Multi-mode processing of texture blocks

摘要

Multi-mode decoding and encoding of texture blocks are disclosed wherein in a default decoding and encoding mode all bits of a codeword sequence are available as payload bits for representing texel values of the texels in the texture block. In an auxiliary encoding and decoding mode one less bit of the codeword sequence is available as payload bits. The auxiliary mode is employed as a complement to the default mode and will be used to process those texture blocks, which the default mode handles poorly.

主权项

1. A multi-mode method of encoding a texture block comprising multiple texels, each texel having a respective texel value, said method comprising:
defining an auxiliary mode space encompassing bit sequence combinations of a first bit sequence, a second bit sequence, a third bit sequence and a fourth bit sequence where i) an integer value represented by said third bit sequence is larger than an integer value represented by said fourth bit sequence, or ii) said integer value represented by said third bit sequence is equal to said integer value represented by said fourth bit sequence and an integer value represented by said first bit sequence is larger than an integer value represented by said second bit sequence, or iii) said integer value represented by said third bit sequence is equal to said integer value represented by said fourth bit sequence, said integer value represented by said first bit sequence is equal to said integer value represented by said second bit sequence and said integer value represented by said third bit sequence is within a predefined value interval; defining a default mode space being complementary to said auxiliary mode space and encompassing bit sequence combinations of said first bit sequence, said second bit sequence, said third bit sequence and said fourth bit sequence not encompassed by said auxiliary mode space; generating at least one default encoded texture block by representing said texture block with a respective combination of said first bit sequence, said second bit sequence, said third bit sequence and said fourth bit sequence selected from said default mode space; estimating, for each default encoded texture block of said at least one default encoded texture block, a default error indicative of representing said texture block with said default encoded texture block; generating at least one auxiliary encoded texture block by representing said texture block with a respective combination of said first bit sequence, said second bit sequence, said third bit sequence and said fourth bit sequence selected from said auxiliary mode space; estimating, for each auxiliary encoded texture block of said at least one auxiliary encoded texture block, an auxiliary error indicative of representing said texture block with said auxiliary encoded texture block; and selecting an encoded texture block resulting in a smallest error from said at least one default encoded texture block and said at least one auxiliary encoded block based on said at least one default error and said at least one auxiliary error.