Apparatus and method for generating an output audio data signal
First Claim
1. An apparatus for generating an output audio data signal, the apparatus comprising:
- a receiving device for receiving an input encoded audio data signal comprising a plurality of encoding layers including a base layer and a plurality of enhancement layers;
a reference unit for generating reference audio data from a reference set of layers of the plurality of encoding layers;
a sampling device for generating sample audio data from a set of layers smaller than the reference set of layers;
a comparison processor for comparing the sample audio data to the reference audio data, the comparison reflecting a difference between a first decoded signal corresponding to the sample audio data and a second decoded signal corresponding to the reference audio data;
an output device for determining whether the comparison meets a criterion andif so, generating the output audio data signal to not include audio data from a first layer, the first layer being a layer of the reference set not included in the smaller set of layers;
and otherwise, generating the output audio data signal to include audio data from the first wherein the comparison is based on a perceptual model,wherein the comparison processor is configured to;
generate a first perceptual indication by applying the perceptual model to the reference audio data; and
generate a second perceptual indication by applying the perceptual model to the sample audio data; and
the output device is arranged to determine whether the comparison meets the criterion in response to a comparison of the first perceptual indication and the second perceptual indication,wherein the perceptual model is configured to;
determine an energy measure for each of a plurality of critical bands;
apply a loudness compensation to the energy measure of each of the plurality of critical bands to generate a perceptual indication comprising loudness compensated energy measures for each of the critical bands; and
the output device is further arranged to determine whether the comparison meets the criterion in response to a comparison of the loudness compensated energy measures for each of the critical bands for the reference audio data and the sample audio data.
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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.
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Citations
13 Claims
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1. An apparatus for generating an output audio data signal, the apparatus comprising:
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a receiving device for receiving an input encoded audio data signal comprising a plurality of encoding layers including a base layer and a plurality of enhancement layers; a reference unit for generating reference audio data from a reference set of layers of the plurality of encoding layers; a sampling device for generating sample audio data from a set of layers smaller than the reference set of layers; a comparison processor for comparing the sample audio data to the reference audio data, the comparison reflecting a difference between a first decoded signal corresponding to the sample audio data and a second decoded signal corresponding to the reference audio data; an output device for determining whether the comparison meets a criterion and if so, generating the output audio data signal to not include audio data from a first layer, the first layer being a layer of the reference set not included in the smaller set of layers; and otherwise, generating the output audio data signal to include audio data from the first wherein the comparison is based on a perceptual model, wherein the comparison processor is configured to; generate a first perceptual indication by applying the perceptual model to the reference audio data; and generate a second perceptual indication by applying the perceptual model to the sample audio data; and the output device is arranged to determine whether the comparison meets the criterion in response to a comparison of the first perceptual indication and the second perceptual indication, wherein the perceptual model is configured to; determine an energy measure for each of a plurality of critical bands; apply a loudness compensation to the energy measure of each of the plurality of critical bands to generate a perceptual indication comprising loudness compensated energy measures for each of the critical bands; and the output device is further arranged to determine whether the comparison meets the criterion in response to a comparison of the loudness compensated energy measures for each of the critical bands for the reference audio data and the sample audio data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A communication system including a network entity which comprises:
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a receiving device for receiving an input encoded audio data signal comprising a plurality of encoding layers including a base layer and a plurality of enhancement layers; a reference unit for generating reference audio data from a reference set of layers of the plurality of encoding layers; a sampling device for generating sample audio data from a set of layers smaller than the reference set of layers; a comparison processor for comparing the sample audio data itself to the reference audio data itself, the comparison reflecting a difference between a first decoded signal corresponding to the sample audio data and a second decoded signal corresponding to the reference audio data; an output device for determining whether the comparison meets a criterion and if so, generating the output audio data signal to not include audio data from a first layer, the first layer being a layer of the reference set not included in the smaller set of layers; and otherwise, generating the output audio data signal to include audio data from the first layer, wherein the comparison is based on a perceptual model, wherein the comparison processor is configured to; generate a first perceptual indication by applying the perceptual model to the reference audio data; generate a second perceptual indication by applying the perceptual model to the sample audio data; and the output device is arranged to determine whether the comparison meets the criterion in response to a comparison of the first perceptual indication and the second perceptual indication, wherein the perceptual model is configured to; determine an energy measure for each of a plurality of critical bands; apply a loudness compensation to the energy measure of each of the plurality of critical bands to generate a perceptual indication comprising loudness compensated energy measures for each of the critical bands; and the output device is further arranged to determine whether the comparison meets the criterion in response to a comparison of the loudness compensated energy measures for each of the critical bands for the reference audio data and the sample audio data. - View Dependent Claims (11, 12)
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13. A method for generating an output audio data signal, the method comprising:
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receiving an input encoded audio data signal comprising a plurality of encoding layers including a base layer and a plurality of enhancement layers; generating reference audio data from a reference set of layers of the plurality of encoding layers; generating sample audio data from a set of layers smaller than the reference set of layers; comparing the sample audio data itself to the reference audio data itself, the comparison reflecting a difference between a first decoded signal corresponding to the sample audio data and a second decoded signal corresponding to the reference audio data; determining whether the comparison meets a criterion and if so, generating the output audio data signal to not include audio data from a first layer, the first layer being a layer of the reference set not included in the smaller set of layers; and otherwise, generating the output audio data signal to include audio data from the first layer, wherein the comparison is based on a perceptual model, wherein the comparison step further comprises; generating a first perceptual indication by applying the perceptual model to the reference audio data; generating a second perceptual indication by applying the perceptual model to the sample audio data; the method further comprising determining whether the comparison meets the criterion in response to a comparison of the first perceptual indication and the second perceptual indication, wherein the perceptual model is configured to; determine an energy measure for each of a plurality of critical bands; and apply a loudness compensation to the energy measure of each of the plurality of critical bands to generate a perceptual indication comprising loudness compensated energy measures for each of the critical bands; and the method further comprises determining whether the comparison meets the criterion in response to a comparison of the loudness compensated energy measures for each of the critical bands for the reference audio data and the sample audio data.
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Specification