초록

A rate control algorithm for an MPEG-2 compliant encoder is described. The rate control algorithm has embodiments useful for constant bit rate and variable bit rate encoding. In particular, the invention relates to rate control with panic mode.

대표청구항 ▼

[ We claim:] [3.] In a method of coding an input sequence of video frames to generate a compressed bitstream, each frame comprising a plurality of macroblocks, a method for coding a frame comprising the steps of:(1) after coding one or more macroblocks in a frame by an encoder, initiating a panic mo

[ We claim:] [3.] In a method of coding an input sequence of video frames to generate a compressed bitstream, each frame comprising a plurality of macroblocks, a method for coding a frame comprising the steps of:(1) after coding one or more macroblocks in a frame by an encoder, initiating a panic mode depending upon a value of N.sub.max, wherein N.sub.max is the maximum number of bits used by said encoder to encode a macroblock, if the coding of the remaining macroblocks will result in an underflow of a VBV buffer maintained by said encoder, and(2) in said panic mode, coding by said encoder macroblocks remaining in said frame by providing no coded block patterns for inter-macroblocks and retaining a DC and a number of AC discrete cosine transform coefficients for the intra-macroblocks, wherein N.sub.max is a selectable number depending upon whether the frame is an I, P, or B frame and depending upon the number of AC coefficients retained for each of said remaining intra-macroblocks.