Constant bitrate (CBR)
Also known as: CBR, fixed bitrate
An encoding mode that spends roughly the same amount of data every second, no matter how complex the picture is. Predictable size, uneven quality.
Updated
What it means
A video encoder has to decide how much data to spend on each moment. With constant bitrate, it aims for the same amount every second. A calm shot of a sky and a chaotic shot of spray and foliage get roughly equal data, so file size is easy to predict: Bitrate multiplied by duration.
The opposite approach is variable bitrate, which spends more on complex scenes and less on simple ones. Many cameras use a form of constant or capped bitrate so they never exceed what the memory card can write.
Live streaming also relies on near-constant bitrate, because the network connection has a fixed capacity.
How it works in practice
CBR is common for live streams, broadcast and some camera modes. It keeps network usage steady and avoids sudden spikes that could cause buffering. For livestreaming from an action camera, a stable constant bitrate below your upload speed is the key setting.
For file exports, CBR is less efficient. Simple scenes waste data they do not need, while busy scenes run short and show artifacts. Most editors default to variable bitrate for exports for that reason.
If a platform or client asks for CBR, choose a bitrate high enough for the busiest part of your footage, not the average scene.
What to watch out for
Setting a low constant bitrate for action footage is a recipe for blocky artifacts in exactly the moments that matter: crashes, water, snow and fast pans. If quality matters more than predictable size, use variable bitrate with a higher target.
Constant bitrate also does not guarantee constant quality. Two files with the same bitrate can look very different depending on the codec and content.
Finally, a camera labeled with a fixed bitrate may still vary slightly. Use the number as a guide for card speed and storage planning, not as an exact figure.
How RawClip handles it
RawClip accepts camera files whatever bitrate mode they used. Upload the originals straight from the card rather than low-bitrate exports, so the AI has the best quality to build your highlight from.