High-bitrate codecs can slow down your editing

For low to mid-range codecs, you don’t have to worry about the bitrates at all. Once you start moving up the ladder, however, high bitrate codecs can cause issues with editing, especially if you’re working on everyday computers.

The reason is that your computer needs to be able to read the data from your hard drive at a rate that is at least as high as your codec’s bitrate. It makes sense — if your codec is 50Mb/s (fifty megabits per second), then your computer needs to be able to read that file from your hard drive at 50Mb/s, or else it’ll fall behind and stutter.

[Note: Mb/s stands for megabits per second, while MB/s stands for megabytes per second. There are eight bits in a byte, so you need to multiply by 8 when converting from MB/s to Mb/s.]

The good news is that hard drives are getting faster every day, so 50Mb/s is never going to cause any problems. But what if you’re editing ProRes 422HQ at 4K, which is 734Mb/s? The average external hard drive is only just barely fast enough to play that back, and some cheaper hard drives won’t manage it.

And then, what if you’re editing a multicam with three cameras? Now you need 3x that data rate: 2,202Mb/s. At that point, you’re going to need to invest in some high-performance hard drives or RAIDs.

Here are some rough guidelines for common data storage speeds, though of course there will always be certain models that underperform or overperform.

Standard spinning drive: 100-120MB/s

Professional spinning drive: 150-200MB/s

Low-end RAID: 200-300 MB/s

Standard SSD: 400-500 MB/s

High-end RAID: 1000-2000 MB/s

High-end SSD: 2000-3000 MB/s

For some editors, working off of a high-performance storage system is not an issue. But there are significant savings both in cost and flexibility with using proxies. If you use proxies, it may be feasible to keep the entire film stored on the internal hard drive of a laptop, allowing you to work from the beach work from home, or from a plane or train.