Texas Instruments Corporation

Pankaj Rabha

Murali Mohan Deshpande

Chanaveeragouda Virupaxagouda Goudar

Ajit Venkat Rao

An electronic circuit () including a processor circuit () and a storage circuit establishing a speech coder () for execution by said processor (), the speech coder () for approximating speech by pulses having pulse positions selectable from a codebook (), the speech coder () operable to obtain () a set of estimated pulse positions having a first number of pulse tracks of the estimated pulse positions, use () a cost function (epsilon tilde {tilde over (&#x3b5;)}) relating to approximation to speech to find a first subset including a second number of one or more pulse tracks fewer in number than the first number wherein the first subset of pulse tracks contributed a lower contribution to the cost function relative to a second subset of pulse tracks, and control () a subsequent pulse position search beginning with the lower-contributing subset of pulse tracks to yield pulse positions to provide a value of the cost function representing a better approximation to speech. Other forms of the invention involve systems, circuits, devices, processes and processes of operation, as disclosed and claimed.

Methods, devices and systems for improved codebook search for voice codecs

An electronic circuit includes a storage circuit and a microprocessor operable together with the storage circuit as a speech coder. The speech coder has a backward pitch enhancement in frames or subframes having a length and at least one main pulse and at least one backward pitch enhancement pulse preceding the main pulse by a portion of the length called a pitch lag, and is operable to limit in number any such backward pitch enhancement pulse or pulses to a predetermined maximum number more than none upon an occurrence when the length divided by the pitch lag is at least one more than that maximum number. Other forms of the invention involve systems, circuits, devices, processes and methods of operation.

Methods, devices and systems for improved pitch enhancement and autocorrelation in voice codecs

According to an aspect of the present invention two streams data encoding corresponding information contained in a multimedia signal are generated with one bitstream ('first stream') providing for reproduction of the information with a base quality (e.g., according to a corresponding standard), and the second bitstream ('second stream') containing information which can be used to further enhance the quality of reproduction.

Codecs providing multiple bit streams

Transcoding from EVRC to G.729ab with LSP parameters interpolated from EVRC to G.729ab, EVRC pitch used as input to G.729ab closed-loop pitch search, and G.729ab fixed codebook pulses found from a search limited to positions of EVRC fixed codebook pulses together with positions of target-impulse correlation maxima on the subframe tracks or full track search if no EVRC pulses.

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Bengaluru, India

Pankaj Rabha