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Efficient design of MDCT/IMDCT filterbanks for speech and audio coding applications

A technology of DCT-II and DCT-IV, applied in the field of encoder and decoder

Active Publication Date: 2013-04-10
QUALCOMM INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] However, if future vocoders are to support block-swapping functionality, support for decimation sizes (160 points, 80 points, 40 points) may also be required

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  • Efficient design of MDCT/IMDCT filterbanks for speech and audio coding applications
  • Efficient design of MDCT/IMDCT filterbanks for speech and audio coding applications
  • Efficient design of MDCT/IMDCT filterbanks for speech and audio coding applications

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Embodiment Construction

[0030] Various embodiments are now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more embodiments. It may be evident, however, that the described embodiments may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing one or more embodiments.

[0031] review

[0032] One feature provides implementing the N-point MDCT transform by mapping the N-point MDCT transform into N / 2-point DCT-IV and DCT-II transforms of smaller size with isolated premultiplication, which can be moved to subsequent Fenestration level. That is, windowing operations can be combined with first / last stage multiplications in the core MDCT / IMDCT functions respectively, thus r...

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Abstract

A more efficient encoder / decoder is provided in which an N-point MDCT transform is mapped into smaller sized N / 2-point DCT-IV and / or DCT-II transforms with isolated pre-multiplications which can be moved to a prior or subsequent windowing stage. That is, the windowing operations may be merged with first / last stage multiplications in the core MDCT / IMDCT functions, respectively, thus reducing the total number of multiplications. Additionally, the MDCT may be systematically decimated by factor of 2 by utilizing a uniformly scaled 5-point DCT-II core function as opposed to the DCT-IV or FFT cores used in many existing MDCT designs in audio codecs. The modified windowing stage merges factors from a transform stage and windowing stage to obtain piece-wise symmetric windowing factors, which can be represented by a sub-set of the piece-wise symmetric windowing factors to save storage space. Such features offer appreciable reduction in complexity and less memory usage than the prior art.

Description

[0001] Claim of priority under 35 U.S.C. §119 [0002] This patent application claims the title of "Design of Fast MDCT / IMDCT Module for G.VBR Codec (Design of Fast MDCT / IMDCT Module for G.VBR Codec)" filed on September 19, 2007. U.S. Provisional Application No. / 973,709 and the November 20, 2007 application titled "Design of Fixed-Point MDCT / IMDCT Module for G.VBR Codec )", both of which are assigned to their assignees and are hereby expressly incorporated herein by reference. technical field [0003] The following description relates generally to encoders and decoders, and in particular to efficient MDCT / IMDCT implementations for speech and audio codecs. Background technique [0004] One goal of audio coding is to compress an audio signal to a desired limited amount of information while maintaining as much of the original sound quality as possible. During the encoding process, the audio signal in the time domain is transformed into the frequency domain, and the correspon...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G10L19/02G06F17/14
CPCG10L19/0212G06F17/147
Inventor 拉维·基兰·基辅库拉尤里亚·热兹尼克
Owner QUALCOMM INC