Package org.xiph.speex

Class 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: 1.2 $
    Author:
    Marc Gimpel, Wimba S.A. (mgimpel@horizonwimba.com)

    • 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.