APPARATUS AND METHOD FOR ENCODING/DECODING FOR HIGH FREQUENCY BANDWIDTH EXTENSION

• US 20130282368A1
• Filed: 12/28/2011
• Published: 10/24/2013
• Est. Priority Date: 09/15/2010
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Choo, Ki-hyun, Oh, Eun-mi, Sung, Ho-sang
• Granted Patent: US 10,152,983 B2
• Time in Patent Office: Days
• US Class Current: 704/219
• CPC Class Codes: G10L 19/00 Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis in musical instruments G10H
• CPC Class Codes: G10L 19/038 Vector quantisation, e.g. TwinVQ audio
• CPC Class Codes: G10L 19/12 the excitation function being a code excitation, e.g. in code excited linear prediction [CELP] vocoders
• CPC Class Codes: G10L 19/24 Variable rate codecs, e.g. for generating different qualities using a scalable representation such as hierarchical encoding or layered encoding
• CPC Class Codes: G10L 21/038 using band spreading techniques

Abstract

A method and apparatus for performing coding and decoding for high-frequency bandwidth extension. The coding apparatus may down-sample an input signal, perform core coding on the down-sampled input signal, perform frequency transformation on the input signal, and perform bandwidth extension coding by using a base signal of the input signal in a frequency domain.

Claims

1-43. -43. (canceled)

44. A coding apparatus comprising:

a signal classification unit configured to determine a coding mode of an input signal, based on characteristics of the input signal;

a code excited linear prediction (CELP) coder configured to perform CELP coding on a low-frequency signal of the input signal when a coding mode of the input signal is determined to be a CELP coding mode;

a time-domain (TD) extension coder configured to perform extension coding on a high-frequency signal of the input signal when CELP coding is performed on the low-frequency signal of the input signal;

a frequency transformer configured to perform frequency transformation on the input signal when the coding mode of the input signal is determined as to be a frequency-domain (FD) mode; and

an FD coder configured to perform FD coding on the transformed input signal.

45. The coding apparatus of claim 44, wherein the FD coder comprises:

a normalization coder configured to extract energy from the transformed input signal for each frequency band and further configured to quantize the extracted energy;

a factorial pulse coder configured to perform factorial pulse coding (FPC) on a value obtained by scaling the transformed input signal by using a quantized normalization value; and

an additional noise information generator configured generate additional noise information according to performing of the FPC,

wherein the transformed input signal input to the FD coder is a transient frame.

46. The coding apparatus of claim 44, wherein the FD coder comprises:

a normalization coder configured to extract energy from the transformed input signal for each frequency band and further configured to quantize the extracted energy;

a factorial pulse coder configured to perform factorial pulse coding (FPC) on a value obtained by scaling the transformed input signal by using a quantized normalization value;

an additional noise information generator configured generate additional noise information according to performing of the FPC; and

an FD extension coder configured to perform extension coding on a high-frequency signal of the transformed input signal,

wherein the transformed input signal input to the FD coder is a stationary frame.

47. The coding apparatus of claim 46, wherein the FD extension coder is further configured to perform energy quantization by using a same codebook at different bitrates.

48. The coding apparatus of claim 44, wherein a bitstream according to a result of performing the FD coding on the transformed input signal includes previous frame mode information.

49. A coding apparatus comprising:

a signal classification unit configured to determine a coding mode of an input signal, based on characteristics of the input signal;

a linear prediction coefficient (LPC) coder configured to extract an LPC from a low-frequency signal of the input signal, and further configured to quantize the LPC;

a code excited linear prediction (CELP) coder configured to perform CELP coding on an LPC excitation signal of a low-frequency signal of the input signal extracted using the LPC when a coding mode of the input signal is determined to be a CELP coding mode;

a time-domain (TD) extension coder configured to perform extension coding on a high-frequency signal of the input signal when CELP coding is performed on the LPC excitation signal;

an audio coder configured to perform audio coding on the LPC excitation signal when a coding mode of the input signal is determined to be an audio mode; and

an FD extension coder configured to perform extension coding on the high-frequency signal of the input signal when audio coding is performed on the LPC excitation signal.

50. The coding apparatus of claim 49, wherein the FD extension coder is further configured to perform energy quantization by using a same codebook at different bitrates.

51. A decoding apparatus comprising:

a mode information checking unit for configured to check mode information of each of frames included in a bitstream;

a code excited linear prediction (CELP) decoder configured to perform CELP decoding on a CELP coded frame, based on a result of the checking;

a time-domain (TD) extension decoder configured generate a decoded signal of a high-frequency band by using at least one of a result of performing the CELP decoding and an excitation signal of a low-frequency signal;

a frequency-domain (FD) decoder configured to perform FD decoding on an FD coded frame, based on the result of the checking; and

an inverse frequency transformer configured to perform inverse frequency transformation on a result of performing the FD decoding.

52. The decoding apparatus of claim 51, wherein the FD decoder comprises:

a normalization decoder configured to perform normalization decoding, based on normalization information included in the bitstream;

a factorial pulse coding (FPC) decoder configured to perform FPC decoding, based on factorial pulse coding information included in the bitstream; and

a noise filling performing unit configured to perform noise filling on a result of performing the FPC decoding.

53. The decoding apparatus of claim 51, wherein the FD decoder comprises:

a normalization decoder configured to perform normalization decoding, based on normalization information included in the bitstream;

a factorial pulse coding (FPC) decoder configured to perform FPC decoding, based on factorial pulse coding information included in the bitstream;

a noise filling performing unit configured to perform noise filling on a result of performing the FPC decoding; and

an FD high-frequency extension decoder configured to perform high-frequency extension decoding, based on the result of performing FPC decoding and a result of performing the noise filling.

54. The decoding apparatus of claim 52, wherein the FD decoder further comprises an FD low-frequency extension coder configured to perform extension coding on the result of performing the FPC decoding and the noise filling when an upper band value of a frequency band performing FPC decoding is less than an upper band value of a frequency band of a core signal.

55. The decoding apparatus of claim 52, wherein the FD high-frequency extension decoder is further configured to perform inverse quantization of energy by sharing a same codebook at different bitrates.

56. The decoding apparatus of claim 51, wherein the FD decoder is further configured to perform FD decoding on an FD coded frame, based on previous frame mode information included in the bitstream.

57. A decoding apparatus comprising:

a mode information checking unit configured to check mode information of each of a plurality of frames included in a bitstream;

a linear prediction coefficient (LPC) decoder configured to perform LPC decoding on the plurality of frames included in the bitstream;

a code excited linear prediction (CELP) decoder configured to perform CELP decoding on a CELP coded frame, based on a result of the checking;

a time-domain (TD) extension decoder configured to generate a decoded signal of a high-frequency band by using at least one of a result of performing the CELP decoding and an excitation signal of a low-frequency signal;

an audio decoder configured to perform audio decoding on an audio coded frame, based on the result of the checking; and

a frequency-domain (FD) extension decoder configured to perform extension decoding by using a result of performing the audio decoding.

58. The decoding apparatus of claim 57, wherein the FD extension decoder is further configured to perform inverse quantization of energy by sharing a same codebook at different bitrates.

59-101. -101. (canceled)

102. A coding method comprising:

determining a coding mode of an input signal, based on characteristics of the input signal;

performing code excited linear prediction (CELP) coding on a low-frequency signal of the input signal when a coding mode of the input signal is determined to be a CELP coding mode;

performing time-domain (TD) extension coding on a high-frequency signal of the input signal when CELP coding is performed on the low-frequency signal of the input signal;

performing frequency transformation on the input signal when the coding mode of the input signal is determined to be a frequency-domain (FD) mode; and

performing FD coding on the transformed input signal.

103. The coding method of claim 102, wherein the performing of the FD coding comprises performing energy quantization by sharing a same codebook at different bitrates.

104. The coding method of claim 102, wherein a bitstream according to a result of performing the FD coding on the transformed input signal includes previous frame mode information.

112. A non-transitory computer readable recording medium having recorded thereon a computer program for executing the method of claim 102.

113. The coding method of claim 102, wherein the performing of the TD coding comprises:

extracting energy from the input signal;

controlling the extracted energy; and

quantizing the controlled energy.

114. The coding method of claim 113, wherein in the extracting of energy, the energy is extracted corresponding to each of frequency bands.

115. The coding method of claim 113, wherein in the controlling of the extracted energy, the energy is controlled by using an energy control factor estimated from the input signal.

116. The coding method of claim 113, wherein in the quantizing of the controlled energy, the energy is vector-quantized by assigning a weight to a low-frequency band of high perceptual importance.

117. The coding method of claim 113, wherein in the quantizing of the controlled energy, the energy is quantized by assigning a larger number of bits to a low-frequency band of high perceptual importance than to a high-frequency band.

105. A coding method comprising:

determining a coding mode of an input signal, based on characteristics of the input signal;

extracting a linear prediction coefficient (LPC) LPC from a low-frequency signal of the input signal, and quantizing the LPC;

performing code excited linear prediction (CELP) coding on an LPC excitation signal of a low-frequency signal of the input signal extracted using the LPC when a coding mode of the input signal is determined as a CELP coding mode;

performing time-domain (TD) extension coding on a high-frequency signal of the input signal when CELP coding is performed on the LPC excitation signal;

performing audio coding on the LPC excitation signal when a coding mode of the input signal is determined as an audio coding mode; and

performing frequency-domain (FD) extension coding on the high-frequency signal of the input signal when audio coding is performed on the LPC excitation signal.

106. The coding method of claim 105, wherein the performing of the FD extension coding comprises performing energy quantization by sharing a same codebook at different bitrates.

118. The coding method of claim 105, wherein the performing of the FD coding comprises:

extracting energy from the input signal;

controlling the extracted energy; and

quantizing the controlled energy.

119. The coding method of claim 118, wherein in the extracting of energy, the energy is extracted corresponding to each of frequency bands.

120. The coding method of claim 118, wherein in the controlling of the extracted energy, the energy is controlled by using an energy control factor estimated from the input signal.

121. The coding method of claim 118, wherein in the quantizing of the controlled energy, the energy is vector-quantized by assigning a weight to a low-frequency band of high perceptual importance.

122. The coding method of claim 118, wherein in the quantizing of the controlled energy, the energy is quantized by assigning a larger number of bits to a low-frequency band of high perceptual importance than to a high-frequency band.

107. A decoding method comprising:

checking mode information of each of a plurality of frames included in a bitstream;

performing code excited linear prediction (CELP) decoding on a CELP coded frame, based on a result of the checking;

generating a decoded signal of a high-frequency band by using at least one of a result of performing the CELP decoding and an excitation signal of a low-frequency signal;

performing frequency-domain (FD) decoding an FD coded frame, based on the result of the checking; and

performing inverse frequency transformation on a result of performing the FD decoding.

108. The decoding method of claim 107, wherein the performing of the FD decoding comprises performing inverse quantization of energy by sharing a same codebook at different bitrates.

109. The decoding method of claim 107, wherein the performing of the FD decoding comprises performing the FD decoding on an FD coded frame, based on previous frame mode information included in the bitstream.

110. A decoding method comprising:

checking mode information of each of a plurality of frames included in a bitstream;

performing linear prediction coefficient (LPC) decoding on the plurality of frames included in the bitstream;

performing code excited linear prediction (CELP) decoding on a CELP coded frame, based on a result of the checking;

generating a decoded signal of a high-frequency band by using at least one of a result of performing the CELP decoding and an excitation signal of a low-frequency signal;

performing audio decoding on an audio coded frame, based on the result of the checking; and

performing frequency-domain (FD) extension decoding by using a result of performing the audio decoding.

111. The decoding method of claim 110, wherein the performing of the FD extension decoding comprises performing inverse quantization of energy by sharing a same codebook at different bitrates.