The amount of data processed per second of video, directly affecting both visual quality and file size.
Video bitrate is the number of bits of data encoded per second of video, typically measured in megabits per second (Mbps) or kilobits per second (kbps). Higher bitrate means more data per second, which generally means better visual quality — but also larger files and higher bandwidth requirements. Think of it like the thread count in fabric: more threads per inch produces a finer weave, but uses more material.
Bitrate and resolution are related but distinct. Resolution defines the dimensions of the video frame (like 1920x1080), while bitrate determines how much data is used to represent those pixels. A 1080p video at 2 Mbps will look noticeably worse than one at 5 Mbps, because there is less data available to capture fine details and motion.
There are two approaches to bitrate: constant bitrate (CBR) and variable bitrate (VBR). CBR maintains the same data rate throughout the video, which is predictable for bandwidth planning but wasteful — a static slide needs far less data than a fast-moving scene. VBR allocates more bits to complex scenes and fewer to simple ones, producing better quality at the same average file size.
For streaming, bitrate determines the minimum connection speed a viewer needs. A 5 Mbps stream requires at least a 5 Mbps connection, and in practice you need headroom above that for reliable playback. This is why adaptive bitrate streaming provides multiple bitrate options — so viewers with varying connections all get smooth playback.
Getting bitrate right is a balancing act. Too low and the video looks blocky or blurry, especially during motion. Too high and you waste bandwidth, increase costs, and cause buffering for viewers on slower connections. The right bitrate depends on resolution, content complexity, and your audience's typical connection speeds.
host.video automatically selects optimal bitrates for each resolution during transcoding, using variable bitrate encoding to maximize quality while minimizing file size. Multiple bitrate levels are generated for adaptive streaming, so every viewer gets the best quality their connection supports.