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Gearing Up for 4K Production, Part 1: Connectivity, Codecs, and Capture

We'll begin this 3-part series with a look at the two 4K formats and a discussion of why you'd want to shoot in 4K today even though most viewers and potential clients aren't demanding it, and start to examine the links in the 4K live production chain with an eye to connectivity, codecs, and capture.

Why 4K?

The big question is, “Why shoot in 4K today?” As online video producers, few or none of us are actually delivering videos to our clients or our online audience in 4K. There is some demand for 4K out there, but it’s nowhere near as big as the demand for HD.

As someone who does a great deal of webcasting in his business, 720p is my format of choice for live delivery. That’s where we are today. We rarely deliver SD webcasts nowadays, because bandwidth is plentiful and readily available. As for our viewers’ download bandwidth, we assume everyone can sustain a 1.5 megabit per second (Mbps) download. As long as a venue can provide the upload bandwidth I need, down is fairly easy.

Today we can choose among lot of services that offer multiple cloud-based encoding. They'll generate five different versions of your webcast. Typically, I use Ustream, which allows me to push the video up in 720p, and then gives me three or four different flavors coming down, including mobile support, 720, 480, and 240p. We don't need to cater to the lowest common denominator. Cloud-based encoding allows us to provide the best possible stream for everybody.

If 720p is the format most viewers want and the best they can currently handle, why do live online video production in 4K today? One reason is to gain a strategic advantage for your business by differentiating yourself from your competitors. Economists say that early adopters enjoy a cumulative advantage as the technology they adopted moves into the mainstream . You just have more balls rolling down the hill for you when larger demand arises.

You can also film in 4K today for future releases. Currently, I’m producing a couple of episodes of a TV series featuring archival footage of TED Talk-style speeches filmed over several years. I was asked to go back into the archives and re-edit everything to produce 40 TV show episodes of this talk. They wanted to mix everything up, take it out of chronological order and just mix up everything.

The footage that was given to the broadcaster was provided in standard definition, but some of it was filmed in high definition. Then others were uploaded to YouTube in HD. Now that they want to produce the shows in HD, I'm pulling sources from YouTube, because the HD YouTube version is better than the SD broadcast version. Some years, they got it wrong, and they uploaded it in 240p, so we had to go back then to the DVCAM tape and up-res the SD footage. Other times, we had the project files with the actual assets in there. I was taking over this project late in the game, so I didn't have that whole legacy of the archive there that I kept intact.

Today, we know demand for 4K is coming. The advantage of shooting in 4K today is that when the client or your own company says, "Now we want to re-encode our entire video library to 4K" because it’s cool, because they can, because it looks better at the trade show booth, or for whatever reason they choose, you’ll have that footage available.

Shooting in 4K also gives you more room to reframe in post, to push in so that you can shoot a little bit more wide if you want. It just gives you more flexibility, more options. For example, if you’re shooting a two-person interview with one camera, you could push in for the responses and still deliver in 1080p. When you film in 4K for HD delivery, you don't have to be as aggressive when you're filming, and push in so tight that you don't have anywhere to go in post.

Outputs and Connectivity

When it comes to 4K live production--or any live production workflow, really--I begin by looking at outputs and connectivity. For most cameras professional producers use today--and all cameras and camcorders offering 4K recording--the primary output option HDMI or SDI. SDI is not a BNC cable, but it looks like one. It has the same, secure bayonet connectors and push-in lock. SDI is the professional standard. Even though HDMI can carry the same HD or 4K signal, it can’t do so nearly as securely, especially over long cable runs, as SDI.

HDMI is a consumer standard, not a professional one like SDI. I much prefer SDI for professional work. I don't want an HDMI cable in my workflow if I can avoid it. All devices that are connected that are split off are interconnected. You unplug one device, like a monitor that's connected on your DA or your splitter, everything goes dead. I just don't want that in my live workflow.

Many cameras have two outputs, HDMI and HD-SDI, but some offer only HDMI. If you must use HDMI, the HDMI standard you're looking for is the 2.0 standard that supports 60p 4K, but the 1.4 standard also does 30p. Just be aware that there are frame rate differences. Don’t assume that everything is available in 60p. You may not need 60p in 4K today, or even ever. Just be aware that there are differences in support.

On the SDI side, SMPTE is still drafting and working on the standards, but that hasn’t stopped companies from releasing products that support 4K over a single HD-SDI cable and they’re calling it 6G or 12G. When doing the research for this article, I came across 24G HD-SDI, which is 120p 4K. Regardless of format or frame rate, make sure you're using great-quality cables, such as Belden or Canare. And get flexible cables if possible; they're better for coiling.

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Two big issues that concern almost everyone making the jump to 4K and UltraHD are throughput and storage. How are you going to manage and transfer all those additional bits?
In part 2 of our 3-part series on gearing up for 4K live production, we'll explore the cameras and lenses available today for professional 4K production.