Fast requantization apparatus and method for MPEG audio decoding

Claim 2

An audio decoder in a multiprocessor multimedia system having a scalar processor and a vector processor comprising: a frame synchronization program code that executes on the scalar processor to synchronize an audio bitstream input signal; an information extraction program code that executes on the scalar processor to extract information from the audio bitstream, the extracted audio bitstream information including nonsequential sample data; a vectorizing program code that executes on the scalar processor to convert the nonsequential sample data to sequential sample data; a requantization program code that executes on the vector processor to requantize the sequential sample data; and a sub-band filtering program code that executes on the vector processor to generate a filtered audio sample output signal.

Claim 3

An audio decoder according to claim 1 wherein: the information extraction program code further includes: a program code that extracts header information from the audio bitstream; a program code that extracts bit allocation bits from the audio bitstream; a program code that extracts scalefactor selection information and a scalefactor from the audio bitstream; and a program code that extracts sample data from the audio bitstream; and the vectorizing program code further includes: a scalefactor vectorizing program code that transforms data in a scalefactor array from nonsequential data that is a function of a bit index into sequential data that is a function of sub-band number.

Claim 4

An audio decoder according to claim 2 wherein the program code that extracts scalefactor selection information and a scalefactor from the audio bitstream further comprises: a program code that extracts a scalefactor index from the audio bitstream; a program code that calculates a plurality of scalefactor coefficients based on the scalefactor index; and a program code that stores the scalefactor coefficients in a scalefactor array.

Claim 5

A audio decoder in a multiprocessor multimedia system according to claim 2 wherein the audio bitstream is an MPEG audio.

Claim 6

An audio decoder according to claim 1 wherein the vectorization program code further comprises: a program code that arranges a plurality of quantization coefficients as all-sequential data corresponding to a channel index and a sub-band number.

Claim 7

An audio decoder according to claim 5 wherein the quantization coefficients include a mask function array and a plurality of requantization coefficient data arrays.

Claim 8

An audio decoder according to claim 1 wherein the vectorization program code further comprises: a program code that arranges a plurality of quantization coefficient arrays, a scalefactor array and a masking data array as all-sequential data arrays corresponding to a channel index and a sub-band number, the arrays being arranged for usage by the requantization program code.

Claim 9

A audio decoder in a multiprocessor multimedia system according to claim 1 wherein the audio bitstream is an MPEG audio.

Claim 12

A method according to claim 9 wherein: the operation of extracting information from the audio bitstream further comprises: extracting header information from the audio bitstream; extracting bit allocation bits from the audio bitstream; extracting scalefactor selection information and a scalefactor from the audio bitstream; and extracting sample data from the audio bitstream the operation of converting nonsequential sample data to sequential sample data further includes: transforming data in a scalefactor array from nonsequential data that is a function of a bit index into sequential data that is a function of sub-band number.

Claim 13

A method according to claim 10 wherein the step of extracting scalefactor selection information and a scalefactor from the audio bitstream further comprises: extracting a scalefactor index from the audio bitstream; calculating a plurality of scalefactor coefficients based on the scalefactor index; and storing the scalefactor coefficients in a scalefactor array.

Claim 14

A method for decoding an audio bitstream according to claim 10 wherein the audio bitstream is an MPEG audio.

Claim 15

A method according to claim 9 wherein the operation of converting nonsequential sample data to sequential sample data further comprises: arranging a plurality of quantization coefficients as all-sequential data corresponding to a channel index and a sub-band number.

Claim 16

A method according to claim 13 wherein the quantization coefficients include a mask function array and a plurality of requantization coefficient data arrays.

Claim 17

A method according to claim 9 wherein the operation of converting nonsequential sample data to sequential sample data further comprises: arranging a plurality of quantization coefficient arrays, a scalefactor array and a masking data array as all-sequential data arrays corresponding to a channel index and a sub-band number, the arrays being arranged for usage by the program code for requantizing sample data.

Claim 18

A method for decoding an audio bitstream according to claim 9 wherein the audio bitstream is an MPEG audio.

Claim 19

A multiprocessor multimedia system comprising: a scalar processor; a vector processor coupled to the scalar processor; an audio decoder program code that executes on the scalar processor and the vector processor in combination to decode an audio bitstream, the audio decoder program including: a program code that receives the audio bitstream; a frame synchronization program code that executes on the scalar processor to synchronize the audio bitstream; an information extraction program code that executes on the scalar processor, the information extraction program code for extracting information from the audio bitstream, the extracted audio bitstream information including nonsequential sample data; a vectorizing program code that executes on the scalar processor to convert the nonsequential sample data to sequential sample data; a program code to requantize the sequential sample data, the program code executing on the vector processor; and a sub-band filtering program code that executes on the vector processor to generate a filtered audio sample output signal.

Claim 20

A multiprocessor multimedia system comprising: a scalar processor; a vector processor coupled to the scalar processor; an audio decoder program code that executes on the scalar processor and the vector processor in combination to decode an audio bitstream, the audio decoder program including: a program code that receives the audio bitstream; a frame synchronization program code that executes on the scalar processor to synchronize the audio bitstream; an information extraction program code that executes on the scalar processor, the information extraction program code for extracting information from the audio bitstream, the extracted audio bitstream information including nonsequential sample data; a vectorizing program code that executes on the scalar processor to convert the nonsequential sample data to sequential sample data; a program code to requantize the sequential sample data, the program code executing on the vector processor; and a sub-band filtering program code that executes on the vector processor to generate a filtered audio sample output signal.

Claim 21

A multiprocessor multimedia system according to claim 17 wherein: the information extraction program code further comprises: a program code that extracts header information from the audio bitstream; a program code that extracts bit allocation bits from the audio bitstream; a program code that extracts scalefactor selection information and a scalefactor from the audio bitstream; and a program code that extracts sample data from the audio bitstream; and the vectorizing program code further includes: a scalefactor vectorizing program code that transforms data in a scalefactor array from nonsequential data that is a function of a bit index into sequential data that is a function of sub-band number.

Claim 22

A multiprocessor multimedia system according to claim 18 wherein the program code that extracts scalefactor selection information and a scalefactor from the audio bitstream further comprises: a program code that extracts a scalefactor index from the audio bitstream; a program code that calculates a plurality of scalefactor coefficients based on the scalefactor index; and a program code that stores the scalefactor coefficients in a scalefactor array.

Claim 23

A multiprocessor multimedia system according to claim 18 wherein the audio bitstream is an MPEG audio.

Claim 24

A multiprocessor multimedia system according to claim 17 wherein the vectorization program code further comprises: a program code that arranges a plurality of quantization coefficients as all-sequential data corresponding to a channel index and a sub-band number.

Claim 25

A multiprocessor multimedia system according to claim 21 wherein the quantization coefficients include a mask function array and a plurality of requantization coefficient data arrays.

Claim 26

A multiprocessor multimedia system according to claim 17 wherein the vectorization program code further comprises: a program code that arranges a plurality of quantization coefficient arrays, a scalefactor array and a masking data array as all-sequential data arrays corresponding to a channel index and a sub-band number, the arrays being arranged for usage by the program code for requantizing sample data.

Claim 27

A multiprocessor multimedia system according to claim 17 wherein the audio bitstream is an MPEG audio.

Claim 28

A computer program product that executes on a computer system including a scalar processor and a vector processor, the computer program product comprising: a computer usable medium having computable readable code embodied therein including: a frame synchronization routine executable on the scalar processor to synchronize an audio bitstream; an information extraction routine executable on the scalar processor, the information extraction program code extracting information from the audio bitstream, the extracted audio bitstream information including nonsequential sample data; a vectorizing routine executable on the scalar processor to convert the nonsequential sample data to sequential sample data; a requantizing routine executable on the vector processor to requantize the sequential sample data; and a sub-band filtering routine executable on the vector processor to supply filtered audio samples.

Claim 29

A computer program product that executes on a computer system including a scalar processor and a vector processor, the computer program product comprising: a computer usable medium having computable readable code embodied therein including: a frame synchronization routine executable on the scalar processor to synchronize an audio bitstream; an information extraction routine executable on the scalar processor, the information extraction program code extracting information from the audio bitstream, the extracted audio bitstream information including nonsequential sample data; a vectorizing routine executable on the scalar processor to convert the nonsequential sample data to sequential sample data; a requantizing routine executable on the vector processor to requantize the sequential sample data; and a sub-band filtering routine executable on the vector processor to supply filtered audio samples.

Claim 30

A computer program product according to claim 25 wherein: the information extraction routine further includes: a header information extracting routine that extracts header information from an audio bitstream; a bit extracting routine that extracts bit allocation bits from the audio bitstream; a scalefactor extracting routine that extracts scalefactor selection information and a scalefactor from the audio bitstream; and a sample data extracting routine that extracts sample data from the audio bitstream; and the vectorizing routine further includes: a scalefactor vectorizing routine that transforms data in a scalefactor array from nonsequential data that is a function of a bit index into sequential data that is a function of sub-band number.

Claim 31

A computer program product according to claim 25 wherein: the scalefactor extracting routine further comprises: a routine that extracts a scalefactor index from the audio bitstream; a routine that calculates a plurality of scalefactor coefficients based on the scalefactor index; and a routine that stores the scalefactor coefficients in a scalefactor array.

Claim 32

A computer program product according to claim 26 wherein the audio bitstream is an MPEG audio bitstream.

Claim 33

A computer program product according to claim 25 wherein the vectorization routine further comprises: a routine that arranges a plurality of quantization coefficients as all-sequential data corresponding to a channel index and a sub-band number.

Claim 34

A computer program product according to claim 29 wherein the quantization coefficients include a mask function array and a plurality of requantization coefficient data arrays.

Claim 35

A computer program product according to claim 29 wherein the vectorization routine further comprises: a routine that arranges a plurality of quantization coefficient arrays, a scalefactor array and a masking data array as all-sequential data arrays corresponding to a channel index and a sub-band number, the arrays being arranged for usage by the requantization routine.

Claim 36

A computer program product according to claim 25 wherein the audio bitstream is an MPEG audio bitstream.

Claim 37

A computer system comprising: a scalar processor; a vector processor coupled to the scalar processor; computer program product that executes on a computer system including a scalar processor and a vector processor, the computer program product including a computer usable medium having computable readable code embodied therein including: a frame synchronization routine that executes on the scalar processor to synchronize an audio bitstream; an information extraction routine that executes on the scalar processor, the information extraction routine extracting information from the audio bitstream, the extracted audio bitstream information including nonsequential sample data; a vectorizing routine that executes on the scalar processor, the vectorizing routine converting the nonsequential sample data to sequential sample data; a requantizing routine that executes on the vector processor to requantize the sequential sample data; and a sub-band filtering routine that executes on the vector processor to supply filtered audio samples.

Claim 38

A computer system comprising: a scalar processor; a vector processor coupled to the scalar processor; computer program product that executes on a computer system including a scalar processor and a vector processor, the computer program product including a computer usable medium having computable readable code embodied therein including: a frame synchronization routine that executes on the scalar processor to synchronize an audio bitstream; an information extraction routine that executes on the scalar processor, the information extraction routine extracting information from the audio bitstream, the extracted audio bitstream information including nonsequential sample data; a vectorizing routine that executes on the scalar processor, the vectorizing routine converting the nonsequential sample data to sequential sample data; a requantizing routine that executes on the vector processor to requantize the sequential sample data; and a sub-band filtering routine that executes on the vector processor to supply filtered audio samples.

Claim 39

A computer program product according to claim 33 wherein: the information extraction routine further includes: a header information extracting routine that extracts header information from the audio bitstream; a bit extracting routine that extracts bit allocation bits from the audio bitstream; a scalefactor extracting routine that extracts scalefactor selection information and a scalefactor from the audio bitstream; and a sample data extracting routine that extracts sample data from the audio bitstream; and the vectorizing routine further includes: a scalefactor vectorizing routine that transforms data in a scalefactor array from nonsequential data that is a function of a bit index into sequential data that is a function of sub-band number.

Claim 40

A computer program product according to claim 34 wherein the audio bitstream is an MPEG audio bitstream.

Claim 41

A computer program product according to claim 33 wherein: the scalefactor extracting routine further comprises: a routine that extracts a scalefactor index from the audio bitstream; a routine that calculates a plurality of scalefactor coefficients based on the scalefactor index; and a routine that stores the scalefactor coefficients in a scalefactor array.

Claim 42

A computer program product according to claim 33 wherein the vectorization routine further comprises: a routine that arranges a plurality of quantization coefficients as all-sequential data corresponding to a channel index and a sub-band number.

Claim 43

A computer program product according to claim 37 wherein the quantization coefficients include a mask function array and a plurality of requantization coefficient data arrays.

Claim 44

A computer program product according to claim 37 wherein the vectorization routine further comprises: a routine that arranges a plurality of quantization coefficient arrays, a scalefactor array and a masking data array as all-sequential data arrays corresponding to a channel index and a sub-band number, the arrays being arranged for usage by the sequential sample data requantizating routine.

Claim 45

A computer system according to claim 33 wherein the audio bitstream is an MPEG audio bitstream.