Video signal decoding apparatus

Claim 2

A video signal decoding apparatus for decoding a coded bit stream of video signals which comprises blocks of quantized coefficient data and which is produced by encoding an input video signal, said apparatus comprising: a variable-length and run-length decoding means for variable-length and run-length decoding the coded bit stream to reconstruct the blocks of quantized coefficient data; an inverse quantization means for inverse quantizing the reconstructed blocks of quantized coefficient data; an inverse coding means for exclusively applying inverse DCT to the inverse quantized blocks of quantized coefficient data to produce decoded blocks which comprise both edge blocks and non-edge blocks; an edge block detection means for determining whether each of the decoded blocks is an edge block; and an adaptive edge enhancement filter means for removing distortions from individual decoded blocks when said edge block detection means determines that a respective decoded block is an edge block.

Claim 3

The video signal decoding apparatus of claim 1, wherein said edge block detection means comprises: a first calculating means for calculating an average value of the decoded block; a second calculating means for calculating a maximum value and a minimum value of the decoded block; a third calculating means for calculating a first absolute difference value between the average value and the maximum value of the decoded block; a fourth calculating means for calculating a second absolute difference value between the average value and the minimum value of the decoded block; and a determining means for determining that the decoded block is an edge block when either the first or second absolute difference value is greater than a predetermined value, and otherwise determining that the decoded block is a non-edge block.

Claim 4

A video signal decoding and encoding apparatus for decoding a coded bit stream of video signals which comprises blocks of quantized coefficient data and which is produced by encoding an input video signal using an encoding apparatus, wherein; said encoding apparatus comprises: a partitioning means for partitioning each frame of the input video signal into smaller blocks of pixel data; a transform coding means for transforming the partitioned blocks of pixel data into blocks of transformed coefficient data; a quantization means for quantizing the transformed coefficients data to produce quantized coefficient data; and a variable-length and run-length coding means for variable-length and run-length coding the quantized coefficient data to produce the coded bit stream; said decoding apparatus comprises: a variable-length and run-length decoding means for variable-length and run-length decoding the coded bit stream to reconstruct the blocks of quantized coefficient data; an inverse quantization means for inverse quantizing the reconstructed blocks of quantized coefficient data; an inverse coding means for transforming! exclusively applying inverse DCT to the inverse quantized blocks of quantized coefficient data to produce decoded blocks which comprise both edge blocks and non-edge blocks; an edge block detection means for determining whether each of the decoded blocks is an edge block; and an adaptive edge enhancement filter means for removing distortions from individual decoded blocks when said edge block detection means determines that a respective decoded block is an edge block.

Claim 5

A video signal decoding and encoding apparatus for decoding a coded bit stream of video signals which comprises blocks of quantized coefficient data and which is produced by encoding an input video signal using an encoding apparatus, wherein; said encoding apparatus comprises: a partitioning means for partitioning each frame of the input video signal into smaller blocks of pixel data; a transform coding means for transforming the partitioned blocks of pixel data into blocks of transformed coefficient data; a quantization means for quantizing the transformed coefficients data to produce quantized coefficient data; and a variable-length and run-length coding means for variable-length and run-length coding the quantized coefficient data to produce the coded bit stream; said decoding apparatus comprises: a variable-length and run-length decoding means for variable-length and run-length decoding the coded bit stream to reconstruct the blocks of quantized coefficient data; an inverse quantization means for inverse quantizing the reconstructed blocks of quantized coefficient data; an inverse coding means for transforming! exclusively applying inverse DCT to the inverse quantized blocks of quantized coefficient data to produce decoded blocks which comprise both edge blocks and non-edge blocks; an edge block detection means for determining whether each of the decoded blocks is an edge block; and an adaptive edge enhancement filter means for removing distortions from individual decoded blocks when said edge block detection means determines that a respective decoded block is an edge block.

Claim 6

The video signal decoding and encoding apparatus of claim 3, wherein said edge block detection means comprises: a first calculating means for calculating an average value of the decoded block; a second calculating means for calculating a maximum value and a minimum value of the decoded block; a third calculating means for calculating a first absolute difference value between the average value and the maximum value of the decoded block; a fourth calculating means for calculating a second absolute difference value between the average value and the minimum value of the decoded block; and a determining means for determining that the decoded block is an edge block when either the first or second absolute difference value is greater than a predetermined value, and otherwise determining that the decoded block is a non-edge block.

Claim 7

The video signal decoding and encoding apparatus as in claim 3, wherein said adaptive edge enhancement filter means comprises: an adaptive averaging filter mask for performing convolution on a pixel by pixel basis for decoded blocks that are classified as edge blocks by comparing a difference between every adjacent pixel of the pixel being convolved with a predetermined value and averaging the pixel being convolved by the adjacent pixel when the difference is determined to be smaller than the predetermined value.

Claim 8

The video signal decoding and encoding apparatus as in claim 3, wherein; said encoding apparatus further comprises: a first motion compensation means for removing temporal redundancies in the partitioned blocks before being transformed by said transform coding means; and said decoding apparatus further comprises: a second motion compensation means for performing an inverse motion compensation of the reconstructed blocks before being processed by said edge block detection means.