Two-pass encoding method of digital motion video sequences for constant-or variable bit rate

Abstract

Systems and methods are provided for encoding units of digital information such as pictures, whereby all the data is first analyzed by running a compression pass over all the data, using the in the encoder embedded rate control mechanism. Picture attributes, such as quantization scale setting and bits produced will be extracted from the resulting bitstream, and analyzing this, indiviudal unit (picture) quantization scale and bit allocation settings are prepared for a next pass for either a constant- or variable bit rate, whereby buffer boundaries are observed. In a second compression pass through the same data, a constant- or variable bit rate compressed bitstream is produced, but this time bypassing the embedded rate control mechanism, and using the prepared picture bit allocation and quantization scale settings instead. Additionally, a mechanism will supervise the total bit production accuracy.