Fast Spherical Code Decoding Algorithms for the Residual Codebook in Celp Coders

نویسندگان

  • Konsta Koppinen
  • Tomi Mikkonen
چکیده

A new method for fast decoding when using algebraic codes for the fixed codebook in CELP speech coders is presented. This method is based on the trellis structure of a block code, and allows fast optimal search of the residual codebook even with a combined scalar gain, unlike previous search methods. The method is flexible, allowing for long block lengths and the use of any code including nonlinear ones. Currently the performance is not as high as with standard algebraic coding methods, but further refinements may make this a viable method.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Adaptive encoding of fixed codebook in CELP coders

In this paper, we propose an adaptive encoding method of xed codebook in CELP coders and implement an adaptive xed code excited linear prediction (AF-CELP) speech coder. AF-CELP exploits the fact that the xed codebook contribution to speech signal is also periodic as the adaptive codebook (or pitch lter) contribution. By modeling the xed codebook with the pitch lag and the gain from the adaptiv...

متن کامل

On Improving the Performance of an ACELP Speech Coder

In this paper we evaluate the performance of a variety of techniques to improve the parameter analysis in CELP speech coders. These methods include using extended cost horizon in the fixed codebook search process, as well as joint optimization and delayed decision coding of the adaptive and fixed codebook parameters. Based on our simulations for the IS-641 speech coder, substantial improvements...

متن کامل

A fast search method of algebraic codebook by reordering search sequence

This paper proposes a fast search method of algebraic codebook in CELP coders. In the proposed method, the sequence of codebook search is reordered according to the criterion of mean squared weighted error between target vector and ltered adaptive codebook vector, and the algebraic codebook is searched until a predetermined threshold is satis ed. This method reduces the computations considerabl...

متن کامل

Selection of excitation vectors for the CELP coders

In this paper, we investigate several algorithms that construct the input for the synthesis filter in the CELP coder, we present them under the same formalism, and we compare their performances. We model the excitation vector by a linear combination of K signals, which are issued from K codebooks and multiplied by K associated gains. We demonstrate that this generalized form incorporates severa...

متن کامل

Codebook Search in LD-CELP Speech Coding Algorithm Based on Multi-SOM Structure

In the family of CELP coders, codebook search has high computational complexity. In this paper, the codebook search in low delay-code excited linear prediction (LD-CELP) G.728 coder is performed by a multi-self organizing map (SOM) neural model. A modified-supervised SOM training algorithm is also used in this work. In this algorithm, the codebook vectors are assigned to a class during training...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2007