Patent ID: 7054363
Filing Date: 2006-05-30
Classification: H04N

Abstract:
1. An encoding method comprising, for encoding a sequence of frames, at least a quantization step of an input bitstream, a coding step of said quantized bitstream, and a control step of the quantization step with respect to a buffer occupancy at the output of said coding step, said method being characterized in that it also comprises an analysis step, for defining on the basis of parameters related to said input bitstream a reserve of bits (ROBC) periodically updated at each frame, and an additional control step, for maintaining, increasing or decreasing the quantization step value according to the state of said reserve of bits wherein evolution of an initial quantization step Q_INIT with respect to the state of the reserve (ROBC) is given by the following relations: If (ROBC<0) and (S then Q=Q_INIT+V If (ROBC<0) and (S then Q=Q_INIT+V If (ROBC<0) and (S then Q=Q_INIT+V If (ROBC<0) and (S then Q=Q_INIT+V If (ROBC<0) and (S then Q=Q_INIT +V If (ROBC<0) and (S then Q=Q_INIT+V If (ROBC<0) and (S then Q=Q_INIT+V If (ROBC>0) and (T then Q=Q_INIT−V Else ROBC=Q_INIT  where TFBB is total fixed bit budget, S