Information Regarding Variable Bit Rate Encoding (290545)

SUMMARY

Variable Bit rate (VBR) encoding allows a user to guarantee a specified quality throughout the course of an encoding session. To maintain this quality, the bitrate of the resultant file may fluctuate. In instances of high motion or detail, the encoder automatically allocates a higher bit rate. In low motion or detailed scenes, the encoder conserves bit rate.

Content should only be encoded at a variable bit rate when it is intended to be downloaded and then played back locally. The buffer associated with variable bit rate content can be quite large making the start-up delay unacceptable for streaming scenarios.

In addition to local playback, VBR encoded content is meant only to be played in Windows Media Player version 7 and later. Although it will sometimes playback, VBR content does not play back well in the Windows Media Player 6.4 and earlier.