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

Acquisition Codecs

While choosing an acquisition codec for 4K production may seem like a camera-centric question, you really have to keep the entire workflow in mind when considering your codec options. What are you going to be doing with the video that you acquire in 4K?

If it's destined for the web or for a live webcast, or to a screen of less than 100 inches, you may not need to go into CinemaDNG, uncompressed QXD, 4K DPX, or those huge RED R3D codecs, or even Apple ProRes HQ. You can probably get by with one of the lower-bitrate implementations, such as Sony XAVC or Panasonic AVCCAM 4K, although you might stay away from older codecs like Motion JPEG.

When considering different codecs, be aware that the bit rates are massively different between them, and they're going to affect your workflow. If you don't want to upgrade your computer systems, you're not going to wait to move into the CinemaDNG and the larger-bit-rate ones, because you may have a bottleneck in your chain. More about that in the next installment in this series.

Recording Media

When you’re considering acquisition codecs, you also have to consider recording media, whether for internal recording in your camera or external recording to a connected recording device. I'm a massive fan of affordable media that's common enough to be purchased from a regular computer store in a pinch. If you can buy it at a computer store, then you know you can always get additional media for a shoot if you forget something or if a card gets corrupted, plus it's a lot more affordable. Also, if your client wants a copy on site, or if you're subcontracting and you need to send the footage, you can send them the recording media if it’s something widely used like an SDXC card. If they're different media, you'll have issues with them.

In the 4K ultra HD recording media lineup, several new acronyms have come on the scene, such as Sony’s XQD and AXSM. CFast is another relatively new recording media option becoming a lot more popular. It looks like a compact flash card, but it's different. For me, the big bottleneck when I'm working with cards is I want to capture them really fast. I prefer USB 3.0 SATA card readers to slower internal card slots that are working on parallel ATA technology. When you start working in 4K, the bit rate is higher, and the file size is a lot larger. You want to make sure that you're not creating a bottleneck in your workflow in terms of the capture.

My first experience in 4K was with the Sony PMW-1000 camera, using XQD memory cards. XQD cards work on ExpressCard, so you can plug it into some laptops and capture it straight from there. My laptop didn’t have the right card slot, so I had to rely on USB 2.0 transfer from within the camera, using the camera as the capture device. That was a pretty painful capture process. It took 3.75 times longer than real time for me to capture the footage.

Atomos is producing CFast cards that work in their Atomos Shogun recorder. Blackmagic Design supports CFast in some of their 4K cameras. CFast is a relatively affordable storage media that I expect will become more common than QXD and AXSM.

Another storage option is RAID. Certain recorders and certain cameras have the ability for you to put in multiple hard drives or SSDs, and the device will actually create its own RAID. That's an interesting concept using regular spinning hard drives or SDDs that are common, inexpensive, and high-capacity.

Other manufacturer-specific options include Panasonic’s P2 and Sony’s SxS. When you're looking at 4K, though, you got to be aware that you need the most current version of the cards, because the legacy ones, the ones you bought with, say, your EX1 seven or eight years ago aren't fast enough.

It’s also important to consider bit rates, which will change with the jump from HD to 4K. On my Sony FS700, with the AVCHD codec, I work in 24 or 28Mbps in HD. AVCHD is a very efficient LongGOP codec--better than the MPEG-2 XDCAM EX 35 Mbps codec, but AVCHD remains on the lower, more highly compressed end of your codec options. If you need to go up to do some extensive color work, you may want to look beyond that. In Ultra HD, you've got a lot of options. We’ll get into those in more detail in Part 2, when we discuss storage, and how your storage considerations and needs will change as you move into 4K.