PARAMETER DECODING DEVICE, PARAMETER ENCODING DEVICE, AND PARAMETER DECODING METHOD

• US 20100057447A1
• Filed: 11/09/2007
• Published: 03/04/2010
• Est. Priority Date: 11/10/2006
• Status: Active Grant

• Current Assignee: III Holdings 12, LLC (Intellectual Ventures LLC)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Ehara, Hiroyuki
• Granted Patent: US 8,468,015 B2
• Time in Patent Office: Days
• US Class Current: 704/219
• CPC Class Codes: G10L 19/005 Correction of errors induced by the transmission channel, if related to the coding algorithm
• CPC Class Codes: G10L 19/04 using predictive techniques
• CPC Class Codes: G10L 19/07 Line spectrum pair [LSP] vocoders
• CPC Class Codes: G10L 19/12 the excitation function being a code excitation, e.g. in code excited linear prediction [CELP] vocoders

Abstract

Provided is a parameter decoding device which performs parameter compensation process so as to suppress degradation of a main observation quality in a prediction quantization. The parameter decoding device includes amplifiers (305-1 to 305-M) which multiply inputted quantization prediction residual vectors x_n−1 to x_n-M by a weighting coefficient β₁ to β_M. The amplifier (306) multiplies the preceding frame decoding LSF vector y_n−1 by the weighting coefficients β₋₁. The amplifier (307) multiplies the code vector x_n+1 outputted from a codebook (301) by the weighting coefficients β₀. An adder (308) calculates the total of the vectors outputted from the amplifiers (305-1 to 305-M), the amplifier (306), and the amplifier (307). A selector switch (309) selects the vector outputted from the adder (308) if the frame erasure coding B_n of the current frame indicates that ‘the n-th frame is an erased frame’ and the frame erasure coding B_n+1 of the next frame indicates that ‘the n+1-th frame is a normal frame’.

Claims

1. A parameter decoding apparatus comprising:

a prediction residue decoding section that finds a quantized prediction residue based on encoded information included in a current frame subject to decoding; and

a parameter decoding section that decodes a parameter based on said quantized prediction residue,

wherein said prediction residue decoding section, when said current frame is erased, finds a current-frame quantized prediction residue from a weighted linear sum of a parameter decoded in the past and a future-frame quantized prediction residue.

2. The parameter decoding apparatus according to claim 1, wherein said prediction residue decoding section, when said current frame is erased, finds a current-frame quantized prediction residue so that a sum total of a distance between a past-frame decoded parameter and a current-frame decoded parameter and a distance between a current-frame decoded parameter and a future-frame decoded parameter becomes a minimum.

3. The parameter decoding apparatus according to claim 1, wherein said prediction residue decoding section stores a plurality of sets of weighting coefficients, and when said current frame is erased, selects a weighting coefficient set based on a directive from a communicating party, and multiplies said weighting coefficient set upon said parameter decoded in the past and said future-frame quantized prediction residue.

4. The parameter decoding apparatus according to claim 1, wherein said prediction residue decoding section, when said current frame is erased, finds a current-frame quantized prediction residue from a weighted linear sum of a parameter decoded in the past, a past-frame quantized prediction residue, and a future-frame quantized prediction residue.

5. A parameter encoding apparatus comprising:

an analysis section that analyzes an input signal and finds an analysis parameter;

an encoding section that predicts said analysis parameter using a predictive coefficient, and obtains a quantized parameter using a quantized prediction residue obtained by quantizing a prediction residue and said predictive coefficient;

a preceding-frame concealment section that stores a plurality of sets of weighting coefficients, finds a weighted sum using said weighting coefficient sets for said quantized prediction residue of a current frame, said quantized prediction residue of two frames back, and said quantized parameter of two frames back, and finds a plurality of said quantized parameters of one frame back using said weighted sum; and

a determination section that compares a plurality of said quantized parameters of said one frame back found by said preceding-frame concealment section and said analysis parameter found by said analysis section one frame back, selects one of said quantized parameters of said one frame back, and selects and encodes a weighting coefficient set corresponding to selected said quantized parameter of said one frame back.

6. A parameter decoding method comprising:

a prediction residue decoding step of finding a quantized prediction residue based on encoding information included in a current frame subject to decoding; and

a parameter decoding step of decoding a parameter based on said quantized prediction residue,

wherein, in said prediction residue decoding step, when said current frame is erased, a current-frame quantized prediction residue is found from a weighted linear sum of a parameter decoded in the past and a future-frame quantized prediction residue.

7. The parameter decoding method according to claim 6, wherein, in said prediction residue decoding step, when said current frame is erased, a current-frame quantized prediction residue is found so that a sum total of a distance between a past-frame decoded parameter and a current-frame decoded parameter and a distance between a current-frame decoded parameter and a future-frame decoded parameter becomes a minimum.