of your monitor so that what you do see is as accurate as possible.
To calibrate a computer monitor to simulate a professional monitor, you’ll need to use an HDMI video output from your computer using one of the methods we already discussed. You’ll want to use an LCD monitor with a resolution of 1920×1080. The resolution is important to ensure that no scaling occurs and that you can see the HD signal pixel for pixel. If your monitor has an HDMI port, then you're ready to go; if it only has a DVI port, you’ll need an HDMI to DVI adapter, or you’ll need to run a HDMI to DVI cable from your computer or interface to your monitor. 
Two images of a barn, one with off-balanced color
Two images of a barn, one with off-balanced color
Once your preview monitor is hooked up and you're sending video from your editing software, you’ll be able to see the footage you’re cutting in full HD. But what about the safe zone markers and color calibration? Well, you can toggle safe zone markers on and off from the monitor controls within your editing software. As for color calibration, you can set brightness and contrast manually using color bars. Unfortunately, getting proper chroma calibration manually with the limited adjustments of most computer monitors may be difficult if not impossible.
Depending on how your monitor is connected, there may be some additional solutions for calibration. Your video interface or video card may have software to aid in calibrating your monitor; check the manufacturer's documentation or website. You can also use an automatic calibration tool to calibrate your monitor. It connects to your computer via USB and runs software that alters the color of the video going to the monitor.
Regardless of how you calibrate your monitor, remember that if the ambient light in the room changes you will need to recalibrate. If your editing room has a lot of windows, some blackout curtains would be a good addition. 

Your Work is Your Calling Card

As video editors, we're only as good as our work. Accordingly, we need the right tools to aid us through post-production. A preview monitor is one of those essential tools that will ensure there are no surprises after your edit. Once you have one, you'll wonder how you managed so long without it. 


Monitoring for Mobile Devices
Did you know that many mobile phones and tablets have aspect ratios that are slightly different from that of video? By default some of the media players on these devices will clip the edges of the video when playing full screen. Because of this, making sure that your action and titles are inside the safe zones is important for videos viewed on mobile devices.
Odin Lindblom is a director, cinematographer and award-winning editor whose work includes film, commercials and corporate video.

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