Video Bit Rate
The video bit rate specifies the amount of bits in one second of video. In general, the higher the bit rate, the higher the video quality.
When a bit rate is specified for an encoding, the actual bit rate is not consistent during playback. Variable bit rate (VBR) stores more data for the portions of videos that have a high level of change between frames (e.g., action scenes) and less data for portions that have little change. As a result, the bit rate will vary during playback, but the average will be the bit rate you specify.
Note: To prevent excessive switching between encodings, we recommend making sure that each encoding of the ABR profile is at least 300Kbps (kilobits per second) apart (e.g., 300, 600, 900, and 1200 instead of 300, 450, 600, and 750).