EXPORT int speex_std_stereo_request_handler(SpeexBits * bits, void *state,
void *data)
{
(void)state;
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;
}
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);
}
}
