net.java.sip.communicator.impl.neomedia.codec.audio.g729
Class Filter

java.lang.Object
  net.java.sip.communicator.impl.neomedia.codec.audio.g729.Filter

 class Filter
extends Object

General filter routines.

Author:

Lubomir Marinov (translation of ITU-T C source code to Java)

Constructor Summary

Filter()

Method Summary

(package private) static void	convolve(float[] x, int x_offset, float[] h, float[] y, int l) Convolve vectors x and h and put result in y.
(package private) static void	residu(float[] a, int a_offset, float[] x, int x_offset, float[] y, int y_offset, int l) Filter input vector with all-zero filter A(Z).
(package private) static void	syn_filt(float[] a, int a_offset, float[] x, int x_offset, float[] y, int y_offset, int l, float[] mem, int mem_offset, int update) Filter with synthesis filter 1/A(z).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Filter

Filter()

Method Detail

convolve

static void convolve(float[] x,
                     int x_offset,
                     float[] h,
                     float[] y,
                     int l)

Convolve vectors x and h and put result in y.

Parameters:

x - input : input vector x[0:l]

x_offset - input : input vector offset

h - input : impulse response or second input h[0:l]

y - output: x convolved with h , y[0:l]

l - input : dimension of all vectors

syn_filt

static void syn_filt(float[] a,
                     int a_offset,
                     float[] x,
                     int x_offset,
                     float[] y,
                     int y_offset,
                     int l,
                     float[] mem,
                     int mem_offset,
                     int update)

Filter with synthesis filter 1/A(z).

Parameters:

a - input : predictor coefficients a[0:m]

a_offset - input : predictor coefficients a offset

x - input : excitation signal

x_offset - input : excitation signal offset

y - output: filtered output signal

y_offset - output: filtered output signal offset

l - input : vector dimension

mem - in/out: filter memory

mem_offset - input : filter memory ofset

update - input : 0 = no memory update, 1 = update

residu

static void residu(float[] a,
                   int a_offset,
                   float[] x,
                   int x_offset,
                   float[] y,
                   int y_offset,
                   int l)

Filter input vector with all-zero filter A(Z).

Parameters:

a - input : prediction coefficients a[0:m+1], a[0]=1.

a_offset - input : prediction coefficients a offset

x - input : input signal x[0:l-1], x[-1:m] are needed

x_offset - input : input signal x offset

y - output: output signal y[0:l-1]. NOTE: x[] and y[] cannot point to same array

y_offset - input : output signal y offset

l - input : dimension of x and y