What is Variable Bitrate?
Variable bitrate is an encoding method used in telecommunication and computing to achieve the best possible video quality. An Encoding pass is a video encoding strategy used to retain the best quality image while compressing.
Types of Variable Bitrate
1. Quality-based VBR Encoding: Quality-based variable bitrate encoding uses only one encoding pass. You can specify the quality of a digital media stream instead of the bit rate. The encoder compresses the content so that all samples are of comparable quality. The advantage of quality-based VBR encoding is that it is consistent both within a file and across multiple files.
2. Unconstrained VBR Encoding: Unconstrained variable bitrate encoding uses two encoding passes. You need to specify a bitrate for the video stream. This value is just the average bitrate, although the actual bitrate can be different at multiple points.
3. Constrained VBR Encoding: Constrained variable bitrate encoding is similar to Unconstrained video bitrate encoding. The only difference is that you need to specify the maximum bitrate instead of the average bitrate.