Data conversion method and apparatus and signal recording and reproduction apparatus utilizing same

A data conversion method for performing data conversion between first-format encoded data in which orthogonal transform coefficients are arranged in an order of DC components and AC components from a low spatial frequency order to a high spatial frequency order in each orthogonal transform block when compression encoding which includes orthogonal transform is applied to video data and second-format encoded data in which orthogonal transform coefficients are arranged in an order of DC components and AC components from a low spatial frequency order to a high spatial frequency order in each block assembly member formed of a plurality of orthogonal transform blocks when compression encoding which includes orthogonal transform is applied to video data, said data conversion method comprising the steps of:

• decoding the second-format encoded data to obtain orthogonal transform coefficients;
• re-arranging the orthogonal transform coefficients of the second-format data obtained in the decoding step in the order of the DC components and AC components from a low spatial frequency order to a high spatial frequency order in each orthogonal transform block of the first format;
• and
• encoding the orthogonal transform coefficients obtained in the re-arranging step to form encoded data having the first format,
• wherein data of the first format includes a plurality of macroblocks having a plurality of luminance blocks and chrominance blocks, and
• wherein the DC components and AC components in each luminance block and in each chrominance block are arranged from the low spatial frequency order to the high spatial frequency order.

A signal recording and reproduction apparatus for recording and reproducing into and from a recording medium encoded data having a second format in which orthogonal transform coefficients are arranged in an order of DC components and AC components from a low spatial frequency order to a high spatial frequency order in each block assembly member formed of a plurality of orthogonal transform blocks when compression encoding which includes orthogonal transform is applied to video data, said signal recording and reproduction apparatus comprising:

• decoding means for decoding the encoded data having the second format reproduced from the recording medium to obtain the orthogonal transform coefficients;
• conversion means for re-arranging the orthogonal transform coefficients of the second-format data obtained by said decoding means to the coefficient arrangement order of a first format in which the coefficients are arranged in the order of the DC components and AC components from a low spatial frequency order to a high spatial frequency order in each orthogonal transform block;
• and
• encoding means for encoding the orthogonal transform coefficients from said conversion means to form encoded data having the first format,
• wherein data of the first format includes a plurality of macroblocks having a plurality of luminance blocks and chrominance blocks, and
• wherein the DC components and AC components in each luminance block and in each chrominance block are arranged from the low spatial frequency order to the high spatial frequency order.

A stream processing apparatus for processing a second format encoded stream to generate a first format encoded stream, the apparatus comprising:

• processing means for processing discrete cosine transform (DCT) coefficients included in a macroblock layer of said second format encoded stream and for re-arranging an order of said DCT coefficients of said macroblock layer to a predetermined order corresponding to said first format encoded stream so as to form said first format encoded stream from said second format encoded stream;
• and
• control means for controlling said processing means so that said second format encoded stream is converted to said first format encoded stream without performing a MPEG decoding process on said second format encoded stream,
• wherein data of the first format includes a plurality of macroblocks having a plurality of luminance blocks and chrominance blocks, and
• wherein the DCT coefficients in each luminance block and in each chrominance block are arranged from a low spatial frequency order to a high spatial frequency order.

A stream processing method for processing a second format encoded stream to generate a first format encoded stream, the method comprising the steps of:

• processing discrete cosine transform (DCT) coefficients included in a macroblock layer of said second format encoded stream and re-arranging an order of said DCT coefficients of said macroblock layer to a predetermined order corresponding to said first format encoded stream so as to form said first format encoded stream from said second format encoded stream;
• and
• controlling the processing step so that said second format encoded stream is converted to said first format encoded stream without performing a MPEG decoding process on said second format encoded stream
• wherein data of the first format includes a plurality of macroblocks having a plurality of luminance blocks and chrominance blocks, and
• wherein the DCT coefficients in each luminance block and in each chrominance block are arranged from a low spatial frequency order to a high spatial frequency order.