Texas Instruments Corporation

Jonathan L Rowlands

Frank L Laczko, Sr

Stephen (Hsiao Yi) Li

Stephen H Li

Maria B H Gill

Gerard V Benbassat

Fuk Ho Pius Ng

Kenneth R Cyr

Alec C Robinson

Charles D Lueck

Stephen (Hsiao Li

Dong-Seok Youm

Karen L Walker

Hsiao Yi Li

Shiu Wai Kam

Paul M Look

Jeffrey Scott Hayes

Fuk Ho Ng

David (Shiu Kam

Maria Bh Gill

David (Shiu) W Kam

A data processing device is provided with an indexed-immediate addressing mode for processing streams of data. An instruction registerreceives an instruction for execution. Decoding circuitryselects a register specified by a field in an instruction to provide an index value. An immediate field from the instruction is combined with the index value by multiplexorto form an address which can be used to access a data value or to form a target address for a branch instruction. Mux controlparses the immediate value to determine how to combine the immediate value and the index value.

Data processing device with an indexed immediate addressing mode

A data processing device uses a portion of a random access memory as an input buffer for holding a portion of a stream of data which is being processed by a processing unit within the processing device. Various break-point source tasksdetermine discontinuities in the portion of data stored in the input buffer and a sorted list of the addresses of the discontinuities is maintained in breakpoint queue. Since the buffer is managed in a FIFO manner, a single breakpoint registeris sufficient to monitor addresses as they are provided by an address registerfor accessing the random access memory. When a breakpoint is detected, the breakpoint queue and the breakpoint register is updated by an update task

Input/output buffer managed by sorted breakpoint hardware/software

According to the present invention, there is developed a proprietary technology for compressing the window tables of audio coders to &frac18; their original size (or less) without any loss of quality. This technology can be applied to all transform based audio coders, or any audio coder that uses a windowing stage. The novel technique for reducing storage requirements for the window tables of audio coders is based on multiple differentiation. Since the difference between any two adjacent samples in the first difference signal is small, so it is more efficient to store this difference. This technique can be carried out several more times, until the returns get smaller, and the computational requirements to &ldquo;undo&rdquo; the compression go up. The optimum number of times to differentiate is dependent on the particular application and the window shape.

TI window compression/expansion method

A method for performing audible fast-forward or reverse of audio content represented in a compressed format, such as, but not limited to, MPEG-1 Layer 3 (MP3) or MPEG-2 Advance Audio Coding (AAC) employs a fast-forward controller which performs fast-forward or reverse by repeatedly skipping forward or reverse in the compressed audio data stream, retrieving a block of data, and then splicing these data blocks back together. A decoder is then used to decode each of these blocks, to detect when a block switch has occurred (a splice in the data stream), and to quickly resynchronize at each transition. Hierarchical or multiplexed data streams may be decoded using a cascade of decoders each employing this technique. The decoder uses a robust sync search for performing resynchronization and error recovery.

Method and apparatus for audible fast-forward or reverse of compressed audio content

A data processing device uses a portion of a random access memory as an output buffer for holding a frame of PCM sample data which is being output after being processed by a processing unit within the processing device. Fine grained synchronization between a reference clock and a stream of PCM data frames is provided by transferring only a portion of selected frame of PCM sample data PCM(n&plus;1), in response to a time difference,A breakpoint address is determined to delineate the portion of the selected frame that is to be transferred. A sorted list of the addresses of the discontinuities is maintained in breakpoint queue. Since the buffer is managed in a FIFO manner, a single breakpoint register is sufficient to monitor addresses as they are provided by an address register for accessing the random access memory. When a breakpoint is detected, the breakpoint queue and the breakpoint register is updated by an update task

Fine-grained synchronization of a decompressed audio stream by skipping or repeating a variable number of samples from a frame

A data processing device is provided with an indexed-immediate addressing mode for processing streams of data. An instruction register,receives an instruction for execution. Decoding circuitry,selects a register specified by a field in an instruction to provide an index value. An immediate field from the instruction is combined with the index value by multiplexor,to form an address which can be used to access a data value or to form a target address for a branch instruction. Mux control,parses the immediate value to determine how to combine the immediate value and the index value.

A data processing device is provided which has multiprocessors that can be configured on a cycle by cycle basis as loosely coupled or tightly coupled. Bit-stream Processing Unit (BPU),executes instructions from ROM,and accesses data from RAM,. Similarly, Arithmetic Unit (AU),executes instructions from ROM,and accesses data from RAM,. Both processor operate in parallel and exchange data by accessing RAM,. AU,can receive an instruction directive from BPU,directing it to perform a selected sequence of instructions in a loosely coupled manner. AU,can also receive an instruction directive from BPU,directing that a portion of AU,operationally replace a portion of BPU,for the duration of one instruction which allows data to be passed directly between the processors in a tightly coupled manner.

Microprocessor with functional units that can be selectively coupled

A data processing device uses a portion of a random access memory as an input buffer for holding a portion of a stream of data which is being processed by a processing unit within the processing device. Various break-point source tasks,determine discontinuities in the portion of data stored in the input buffer and a sorted list of the addresses of the discontinuities is maintained in breakpoint queue,. Since the buffer is managed in a FIFO manner, a single breakpoint register,is sufficient to monitor addresses as they are provided by an address register,for accessing the random access memory. When a breakpoint is detected, the breakpoint queue and the breakpoint register is updated by an update task

A method for encoding a digital audio signal includes filtering a portion of the digital audio signal into a first number of frequency ranges to produce a respective first number of filtered signals and performing a discrete frequency analysis on each of the first number of filtered signals to produce a frequency representation of the digital audio signal. The method also includes generating a psychoacoustic representation of the portion of the digital audio signal based on the frequency representation of the digital audio signal and formatting the first number of filtered signals based on the psychoacoustic representation of the portion of the digital audio signal to produce a digitally-compressed encoded bit stream representing the portion of the digital audio signal.

Method and system for encoding a digital audio signal

A data processing device is programmed to decode and transform a stream of data representing a plurality of subband encoded channels of audio data into one or more channels of PCM encoded data for reproduction by a speaker subsystem. An improved method for decoding and transforming utilizes downmix matrices (1021 and 1022) to form downmixed frequency domain channels in buffers (1031-1034). Only two long DCT transform operations (1041 and 1042) and two short DCT transform operations (1043 and 1044) are needed to transform the downmixed frequency domain channels into a left PCM output (1071) and a right PCM output (1072).

Method and apparatus for downmixing decoded data streams in the

A data processing device 100 uses a portion of a random access memory 111 as an input buffer for holding a portion of a stream of data which is received by an input interface 130. Likewise, a portion of a memory 121 is used as an output buffer for holding a portion of processed data which is output by an output interface 140. A processing unit 110 within the processing device manages the flow of input and output data. The input interface asserts an I/O request 860 when it receives a data word, and the output interface asserts an I/O request 870 when it needs a data word. In response to an I/O request, fast interrupt circuitry inserts a ghost instruction which is formed by doppelganger circuitry into an instruction sequence which is being accessed from a ROM 112. The ghost instruction performs the requested data transfer.

Method and apparatus for providing fast interrupt response using a ghost

A data processing device uses a portion of a random access memory as an input buffer 114 for holding a portion of a stream of data which is being processed by a processing unit within the processing device. A Get Bit-Field instruction is provided which directs the processing unit to extract selected bit fields from the data stream stored in the input buffer. A register R6 holds a bit address which points to the end of a selected bit field, while a register R0 holds the width of the selected bit field. An address register is connected to a register R6 in a manner that allows data words to be accessed in input buffer 114 using only a word portion of the bit address. A funnel shifter 203 is disposed to extract the selected bit field from concatenated data words in response to a bit address portion of the bit address in register R6.

Device and method for extracting a bit field from a stream of data

A data processing system (10) is disclosed which comprises a microprocessor host (12) coupled to a decoding system (14). A host interface block (18) receives a bit stream and passes bit stream on to a system decoder block (20). The system decoder block (20) extracts the appropriate data from the bit stream and loads an input buffer (24) or an optional external buffer (26). An audio decoder block (28) retrieves the data from the input buffer (24) and generates scale factor indices, bit per code word values and subband samples which are stored in an arithmetic unit buffer (30). A hardware filter arithmetic unit block (32) retrieves the information from the arithmetic unit buffer (30) and dequantizes, transforms and filters the data to generate PCM output data which is loaded into a PCM buffer (34). The data within the PCM buffer (34) is output by a PCM output block (36) to a digital-to-analog converter (16).

Method for processing a subband encoded audio data stream

A data processing system (10) uses a microprocessor host (12) coupled to a decoding system (14). A hardware filter arithmetic unit block (32) retrieves decoded information from the arithmetic unit buffer (30) and dequantizes, transforms and filters the data to generate PCM output data which is loaded into a PCM buffer (34). An address circuit forms several addresses from a single value to accesses multiple sources of data and coefficients simultaneously for use by the hardware filter arithmetic unit.

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Dallas, TX, United States of America

Jonathan L Rowlands