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diff --git a/src/libspeex/stereo.c b/src/libspeex/stereo.c
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+/* Copyright (C) 2002 Jean-Marc Valin
+ File: stereo.c
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions
+ are met:
+
+ - Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+
+ - Redistributions in binary form must reproduce the above copyright
+ notice, this list of conditions and the following disclaimer in the
+ documentation and/or other materials provided with the distribution.
+
+ - Neither the name of the Xiph.org Foundation nor the names of its
+ contributors may be used to endorse or promote products derived from
+ 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
+ LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION 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 OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <speex/speex_stereo.h>
+#include <speex/speex_callbacks.h>
+#include "math_approx.h"
+#include "vq.h"
+#include <math.h>
+#include "os_support.h"
+
+typedef struct RealSpeexStereoState {
+ spx_word32_t balance; /**< Left/right balance info */
+ spx_word32_t e_ratio; /**< Ratio of energies: E(left+right)/[E(left)+E(right)] */
+ spx_word32_t smooth_left; /**< Smoothed left channel gain */
+ spx_word32_t smooth_right; /**< Smoothed right channel gain */
+ spx_uint32_t reserved1; /**< Reserved for future use */
+ spx_int32_t reserved2; /**< Reserved for future use */
+} RealSpeexStereoState;
+
+
+/*float e_ratio_quant[4] = {1, 1.26, 1.587, 2};*/
+#ifndef FIXED_POINT
+static const float e_ratio_quant[4] = {.25f, .315f, .397f, .5f};
+static const float e_ratio_quant_bounds[3] = {0.2825f, 0.356f, 0.4485f};
+#else
+static const spx_word16_t e_ratio_quant[4] = {8192, 10332, 13009, 16384};
+static const spx_word16_t e_ratio_quant_bounds[3] = {9257, 11665, 14696};
+static const spx_word16_t balance_bounds[31] = {18, 23, 30, 38, 49, 63, 81, 104,
+ 134, 172, 221, 284, 364, 468, 600, 771,
+ 990, 1271, 1632, 2096, 2691, 3455, 4436, 5696,
+ 7314, 9392, 12059, 15484, 19882, 25529, 32766};
+#endif
+
+/* This is an ugly compatibility hack that properly resets the stereo state
+ In case it it compiled in fixed-point, but initialised with the deprecated
+ floating point static initialiser */
+#ifdef FIXED_POINT
+#define COMPATIBILITY_HACK(s) do {if ((s)->reserved1 != 0xdeadbeef) speex_stereo_state_reset((SpeexStereoState*)s); } while (0);
+#else
+#define COMPATIBILITY_HACK(s)
+#endif
+
+SpeexStereoState *speex_stereo_state_init()
+{
+ SpeexStereoState *stereo = speex_alloc(sizeof(SpeexStereoState));
+ speex_stereo_state_reset(stereo);
+ return stereo;
+}
+
+void speex_stereo_state_reset(SpeexStereoState *_stereo)
+{
+ RealSpeexStereoState *stereo = (RealSpeexStereoState*)_stereo;
+#ifdef FIXED_POINT
+ stereo->balance = 65536;
+ stereo->e_ratio = 16384;
+ stereo->smooth_left = 16384;
+ stereo->smooth_right = 16384;
+ stereo->reserved1 = 0xdeadbeef;
+ stereo->reserved2 = 0;
+#else
+ stereo->balance = 1.0f;
+ stereo->e_ratio = .5f;
+ stereo->smooth_left = 1.f;
+ stereo->smooth_right = 1.f;
+ stereo->reserved1 = 0;
+ stereo->reserved2 = 0;
+#endif
+}
+
+void speex_stereo_state_destroy(SpeexStereoState *stereo)
+{
+ speex_free(stereo);
+}
+
+#ifndef DISABLE_FLOAT_API
+void speex_encode_stereo(float *data, int frame_size, SpeexBits *bits)
+{
+ int i, tmp;
+ float e_left=0, e_right=0, e_tot=0;
+ float balance, e_ratio;
+ for (i=0;i<frame_size;i++)
+ {
+ e_left += ((float)data[2*i])*data[2*i];
+ e_right += ((float)data[2*i+1])*data[2*i+1];
+ data[i] = .5*(((float)data[2*i])+data[2*i+1]);
+ e_tot += ((float)data[i])*data[i];
+ }
+ balance=(e_left+1)/(e_right+1);
+ e_ratio = e_tot/(1+e_left+e_right);
+
+ /*Quantization*/
+ speex_bits_pack(bits, 14, 5);
+ speex_bits_pack(bits, SPEEX_INBAND_STEREO, 4);
+
+ balance=4*log(balance);
+
+ /*Pack sign*/
+ if (balance>0)
+ speex_bits_pack(bits, 0, 1);
+ else
+ speex_bits_pack(bits, 1, 1);
+ balance=floor(.5+fabs(balance));
+ if (balance>30)
+ balance=31;
+
+ speex_bits_pack(bits, (int)balance, 5);
+
+ /* FIXME: this is a hack */
+ tmp=scal_quant(e_ratio*Q15_ONE, e_ratio_quant_bounds, 4);
+ speex_bits_pack(bits, tmp, 2);
+}
+#endif /* #ifndef DISABLE_FLOAT_API */
+
+void speex_encode_stereo_int(spx_int16_t *data, int frame_size, SpeexBits *bits)
+{
+ int i, tmp;
+ spx_word32_t e_left=0, e_right=0, e_tot=0;
+ spx_word32_t balance, e_ratio;
+ spx_word32_t largest, smallest;
+ int balance_id;
+#ifdef FIXED_POINT
+ int shift;
+#endif
+
+ /* In band marker */
+ speex_bits_pack(bits, 14, 5);
+ /* Stereo marker */
+ speex_bits_pack(bits, SPEEX_INBAND_STEREO, 4);
+
+ for (i=0;i<frame_size;i++)
+ {
+ e_left += SHR32(MULT16_16(data[2*i],data[2*i]),8);
+ e_right += SHR32(MULT16_16(data[2*i+1],data[2*i+1]),8);
+#ifdef FIXED_POINT
+ /* I think this is actually unbiased */
+ data[i] = SHR16(data[2*i],1)+PSHR16(data[2*i+1],1);
+#else
+ data[i] = .5*(((float)data[2*i])+data[2*i+1]);
+#endif
+ e_tot += SHR32(MULT16_16(data[i],data[i]),8);
+ }
+ if (e_left > e_right)
+ {
+ speex_bits_pack(bits, 0, 1);
+ largest = e_left;
+ smallest = e_right;
+ } else {
+ speex_bits_pack(bits, 1, 1);
+ largest = e_right;
+ smallest = e_left;
+ }
+
+ /* Balance quantization */
+#ifdef FIXED_POINT
+ shift = spx_ilog2(largest)-15;
+ largest = VSHR32(largest, shift-4);
+ smallest = VSHR32(smallest, shift);
+ balance = DIV32(largest, ADD32(smallest, 1));
+ if (balance > 32767)
+ balance = 32767;
+ balance_id = scal_quant(EXTRACT16(balance), balance_bounds, 32);
+#else
+ balance=(largest+1.)/(smallest+1.);
+ balance=4*log(balance);
+ balance_id=floor(.5+fabs(balance));
+ if (balance_id>30)
+ balance_id=31;
+#endif
+
+ speex_bits_pack(bits, balance_id, 5);
+
+ /* "coherence" quantisation */
+#ifdef FIXED_POINT
+ shift = spx_ilog2(e_tot);
+ e_tot = VSHR32(e_tot, shift-25);
+ e_left = VSHR32(e_left, shift-10);
+ e_right = VSHR32(e_right, shift-10);
+ e_ratio = DIV32(e_tot, e_left+e_right+1);
+#else
+ e_ratio = e_tot/(1.+e_left+e_right);
+#endif
+
+ tmp=scal_quant(EXTRACT16(e_ratio), e_ratio_quant_bounds, 4);
+ /*fprintf (stderr, "%d %d %d %d\n", largest, smallest, balance_id, e_ratio);*/
+ speex_bits_pack(bits, tmp, 2);
+}
+
+#ifndef DISABLE_FLOAT_API
+void speex_decode_stereo(float *data, int frame_size, SpeexStereoState *_stereo)
+{
+ int i;
+ spx_word32_t balance;
+ spx_word16_t e_left, e_right, e_ratio;
+ RealSpeexStereoState *stereo = (RealSpeexStereoState*)_stereo;
+
+ COMPATIBILITY_HACK(stereo);
+
+ balance=stereo->balance;
+ e_ratio=stereo->e_ratio;
+
+ /* These two are Q14, with max value just below 2. */
+ e_right = DIV32(QCONST32(1., 22), spx_sqrt(MULT16_32_Q15(e_ratio, ADD32(QCONST32(1., 16), balance))));
+ e_left = SHR32(MULT16_16(spx_sqrt(balance), e_right), 8);
+
+ for (i=frame_size-1;i>=0;i--)
+ {
+ spx_word16_t tmp=data[i];
+ stereo->smooth_left = EXTRACT16(PSHR32(MAC16_16(MULT16_16(stereo->smooth_left, QCONST16(0.98, 15)), e_left, QCONST16(0.02, 15)), 15));
+ stereo->smooth_right = EXTRACT16(PSHR32(MAC16_16(MULT16_16(stereo->smooth_right, QCONST16(0.98, 15)), e_right, QCONST16(0.02, 15)), 15));
+ data[2*i] = (float)MULT16_16_P14(stereo->smooth_left, tmp);
+ data[2*i+1] = (float)MULT16_16_P14(stereo->smooth_right, tmp);
+ }
+}
+#endif /* #ifndef DISABLE_FLOAT_API */
+
+void speex_decode_stereo_int(spx_int16_t *data, int frame_size, SpeexStereoState *_stereo)
+{
+ int i;
+ spx_word32_t balance;
+ spx_word16_t e_left, e_right, e_ratio;
+ RealSpeexStereoState *stereo = (RealSpeexStereoState*)_stereo;
+
+ COMPATIBILITY_HACK(stereo);
+
+ balance=stereo->balance;
+ e_ratio=stereo->e_ratio;
+
+ /* These two are Q14, with max value just below 2. */
+ e_right = DIV32(QCONST32(1., 22), spx_sqrt(MULT16_32_Q15(e_ratio, ADD32(QCONST32(1., 16), balance))));
+ e_left = SHR32(MULT16_16(spx_sqrt(balance), e_right), 8);
+
+ for (i=frame_size-1;i>=0;i--)
+ {
+ spx_int16_t tmp=data[i];
+ stereo->smooth_left = EXTRACT16(PSHR32(MAC16_16(MULT16_16(stereo->smooth_left, QCONST16(0.98, 15)), e_left, QCONST16(0.02, 15)), 15));
+ stereo->smooth_right = EXTRACT16(PSHR32(MAC16_16(MULT16_16(stereo->smooth_right, QCONST16(0.98, 15)), e_right, QCONST16(0.02, 15)), 15));
+ data[2*i] = (spx_int16_t)MULT16_16_P14(stereo->smooth_left, tmp);
+ data[2*i+1] = (spx_int16_t)MULT16_16_P14(stereo->smooth_right, tmp);
+ }
+}
+
+int speex_std_stereo_request_handler(SpeexBits *bits, void *state, void *data)
+{
+ RealSpeexStereoState *stereo;
+ spx_word16_t sign=1, dexp;
+ int tmp;
+
+ stereo = (RealSpeexStereoState*)data;
+
+ COMPATIBILITY_HACK(stereo);
+
+ if (speex_bits_unpack_unsigned(bits, 1))
+ sign=-1;
+ dexp = speex_bits_unpack_unsigned(bits, 5);
+#ifndef FIXED_POINT
+ stereo->balance = exp(sign*.25*dexp);
+#else
+ stereo->balance = spx_exp(MULT16_16(sign, SHL16(dexp, 9)));
+#endif
+ tmp = speex_bits_unpack_unsigned(bits, 2);
+ stereo->e_ratio = e_ratio_quant[tmp];
+
+ return 0;
+}
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