“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 colour or grading or keying and compositing, all that extra information is crucial for me to manipulate it and end up with a clean image.”