Abstract:
PROBLEM TO BE SOLVED: To provide an improved method and apparatus for allowing efficient coding of a plurality of pulse position tracks. SOLUTION: A speech coder takes advantage of the fact that any given pulse combination can be uniquely described by the following four properties: number of degenerate pulses, signs of pulses, positions of pulses, and pulse magnitudes. In accordance with the invention, a four-stage iterative classification of the pulse combinations, where each stage groups the pulse combinations by one of these four properties, is performed. The process starts with the number of pulses and then determines the total number of possible sign combinations, pulse position combinations, and pulse magnitude combinations. COPYRIGHT: (C)2011,JPO&INPIT
Abstract:
Un sistema para la codificacion o la decodificacion de baja velocidad que incluye el uso de un indicador de modo en la señal codificada para indicar si se está enviando informacion de precuantificador (es decir, gruesa) o de cuantificador (es decir, fina). En una modalidad de transmisor (300) se efectua la busqueda de las palabras codigo de precuantificador ("P") y de cuantificador ("V") tanto de un precuantificador (212) como de un cuantificador restringido (214), respectivamente, para determinar las palabras codigo con la menor energía residual. (El índice de la palabra codigo P o V con el menor residuo se determina entonces (220) y, este índice se transmite junto con un indicador de modo P o V apropiado. En una modalidad de receptor (330), el indicador de modo se utiliza para ajustar al decodificador (por ejemplo, un vocodificador) (350) para formar una replica de señal de una palabra codigo P (determinada del índice transmitido) o, de una palabra codigo V (del índice V transmitido) y la palabra codigo P previamente determinada (por ejemplo, el centroide de la palabra codigo V).
Abstract:
A method and system for providing split vector quantization for use in determining constrained ordered set values, such as line spectrum pair parameters to determine spectral parameters in a data compression system, utilizes multiple codebooks (22a-22c) containing delta coded constrained ordered set values that are normalized to an upper and lower bound. An LSP reconstructor (34) reconstructs received spectral parameters to decode data, such as speech, based on the normalized delta quantization data of line spectrum pair parameters obtained from the split vector reconstruction codebooks (22a-22c). The LSP reconstructor (34) dynamically generates line spectrum pair parameters based on the normalized delta quantization data. In another embodiment, instead of storing the absolute value of the line spectrum pair parameters in segmented codebooks, the combination of at least two absolute value vectors and at least one normalized delta quantization vector is used for spectral quantization.
Abstract:
To achieve high quality speech reconstruction at low bit rates, constraints on position combinations among two or more pulses (403) are implemented. By placing constraints on position combinations, certain combinations of pulses are prohibited which allows the most significant pulses to always be coded, thereby improving speech quality. After all valid combinations are considered, a list of pulse pairs (codebook) which can be indexed using a single, predetermined bit length codeword is produced. The codeword is transmitted to a destination where it is used by a decoder to reconstruct the original information signal.
Abstract:
A system for low rate coding or decoding includes the use of a mode indicator in the coded signal to indicate whether prequantizer (i.e., coarse) or quantizer (i.e., fine) information is being sent. In a transmitter (300) embodiment both a prequantizer (212) and a restricted quantizer (214) search is performed of predefined prequantizer ("P") and quantizer ("V") codewords, respectively, to determine the codewords with the least residual energy. The index of the P or V codeword with the least residual is then determined (220), and this index is transmitted along with an appropriate P or V mode indicator. In a receiver (330) embodiment, the mode indicator is used to set the decoder (e.g., a vocoder) (350) to form a signal replica from a P codeword (determined from the transmitted index), or from a V codeword (from the transmitted V index) and previously determined P codeword (e.g., the centroid of the V codeword).