Patent ID: 8144789
Filing Date: 2012-03-27
Classification: H04N

Abstract:
1. A picture coding apparatus controlling coding by predicting a code amount, said picture coding apparatus comprising: a predictive residual calculating unit including a processor calculating a predictive residual by applying prediction processing to an input picture, the predictive residual being calculated according to a difference in pixel value between the input picture and a predicted picture; a code amount predicting unit predicting a code amount to be generated when the input picture is coded, the code amount being predicted based on (i) one of a value and a data amount of the calculated predictive residual, and (ii) one of a value and a data amount of at least one of: (a) a coding condition indicating a condition for coding the input picture; and (b) motion prediction information indicating motion between the input picture and a reference picture; and a coding unit coding the input picture based on the predicted code amount, wherein said coding unit increases a value of a quantization step used in quantizing the predictive residual when the predicted code amount exceeds a first threshold, and decreases the value of the quantization step when the predicted code amount is equal to or smaller than a second threshold which is smaller than the first threshold, and wherein the coding condition is at least one of a block size, a direction of prediction, a picture type, a direct coding mode and a skip coding mode.