Patent ID: 8331437
Filing Date: 2012-12-11
Classification: H04N

Abstract:
1. A coding apparatus for coding an image sequence of a plurality of frames, the apparatus comprising: skip binary search means for coding a frame out of every first skip number of frames of the image sequence, while changing a quantization step size according to a binary search algorithm, and determining a quantization step size with which a generated bit rate is approximate to a target bit rate; quantization step size correction means for determining the quantization step size good for achieving the target bit rate by using an approximate straight line expressing the relationship of the quantization step size determined by the skip binary search means and the generated bit rate, wherein the quantization step size correcting means connects a first point that indicates an outcome of the skip binary search and a second point of an immediately preceding loop by a straight line to determine an intersection of a straight line and the target bit rate and selects a value of an intersection on the horizontal axis as a corrected quantization step size; first coding means for coding a frame out of every second skip number of frames of the image sequence with the quantization step size corrected by the quantization step size correction means; quantization step size forecasting means for determining the quantization step size good for achieving the target bit rate by using the generated bit rate generated by the first coding means; and second coding means for coding all the frames of the image sequence with the quantization step size forecast by the quantization step size forecasting means.