Storage, CPU And Memory
System Configurations for Video Editing
This can be a touchy topic, and it delves far into the 'Mac versus PC' realm often.
First up, if you aren't using Final Cut or Smoke as your editing software, there is no real reason to use a Mac for video editing anymore. At a basic level, the hardware is the same—and Macs, especially the Mac Pro, tend to lag behind PC technology by several months, with a limited selection of available hardware for your machine.
If you're worried about reliability and stability, then use a workstation-class PC instead of a desktop. And don't install anything unnecessary on the machine. There is a reason why professional video editors look to tier one machines instead of having the IT guy run down to Fry's and buy a bunch of components. I'm not saying there's anything wrong with doing that, especially if you're just starting out. But there comes a point where professionally-integrated systems should be a consideration, especially if you're moving into a lot of paid work.
Beyond the software you are using, there are two immediately relevant questions to be asked when discussing how to configure a system for video editing: what type of projects are you planning on editing, and what format will you be working in?
Storage
If you are just shooting video of your kid skateboarding on a consumer camera, you're likely to be editing long single takes. On the other hand, if you're editing a feature-length film, you'll be working with many relatively short takes, multiple takes of the exact same scene from different angles, and ten times the footage for the final running time of your film—in professional parlance, your shooting ratio. For documentary films, higher shooting ratios are common, even 16:1 or 18:1 (eighteen times more footage than the final running time) is not unheard of.
The format of your video is the next consideration. If you are shooting H.264 or AVCHD on a consumer, prosumer or professional camera, including most SLRs set up for filmmaking, then your data rate is going to be relatively low. On the other hand, if you are shooting 5K RAW video on a RED camera, the data rate is going to be comparatively huge.
| Format | Data Rule |
|---|---|
| H.264 (4.2, Main Profile) | 20 Mb/s |
| ProRes 10-bit 4:2:2 (1080 @ 24p) | 220 Mb/s |
| RED 2K RAW (@24p, 3:1 compression) | 202 Mb/s |
| BMD 2.4K RAW (@24p, 12-bit) | 960 Mb/s |
Briefly, a look at the common video formats shows that you're going to need lots of drive bandwidth to directly edit the more professional formats. RAID arrays and even hardware RAID cards become advisable, as does working with proxies (lower-resolution, often more compressed copies of the video made specifically for editing purposes) instead of the full-resolution original formats.
CPU
All rendering takes place on the CPU. Alright, that was more true five years ago. Now, many pieces of video editing software (to varying degrees) use GPU acceleration to greatly increase speed. The more professional an application is, the more likely it is to leverage GPU-based parallelization. But that doesn't mean you should skimp on the CPU. Many third-party effects haven't yet been optimized for GPUs, and many more complex effects are not accelerated or only partially accelerated. For instance, in the popular Boris FX plug-in, some effects can be offloaded, while others use OpenGL. Most editing software responds well to additional CPU cores, and as a result more cores are preferable to higher clock rates. A caveat: most of the calculations for video rendering are floating-point math. And in most cases, the audio is calculated in floating-point as well. Sorry AMD fans. Those extra integer cores won't help much here. Memory bandwidth is another consideration. If you can make the jump to an LGA 2011-based CPU, even at the expense of frequency, do so.
Memory
Although video is streamed from disk, a system's memory is relevant to the size of the project that can be handled. We're not saying you need 32GB to edit your feature-length epic, but 8GB might not cut it and 4GB is out the window. Also, check the recommendations for your application and target project. Avid, in particular, has specific memory recommendations and requirements for different project types. If you're using Adobe products and have embedded After Effects projects and/or SpeedGrade color correction, expect the project to use additional RAM. Ultimately, memory bandwidth is more important than data rate (see CPU, above).
