Source: http://www.google.com/patents/US8160870?dq=7,603,356
Timestamp: 2015-04-18 12:25:58
Document Index: 355263026

Matched Legal Cases: ['Application No. 2005', 'art 13', 'arts 13', 'art 13', 'art 13', 'art 17', 'arts 13', 'Application No. 10195915']

Patent US8160870 - Method, apparatus, program, and recording medium for long-term prediction ... - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA method and apparatus multiplies a past sample a time lag τ older than a current sample by a quantized multiplier ρ′ on a frame by frame basis, subtracts the multiplication result from the current sample, codes the subtraction result, and codes the time lag using a fixed-length coder if the multiplier...http://www.google.com/patents/US8160870?utm_source=gb-gplus-sharePatent US8160870 - Method, apparatus, program, and recording medium for long-term prediction coding and long-term prediction decodingAdvanced Patent SearchPublication numberUS8160870 B2Publication typeGrantApplication numberUS 13/049,442Publication dateApr 17, 2012Filing dateMar 16, 2011Priority dateJan 12, 2005Also published asCN101091317A, CN101091317B, CN101794579A, CN101996637A, CN101996637B, DE602006020686D1, EP1837997A1, EP1837997A4, EP1837997B1, EP2290824A1, EP2290824B1, US7970605, US20080126083, US20110166854, WO2006075605A1Publication number049442, 13049442, US 8160870 B2, US 8160870B2, US-B2-8160870, US8160870 B2, US8160870B2InventorsTakehiro Moriya, Noboru Harada, Yutaka Kamamoto, Takuya Nishimoto, Shigeki SagayamaOriginal AssigneeNippon Telegraph And Telephone Corporation, The University Of TokyoExport CitationBiBTeX, EndNote, RefManPatent Citations (16), Non-Patent Citations (2), Classifications (8) External Links: USPTO, USPTO Assignment, EspacenetMethod, apparatus, program, and recording medium for long-term prediction coding and long-term prediction decoding
US 8160870 B2Abstract
A method and apparatus multiplies a past sample a time lag τ older than a current sample by a quantized multiplier ρ′ on a frame by frame basis, subtracts the multiplication result from the current sample, codes the subtraction result, and codes the time lag using a fixed-length coder if the multiplier ρ′ is smaller than 0.2 or if information about the previous frame is unavailable, or codes the time lag using a variable-length coder if ρ′ is not smaller than 0.2. A multiplier ρ is coded by a multiplier coder and the multiplier ρ′ obtained by decoding the multiplier ρ is outputted. The process is performed for each frame.
This application is a divisional application of U.S. Ser. No. 11/793,821 filed Jun. 22, 2007, the entire contents of which are incorporated in its entirety herein by reference. U.S. Ser. No. 11/793,821 is a National Stage of PCT JP06/300194 filed Jan. 11, 2006, and claims the benefit of priority under 35 U.S.C. �119 of Japanese Application No. 2005-004915 filed Jan. 12, 2005.
The present invention relates to a method, apparatus, program, and recording medium for coding a time-series speech signal by compressing the signal into a smaller number of bits using long-term prediction coefficients, i.e., a pitch period (time lag) τ and gain ρ, of the time-series signal, and a method, apparatus, program, and recording medium for decoding. More particularly, the present invention relates to a technique for lossless coding.
Coding of telephone speech signals uses the long-term prediction to predict similarity of waveforms among pitch periods. Since it is highly likely that coding of telephone speech signals is used in wireless communications and the like, codes of a fixed length are used for coding of pitch prediction parameters τ and ρ. In lossless coding of audio signals, a method for making predictions using a correlation between efficiency coding apparatus and high efficiency decoding apparatus and again, fixed-length coding is used for coding of a multiplier ρ and time lag parameter τ.
Patent literature: Japanese Patent No. 3218630 DISCLOSURE OF THE INVENTION
In the conventional speech signal coding, long-term prediction coefficients, i.e., a pitch period (time lag) τ and gain (multiplier) ρ, are coded into fixed length codes, and consequently there are limits to improvement of compression efficiency.
A long-term prediction coding method according to the present invention comprises:
Values of auxiliary information such as time lag τ and multiplier ρ used in long-term prediction coding sometimes occur at biased frequencies. In case of such biased occurrence frequencies, the present invention, which variable-length encodes the auxiliary information into variable-length codes, can increase coding efficiency.
FIG. 1 is a block diagram showing a functional configuration example of a coding apparatus according to a first embodiment;
Next, by substituting Eq. (2) into Eq. (1), the following equation is obtained.
According to the first embodiment, the time lag τ is variable-length coded depending on a condition. According to the second embodiment, the multiplier ρ is variable-length coded depending on a condition. The coder 23 may variable-length encode the time lag τ depending on a condition as in the case of the first embodiment or may only fixed-length encode as is conventionally the case. Depending on the method of coding, the lag decoder 60 of the decoding apparatus is designed for either variable-length decoding, or fixed-length decoding as is conventionally the case.
The multiplier coder 22 in FIG. 8 may be applied to FIG. 1 in such a way as to optimize a combination of coding by the waveform coder 21 and coding by the multiplier coder 22. Such a configuration can be obtained by adding an optimizing part to the configuration in FIG. 1. Its essence is shown in FIG. 21.
In the embodiments described above, a prediction signal ρ′Xτ for a signal X is generated by multiplying a signal Xτ of each time lag τ (i.e., one delay tap) by one multiplier ρ′ as illustrated in FIG. 3, but a prediction signal may be generated based on signals of a time lag τ and multiple adjacent time lags. A configuration of a coding apparatus used for that is shown in FIG. 22. In the configuration FIG. 22, there are three delay taps and the delay part 13 in FIG. 1 is replaced with a τ−1 sample delay part (Zτ−1) 13A and two unit delay parts 13B and 13C which are connected in series. The delay part 13 sets a delay of τ−1 samples in the delay part 13A with respect to the time lag τ provided by the lag search part 17. Thus, with respect to the input signal X, the delay parts 13A, 13B, and 13C output a signal Xτ−1 delayed by τ−1 samples, a signal Xτ delayed by τ samples, and a signal Xτ+1 delayed by τ+1 samples, respectively.
Such multipliers ρ−1, ρ, and ρ+1 can be calculated using the following equation.
In this way, the use of signals from multiple delay taps in generating a prediction signal, makes it possible to increase prediction accuracy, reduce energy of the error signal obtained by the subtractor 15, and provide more efficient coding. Although three delay taps are used in FIG. 22, this is not restrictive and any desired number of taps may be used.
Description will be given of a fifth embodiment in which a frame is coded after being divided into four sub-frames. In this case, there are four possible methods for outputting parameters of a quantized multiplier ρ′ and time lag τ as follows.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS5729655Sep 24, 1996Mar 17, 1998Alaris, Inc.Method and apparatus for speech compression using multi-mode code excited linear predictive codingUS6271885Jun 23, 1999Aug 7, 2001Victor Company Of Japan, Ltd.Apparatus and method of motion-compensated predictive codingUS7225136Jun 21, 2004May 29, 2007Koninklijke Philips Electronics N.V.Data compression and expansion of an audio signalUS7599835 *Mar 10, 2003Oct 6, 2009Nippon Telegraph And Telephone CorporationDigital signal encoding method, decoding method, encoding device, decoding device, digital signal encoding program, and decoding programUS7970605 *Jan 11, 2006Jun 28, 2011Nippon Telegraph And Telephone CorporationMethod, apparatus, program and recording medium for long-term prediction coding and long-term prediction decodingJP3218630B2 Title not availableJP2000022545A Title not availableJP2000235399A Title not availableJPH0470800A Title not availableJPH0535297A Title not availableJPH03123113A Title not availableJPH03171830A Title not availableJPH05119800A Title not availableJPH07168597A Title not availableJPH08123492A Title not availableJPS61177822A Title not available* Cited by examinerNon-Patent CitationsReference1Extended European Search Report issued Jan. 27, 2011, in European Patent Application No. 10195915.3.2Tilman Liebchen, et al., "MPEG-4 ALS: An Emerging Standard for Lossless Audio Coding", Data Compression Conference, Mar. 23, 2004, XP010692571, pp. 439-448.Classifications U.S. Classification704/219International ClassificationG10L19/04Cooperative ClassificationG10L19/08, G10L19/09, G10L19/0017European ClassificationG10L19/08, G10L19/00L, G10L19/09RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services