Abstract: A multiple description (MD) joint source-channel (JSC) encoder in accordance with the invention encodes n components of an image signal for transmission over m channels of a communication medium. In an illustrative embodiment which uses statistical redundancy between the different descriptions of the image signal, the encoder forms vectors from transform coefficients of the image signal separated both in frequency and in space. The vectors may be formed such that the spatial separation between the transform coefficients is maximized. A correlating transform is then applied, followed by entropy coding, grouping as a function of frequency, and application of a cascade transform. In an illustrative embodiment which uses deterministic redundancy between the different descriptions of the image signal, the encoder may apply a linear transform, followed by quantization, to generate the multiple descriptions of the image signal.

Abstract: A multiple description (MD) joint source-channel (JSC) encoder in accordance with the invention encodes n components of a signal for transmission over m channels of a communication medium. In illustrative embodiments, the invention provides optimal or near-optimal transforms for applications in which at least one of n and m is greater than two, and applications in which the failure probabilities of the m channels are non-independent and non-equivalent. The signal to be encoded may be a data signal, a speech signal, an audio signal, an image signal, a video signal or other type of signal, and each of the m channels may correspond to a packet or a group of packets to be transmitted over the medium. A given n×m transform implemented by the MD JSC encoder may be in the form of a cascade structure of several transforms each having dimension less than n×m. The transform may also be configured to provide a substantially equivalent rate for each of the m channels.

Abstract: A multiple description (MD) joint source-channel (JSC) encoder in accordance with the invention encodes n components of an image signal for transmission over m channels of a communication medium. In an illustrative embodiment which uses statistical redundancy between the different descriptions of the image signal, the encoder forms vectors from transform coefficients of the image signal separated both in frequency and in space. The vectors may be formed such that the spatial separation between the transform coefficients is maximized. A correlating transform is then applied, followed by entropy coding, grouping as a function of frequency, and application of a cascade transform. In an illustrative embodiment which uses deterministic redundancy between the different descriptions of the image signal, the encoder may apply a linear transform, followed by quantization, to generate the multiple descriptions of the image signal.

Abstract: A multiple description (MD) joint source-channel (JSC) encoder in accordance with the invention encodes n components of an audio signal for transmission over m channels of a communication medium, where n and m may take on any desired values. In an illustrative embodiment, the encoder combines a multiple description transform coder with elements of a perceptual audio coder (PAC). The encoder is configured to select one or more transform parameters for a multiple description transform, based on a characteristic of the audio signal to be encoded. For example, the transform parameters may be selected such that the resulting transformed coefficients have a variance distribution of a type expected by a subsequent entropy coding operation. The components of the audio signal may be quantized coefficients separated into a number of factor bands, and the transform parameter for a given factor band may be set to a value determined based on a transform parameter from at least one other factor band, e.g.

Abstract: Transform encoding techniques are disclosed which permit reductions in entropy coding memory requirements. In an illustrative embodiment, a selected discrete linear transform is applied to a discrete-valued version of an information signal to be encoded. The transform is selected such that it produces a transformed output that can be entropy coded using a reduced codeword memory without a substantial increase in entropy coding rate. The entropy coding may be, for example, scalar entropy coding which independently codes each of the components of the transformed discrete-valued version of the information signal, using a single entropy codebook for all of the components to be encoded.