org.xiph.speex
Class NbCodec

java.lang.Object
  org.xiph.speex.NbCodec

All Implemented Interfaces:

Codebook

Direct Known Subclasses:

NbDecoder, NbEncoder, SbCodec

public class NbCodec

extends java.lang.Object

implements Codebook

Narrowband Codec. This class contains all the basic structures needed by the Narrowband encoder and decoder.

Version:

$Revision: 1.5 $

Author:

Marc Gimpel, Wimba S.A. (marc@wimba.com)

Field Summary

protected float[]	awk1 Gain of LPC filter at theta=pi (fe/2)
protected float[]	awk2 Gain of LPC filter at theta=pi (fe/2)
protected float[]	awk3 Gain of LPC filter at theta=pi (fe/2)
protected int	bufSize LPC order
protected int	dtx_enabled
static float[]	exc_gain_quant_scal1
static float[]	exc_gain_quant_scal3
protected float[]	excBuf
protected int	excIdx Excitation buffer
protected Filters	filters
protected int	first Activated sub-mode
protected int	frameSize Is this the first frame?
protected float[]	frmBuf 1-element memory for pre-emphasis
protected int	frmIdx Input buffer (original signal)
protected float	gamma1 Maximum pitch value allowed
protected float	gamma2 Perceptual filter: A(z/gamma1)
protected float[]	innov Start of excitation frame
protected float[]	interp_qlpc Interpolated quantized LSPs
protected float[]	interp_qlsp Quantized LSPs for previous frame
protected float	lag_factor Perceptual filter: A(z/gamma2)
protected float[]	lpc Innovation for the frame
protected float	lpc_floor Lag windowing Gaussian width
protected int	lpcSize Analysis (LPC) window length
protected Lsp	m_lsp
protected int	max_pitch Minimum pitch value allowed
protected float[]	mem_sp Interpolated quantized LPCs
protected int	min_pitch Buffer size
static int[]	NB_FRAME_SIZE The Narrowband Frame Size gives the size in bits of a Narrowband frame for a given narrowband submode.
static int	NB_SUBMODE_BITS The Narrowband Submodes Bits gives the number bits used to encode the Narrowband Submode
static int	NB_SUBMODES The Narrowband Submodes gives the number of submodes possible for the Narrowband codec.
protected int	nbSubframes Size of sub-frames
protected float[]	old_qlsp Quantized LSPs for current frame
protected float[]	pi_gain Filter memory for synthesis signal
protected float	pre_mem Pre-emphasis: P(z) = 1 - a*z^-1
protected float	preemph Noise floor multiplier for A[0] in LPC analysis
protected float[]	qlsp LPCs for current frame
protected int	subframeSize Size of frames
protected int	submodeID Sub-mode data
protected SubMode[]	submodes
static float	VERY_SMALL Very small initial value for some of the buffers.
protected float	voc_m1
protected float	voc_m2
protected float	voc_mean
protected int	voc_offset
protected int	windowSize Number of sub-frames

Fields inherited from interface org.xiph.speex.Codebook

cdbk_nb, cdbk_nb_high1, cdbk_nb_high2, cdbk_nb_low1, cdbk_nb_low2, exc_10_16_table, exc_10_32_table, exc_20_32_table, exc_5_256_table, exc_5_64_table, exc_8_128_table, gain_cdbk_lbr, gain_cdbk_nb, h0, h1, hexc_10_32_table, hexc_table, high_lsp_cdbk, high_lsp_cdbk2, NB_CDBK_SIZE, NB_CDBK_SIZE_HIGH1, NB_CDBK_SIZE_HIGH2, NB_CDBK_SIZE_LOW1, NB_CDBK_SIZE_LOW2

Constructor Summary

NbCodec()
Constructor.

Method Summary

private static SubMode[]	buildNbSubModes() Build narrowband submodes
boolean	getDtx() Returns whether or not we are using Discontinuous Transmission encoding.
float[]	getExc() Returns the excitation array.
int	getFrameSize() Returns the size of a frame (ex: 160 samples for a narrowband frame, 320 for wideband and 640 for ultra-wideband).
float[]	getInnov() Returns the innovation array.
float[]	getPiGain() Returns the Pitch Gain array.
protected void	init(int frameSize, int subframeSize, int lpcSize, int bufSize) Initialisation.
void	nbinit() Narrowband initialisation.

Methods inherited from class java.lang.Object

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

Field Detail

VERY_SMALL

public static final float VERY_SMALL

Very small initial value for some of the buffers.

See Also:

Constant Field Values

NB_FRAME_SIZE

public static final int[] NB_FRAME_SIZE

The Narrowband Frame Size gives the size in bits of a Narrowband frame for a given narrowband submode.

NB_SUBMODES

public static final int NB_SUBMODES

The Narrowband Submodes gives the number of submodes possible for the Narrowband codec.

See Also:

Constant Field Values

NB_SUBMODE_BITS

public static final int NB_SUBMODE_BITS

The Narrowband Submodes Bits gives the number bits used to encode the Narrowband Submode

See Also:

Constant Field Values

exc_gain_quant_scal1

public static final float[] exc_gain_quant_scal1

exc_gain_quant_scal3

public static final float[] exc_gain_quant_scal3

m_lsp

protected Lsp m_lsp

filters

protected Filters filters

submodes

protected SubMode[] submodes

submodeID

protected int submodeID

Sub-mode data

first

protected int first

Activated sub-mode

frameSize

protected int frameSize

Is this the first frame?

subframeSize

protected int subframeSize

Size of frames

nbSubframes

protected int nbSubframes

Size of sub-frames

windowSize

protected int windowSize

Number of sub-frames

lpcSize

protected int lpcSize

Analysis (LPC) window length

bufSize

protected int bufSize

LPC order

min_pitch

protected int min_pitch

Buffer size

max_pitch

protected int max_pitch

Minimum pitch value allowed

gamma1

protected float gamma1

Maximum pitch value allowed

gamma2

protected float gamma2

Perceptual filter: A(z/gamma1)

lag_factor

protected float lag_factor

Perceptual filter: A(z/gamma2)

lpc_floor

protected float lpc_floor

Lag windowing Gaussian width

preemph

protected float preemph

Noise floor multiplier for A[0] in LPC analysis

pre_mem

protected float pre_mem

Pre-emphasis: P(z) = 1 - a*z^-1

frmBuf

protected float[] frmBuf

1-element memory for pre-emphasis

frmIdx

protected int frmIdx

Input buffer (original signal)

excBuf

protected float[] excBuf

excIdx

protected int excIdx

Excitation buffer

innov

protected float[] innov

Start of excitation frame

lpc

protected float[] lpc

Innovation for the frame

qlsp

protected float[] qlsp

LPCs for current frame

old_qlsp

protected float[] old_qlsp

Quantized LSPs for current frame

interp_qlsp

protected float[] interp_qlsp

Quantized LSPs for previous frame

interp_qlpc

protected float[] interp_qlpc

Interpolated quantized LSPs

mem_sp

protected float[] mem_sp

Interpolated quantized LPCs

pi_gain

protected float[] pi_gain

Filter memory for synthesis signal

awk1

protected float[] awk1

Gain of LPC filter at theta=pi (fe/2)

awk2

protected float[] awk2

Gain of LPC filter at theta=pi (fe/2)

awk3

protected float[] awk3

Gain of LPC filter at theta=pi (fe/2)

voc_m1

protected float voc_m1

voc_m2

protected float voc_m2

voc_mean

protected float voc_mean

voc_offset

protected int voc_offset

dtx_enabled

protected int dtx_enabled

Constructor Detail

NbCodec

public NbCodec()

Constructor.

Method Detail

nbinit

public void nbinit()

Narrowband initialisation.

init

protected void init(int frameSize,
                    int subframeSize,
                    int lpcSize,
                    int bufSize)

Initialisation.

Parameters:

frameSize -

subframeSize -

lpcSize -

bufSize -

buildNbSubModes

private static SubMode[] buildNbSubModes()

Build narrowband submodes

getFrameSize

public int getFrameSize()

Returns the size of a frame (ex: 160 samples for a narrowband frame, 320 for wideband and 640 for ultra-wideband).

Returns:

the size of a frame (number of audio samples in a frame).

getDtx

public boolean getDtx()

Returns whether or not we are using Discontinuous Transmission encoding.

Returns:

whether or not we are using Discontinuous Transmission encoding.

getPiGain

public float[] getPiGain()

Returns the Pitch Gain array.

Returns:

the Pitch Gain array.

getExc

public float[] getExc()

Returns the excitation array.

Returns:

the excitation array.

getInnov

public float[] getInnov()

Returns the innovation array.

Returns:

the innovation array.