summaryrefslogtreecommitdiffstats
path: root/libSBRenc/src/sbrenc_freq_sca.cpp
diff options
context:
space:
mode:
authorThe Android Open Source Project <initial-contribution@android.com>2012-07-11 10:15:24 -0700
committerThe Android Open Source Project <initial-contribution@android.com>2012-07-11 10:15:24 -0700
commit2228e360595641dd906bf1773307f43d304f5b2e (patch)
tree57f3d390ebb0782cc0de0fb984c8ea7e45b4f386 /libSBRenc/src/sbrenc_freq_sca.cpp
downloadODR-AudioEnc-2228e360595641dd906bf1773307f43d304f5b2e.tar.gz
ODR-AudioEnc-2228e360595641dd906bf1773307f43d304f5b2e.tar.bz2
ODR-AudioEnc-2228e360595641dd906bf1773307f43d304f5b2e.zip
Snapshot 2bda038c163298531d47394bc2c09e1409c5d0db
Change-Id: If584e579464f28b97d50e51fc76ba654a5536c54
Diffstat (limited to 'libSBRenc/src/sbrenc_freq_sca.cpp')
-rw-r--r--libSBRenc/src/sbrenc_freq_sca.cpp671
1 files changed, 671 insertions, 0 deletions
diff --git a/libSBRenc/src/sbrenc_freq_sca.cpp b/libSBRenc/src/sbrenc_freq_sca.cpp
new file mode 100644
index 0000000..bbcb29e
--- /dev/null
+++ b/libSBRenc/src/sbrenc_freq_sca.cpp
@@ -0,0 +1,671 @@
+
+/* -----------------------------------------------------------------------------------------------------------
+Software License for The Fraunhofer FDK AAC Codec Library for Android
+
+© Copyright 1995 - 2012 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
+ All rights reserved.
+
+ 1. INTRODUCTION
+The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software that implements
+the MPEG Advanced Audio Coding ("AAC") encoding and decoding scheme for digital audio.
+This FDK AAC Codec software is intended to be used on a wide variety of Android devices.
+
+AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient general perceptual
+audio codecs. AAC-ELD is considered the best-performing full-bandwidth communications codec by
+independent studies and is widely deployed. AAC has been standardized by ISO and IEC as part
+of the MPEG specifications.
+
+Patent licenses for necessary patent claims for the FDK AAC Codec (including those of Fraunhofer)
+may be obtained through Via Licensing (www.vialicensing.com) or through the respective patent owners
+individually for the purpose of encoding or decoding bit streams in products that are compliant with
+the ISO/IEC MPEG audio standards. Please note that most manufacturers of Android devices already license
+these patent claims through Via Licensing or directly from the patent owners, and therefore FDK AAC Codec
+software may already be covered under those patent licenses when it is used for those licensed purposes only.
+
+Commercially-licensed AAC software libraries, including floating-point versions with enhanced sound quality,
+are also available from Fraunhofer. Users are encouraged to check the Fraunhofer website for additional
+applications information and documentation.
+
+2. COPYRIGHT LICENSE
+
+Redistribution and use in source and binary forms, with or without modification, are permitted without
+payment of copyright license fees provided that you satisfy the following conditions:
+
+You must retain the complete text of this software license in redistributions of the FDK AAC Codec or
+your modifications thereto in source code form.
+
+You must retain the complete text of this software license in the documentation and/or other materials
+provided with redistributions of the FDK AAC Codec or your modifications thereto in binary form.
+You must make available free of charge copies of the complete source code of the FDK AAC Codec and your
+modifications thereto to recipients of copies in binary form.
+
+The name of Fraunhofer may not be used to endorse or promote products derived from this library without
+prior written permission.
+
+You may not charge copyright license fees for anyone to use, copy or distribute the FDK AAC Codec
+software or your modifications thereto.
+
+Your modified versions of the FDK AAC Codec must carry prominent notices stating that you changed the software
+and the date of any change. For modified versions of the FDK AAC Codec, the term
+"Fraunhofer FDK AAC Codec Library for Android" must be replaced by the term
+"Third-Party Modified Version of the Fraunhofer FDK AAC Codec Library for Android."
+
+3. NO PATENT LICENSE
+
+NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without limitation the patents of Fraunhofer,
+ARE GRANTED BY THIS SOFTWARE LICENSE. Fraunhofer provides no warranty of patent non-infringement with
+respect to this software.
+
+You may use this FDK AAC Codec software or modifications thereto only for purposes that are authorized
+by appropriate patent licenses.
+
+4. DISCLAIMER
+
+This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright holders and contributors
+"AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, including but not limited to the implied warranties
+of merchantability and fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary, or consequential damages,
+including but not limited to procurement of substitute goods or services; loss of use, data, or profits,
+or business interruption, however caused and on any theory of liability, whether in contract, strict
+liability, or tort (including negligence), arising in any way out of the use of this software, even if
+advised of the possibility of such damage.
+
+5. CONTACT INFORMATION
+
+Fraunhofer Institute for Integrated Circuits IIS
+Attention: Audio and Multimedia Departments - FDK AAC LL
+Am Wolfsmantel 33
+91058 Erlangen, Germany
+
+www.iis.fraunhofer.de/amm
+amm-info@iis.fraunhofer.de
+----------------------------------------------------------------------------------------------------------- */
+
+/*!
+ \file
+ \brief frequency scale
+*/
+
+#include "sbrenc_freq_sca.h"
+#include "sbr_misc.h"
+
+#include "genericStds.h"
+
+/* StartFreq */
+static INT getStartFreq(INT fs, const INT start_freq);
+
+/* StopFreq */
+static INT getStopFreq(INT fs, const INT stop_freq, const INT noChannels);
+
+static INT numberOfBands(INT b_p_o, INT start, INT stop, FIXP_DBL warp_factor);
+static void CalcBands(INT * diff, INT start , INT stop , INT num_bands);
+static INT modifyBands(INT max_band, INT * diff, INT length);
+static void cumSum(INT start_value, INT* diff, INT length, UCHAR *start_adress);
+
+
+
+/*******************************************************************************
+ Functionname: FDKsbrEnc_getSbrStartFreqRAW
+ *******************************************************************************
+ Description:
+
+ Arguments:
+
+ Return:
+ *******************************************************************************/
+
+INT
+FDKsbrEnc_getSbrStartFreqRAW (INT startFreq, INT QMFbands, INT fs)
+{
+ INT result;
+
+ if ( startFreq < 0 || startFreq > 15) {
+ return -1;
+ }
+ /* Update startFreq struct */
+ result = getStartFreq(fs, startFreq);
+
+ result = (result*fs/QMFbands+1)>>1;
+
+ return (result);
+
+} /* End FDKsbrEnc_getSbrStartFreqRAW */
+
+
+/*******************************************************************************
+ Functionname: getSbrStopFreq
+ *******************************************************************************
+ Description:
+
+ Arguments:
+
+ Return:
+ *******************************************************************************/
+INT FDKsbrEnc_getSbrStopFreqRAW (INT stopFreq, INT QMFbands, INT fs)
+{
+ INT result;
+
+ if ( stopFreq < 0 || stopFreq > 13)
+ return -1;
+
+
+ /* Uppdate stopFreq struct */
+ result = getStopFreq( fs, stopFreq, QMFbands);
+ result = (result*fs/QMFbands+1)>>1;
+
+ return (result);
+} /* End getSbrStopFreq */
+
+
+/*******************************************************************************
+ Functionname: getStartFreq
+ *******************************************************************************
+ Description:
+
+ Arguments:
+
+ Return:
+ *******************************************************************************/
+static INT
+getStartFreq(INT fs, const INT start_freq)
+{
+ INT k0_min;
+
+ switch(fs){
+ case 16000: k0_min = 24;
+ break;
+ case 22050: k0_min = 17;
+ break;
+ case 24000: k0_min = 16;
+ break;
+ case 32000: k0_min = 16;
+ break;
+ case 44100: k0_min = 12;
+ break;
+ case 48000: k0_min = 11;
+ break;
+ case 64000: k0_min = 10;
+ break;
+ case 88200: k0_min = 7;
+ break;
+ case 96000: k0_min = 7;
+ break;
+ default:
+ k0_min=11; /* illegal fs */
+ }
+
+
+ switch (fs) {
+
+ case 16000:
+ {
+ INT v_offset[]= {-8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7};
+ return (k0_min + v_offset[start_freq]);
+ }
+ case 22050:
+ {
+ INT v_offset[]= {-5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 9, 11, 13};
+ return (k0_min + v_offset[start_freq]);
+ }
+ case 24000:
+ {
+ INT v_offset[]= {-5, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 9, 11, 13, 16};
+ return (k0_min + v_offset[start_freq]);
+ }
+ case 32000:
+ {
+ INT v_offset[]= {-6, -4, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 9, 11, 13, 16};
+ return (k0_min + v_offset[start_freq]);
+ }
+ case 44100:
+ case 48000:
+ case 64000:
+ {
+ INT v_offset[]= {-4, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 9, 11, 13, 16, 20};
+ return (k0_min + v_offset[start_freq]);
+ }
+ case 88200:
+ case 96000:
+ {
+ INT v_offset[]= {-2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 9, 11, 13, 16, 20, 24};
+ return (k0_min + v_offset[start_freq]);
+ }
+ default:
+ {
+ INT v_offset[]= {0, 1, 2, 3, 4, 5, 6, 7, 9, 11, 13, 16, 20, 24, 28, 33};
+ return (k0_min + v_offset[start_freq]);
+ }
+ }
+} /* End getStartFreq */
+
+
+/*******************************************************************************
+ Functionname: getStopFreq
+ *******************************************************************************
+ Description:
+
+ Arguments:
+
+ Return:
+ *******************************************************************************/
+ static INT
+getStopFreq(INT fs, const INT stop_freq, const INT noChannels)
+{
+ INT result,i;
+ INT k1_min;
+ INT v_dstop[13];
+
+
+ INT *v_stop_freq = NULL;
+ INT v_stop_freq_16[14] = {48,49,50,51,52,54,55,56,57,59,60,61,63,64};
+ INT v_stop_freq_22[14] = {35,37,38,40,42,44,46,48,51,53,56,58,61,64};
+ INT v_stop_freq_24[14] = {32,34,36,38,40,42,44,46,49,52,55,58,61,64};
+ INT v_stop_freq_32[14] = {32,34,36,38,40,42,44,46,49,52,55,58,61,64};
+ INT v_stop_freq_44[14] = {23,25,27,29,32,34,37,40,43,47,51,55,59,64};
+ INT v_stop_freq_48[14] = {21,23,25,27,30,32,35,38,42,45,49,54,59,64};
+ INT v_stop_freq_64[14] = {20,22,24,26,29,31,34,37,41,45,49,54,59,64};
+ INT v_stop_freq_88[14] = {15,17,19,21,23,26,29,33,37,41,46,51,57,64};
+ INT v_stop_freq_96[14] = {13,15,17,19,21,24,27,31,35,39,44,50,57,64};
+
+ switch(fs){
+ case 16000: k1_min = 48;
+ v_stop_freq =v_stop_freq_16;
+ break;
+ case 22050: k1_min = 35;
+ v_stop_freq =v_stop_freq_22;
+ break;
+ case 24000: k1_min = 32;
+ v_stop_freq =v_stop_freq_24;
+ break;
+ case 32000: k1_min = 32;
+ v_stop_freq =v_stop_freq_32;
+ break;
+ case 44100: k1_min = 23;
+ v_stop_freq =v_stop_freq_44;
+ break;
+ case 48000: k1_min = 21;
+ v_stop_freq =v_stop_freq_48;
+ break;
+ case 64000: k1_min = 20;
+ v_stop_freq =v_stop_freq_64;
+ break;
+ case 88200: k1_min = 15;
+ v_stop_freq =v_stop_freq_88;
+ break;
+ case 96000: k1_min = 13;
+ v_stop_freq =v_stop_freq_96;
+ break;
+ default:
+ k1_min = 21; /* illegal fs */
+ }
+
+
+ /* Ensure increasing bandwidth */
+ for(i = 0; i <= 12; i++) {
+ v_dstop[i] = v_stop_freq[i+1] - v_stop_freq[i];
+ }
+
+ FDKsbrEnc_Shellsort_int(v_dstop, 13); /* Sort bandwidth changes */
+
+ result = k1_min;
+ for(i = 0; i < stop_freq; i++) {
+ result = result + v_dstop[i];
+ }
+
+ return(result);
+
+}/* End getStopFreq */
+
+
+/*******************************************************************************
+ Functionname: FDKsbrEnc_FindStartAndStopBand
+ *******************************************************************************
+ Description:
+
+ Arguments:
+
+ Return:
+ *******************************************************************************/
+INT
+FDKsbrEnc_FindStartAndStopBand(const INT samplingFreq,
+ const INT noChannels,
+ const INT startFreq,
+ const INT stopFreq,
+ const SR_MODE sampleRateMode,
+ INT *k0,
+ INT *k2)
+{
+
+ /* Update startFreq struct */
+ *k0 = getStartFreq(samplingFreq, startFreq);
+
+ /* Test if start freq is outside corecoder range */
+ if( ( sampleRateMode == 1 ) &&
+ ( samplingFreq*noChannels <
+ 2**k0 * samplingFreq) ) {
+ return (1); /* raise the cross-over frequency and/or lower the number
+ of target bands per octave (or lower the sampling frequency) */
+ }
+
+ /*Update stopFreq struct */
+ if ( stopFreq < 14 ) {
+ *k2 = getStopFreq(samplingFreq, stopFreq, noChannels);
+ } else if( stopFreq == 14 ) {
+ *k2 = 2 * *k0;
+ } else {
+ *k2 = 3 * *k0;
+ }
+
+ /* limit to Nyqvist */
+ if (*k2 > noChannels) {
+ *k2 = noChannels;
+ }
+
+
+
+ /* Test for invalid k0 k2 combinations */
+ if ( (samplingFreq == 44100) && ( (*k2 - *k0) > MAX_FREQ_COEFFS_FS44100 ) )
+ return (1); /* Number of bands exceeds valid range of MAX_FREQ_COEFFS for fs=44.1kHz */
+
+ if ( (samplingFreq >= 48000) && ( (*k2 - *k0) > MAX_FREQ_COEFFS_FS48000 ) )
+ return (1); /* Number of bands exceeds valid range of MAX_FREQ_COEFFS for fs>=48kHz */
+
+ if ((*k2 - *k0) > MAX_FREQ_COEFFS)
+ return (1);/*Number of bands exceeds valid range of MAX_FREQ_COEFFS */
+
+ if ((*k2 - *k0) < 0)
+ return (1);/* Number of bands is negative */
+
+
+ return(0);
+}
+
+/*******************************************************************************
+ Functionname: FDKsbrEnc_UpdateFreqScale
+ *******************************************************************************
+ Description:
+
+ Arguments:
+
+ Return:
+ *******************************************************************************/
+INT
+FDKsbrEnc_UpdateFreqScale(UCHAR *v_k_master, INT *h_num_bands,
+ const INT k0, const INT k2,
+ const INT freqScale,
+ const INT alterScale)
+
+{
+
+ INT b_p_o = 0; /* bands_per_octave */
+ FIXP_DBL warp = FL2FXCONST_DBL(0.0f);
+ INT dk = 0;
+
+ /* Internal variables */
+ INT k1 = 0, i;
+ INT num_bands0;
+ INT num_bands1;
+ INT diff_tot[MAX_OCTAVE + MAX_SECOND_REGION];
+ INT *diff0 = diff_tot;
+ INT *diff1 = diff_tot+MAX_OCTAVE;
+ INT k2_achived;
+ INT k2_diff;
+ INT incr = 0;
+
+ /* Init */
+ if (freqScale==1) b_p_o = 12;
+ if (freqScale==2) b_p_o = 10;
+ if (freqScale==3) b_p_o = 8;
+
+
+ if(freqScale > 0) /*Bark*/
+ {
+ if(alterScale==0)
+ warp = FL2FXCONST_DBL(0.5f); /* 1.0/(1.0*2.0) */
+ else
+ warp = FL2FXCONST_DBL(1.0f/2.6f); /* 1.0/(1.3*2.0); */
+
+
+ if(4*k2 >= 9*k0) /*two or more regions*/
+ {
+ k1=2*k0;
+
+ num_bands0=numberOfBands(b_p_o, k0, k1, FL2FXCONST_DBL(0.5f));
+ num_bands1=numberOfBands(b_p_o, k1, k2, warp);
+
+ CalcBands(diff0, k0, k1, num_bands0);/*CalcBands1 => diff0 */
+ FDKsbrEnc_Shellsort_int( diff0, num_bands0);/*SortBands sort diff0 */
+
+ if (diff0[0] == 0) /* too wide FB bands for target tuning */
+ {
+ return (1);/* raise the cross-over frequency and/or lower the number
+ of target bands per octave (or lower the sampling frequency */
+ }
+
+ cumSum(k0, diff0, num_bands0, v_k_master); /* cumsum */
+
+ CalcBands(diff1, k1, k2, num_bands1); /* CalcBands2 => diff1 */
+ FDKsbrEnc_Shellsort_int( diff1, num_bands1); /* SortBands sort diff1 */
+ if(diff0[num_bands0-1] > diff1[0]) /* max(1) > min(2) */
+ {
+ if(modifyBands(diff0[num_bands0-1],diff1, num_bands1))
+ return(1);
+ }
+
+ /* Add 2'nd region */
+ cumSum(k1, diff1, num_bands1, &v_k_master[num_bands0]);
+ *h_num_bands=num_bands0+num_bands1; /* Output nr of bands */
+
+ }
+ else /* one region */
+ {
+ k1=k2;
+
+ num_bands0=numberOfBands(b_p_o, k0, k1, FL2FXCONST_DBL(0.5f));
+ CalcBands(diff0, k0, k1, num_bands0);/* CalcBands1 => diff0 */
+ FDKsbrEnc_Shellsort_int( diff0, num_bands0); /* SortBands sort diff0 */
+
+ if (diff0[0] == 0) /* too wide FB bands for target tuning */
+ {
+ return (1); /* raise the cross-over frequency and/or lower the number
+ of target bands per octave (or lower the sampling frequency */
+ }
+
+ cumSum(k0, diff0, num_bands0, v_k_master);/* cumsum */
+ *h_num_bands=num_bands0; /* Output nr of bands */
+
+ }
+ }
+ else /* Linear mode */
+ {
+ if (alterScale==0) {
+ dk = 1;
+ num_bands0 = 2 * ((k2 - k0)/2); /* FLOOR to get to few number of bands*/
+ } else {
+ dk = 2;
+ num_bands0 = 2 * (((k2 - k0)/dk +1)/2); /* ROUND to get closest fit */
+ }
+
+ k2_achived = k0 + num_bands0*dk;
+ k2_diff = k2 - k2_achived;
+
+ for(i=0;i<num_bands0;i++)
+ diff_tot[i] = dk;
+
+ /* If linear scale wasn't achived */
+ /* and we got wide SBR are */
+ if (k2_diff < 0) {
+ incr = 1;
+ i = 0;
+ }
+
+ /* If linear scale wasn't achived */
+ /* and we got small SBR are */
+ if (k2_diff > 0) {
+ incr = -1;
+ i = num_bands0-1;
+ }
+
+ /* Adjust diff vector to get sepc. SBR range */
+ while (k2_diff != 0) {
+ diff_tot[i] = diff_tot[i] - incr;
+ i = i + incr;
+ k2_diff = k2_diff + incr;
+ }
+
+ cumSum(k0, diff_tot, num_bands0, v_k_master);/* cumsum */
+ *h_num_bands=num_bands0; /* Output nr of bands */
+
+ }
+
+ if (*h_num_bands < 1)
+ return(1); /*To small sbr area */
+
+ return (0);
+}/* End FDKsbrEnc_UpdateFreqScale */
+
+static INT
+numberOfBands(INT b_p_o, INT start, INT stop, FIXP_DBL warp_factor)
+{
+ INT result=0;
+ /* result = 2* (INT) ( (double)b_p_o * (double)(FDKlog((double)stop/(double)start)/FDKlog((double)2)) * (double)FX_DBL2FL(warp_factor) + 0.5); */
+ result = ( ( b_p_o * fMult( (CalcLdInt(stop) - CalcLdInt(start)), warp_factor) + (FL2FX_DBL(0.5f)>>LD_DATA_SHIFT)
+ ) >> ((DFRACT_BITS-1)-LD_DATA_SHIFT) ) << 1; /* do not optimize anymore (rounding!!) */
+
+ return(result);
+}
+
+
+static void
+CalcBands(INT * diff, INT start , INT stop , INT num_bands)
+{
+ INT i, qb, qe, qtmp;
+ INT previous;
+ INT current;
+ FIXP_DBL base, exp, tmp;
+
+ previous=start;
+ for(i=1; i<= num_bands; i++)
+ {
+ base = fDivNorm((FIXP_DBL)stop, (FIXP_DBL)start, &qb);
+ exp = fDivNorm((FIXP_DBL)i, (FIXP_DBL)num_bands, &qe);
+ tmp = fPow(base, qb, exp, qe, &qtmp);
+ tmp = fMult(tmp, (FIXP_DBL)(start<<24));
+ current = (INT)scaleValue(tmp, qtmp-23);
+ current = (current+1) >> 1; /* rounding*/
+ diff[i-1] = current-previous;
+ previous = current;
+ }
+
+}/* End CalcBands */
+
+
+static void
+cumSum(INT start_value, INT* diff, INT length, UCHAR *start_adress)
+{
+ INT i;
+ start_adress[0]=start_value;
+ for(i=1;i<=length;i++)
+ start_adress[i]=start_adress[i-1]+diff[i-1];
+} /* End cumSum */
+
+
+static INT
+modifyBands(INT max_band_previous, INT * diff, INT length)
+{
+ INT change=max_band_previous-diff[0];
+
+ /* Limit the change so that the last band cannot get narrower than the first one */
+ if ( change > (diff[length-1] - diff[0]) / 2 )
+ change = (diff[length-1] - diff[0]) / 2;
+
+ diff[0] += change;
+ diff[length-1] -= change;
+ FDKsbrEnc_Shellsort_int(diff, length);
+
+ return(0);
+}/* End modifyBands */
+
+
+/*******************************************************************************
+ Functionname: FDKsbrEnc_UpdateHiRes
+ *******************************************************************************
+ Description:
+
+ Arguments:
+
+ Return:
+ *******************************************************************************/
+INT
+FDKsbrEnc_UpdateHiRes(UCHAR *h_hires, INT *num_hires,UCHAR * v_k_master,
+ INT num_master , INT *xover_band, SR_MODE drOrSr,
+ INT noQMFChannels)
+{
+ INT i;
+ INT divider;
+ INT max1,max2;
+
+ /* Check if we use a Dual rate => diver=2 else 1 */
+ divider = (drOrSr == DUAL_RATE) ? 2 : 1;
+
+ if( (v_k_master[*xover_band] > (noQMFChannels/divider) ) ||
+ ( *xover_band > num_master ) ) {
+ /* xover_band error, too big for this startFreq. Will be clipped */
+
+ /* Calculate maximum value for xover_band */
+ max1=0;
+ max2=num_master;
+ while( (v_k_master[max1+1] < (noQMFChannels/divider)) &&
+ ( (max1+1) < max2) )
+ {
+ max1++;
+ }
+
+ *xover_band=max1;
+ }
+
+ *num_hires = num_master - *xover_band;
+ for(i = *xover_band; i <= num_master; i++)
+ {
+ h_hires[i - *xover_band] = v_k_master[i];
+ }
+
+ return (0);
+}/* End FDKsbrEnc_UpdateHiRes */
+
+
+/*******************************************************************************
+ Functionname: FDKsbrEnc_UpdateLoRes
+ *******************************************************************************
+ Description:
+
+ Arguments:
+
+ Return:
+ *******************************************************************************/
+void
+FDKsbrEnc_UpdateLoRes(UCHAR * h_lores, INT *num_lores, UCHAR * h_hires, INT num_hires)
+{
+ INT i;
+
+ if(num_hires%2 == 0) /* if even number of hires bands */
+ {
+ *num_lores=num_hires/2;
+ /* Use every second lores=hires[0,2,4...] */
+ for(i=0;i<=*num_lores;i++)
+ h_lores[i]=h_hires[i*2];
+
+ }
+ else /* odd number of hires which means xover is odd */
+ {
+ *num_lores=(num_hires+1)/2;
+
+ /* Use lores=hires[0,1,3,5 ...] */
+ h_lores[0]=h_hires[0];
+ for(i=1;i<=*num_lores;i++)
+ {
+ h_lores[i]=h_hires[i*2-1];
+ }
+ }
+
+}/* End FDKsbrEnc_UpdateLoRes */