libcelt/bands.h

/* (C) 2007 Jean-Marc Valin, CSIRO
*/
/*
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   this software without specific prior written permission.
   
   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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*/

#ifndef BANDS_H
#define BANDS_H

#include "arch.h"
#include "modes.h"
#include "entenc.h"
#include "entdec.h"
#include "rate.h"

/** Applies a series of rotations so that pulses are spread like a two-sided
exponential. The effect of this is to reduce the tonal noise created by the
sparse spectrum resulting from the pulse codebook */
void exp_rotation(celt_norm_t *X, int len, celt_word16_t theta, int dir, int stride, int iter);

/** Normalise each band of X such that the energy in each band is 
    equal to 1
 * @param m Mode data 
 * @param X Spectrum (returned normalised)
 * @param bands Square root of the energy for each band
 */
void normalise_bands(const CELTMode *m, const celt_sig_t *freq, celt_norm_t *X, celt_ener_t *bands);

void renormalise_bands(const CELTMode *m, celt_norm_t *X);

/** Denormalise each band of X to restore full amplitude
 * @param m Mode data 
 * @param X Spectrum (returned de-normalised)
 * @param bands Square root of the energy for each band
 */
void denormalise_bands(const CELTMode *m, const celt_norm_t *X, celt_sig_t *freq, const celt_ener_t *bands);

/** Compute the pitch predictor gain for each pitch band
 * @param m Mode data 
 * @param X Spectrum to predict
 * @param P Pitch vector (normalised)
 * @param gains Gain computed for each pitch band (returned)
 * @param bank Square root of the energy for each band
 */
void compute_pitch_gain(const CELTMode *m, const celt_norm_t *X, const celt_norm_t *P, celt_pgain_t *gains);

void pitch_quant_bands(const CELTMode *m, celt_norm_t *P, const celt_pgain_t *gains);

/** Quantisation/encoding of the residual spectrum
 * @param m Mode data 
 * @param X Residual (normalised)
 * @param P Pitch vector (normalised)
 * @param W Perceptual weighting
 * @param total_bits Total number of bits that can be used for the frame (including the ones already spent)
 * @param enc Entropy encoder
 */
void quant_bands(const CELTMode *m, celt_norm_t *X, celt_norm_t *P, celt_mask_t *W, int total_bits, ec_enc *enc);

/** Decoding of the residual spectrum
 * @param m Mode data 
 * @param X Residual (normalised)
 * @param P Pitch vector (normalised)
 * @param total_bits Total number of bits that can be used for the frame (including the ones already spent)
 * @param dec Entropy decoder
*/
void unquant_bands(const CELTMode *m, celt_norm_t *X, celt_norm_t *P, int total_bits, ec_dec *dec);

void stereo_mix(const CELTMode *m, celt_norm_t *X, const celt_ener_t *bank, int dir);

#endif /* BANDS_H */