As the myth of convergence comes stumbling to a gig near you, some confusion arises about one of the hottest buttons to hit the media server market since its inception. To go HD, or not to go HD: this is the question of the current age, both on the job and at home. Whether ‘tis nobler to suffer the constraints of SD or venture off to the mysterious territory of HD, perhaps to never work for those producers again!
For those of you who haven't run into this conundrum yet, Standard Definition (SD) is what most people have been using for around the last 50 years in most aspects of video production. In the last several years, HD, or High Definition, has become a popular medium for TV systems, as well as for live production, thanks to the strides in technology that have allowed us to expand our usable visual space. Although this may sound vague, HD video is pretty much anything 720p or higher. Since many computer monitors, and hence media servers, can output a pixel resolution equal to 1024×768 without a problem, this may not seem “high def,” but according to broadcast standards, it is.
The most common HD formats are known as 720p (progressive), 1080i (interlaced), and 1080p, and many newer media servers are now starting to cater toward those as target resolutions for playback on HD screens as projection surfaces, bringing with them more processing horsepower geared toward frame-accurate playback of high resolution sources. I'm not going to get into a long explanation of the specifics of video resolutions and how or why they are the way they are. Suffice it to say these are the standards we have acquired and deal with on a daily basis. It is important to remember however, that with this influx of HD power to the market comes great responsibility.
When using any type of HD, the most important phrase is the same as with SD: media content. Having custom or stock content rendered at the correct resolution is key for working in HD. Many people worry about the pixel accuracy of a content deployment system, making sure that every pixel that was rendered in After Effects or Final Cut Pro is exactly represented in the final output display and color-accurate. In the real world, this is not always the case. With media traveling through a variety of processors to get from your server to the wall or output device of your choice, there will always be some sort of loss or correction that you've got to anticipate and minimize as much as possible.
That said, content quality is key in making the final image look as close as possible to what you intended. Most HD systems that you run into will be set to work at 1080i, which is a fairly common standard and easily integrated into most existing HD video setups provided by a video vendor. With that in mind, the content provider must also show up with content formatted for a 1080i system. Saying “HD” to someone can mean a variety of sizes, so the more specific you can be for the content provider, the happier you'll be when it comes time to play it back.
Each media server typically comes with its own requirements for media formats, including the compression codec, the bit rate, resolution, and overall file size. These requirements are crucial to share with your content providers, as they can make or break your show in a matter of moments. Getting the wrong formatted content late in the game can mean that your show (and the audience) may never see the right content, as it typically needs to be re-rendered or trans-coded to a new format, which can take longer.
This may seem obvious to many of you, but remember that HD can be twice the file size, if not more, than an SD movie clip, so re-rendering that 30-second loop would take twice as long, and just think about that seven-minute video with audio. If the content shows up in the wrong size and can be scaled to fit the output device, this may not be the end of the world, but even if the audience doesn't notice it, you will and the content creator surely will. One way to really make friends with the folks in the video art department is to scale or distort their hard work to a point where it looks grainy and skewed.
Another point to remember when making the switch to HD is to have a good transmission standard. Getting the video to the display device can usually make the difference between a good gig and a total nightmare. Typically, for most long distance runs over 100', the most secure method of transport is HD-SDI or fiber optic. As most media servers output from the graphics card on a computer, Mac or PC, this output is a DVI connection, which is not designed to extend much beyond your desktop monitor. The most useful device, in this case, is the Barco/Folsom Image Pro™, everyone's best friend on a hostile media server gig. The Image Pro is designed to take almost any video signal and change it in to almost anything you want. This is perfect for taking a DVI signal from a graphics card and sending it out as a standard HD-SDI signal for the video department to route into the wall or any other system. If you happen to be playing without a video vendor, there are a variety of boxes that will convert a DVI signal into a fiber optic cable run, and then convert it back on the other end. This is great if you happen to be using a display device like Element Labs VersaTube® HDs where they natively take DVI signal in, so there is no need to change the signal type, simply extend it.
All in all, the key to having a successful HD experience is planning — just making sure you're all set from content creation to the media server's capabilities, to the transport system you choose to use, to the ultimate display and what its capabilities are. There isn't a hard-and-fast, right or wrong way to do this, but without the proper planning, I guarantee you will be finding yourself ice skating uphill in a hurry.