Abstract: An apparatus receives an input encoded audio data signal comprising a base layer and at least one enhancement layer. A reference unit (103) generates reference audio data corresponding to audio data of a reference set of layers. A layer unit (105) divides the layers of the input signal into a first subset and a second subset. A sample unit (107) generates sample audio data corresponding to the audio data of the first subset. A comparison unit (109) generates a difference measure by comparing the sample audio data to the reference audio data based on a perceptual model. An output unit (111) then determines if the difference measure meets a similarity criterion and generates an output signal without audio data from a layer of the second subset if the similarity criterion is met and including the audio data of the layer otherwise. The invention may provide reduced data rates without an unacceptable degradation of quality.

Abstract: A communications operating system is provided herein. The communications operating system having a common communication system comprising a radio frequency transceiving means for transmitting and receiving radio frequency signals and a system list means for storing a list of communication systems available. The system also includes a feature list means for storing a list of feature programs, where the feature programs comprise at least one of an enabling program to enable resident functions, a high-level design specification, and an executable feature specification.