Patent ID: 7412381

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 or 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 quantization processes each comprise a pulse code modulation scheme which selects said corresponding quantized data values from a single predetermined set of scalar quantization values, wherein said first data value based on the source signal and said second data value based on the source signal are equal to a common scalar value representative of a portion of said source signal, wherein said first quantized data value is selected from said set of scalar quantization values as an approximation to said common scalar value, and wherein said second quantized data value is selected as a neighboring value in said set of quantization values to said first quantized data value when said common scalar value is closer to an average of said first quantized data value and said neighboring value than to any value in said set of quantization values.