FILTERING STRENGTH DETERMINATION METHOD, MOVING PICTURE CODING METHOD AND MOVING PICTURE DECODING METHOD

摘要

A moving picture coding apparatus includes an inter-pixel filter having filters for filtering decoded image data so as to remove block distortion which is high frequency noise around block boundaries. The inter-pixel filter includes filters having different filtering strengths. The coding apparatus also includes a filter processing control unit for determining a filtering strength of the inter-pixel filter.

主权项

1. A decoding apparatus which decodes a block in a B-picture, the decoding apparatus comprising:
a motion-compensation unit operable to generate a predictive image for a current block to be decoded by referring to one or two reference pictures; a difference image decoding unit operable to decode coded data of the current block in a bit stream to obtain a decoded difference image between the current block and the predictive image of the current block, the coded data in the bit stream being generated by coding a coefficient that indicates a spatial frequency component resulting from an orthogonal transformation and a quantization of the difference image; a block reconstructing unit operable to generate a reconstructed block by adding the decoded difference image and the predictive image; a filtering strength determining unit operable to determine a filtering strength from among a plurality of filtering strengths including one filtering strength corresponding to no filtering being performed; a coding distortion removing unit operable to remove a coding distortion between the current block and a neighboring block adjacent to the current block by performing a filtering on the current block and the neighboring block; and a storing unit operable to store the reconstructed block for which a coding distortion is removed, into a memory, wherein, in the case where both of the current block and the neighboring block do not contain the coded data in the bit stream, the filtering strength determining unit is operable to: select, as the filtering strength, a weakest filtering strength among the plurality of the filtering strengths, excluding the one filtering strength corresponding to no filtering being performed, when the number of reference pictures referred to by the current block and the number of reference pictures referred to by the neighboring block are not the same; and select, as the filtering strength, one of (i) a weakest filtering strength among the plurality of the filtering strengths, excluding the one filtering strength corresponding to no filtering being performed, and (ii) the filtering strength corresponding to no filtering being performed, when the number of reference pictures referred to by the current block and the number of reference pictures referred to by the neighboring block are the same.