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+/***************************** MPEG-4 AAC Decoder **************************
+
+ (C) Copyright Fraunhofer IIS (2004)
+ All Rights Reserved
+
+ Please be advised that this software and/or program delivery is
+ Confidential Information of Fraunhofer and subject to and covered by the
+
+ Fraunhofer IIS Software Evaluation Agreement
+ between Google Inc. and Fraunhofer
+ effective and in full force since March 1, 2012.
+
+ You may use this software and/or program only under the terms and
+ conditions described in the above mentioned Fraunhofer IIS Software
+ Evaluation Agreement. Any other and/or further use requires a separate agreement.
+
+
+ $Id$
+ Author(s): Josef Hoepfl
+ Description: perceptual noise substitution tool
+
+ This software and/or program is protected by copyright law and international
+ treaties. Any reproduction or distribution of this software and/or program,
+ or any portion of it, may result in severe civil and criminal penalties, and
+ will be prosecuted to the maximum extent possible under law.
+
+******************************************************************************/
+
+#include "aacdec_pns.h"
+
+
+#include "aac_ram.h"
+#include "aac_rom.h"
+#include "channelinfo.h"
+#include "block.h"
+#include "FDK_bitstream.h"
+
+#include "genericStds.h"
+
+
+#define NOISE_OFFSET 90 /* cf. ISO 14496-3 p. 175 */
+
+/*!
+ \brief Reset InterChannel and PNS data
+
+ The function resets the InterChannel and PNS data
+*/
+void CPns_ResetData(
+ CPnsData *pPnsData,
+ CPnsInterChannelData *pPnsInterChannelData
+ )
+{
+ /* Assign pointer always, since pPnsData is not persistent data */
+ pPnsData->pPnsInterChannelData = pPnsInterChannelData;
+ pPnsData->PnsActive = 0;
+ pPnsData->CurrentEnergy = 0;
+
+ FDKmemclear(pPnsData->pnsUsed,(8*16)*sizeof(UCHAR));
+ FDKmemclear(pPnsInterChannelData->correlated,(8*16)*sizeof(UCHAR));
+}
+
+/*!
+ \brief Initialize PNS data
+
+ The function initializes the PNS data
+*/
+void CPns_InitPns(
+ CPnsData *pPnsData,
+ CPnsInterChannelData *pPnsInterChannelData,
+ INT* currentSeed, INT* randomSeed)
+{
+ /* save pointer to inter channel data */
+ pPnsData->pPnsInterChannelData = pPnsInterChannelData;
+
+ /* use pointer because seed has to be
+ same, left and right channel ! */
+ pPnsData->currentSeed = currentSeed;
+ pPnsData->randomSeed = randomSeed;
+}
+
+/*!
+ \brief Indicates if PNS is used
+
+ The function returns a value indicating whether PNS is used or not
+ acordding to the noise energy
+
+ \return PNS used
+*/
+int CPns_IsPnsUsed (const CPnsData *pPnsData,
+ const int group,
+ const int band)
+{
+ unsigned pns_band = group*16+band;
+
+ return pPnsData->pnsUsed[pns_band] & (UCHAR)1;
+}
+
+/*!
+ \brief Set correlation
+
+ The function activates the noise correlation between the channel pair
+*/
+void CPns_SetCorrelation(CPnsData *pPnsData,
+ const int group,
+ const int band,
+ const int outofphase)
+{
+ CPnsInterChannelData *pInterChannelData = pPnsData->pPnsInterChannelData;
+ unsigned pns_band = group*16+band;
+
+ pInterChannelData->correlated[pns_band] = (outofphase) ? 3 : 1;
+}
+
+/*!
+ \brief Indicates if correlation is used
+
+ The function indicates if the noise correlation between the channel pair
+ is activated
+
+ \return PNS is correlated
+*/
+static
+int CPns_IsCorrelated(const CPnsData *pPnsData,
+ const int group,
+ const int band)
+{
+ CPnsInterChannelData *pInterChannelData = pPnsData->pPnsInterChannelData;
+ unsigned pns_band = group*16+band;
+
+ return (pInterChannelData->correlated[pns_band] & 0x01) ? 1 : 0;
+}
+
+/*!
+ \brief Indicates if correlated out of phase mode is used.
+
+ The function indicates if the noise correlation between the channel pair
+ is activated in out-of-phase mode.
+
+ \return PNS is out-of-phase
+*/
+static
+int CPns_IsOutOfPhase(const CPnsData *pPnsData,
+ const int group,
+ const int band)
+{
+ CPnsInterChannelData *pInterChannelData = pPnsData->pPnsInterChannelData;
+ unsigned pns_band = group*16+band;
+
+ return (pInterChannelData->correlated[pns_band] & 0x02) ? 1 : 0;
+}
+
+/*!
+ \brief Read PNS information
+
+ The function reads the PNS information from the bitstream
+*/
+void CPns_Read (CPnsData *pPnsData,
+ HANDLE_FDK_BITSTREAM bs,
+ const CodeBookDescription *hcb,
+ SHORT *pScaleFactor,
+ UCHAR global_gain,
+ int band,
+ int group /* = 0 */)
+{
+ int delta ;
+ UINT pns_band = group*16+band;
+
+ if (pPnsData->PnsActive) {
+ /* Next PNS band case */
+ delta = CBlock_DecodeHuffmanWord (bs, hcb) - 60;
+ } else {
+ /* First PNS band case */
+ int noiseStartValue = FDKreadBits(bs,9);
+
+ delta = noiseStartValue - 256 ;
+ pPnsData->PnsActive = 1;
+ pPnsData->CurrentEnergy = global_gain - NOISE_OFFSET;
+ }
+
+ pPnsData->CurrentEnergy += delta ;
+ pScaleFactor[pns_band] = pPnsData->CurrentEnergy;
+
+ pPnsData->pnsUsed[pns_band] = 1;
+}
+
+
+/**
+ * \brief Generate a vector of noise of given length. The noise values are
+ * scaled in order to yield a noise energy of 1.0
+ * \param spec pointer to were the noise values will be written to.
+ * \param size amount of noise values to be generated.
+ * \param pRandomState pointer to the state of the random generator being used.
+ * \return exponent of generated noise vector.
+ */
+static int GenerateRandomVector (FIXP_DBL *RESTRICT spec,
+ int size,
+ int *pRandomState)
+{
+ int i, invNrg_e = 0, nrg_e = 0;
+ FIXP_DBL invNrg_m, nrg_m = FL2FXCONST_DBL(0.0f) ;
+ FIXP_DBL *RESTRICT ptr = spec;
+ int randomState = *pRandomState;
+
+#define GEN_NOISE_NRG_SCALE 7
+
+ /* Generate noise and calculate energy. */
+ for (i=0; i<size; i++)
+ {
+ randomState = (1664525L * randomState) + 1013904223L; // Numerical Recipes
+ nrg_m = fPow2AddDiv2(nrg_m, (FIXP_DBL)randomState>>GEN_NOISE_NRG_SCALE);
+ *ptr++ = (FIXP_DBL)randomState;
+ }
+ nrg_e = GEN_NOISE_NRG_SCALE*2 + 1;
+
+ /* weight noise with = 1 / sqrt_nrg; */
+ invNrg_m = invSqrtNorm2(nrg_m<<1, &invNrg_e);
+ invNrg_e += -((nrg_e-1)>>1);
+
+ for (i=size; i--; )
+ {
+ spec[i] = fMult(spec[i], invNrg_m);
+ }
+
+ /* Store random state */
+ *pRandomState = randomState;
+
+ return invNrg_e;
+}
+
+static void ScaleBand (FIXP_DBL *RESTRICT spec, int size, int scaleFactor, int specScale, int noise_e, int out_of_phase)
+{
+ int i, shift, sfExponent;
+ FIXP_DBL sfMatissa;
+
+ /* Get gain from scale factor value = 2^(scaleFactor * 0.25) */
+ sfMatissa = MantissaTable[scaleFactor & 0x03][0];
+ /* sfExponent = (scaleFactor >> 2) + ExponentTable[scaleFactor & 0x03][0]; */
+ /* Note: ExponentTable[scaleFactor & 0x03][0] is always 1. */
+ sfExponent = (scaleFactor >> 2) + 1;
+
+ if (out_of_phase != 0) {
+ sfMatissa = -sfMatissa;
+ }
+
+ /* +1 because of fMultDiv2 below. */
+ shift = sfExponent - specScale + 1 + noise_e;
+
+ /* Apply gain to noise values */
+ if (shift>=0) {
+ shift = fixMin( shift, DFRACT_BITS-1 );
+ for (i = size ; i-- != 0; ) {
+ spec [i] = fMultDiv2 (spec [i], sfMatissa) << shift;
+ }
+ } else {
+ shift = fixMin( -shift, DFRACT_BITS-1 );
+ for (i = size ; i-- != 0; ) {
+ spec [i] = fMultDiv2 (spec [i], sfMatissa) >> shift;
+ }
+ }
+}
+
+
+/*!
+ \brief Apply PNS
+
+ The function applies PNS (i.e. it generates noise) on the bands
+ flagged as noisy bands
+
+*/
+void CPns_Apply (const CPnsData *pPnsData,
+ const CIcsInfo *pIcsInfo,
+ SPECTRAL_PTR pSpectrum,
+ const SHORT *pSpecScale,
+ const SHORT *pScaleFactor,
+ const SamplingRateInfo *pSamplingRateInfo,
+ const INT granuleLength,
+ const int channel)
+{
+ if (pPnsData->PnsActive) {
+ const short *BandOffsets = GetScaleFactorBandOffsets(pIcsInfo, pSamplingRateInfo);
+
+ int ScaleFactorBandsTransmitted = GetScaleFactorBandsTransmitted(pIcsInfo);
+
+ for (int window = 0, group = 0; group < GetWindowGroups(pIcsInfo); group++) {
+ for (int groupwin = 0; groupwin < GetWindowGroupLength(pIcsInfo, group); groupwin++, window++) {
+ FIXP_DBL *spectrum = SPEC(pSpectrum, window, granuleLength);
+
+ for (int band = 0 ; band < ScaleFactorBandsTransmitted; band++) {
+ if (CPns_IsPnsUsed (pPnsData, group, band)) {
+ UINT pns_band = group*16+band;
+
+ int bandWidth = BandOffsets [band + 1] - BandOffsets [band] ;
+ int noise_e;
+
+ FDK_ASSERT(bandWidth >= 0);
+
+ if (channel > 0 && CPns_IsCorrelated(pPnsData, group, band))
+ {
+ noise_e = GenerateRandomVector (spectrum + BandOffsets [band], bandWidth,
+ &pPnsData->randomSeed [pns_band]) ;
+ }
+ else
+ {
+ pPnsData->randomSeed [pns_band] = *pPnsData->currentSeed ;
+
+ noise_e = GenerateRandomVector (spectrum + BandOffsets [band], bandWidth,
+ pPnsData->currentSeed) ;
+ }
+
+ int outOfPhase = CPns_IsOutOfPhase (pPnsData, group, band);
+
+ ScaleBand (spectrum + BandOffsets [band], bandWidth,
+ pScaleFactor[pns_band],
+ pSpecScale[window], noise_e, outOfPhase) ;
+ }
+ }
+ }
+ }
+ }
+}
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