Explore video bitrate.

Bitrate is a slightly misleading term. Most bitrates are measured in bytes and megabytes. A megabyte is equal to a million bytes and a byte is 8 bits. So, despite being called “bitrate,” bits are not measured directly.

Bitrate encoding can vary a good deal given types of footage. On the low end, 720p is the type of video common in older HD televisions. 720p has a bitrate of about 6.5Mbps at a standard frame rate (24–30 frames per second) or 9.5Mbps on a high frame rate (48–60fps).

High-resolution 4K video encodes at 2160p and has a bitrate between 44 and 56Mbps on a low frame rate and 65 to 85Mbps with a high frame rate. That higher quality footage will look great, but the level of quality and usability are often at odds with each other.

“If you’re out filming B-roll and you know you’re going to be out there for five hours and you don’t want to come back with massive files, you might decide to shoot at a lower bitrate,” says Leonard. Professionals need to think about time for processing, uploading, or downloading deliverables. They often need to balance project management considerations with video quality considerations.

In general, final footage for video content will have a lower bitrate than files filmmakers work with. “With streaming, there’s a restriction on bitrate,” says Hara. “If there’s too high of a bitrate you get a frozen or choppy image.”

Bitrate and visual effects.

Most viewers won’t be able to tell the difference between different bitrates. Bitrate matters most during production, especially when it comes to creating visual effects. “If we’re doing any sort of visual effects, we ideally aim to film in a higher bitrate, such as 10- or 12-bit, and at a larger picture resolution, like 4K or higher,” says Leonard.

The human eye might not be able to tell high bitrates apart, but the hardware and software used to make CGI certainly can. “If you were to show me an 8-bit and a 12-bit image I may not be able to look at it and tell the difference,” says Leonard. “But when I go in to do something like color or grading or keying and compositing, all that extra information is crucial for me to manipulate it and end up with a clean image.”

Video bitrate matters very much when visual effects artists work with a green screen, as well. Effects artists need to pull what’s known as a clean key from the green. That is, they need to be able to eliminate that specific green color effectively in order to replace it with visual effects. A higher bitrate means better video data, which allows for visual effects artists to more precisely eliminate that color green, and that color green only. When they do, they can replace it with visual effects that look much more convincing because they’re built on a good foundation of digital visual information.

Find the right bitrate.

There is no ideal bitrate, but it’s wise to use the highest bitrate your technology, budget, and capabilities will allow. “The rule of thumb that I think every DP (director of photography) or cinematographer will tell you is that you can always downgrade footage, but you can never upgrade footage once it’s shot,” says Leonard.

“Whenever you’re shooting something, you want to think of it as your foundation,” says Hara. “If you start with a lower-quality image, you’ll never be able to go higher than that. You always want the highest quality to start with.”

Your initial bitrate will inform the quality of all subsequent footage that comes from that video data. Aim for the highest practical bitrate. Think about what you need to create your project and how you’ll manipulate footage in post-production, and shoot accordingly.