Image information encoding apparatus and image information encoding method for motion prediction and/or compensation of images

An image information encoding method for encoding an input image signal at least including intraframe encoding image, interframe forward predictive encoding image and interframe bi-directional predictive encoding image by orthogonal transform and motion prediction and/or compensation processing to generate image compressed information, the image information encoding method including:

• performing motion prediction and/or compensation processing, using an image information encoding apparatus, based on different interpolation methods with respect to the interframe forward predictive encoding image and the interframe bi-directional predictive encoding image,
• wherein the performing motion prediction and/or compensation processing comprises performing motion prediction and/or compensation processing by using a first digital filter with respect to the interframe forward predictive encoding image, and performing motion prediction and/or compensation processing by using a second digital filter having a fewer number of taps relative to the first filter with respect to the interframe bi-directional predictive encoding image, the performing motion prediction and/or compensation processing including performing motion prediction and/or compensation of ¼ pixel accuracy, and performing, with respect to the interframe forward predictive encoding image, interpolation processing of ½ pixel accuracy by using filter coefficients having 6 taps {1, −5, 20, 20, −5, 1}/32 to perform interpolation processing of ¼ pixel accuracy by linear interpolation in accordance with generated pixels.

A computer-readable storage medium having embedded therein instructions, which when executed by a processor, cause the processor to perform processing which encodes an input image signal at least including intraframe encoding image, interframe forward predictive encoding image and interframe bi-directional predictive encoding image by orthogonal transform and motion prediction and/or compensation processing to generate image compressed information, the processing including:

• performing motion prediction and/or compensation processing based on different interpolation methods with respect to the interframe forward predictive encoding image and the interframe bi-directional predictive image,
• wherein the performing motion prediction and/or compensation processing comprises performing motion prediction and/or compensation processing by using a first filter with respect to the interframe forward predictive encoding image, and performing motion prediction and/or compensation processing by using a second filter having a fewer number of taps relative to the first filter with respect to the interframe bi-directional predictive encoding image, the performing motion prediction and/or compensation processing including performing motion prediction and/or compensation of ¼ pixel accuracy, and performing, with respect to the interframe forward predictive encoding image, interpolation processing of ½ pixel accuracy by using filter coefficients having 6 taps {1, −5, 20, 20, −5, 1}/32 to perform interpolation processing of ¼ pixel accuracy by linear interpolation in accordance with generated pixels.