Audio Encoder and Decoder
First Claim
1. Audio coding system comprising:
- a linear prediction unit for filtering an input signal based on an adaptive filter;
a transformation unit for transforming a frame of the filtered input signal into a transform domain; and
a quantization unit for quantizing the transform domain signal;
wherein the quantization unit decides, based on input signal characteristics to encode the transform domain signal with a model-based quantizer or a non-model-based quantizer.
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Abstract
The present invention teaches a new audio coding system that can code both general audio and speech signals well at low bit rates. A proposed audio coding system comprises linear prediction unit for filtering an input signal based on an adaptive filter; a transformation unit for transforming a frame of the filtered input signal into a transform domain; and a quantization unit for quantizing the transform domain signal. The quantization unit decides, based on input signal characteristics, to encode the transform domain signal with a model-based quantizer or a non-model-based quantizer. Preferably, the decision is based on the frame size applied by the transformation unit.
9 Citations
23 Claims
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1. Audio coding system comprising:
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a linear prediction unit for filtering an input signal based on an adaptive filter; a transformation unit for transforming a frame of the filtered input signal into a transform domain; and a quantization unit for quantizing the transform domain signal; wherein the quantization unit decides, based on input signal characteristics to encode the transform domain signal with a model-based quantizer or a non-model-based quantizer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. Audio decoder comprising:
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a model-based de-quantization unit for de-quantizing a frame of an input bitstream; an inverse transformation unit for inversely transforming a transform domain signal; and a linear prediction unit for filtering the inversely transformed transform domain signal; wherein the de-quantization unit comprises a non-model based and a model based de-quantizer. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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23. Audio decoding method comprising the steps:
de-quantizing a frame of an input bitstream; inversely transforming a transform domain signal; and linear prediction filtering the inversely transformed transform domain signal; wherein the de-quantization is using a non-model and a model-based quantizer.
Specification