Apparatus and method for encoding and decoding multi-channel audio signal
Disclosed is an apparatus for encoding and decoding a multi-channel audio signal. The apparatus for encoding the multi-channel audio signal groups channels of a multi-channel audio signal, eliminates redundant information between channels using a mixing matrix including phase information, converts a frequency of the signal, and encodes the signal.
1. An apparatus encoding a multi-channel audio signal, the apparatus comprising:
a channel grouping unit to group channels based on a channel characteristic of the multi-channel audio signal;
a signal converter to eliminate redundant information between the grouped channels using the mixing matrix and to convert a frequency of the multi-channel audio signal having the grouped channels exclusive of the redundant information to produce a frequency-converted multi-channel audio signal;
a quantization unit to quantize the frequency-converted multi-channel audio signal to produce a quantized multi-channel audio signal; and
an encoder to encode the quantized multi-channel audio signal and the mixing matrix,
wherein the mixing matrix is generated in each group.
2. The apparatus of claim 1 , wherein the channel grouping unit groups channels using a geometric structure of the multi-channel audio signal in each channel.
3. The apparatus of claim 1 , wherein the channel grouping unit groups channels using a similarity between channels of the multi-channel audio signal.
4. The apparatus of claim 1 , wherein the channel grouping unit determines a group criterion using a multi-channel psychoacoustic model.
5. The apparatus of claim 1 , further comprising:
a domain transformer to transform the multi-channel audio signal in each group into a domain expressed by a complex number coefficient; and
a matrix generation unit to generate a mixing matrix eliminating redundant information about the multi-channel audio signal converted into the domain between channels,
wherein the signal converter applies the mixing matrix and converts the frequency of the multi-channel audio signal.
6. The apparatus of claim 5 , wherein the matrix generation unit generates a mixing matrix in each frequency band using a Karhunen-Loeve Transform (KLT).
7. The apparatus of claim 5 , wherein the encoder encodes a coefficient of the mixing matrix separately in a phase and a magnitude.
8. The apparatus of claim 7 , wherein the encoder encodes the phase using a room response expressed by a peak and a slope based on phase information between bands.
9. The apparatus of claim 5 , wherein the domain transformer performs domain transformation using one of a Complex Quadrature Mirror Filter (QMF) and a Modified Discrete Cosine Transform (MDCT) & Modified Discrete Sine Transform (MDST).
10. The apparatus of claim 1 , wherein the quantization unit includes a mixing coefficient in a quantization coefficient and quantizes at a same time.
11. A method of encoding a multi-channel audio signal, the method comprising:
grouping channels based on a channel characteristic of the multi-channel audio signal;
eliminating redundant information between the grouped channels using the mixing matrix and converting a frequency of the multi-channel audio signal having the grouped channels exclusive of the redundant information to produce a frequency-converted multi-channel audio signal;
quantizing the frequency-converted multi-channel audio signal to produce a quantized multi-channel audio signal; and
encoding the quantized multi-channel audio signal and the mixing matrix,
wherein the mixing matrix is generated in each group.
12. The method of claim 11 , wherein the grouping of the channels groups channels using a geometric structure of the multi-channel audio signal in each channel.
13. The method of claim 11 , wherein the grouping of the channels groups channels using a similarity between channels of the multi-channel audio signal.
14. The method of claim 11 , wherein the grouping of the channels determines a group criterion using a multi-channel psychoacoustic model.
15. The method of claim 11 , further comprising:
transforming the multi-channel audio signal in each group into a domain expressed by a complex number coefficient; and
generating a mixing matrix eliminating redundant information about the multi-channel audio signal converted into the domain between channels,
wherein the converting of the frequency of the multi-channel audio signal applies the mixing matrix and converts the frequency of the multi-channel audio signal.
16. The method of claim 15 , wherein the generating of the mixing matrix generates a mixing matrix in each frequency band using a Karhunen-Loeve Transform (KLT).
17. The method of claim 15 , wherein an encoder encodes a coefficient of the mixing matrix separately in a phase and a magnitude.
18. The method of claim 17 , wherein the encoding of the quantized multi-channel audio signal encodes the phase using a room response expressed by a peak and a slope based on phase information between bands.
19. The method of claim 15 , wherein the transforming the multi-channel audio signal in each group into the domain expressed by a complex number coefficient performs domain transformation using one of a Complex Quadrature Mirror Filter (QMF), and a Modified Discrete Cosine Transform (MDCT) & Modified Discrete Sine Transform (MDST).
20. A non-transitory computer-readable medium comprising a program for instructing a computer to perform the method of claim 11 .