sbrside.c

/* ***** BEGIN LICENSE BLOCK *****  
 * Source last modified: $Id: sbrside.c,v 1.2 2005/05/24 16:01:55 albertofloyd Exp $ 
 *   
 * Portions Copyright (c) 1995-2005 RealNetworks, Inc. All Rights Reserved.  
 *       
 * The contents of this file, and the files included with this file, 
 * are subject to the current version of the RealNetworks Public 
 * Source License (the "RPSL") available at 
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 * the file under the current version of the RealNetworks Community 
 * Source License (the "RCSL") available at 
 * http://www.helixcommunity.org/content/rcsl, in which case the RCSL 
 * will apply. You may also obtain the license terms directly from 
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 * to this file, the RCSL.  Please see the applicable RPSL or RCSL for 
 * the rights, obligations and limitations governing use of the 
 * contents of the file. 
 *   
 * This file is part of the Helix DNA Technology. RealNetworks is the 
 * developer of the Original Code and owns the copyrights in the 
 * portions it created. 
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 * This file, and the files included with this file, is distributed 
 * and made available on an 'AS IS' basis, WITHOUT WARRANTY OF ANY 
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 * ENJOYMENT OR NON-INFRINGEMENT. 
 *  
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 *  
 * Contributor(s):  
 *   
 * ***** END LICENSE BLOCK ***** */  

/**************************************************************************************
 * Fixed-point HE-AAC decoder
 * Jon Recker (jrecker@real.com)
 * February 2005
 *
 * sbrside.c - functions for unpacking side info from SBR bitstream
 **************************************************************************************/

#include "sbr.h"

/**************************************************************************************
 * Function:    GetSampRateIdx
 *
 * Description: get index of given sample rate
 *
 * Inputs:      sample rate (in Hz)
 *
 * Outputs:     none
 *
 * Return:      index of sample rate (table 1.15 in 14496-3:2001(E))
 *              -1 if sample rate not found in table
 **************************************************************************************/
int GetSampRateIdx(int sampRate)
{
	int idx;

	for (idx = 0; idx < NUM_SAMPLE_RATES; idx++) {
		if (sampRate == sampRateTab[idx])
			return idx;
	}

	return -1;
}

/**************************************************************************************
 * Function:    UnpackSBRHeader
 *
 * Description: unpack SBR header (table 4.56)
 *
 * Inputs:      BitStreamInfo struct pointing to start of SBR header
 *
 * Outputs:     initialized SBRHeader struct for this SCE/CPE block
 *
 * Return:      non-zero if frame reset is triggered, zero otherwise
 **************************************************************************************/
int UnpackSBRHeader(BitStreamInfo *bsi, SBRHeader *sbrHdr)
{
	SBRHeader sbrHdrPrev;

	/* save previous values so we know whether to reset decoder */
	sbrHdrPrev.startFreq =     sbrHdr->startFreq;
	sbrHdrPrev.stopFreq =      sbrHdr->stopFreq;
	sbrHdrPrev.freqScale =     sbrHdr->freqScale;
	sbrHdrPrev.alterScale =    sbrHdr->alterScale;
	sbrHdrPrev.crossOverBand = sbrHdr->crossOverBand;
	sbrHdrPrev.noiseBands =    sbrHdr->noiseBands;

	sbrHdr->ampRes =        GetBits(bsi, 1);
	sbrHdr->startFreq =     GetBits(bsi, 4);
	sbrHdr->stopFreq =      GetBits(bsi, 4);
	sbrHdr->crossOverBand = GetBits(bsi, 3);
	sbrHdr->resBitsHdr =    GetBits(bsi, 2);
	sbrHdr->hdrExtra1 =     GetBits(bsi, 1);
	sbrHdr->hdrExtra2 =     GetBits(bsi, 1);

	if (sbrHdr->hdrExtra1) {
		sbrHdr->freqScale =    GetBits(bsi, 2);
		sbrHdr->alterScale =   GetBits(bsi, 1);
		sbrHdr->noiseBands =   GetBits(bsi, 2);
	} else {
		/* defaults */
		sbrHdr->freqScale =    2;
		sbrHdr->alterScale =   1;
		sbrHdr->noiseBands =   2;
	}

	if (sbrHdr->hdrExtra2) {
		sbrHdr->limiterBands = GetBits(bsi, 2);
		sbrHdr->limiterGains = GetBits(bsi, 2);
		sbrHdr->interpFreq =   GetBits(bsi, 1);
		sbrHdr->smoothMode =   GetBits(bsi, 1);
	} else {
		/* defaults */
		sbrHdr->limiterBands = 2;
		sbrHdr->limiterGains = 2;
		sbrHdr->interpFreq =   1;
		sbrHdr->smoothMode =   1;
	}
	sbrHdr->count++;

	/* if any of these have changed from previous frame, reset the SBR module */
	if (sbrHdr->startFreq != sbrHdrPrev.startFreq || sbrHdr->stopFreq != sbrHdrPrev.stopFreq ||
		sbrHdr->freqScale != sbrHdrPrev.freqScale || sbrHdr->alterScale != sbrHdrPrev.alterScale ||
		sbrHdr->crossOverBand != sbrHdrPrev.crossOverBand || sbrHdr->noiseBands != sbrHdrPrev.noiseBands
		)
		return -1;
	else
		return 0;
}

/* cLog2[i] = ceil(log2(i)) (disregard i == 0) */
static const unsigned char cLog2[9] = {0, 0, 1, 2, 2, 3, 3, 3, 3};

/**************************************************************************************
 * Function:    UnpackSBRGrid
 *
 * Description: unpack SBR grid (table 4.62)
 *
 * Inputs:      BitStreamInfo struct pointing to start of SBR grid
 *              initialized SBRHeader struct for this SCE/CPE block
 * 
 * Outputs:     initialized SBRGrid struct for this channel
 *
 * Return:      0 if successful, error code (< 0) if error
 **************************************************************************************/
static int UnpackSBRGrid(BitStreamInfo *bsi, SBRHeader *sbrHdr, SBRGrid *sbrGrid)
{
	int numEnvRaw, env, rel, pBits, border, middleBorder=0;
	unsigned char relBordLead[MAX_NUM_ENV] = {0}, relBordTrail[MAX_NUM_ENV] = {0};
	unsigned char relBorder0[3], relBorder1[3], relBorder[3];
	unsigned char numRelBorder0, numRelBorder1, numRelBorder, numRelLead=0, numRelTrail;
	unsigned char absBordLead=0, absBordTrail=0, absBorder;
	
	sbrGrid->ampResFrame = sbrHdr->ampRes;
	sbrGrid->frameClass = GetBits(bsi, 2);
	switch (sbrGrid->frameClass) {

	case SBR_GRID_FIXFIX:
		numEnvRaw = GetBits(bsi, 2);
		sbrGrid->numEnv = (1 << numEnvRaw);
		if (sbrGrid->numEnv == 1)
			sbrGrid->ampResFrame = 0;

		if(sbrGrid->numEnv != 1 && sbrGrid->numEnv != 2 && sbrGrid->numEnv != 4)
			return ERR_AAC_UNKNOWN;

		sbrGrid->freqRes[0] = GetBits(bsi, 1);
		for (env = 1; env < sbrGrid->numEnv; env++)
			 sbrGrid->freqRes[env] = sbrGrid->freqRes[0];

		absBordLead =  0;
		absBordTrail = NUM_TIME_SLOTS;
		numRelLead =   sbrGrid->numEnv - 1;
		numRelTrail =  0;

		/* numEnv = 1, 2, or 4 */
		if (sbrGrid->numEnv == 1)		border = NUM_TIME_SLOTS / 1;
		else if (sbrGrid->numEnv == 2)	border = NUM_TIME_SLOTS / 2;
		else							border = NUM_TIME_SLOTS / 4;

		for (rel = 0; rel < numRelLead; rel++)
			relBordLead[rel] = border;

		middleBorder = (sbrGrid->numEnv >> 1);

		break;

	case SBR_GRID_FIXVAR:
		absBorder = GetBits(bsi, 2) + NUM_TIME_SLOTS;
		numRelBorder = GetBits(bsi, 2);
		sbrGrid->numEnv = numRelBorder + 1;
		for (rel = 0; rel < numRelBorder; rel++)
			relBorder[rel] = 2*GetBits(bsi, 2) + 2;

		pBits = cLog2[sbrGrid->numEnv + 1];
		sbrGrid->pointer = GetBits(bsi, pBits);

		for (env = sbrGrid->numEnv - 1; env >= 0; env--)
			sbrGrid->freqRes[env] = GetBits(bsi, 1);

		absBordLead =  0;
		absBordTrail = absBorder;
		numRelLead =   0;
		numRelTrail =  numRelBorder;

		for (rel = 0; rel < numRelTrail; rel++)
			relBordTrail[rel] = relBorder[rel];

		if (sbrGrid->pointer > 1)			middleBorder = sbrGrid->numEnv + 1 - sbrGrid->pointer;
		else								middleBorder = sbrGrid->numEnv - 1;

		break;

	case SBR_GRID_VARFIX:
		absBorder = GetBits(bsi, 2);
		numRelBorder = GetBits(bsi, 2);
		sbrGrid->numEnv = numRelBorder + 1;
		for (rel = 0; rel < numRelBorder; rel++)
			relBorder[rel] = 2*GetBits(bsi, 2) + 2;

		pBits = cLog2[sbrGrid->numEnv + 1];
		sbrGrid->pointer = GetBits(bsi, pBits);

		for (env = 0; env < sbrGrid->numEnv; env++)
			sbrGrid->freqRes[env] = GetBits(bsi, 1);

		absBordLead =  absBorder;
		absBordTrail = NUM_TIME_SLOTS;
		numRelLead =   numRelBorder;
		numRelTrail =  0;

		for (rel = 0; rel < numRelLead; rel++)
			relBordLead[rel] = relBorder[rel];

		if (sbrGrid->pointer == 0)			middleBorder = 1;
		else if (sbrGrid->pointer == 1)		middleBorder = sbrGrid->numEnv - 1;
		else								middleBorder = sbrGrid->pointer - 1;

		break;

	case SBR_GRID_VARVAR:
		absBordLead =   GetBits(bsi, 2);	/* absBorder0 */
		absBordTrail =  GetBits(bsi, 2) + NUM_TIME_SLOTS;	/* absBorder1 */
		numRelBorder0 = GetBits(bsi, 2);
		numRelBorder1 = GetBits(bsi, 2);

		sbrGrid->numEnv = numRelBorder0 + numRelBorder1 + 1;
		if(sbrGrid->numEnv > 5)
			return ERR_AAC_UNKNOWN;

		for (rel = 0; rel < numRelBorder0; rel++)
			relBorder0[rel] = 2*GetBits(bsi, 2) + 2;

		for (rel = 0; rel < numRelBorder1; rel++)
			relBorder1[rel] = 2*GetBits(bsi, 2) + 2;

		pBits = cLog2[numRelBorder0 + numRelBorder1 + 2];
		sbrGrid->pointer = GetBits(bsi, pBits);

		for (env = 0; env < sbrGrid->numEnv; env++)
			sbrGrid->freqRes[env] = GetBits(bsi, 1);

		numRelLead =  numRelBorder0;
		numRelTrail = numRelBorder1;

		for (rel = 0; rel < numRelLead; rel++)
			relBordLead[rel] = relBorder0[rel];

		for (rel = 0; rel < numRelTrail; rel++)
			relBordTrail[rel] = relBorder1[rel];

		if (sbrGrid->pointer > 1)			middleBorder = sbrGrid->numEnv + 1 - sbrGrid->pointer;
		else								middleBorder = sbrGrid->numEnv - 1;

		break;
	}

	/* build time border vector */
	sbrGrid->envTimeBorder[0] = absBordLead * SAMPLES_PER_SLOT;

	rel = 0;
	border = absBordLead;
	for (env = 1; env <= numRelLead; env++) {
		border += relBordLead[rel++];
		sbrGrid->envTimeBorder[env] = border * SAMPLES_PER_SLOT;
	}

	rel = 0;
	border = absBordTrail;
	for (env = sbrGrid->numEnv - 1; env > numRelLead; env--) {
		border -= relBordTrail[rel++];
		sbrGrid->envTimeBorder[env] = border * SAMPLES_PER_SLOT;
	}

	sbrGrid->envTimeBorder[sbrGrid->numEnv] = absBordTrail * SAMPLES_PER_SLOT;

	if (sbrGrid->numEnv > 1) {
		sbrGrid->numNoiseFloors = 2;
		sbrGrid->noiseTimeBorder[0] = sbrGrid->envTimeBorder[0];
		sbrGrid->noiseTimeBorder[1] = sbrGrid->envTimeBorder[middleBorder];
		sbrGrid->noiseTimeBorder[2] = sbrGrid->envTimeBorder[sbrGrid->numEnv];
	} else {
		sbrGrid->numNoiseFloors = 1;
		sbrGrid->noiseTimeBorder[0] = sbrGrid->envTimeBorder[0];
		sbrGrid->noiseTimeBorder[1] = sbrGrid->envTimeBorder[1];
	}

	return ERR_AAC_NONE;
}

/**************************************************************************************
 * Function:    UnpackDeltaTimeFreq
 *
 * Description: unpack time/freq flags for delta coding of SBR envelopes (table 4.63)
 *
 * Inputs:      BitStreamInfo struct pointing to start of dt/df flags
 *              number of envelopes
 *              number of noise floors
 * 
 * Outputs:     delta flags for envelope and noise floors
 *
 * Return:      none
 **************************************************************************************/
static void UnpackDeltaTimeFreq(BitStreamInfo *bsi, int numEnv, unsigned char *deltaFlagEnv, 
								int numNoiseFloors, unsigned char *deltaFlagNoise)
{
	int env, noiseFloor;

	for (env = 0; env < numEnv; env++)
		deltaFlagEnv[env] = GetBits(bsi, 1);

	for (noiseFloor = 0; noiseFloor < numNoiseFloors; noiseFloor++)
		deltaFlagNoise[noiseFloor] = GetBits(bsi, 1);
}

/**************************************************************************************
 * Function:    UnpackInverseFilterMode
 *
 * Description: unpack invf flags for chirp factor calculation (table 4.64)
 *
 * Inputs:      BitStreamInfo struct pointing to start of invf flags
 *              number of noise floor bands
 * 
 * Outputs:     invf flags for noise floor bands
 *
 * Return:      none
 **************************************************************************************/
static void UnpackInverseFilterMode(BitStreamInfo *bsi, int numNoiseFloorBands, unsigned char *mode)
{
	int n;	

	for (n = 0; n < numNoiseFloorBands; n++)
		mode[n] = GetBits(bsi, 2);
}

/**************************************************************************************
 * Function:    UnpackSinusoids
 *
 * Description: unpack sinusoid (harmonic) flags for each SBR subband (table 4.67)
 *
 * Inputs:      BitStreamInfo struct pointing to start of sinusoid flags
 *              number of high resolution SBR subbands (nHigh)
 * 
 * Outputs:     sinusoid flags for each SBR subband, zero-filled above nHigh
 *
 * Return:      none
 **************************************************************************************/
static void UnpackSinusoids(BitStreamInfo *bsi, int nHigh, int addHarmonicFlag, unsigned char *addHarmonic)
{
	int n;

	n = 0;
	if (addHarmonicFlag) {
		for (  ; n < nHigh; n++)
			addHarmonic[n] = GetBits(bsi, 1);
	}

	/* zero out unused bands */
	for (     ; n < MAX_QMF_BANDS; n++)
		addHarmonic[n] = 0;
}

/**************************************************************************************
 * Function:    CopyCouplingGrid
 *
 * Description: copy grid parameters from left to right for channel coupling
 *
 * Inputs:      initialized SBRGrid struct for left channel
 * 
 * Outputs:     initialized SBRGrid struct for right channel
 *
 * Return:      none
 **************************************************************************************/
static void CopyCouplingGrid(SBRGrid *sbrGridLeft, SBRGrid *sbrGridRight)
{
	int env, noiseFloor;

	sbrGridRight->frameClass =     sbrGridLeft->frameClass;
	sbrGridRight->ampResFrame =    sbrGridLeft->ampResFrame;
	sbrGridRight->pointer =        sbrGridLeft->pointer;

	sbrGridRight->numEnv =         sbrGridLeft->numEnv;
	for (env = 0; env < sbrGridLeft->numEnv; env++) {
		sbrGridRight->envTimeBorder[env] = sbrGridLeft->envTimeBorder[env];
		sbrGridRight->freqRes[env] =       sbrGridLeft->freqRes[env];
	}
	sbrGridRight->envTimeBorder[env] = sbrGridLeft->envTimeBorder[env];	/* borders are [0, numEnv] inclusive */

	sbrGridRight->numNoiseFloors = sbrGridLeft->numNoiseFloors;
	for (noiseFloor = 0; noiseFloor <= sbrGridLeft->numNoiseFloors; noiseFloor++)
		sbrGridRight->noiseTimeBorder[noiseFloor] = sbrGridLeft->noiseTimeBorder[noiseFloor];

	/* numEnvPrev, numNoiseFloorsPrev, freqResPrev are updated in DecodeSBREnvelope() and DecodeSBRNoise() */
}

/**************************************************************************************
 * Function:    CopyCouplingInverseFilterMode
 *
 * Description: copy invf flags from left to right for channel coupling
 *
 * Inputs:      invf flags for left channel
 *              number of noise floor bands
 * 
 * Outputs:     invf flags for right channel
 *
 * Return:      none
 **************************************************************************************/
static void CopyCouplingInverseFilterMode(int numNoiseFloorBands, unsigned char *modeLeft, unsigned char *modeRight)
{
	int band;

	for (band = 0; band < numNoiseFloorBands; band++)
		modeRight[band] = modeLeft[band];
}

/**************************************************************************************
 * Function:    UnpackSBRSingleChannel
 *
 * Description: unpack sideband info (grid, delta flags, invf flags, envelope and 
 *                noise floor configuration, sinusoids) for a single channel
 *
 * Inputs:      BitStreamInfo struct pointing to start of sideband info
 *              initialized PSInfoSBR struct (after parsing SBR header and building
 *                frequency tables)
 *              base output channel (range = [0, nChans-1])
 * 
 * Outputs:     updated PSInfoSBR struct (SBRGrid and SBRChan)
 *
 * Return:      0 if successful, error code (< 0) if error
 **************************************************************************************/
int UnpackSBRSingleChannel(BitStreamInfo *bsi, PSInfoSBR *psi, int chBase)
{
	int bitsLeft, ret;
	SBRHeader *sbrHdr = &(psi->sbrHdr[chBase]);
	SBRGrid *sbrGridL = &(psi->sbrGrid[chBase+0]);
	SBRFreq *sbrFreq =  &(psi->sbrFreq[chBase]);
	SBRChan *sbrChanL = &(psi->sbrChan[chBase+0]);

	psi->dataExtra = GetBits(bsi, 1);
	if (psi->dataExtra)
		psi->resBitsData = GetBits(bsi, 4);

	ret = UnpackSBRGrid(bsi, sbrHdr, sbrGridL);
	if(ret != ERR_AAC_NONE)
		return ret;

	UnpackDeltaTimeFreq(bsi, sbrGridL->numEnv, sbrChanL->deltaFlagEnv, sbrGridL->numNoiseFloors, sbrChanL->deltaFlagNoise);
	UnpackInverseFilterMode(bsi, sbrFreq->numNoiseFloorBands, sbrChanL->invfMode[1]);

	ret = DecodeSBREnvelope(bsi, psi, sbrGridL, sbrFreq, sbrChanL, 0);
	if(ret != ERR_AAC_NONE)
		return ret;

	ret = DecodeSBRNoise(bsi, psi, sbrGridL, sbrFreq, sbrChanL, 0);
	if (ret != ERR_AAC_NONE)
		return ret;

	sbrChanL->addHarmonicFlag[1] = GetBits(bsi, 1);
	UnpackSinusoids(bsi, sbrFreq->nHigh, sbrChanL->addHarmonicFlag[1], sbrChanL->addHarmonic[1]);
	
	psi->extendedDataPresent = GetBits(bsi, 1);
	if (psi->extendedDataPresent) {
		psi->extendedDataSize = GetBits(bsi, 4);
		if (psi->extendedDataSize == 15)
			psi->extendedDataSize += GetBits(bsi, 8);

		bitsLeft = 8 * psi->extendedDataSize;

		/* get ID, unpack extension info, do whatever is necessary with it... */
		while (bitsLeft > 0) {
			GetBits(bsi, 8);
			bitsLeft -= 8;
		}
	}

	return ERR_AAC_NONE;
}

/**************************************************************************************
 * Function:    UnpackSBRChannelPair
 *
 * Description: unpack sideband info (grid, delta flags, invf flags, envelope and 
 *                noise floor configuration, sinusoids) for a channel pair
 *
 * Inputs:      BitStreamInfo struct pointing to start of sideband info
 *              initialized PSInfoSBR struct (after parsing SBR header and building
 *                frequency tables)
 *              base output channel (range = [0, nChans-1])
 * 
 * Outputs:     updated PSInfoSBR struct (SBRGrid and SBRChan for both channels)
 *
 * Return:      0 if successful, error code (< 0) if error
 **************************************************************************************/
int UnpackSBRChannelPair(BitStreamInfo *bsi, PSInfoSBR *psi, int chBase)
{
	int bitsLeft, ret;
	SBRHeader *sbrHdr = &(psi->sbrHdr[chBase]);
	SBRGrid *sbrGridL = &(psi->sbrGrid[chBase+0]), *sbrGridR = &(psi->sbrGrid[chBase+1]);
	SBRFreq *sbrFreq =  &(psi->sbrFreq[chBase]);
	SBRChan *sbrChanL = &(psi->sbrChan[chBase+0]), *sbrChanR = &(psi->sbrChan[chBase+1]);

	psi->dataExtra = GetBits(bsi, 1);
	if (psi->dataExtra) {
		psi->resBitsData = GetBits(bsi, 4);
		psi->resBitsData = GetBits(bsi, 4);
	}

	psi->couplingFlag = GetBits(bsi, 1);
	if (psi->couplingFlag) {
		ret = UnpackSBRGrid(bsi, sbrHdr, sbrGridL);
		if (ret != ERR_AAC_NONE)
			return ret;

		CopyCouplingGrid(sbrGridL, sbrGridR);

		UnpackDeltaTimeFreq(bsi, sbrGridL->numEnv, sbrChanL->deltaFlagEnv, sbrGridL->numNoiseFloors, sbrChanL->deltaFlagNoise);
		UnpackDeltaTimeFreq(bsi, sbrGridR->numEnv, sbrChanR->deltaFlagEnv, sbrGridR->numNoiseFloors, sbrChanR->deltaFlagNoise);

		UnpackInverseFilterMode(bsi, sbrFreq->numNoiseFloorBands, sbrChanL->invfMode[1]);
		CopyCouplingInverseFilterMode(sbrFreq->numNoiseFloorBands, sbrChanL->invfMode[1], sbrChanR->invfMode[1]);
		
		ret = DecodeSBREnvelope(bsi, psi, sbrGridL, sbrFreq, sbrChanL, 0);
		if (ret != ERR_AAC_NONE)
			return ret;

		ret = DecodeSBRNoise(bsi, psi, sbrGridL, sbrFreq, sbrChanL, 0);
		if (ret != ERR_AAC_NONE)
			return ret;

		ret = DecodeSBREnvelope(bsi, psi, sbrGridR, sbrFreq, sbrChanR, 1);
		if (ret != ERR_AAC_NONE)
			return ret;

		ret = DecodeSBRNoise(bsi, psi, sbrGridR, sbrFreq, sbrChanR, 1);
		if (ret != ERR_AAC_NONE)
			return ret;

		/* pass RIGHT sbrChan struct */
		UncoupleSBREnvelope(psi, sbrGridL, sbrFreq, sbrChanR);
		UncoupleSBRNoise(psi, sbrGridL, sbrFreq, sbrChanR);

	} else {
		ret = UnpackSBRGrid(bsi, sbrHdr, sbrGridL);
		if (ret != ERR_AAC_NONE)
			return ret;

		ret = UnpackSBRGrid(bsi, sbrHdr, sbrGridR);
		if (ret != ERR_AAC_NONE)
			return ret;

		UnpackDeltaTimeFreq(bsi, sbrGridL->numEnv, sbrChanL->deltaFlagEnv, sbrGridL->numNoiseFloors, sbrChanL->deltaFlagNoise);
		UnpackDeltaTimeFreq(bsi, sbrGridR->numEnv, sbrChanR->deltaFlagEnv, sbrGridR->numNoiseFloors, sbrChanR->deltaFlagNoise);
		UnpackInverseFilterMode(bsi, sbrFreq->numNoiseFloorBands, sbrChanL->invfMode[1]);
		UnpackInverseFilterMode(bsi, sbrFreq->numNoiseFloorBands, sbrChanR->invfMode[1]);

		ret = DecodeSBREnvelope(bsi, psi, sbrGridL, sbrFreq, sbrChanL, 0);
		if (ret != ERR_AAC_NONE)
			return ret;

		ret = DecodeSBREnvelope(bsi, psi, sbrGridR, sbrFreq, sbrChanR, 1);
		if (ret != ERR_AAC_NONE)
			return ret;

		ret = DecodeSBRNoise(bsi, psi, sbrGridL, sbrFreq, sbrChanL, 0);
		if (ret != ERR_AAC_NONE)
			return ret;

		ret = DecodeSBRNoise(bsi, psi, sbrGridR, sbrFreq, sbrChanR, 1);
		if (ret != ERR_AAC_NONE)
			return ret;
	}

	sbrChanL->addHarmonicFlag[1] = GetBits(bsi, 1);
	UnpackSinusoids(bsi, sbrFreq->nHigh, sbrChanL->addHarmonicFlag[1], sbrChanL->addHarmonic[1]);

	sbrChanR->addHarmonicFlag[1] = GetBits(bsi, 1);
	UnpackSinusoids(bsi, sbrFreq->nHigh, sbrChanR->addHarmonicFlag[1], sbrChanR->addHarmonic[1]);

	psi->extendedDataPresent = GetBits(bsi, 1);
	if (psi->extendedDataPresent) {
		psi->extendedDataSize = GetBits(bsi, 4);
		if (psi->extendedDataSize == 15)
			psi->extendedDataSize += GetBits(bsi, 8);

		bitsLeft = 8 * psi->extendedDataSize;

		/* get ID, unpack extension info, do whatever is necessary with it... */
		while (bitsLeft > 0) {
			GetBits(bsi, 8);
			bitsLeft -= 8;
		}
	}

	return ERR_AAC_NONE;
}