Variable Bitrate

Variable bitrate (VBR) encoding lets the data rate rise and fall with the content: busy, detailed, or fast-moving scenes get more bits while flat or static shots get fewer. The result is better overall quality for a given average file size than constant bitrate (CBR), which spends the same rate everywhere. VBR can run in one pass or two; two-pass first analyzes the whole video, then allocates bits smartly, producing the best quality at a target size at the cost of longer encode time. Editors choose VBR for most file-based deliveries like YouTube and client review, setting a target and maximum bitrate. CBR is reserved for cases needing predictable rate, such as some broadcast or live-streaming pipelines where steady bandwidth matters more than per-scene efficiency.