Patent ID: 8059713

Claim:
A video coding apparatus carrying out a compression coding of a video based on a prediction result of a motion vector which is predicted between frames of the aforementioned video which is expressed by a brightness component and a color difference component, comprising: a brightness component prediction error calculation unit which calculates a prediction error of a brightness component by a motion compensation prediction based on the prediction result of the motion vector for a small block designated in the frame of the video; a color difference component prediction error calculation unit which calculates a prediction error of a color difference component by the motion compensation prediction; a quantization method determination unit which determines a most optimal quantization method from among a plurality thereof, based on inputs of the prediction error of the brightness component which is calculated by the brightness component prediction error calculation unit and of the prediction error of the color difference component which is calculated by the color difference component prediction error calculation unit; and a quantization unit which quantizes image data by the quantization method determined by the quantization method determination unit, wherein the quantization method determination unit indicates a degradation of a prediction accuracy of the motion vector as a prediction accuracy indicator when an accumulation value of a prediction error of the color difference component within the small block becomes larger than an accumulation value of a prediction error of the brightness component within the small block and when a ratio of the accumulation value of the prediction error of the color difference component within the small block to the accumulation value of the prediction error of the brightness component within the small block becomes larger than a predefined threshold value.