Patent ID: 7756705

Claim:
A multi-descriptive encoder for generating a plurality of multi-descriptive bit streams from a single source signal, the encoder comprising: a source signal input port for supplying the source signal; a first coder applied to the source signal input port, the first coder for generating a first multi-descriptive bit stream from the source signal, the first coder employing a first coding algorithm which includes a first quantization process in which a first data value based on the source signal is coded with use of a corresponding first quantized data value, thereby resulting in a corresponding first quantization error representative of a difference between said first data value and said first quantized data value; and a second coder applied to the source signal input port, the second coder for generating a second multi-descriptive bit stream from the source signal, the second coder employing a second coding algorithm which includes a second quantization process in which a second data value, based on the source signal and corresponding to said first data value, is coded with use of a corresponding second quantized data value, thereby resulting in a corresponding second quantization error representative of a difference between said second data value and said second quantized data value, wherein said second quantized data value as produced by said second quantization process is based at least in part on said first quantization error resulting from said first quantization process, wherein said first quantization process and said second quantization process each select said corresponding quantized data values from a single predetermined set of quantization values, and wherein said first and second coding algorithms each comprise a code excited linear predictive coding scheme, wherein said first and second quantization processes select said corresponding quantized data values from a single predetermined set of excitation vectors, and wherein said second quantization process selects a different excitation vector than said first quantization process.