Orthogonal transform method, orthogonal transform apparatus, encoding method, encoding apparatus, inverse orthogonal transform method, inverse orthogonal transform apparatus, decoding method, and decoding apparatus

An orthogonal transform apparatus operable to perform one of an N-by-N orthogonal transformation and an N/2-by-N/2 orthogonal transformation on data on an N-pixels-by-N-lines-formed pixel block, where N is equal to 2x, and x is an exponent, said orthogonal transform apparatus comprising:

• an input unit operable to enter N-pieces of pixel data after receipt of the N-pieces of pixel data in an N-by-N orthogonal transform mode, and
• said input unit operable to enter N/2-pieces of first pixel data and N/2 pieces of second pixel data after receipt of the N-pieces of pixel data in an N/2-by-N/2 orthogonal transform mode;
• and
• an orthogonal transform operation unit operable to, in the N-by-N orthogonal transform mode, perform an operation on the entered N-pieces of pixel data and given N-by-N orthogonal transformation-related coefficient data, thereby producing N-number of orthogonal transform coefficients,
• said orthogonal transform operation unit operable to, in the N/2-by-N/2 orthogonal transform mode, perform an operation on the entered N/2-pieces of first pixel data and given N/2-by-N/2 orthogonal transformation-related coefficient data, thereby producing a first N/2-number of orthogonal transform coefficients, and
• said orthogonal transform operation unit operable to, in the N/2-by-N/2 orthogonal transform mode, perform an operation on the entered N/2-pieces of second pixel data and the given N/2-by-N/2 orthogonal transformation-related coefficient data, thereby producing a second N/2-number of orthogonal transform coefficients.

An encoding method comprising:

• encoding data on an N-pixels-by-N-lines-formed pixel block, where N is equal to 2x, and x is an exponent;
• in an N-by-N orthogonal transform mode, entering N-pieces of pixel data after receipt of the N-pieces of pixel data into an operation block in which an orthogonal transform operation is performed;
• in an N/2-by-N/2 orthogonal transform mode, entering N/2-pieces of first pixel data and N/2-pieces of second pixel data after receipt of the N-pieces of pixel data into a first operation block of the operation block and a second operation block of the operation block, respectively;
• in the N-by-N orthogonal transform mode, performing an N-by-N orthogonal transformation in the operation block using the entered N-pieces of pixel data and given N-by-N orthogonal transformation-related coefficient data, thereby producing N-number of orthogonal transform coefficients;
• in the N/2-by-N/2 orthogonal transform mode, performing an N/2-by-N/2 orthogonal transformation in the first operation block using the entered N/2-pieces of first pixel data and given N/2-by-N/2 orthogonal transformation-related coefficient data, thereby producing a first N/2-number of orthogonal transform coefficients;
• in the N/2-by-N/2 orthogonal transform mode, performing the N/2-by-N/2 orthogonal transformation in the second operation block using the entered N/2-pieces of second pixel data and the given N/2-by-N/2 orthogonal transformation-related coefficient data, thereby producing a second N/2-number of orthogonal transform coefficients;
• quantizing the produced orthogonal transform coefficients, thereby producing quantized data;
• and
• performing variable length encoding of the quantized data, thereby producing encoded data.

An encoding apparatus comprising:

• an orthogonal transform unit operable to orthogonally transform data on an N-pixels-by-N-lines-formed pixel block, where N is equal to 2x, and x is an exponent, thereby producing orthogonal transform coefficient data;
• a quantizing unit operable to quantize the produced orthogonal transform coefficient data, thereby producing quantized data;
• and
• a variable length encoding unit operable to perform variable length encoding of the quantized data, thereby producing encoded data,
• wherein said orthogonal transform unit comprises:
• an input unit operable to enter N-pieces of pixel data after receipt of the N-pieces of pixel data in an N-by-N orthogonal transform mode, and
• said input unit operable to enter N/2-pieces of first pixel data and N/2 pieces of second pixel data after receipt of the N-pieces of pixel data in an N/2-by-N/2 orthogonal transform mode;
• and
• an orthogonal transform operation unit operable to, in the N-by-N orthogonal transform mode, perform an operation on the entered N-pieces of pixel data and given N-by-N orthogonal transformation-related coefficient data, thereby producing N-pieces of orthogonal transform coefficient data,
• said orthogonal transform operation unit operable to, in the N/2-by-N/2 orthogonal transform mode, perform an operation on the entered N/2-pieces of first pixel data and given N/2-by-N/2 orthogonal transformation-related coefficient data, thereby producing a first N/2-pieces of orthogonal transform coefficient data, and
• said orthogonal transform operation operable to, in the N/2-by-N/2 orthogonal transform mode, perform an operation on the entered N/2-pieces of second pixel data and the given N/2-by-N/2 orthogonal transformation-related coefficient data, thereby producing a second N/2-pieces of orthogonal transform coefficient data.

An inverse orthogonal transform method comprising:

• performing one of an N-by-N inverse orthogonal transformation and an N/2-by-N/2 inverse orthogonal transformation on orthogonal transform coefficient data on an N-pixels-by-N-lines-formed block, where N is equal to 2x, and x is an exponent;
• in an N-by-N inverse orthogonal transform mode, entering N-number-of-pixels-based orthogonal transform coefficient data after receipt of the N-number-of-pixels-based orthogonal transform coefficient data into an operation block in which an inverse orthogonal transform operation is performed;
• in an N/2-by-N/2 inverse orthogonal transform mode, entering N/2-number-of-first pixels-based orthogonal transform coefficient data and N/2-number-of-second pixels-based orthogonal transform coefficient data after receipt of the N-number-of-pixels-based orthogonal transform coefficient data into a first operation block of the operation block and a second operation block of the operation block, respectively;
• in the N-by-N inverse orthogonal transform mode, performing the N-by-N inverse orthogonal transformation in the operation block using the entered N-number-of-pixels-based orthogonal transform coefficient data and given N-by-N inverse orthogonal transformation-related coefficient data, thereby producing N-pieces of pixel data;
• in the N/2-by-N/2 orthogonal transform mode, performing the N/2-by-N/2 inverse orthogonal transformation in the first operation block using the entered N/2-number-of-first pixels-based orthogonal transform coefficient data and given N/2-by-N/2 inverse orthogonal transformation-related coefficient data, thereby producing a first N/2-pieces of pixel data;
• and
• in the N/2-by-N/2 orthogonal transform mode, performing the N/2-by-N/2 inverse orthogonal transformation in the second operation block using the entered N/2-number-of-second pixels-based orthogonal transform coefficient data and the given N/2-by-N/2 inverse orthogonal transformation-related coefficient data, thereby producing a second N/2-pieces of pixel data.

An inverse orthogonal transform apparatus operable to perform one of an N-by-N inverse orthogonal transformation and an N/2-by-N/2 inverse orthogonal transformation on orthogonal transform coefficient data on an N-pixels-by-N-lines-formed block, where N is equal to 2x, and x is an exponent, said inverse orthogonal transform apparatus comprising:

• an input unit operable to, in an N-by-N inverse orthogonal transform mode, enter N-number-of-pixels-based orthogonal transform coefficient data after receipt of the N-number-of-pixels-based orthogonal transform coefficient data, and
• said input unit operable to, in an N/2-by-N/2 inverse orthogonal transform mode, enter N/2-number-of-first pixels-based orthogonal transform coefficient data and N/2 number-of-second pixels-based orthogonal transform coefficient data after receipt of the N-number-of-pixels-based orthogonal transform coefficient data;
• and
• an inverse orthogonal transform operation unit operable to, in the N-by-N inverse orthogonal transform mode, perform an operation on the entered N-number-of-pixels-based orthogonal transform coefficient data and given N-by-N inverse orthogonal transformation-related coefficient data, thereby producing N-pieces of pixel data,
• said inverse orthogonal transform operation unit operable to, in the N/2-by-N/2 inverse orthogonal transform mode, perform an operation on the entered N/2-number-of-first pixels-based orthogonal transform coefficient data and given N/2-by-N/2 inverse orthogonal transformation-related coefficient data, thereby producing a first N/2-pieces of pixel data, and
• said inverse orthogonal transform operation unit operable to, in the N/2-by-N/2 inverse orthogonal transform mode, perform an operation on the entered N/2-number-of-second pixels-based orthogonal transform coefficient data and the given N/2-by-N/2 inverse orthogonal transformation-related coefficient data, thereby producing a second N/2-pieces of pixel data.

A decoding method comprising:

• decoding data on an N-pixels-by-N-lines-formed block, where N is equal to 2x, and x is an exponent;
• performing variable length decoding of encoded data, thereby producing quantized data;
• inversely quantizing the quantized data, thereby producing orthogonal transform coefficient data;
• in an N-by-N inverse orthogonal transform mode, entering N-number-of-pixels-based orthogonal transform coefficient data after receipt of the N-number-of-pixels-based orthogonal transform coefficient data into an operation block in which an inverse orthogonal transform operation is performed;
• in an N/2-by-N/2 inverse orthogonal transform mode, entering N/2-number-of-first pixels-based orthogonal transform coefficient data and N/2-number-of-second pixels-based orthogonal transform coefficient data after receipt of the N-number-of-pixels-based orthogonal transform coefficient data into a first operation block of the operation block and a second operation block of the operation block, respectively;
• in the N-by-N inverse orthogonal transform mode, performing an N-by-N inverse orthogonal transformation in the operation block using the entered N-number-of-pixels-based orthogonal transform coefficient data and given N-by-N inverse orthogonal transformation-related coefficient data, thereby producing N-pieces of pixel data;
• in the N/2-by-N/2 inverse orthogonal transform mode, performing an N/2-by-N/2 inverse orthogonal transformation in the first operation block using the entered N/2-number-of-first pixels-based orthogonal transform coefficient data and given N/2-by-N/2 inverse orthogonal transformation-related coefficient data, thereby producing a first N/2-pieces of pixel data;
• and
• in the N/2-by-N/2 inverse orthogonal transform mode, performing the N/2-by-N/2 inverse orthogonal transformation in the second operation block using the entered N/2-number-of-second pixels-based orthogonal transform coefficient data and the given N/2-by-N/2 inverse orthogonal transformation-related coefficient data, thereby producing a second N/2-pieces of pixel data.

A decoding apparatus for decoding data on an N-pixels-by-N-lines-formed block, where N is equal to 2x, and x is an exponent, comprising:

• a variable length decoding unit operable to perform variable length decoding of encoded data, thereby producing quantized data;
• an inverse quantizing unit operable to inversely quantize the quantized data, thereby producing orthogonal transform coefficient data;
• and
• an inverse orthogonal transform unit operable to inversely orthogonally transform the produced orthogonal transform coefficient data, thereby producing pixel data,
• wherein said inverse orthogonal transform unit comprises:
• an input unit operable to, in an N-by-N inverse orthogonal transform mode, enter N-number-of-pixels-based orthogonal transform coefficient data after receipt of the N-number-of-pixels-based orthogonal transform coefficient data, and
• said input unit operable to, in an N/2-by-N/2 inverse orthogonal transform mode, enter N/2-number-of-first pixels-based orthogonal transform coefficient data and N/2-number-of-second pixels-based orthogonal transform coefficient data after receipt of the N-number-of-pixels-based orthogonal transform coefficient data;
• and
• an inverse orthogonal transform operation unit operable to, in the N-by-N inverse orthogonal transform mode, perform an operation on the entered N-number-of-pixels-based orthogonal transform coefficient data and given N-by-N inverse orthogonal transformation-related coefficient data, thereby producing N-pieces of pixel data,
• said inverse orthogonal transform operation unit operable to, in the N/2-by-N/2 inverse orthogonal transform mode, perform an operation on the entered N/2-number-of-first pixels-based orthogonal transform coefficient data and given N/2-by-N/2 inverse orthogonal transformation-related coefficient data, thereby producing a first N/2-pieces of pixel data, and
• said inverse orthogonal transform operation unit operable to, in the N/2-by-N/2 inverse orthogonal transform mode, perform an operation on the entered N/2-number-of-second pixels-based orthogonal transform coefficient data and the given N/2-by-N/2 inverse orthogonal transformation-related coefficient data, thereby producing a second N/2-pieces of pixel data.