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/*
* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
/*
* This file contains the function WebRtcSpl_ComplexIFFT().
* The description header can be found in signal_processing_library.h
*
*/
#include "signal_processing_library.h"
#define CIFFTSFT 14
#define CIFFTRND 1
#if (defined ARM9E_GCC) || (defined ARM_WINM) || (defined ANDROID_AECOPT)
extern "C" int FFT_4OIQ14(void *src, void *dest, int NC, int shift);
// For detailed description of the fft functions, check the readme files in fft_ARM9E folder.
int WebRtcSpl_ComplexIFFT2(WebRtc_Word16 frfi[], WebRtc_Word16 frfiOut[], int stages, int mode)
{
FFT_4OIQ14(frfi, frfiOut, 1 << stages, 0);
return 0;
}
#endif
int WebRtcSpl_ComplexIFFT(WebRtc_Word16 frfi[], int stages, int mode)
{
int i, j, l, k, istep, n, m, scale, shift;
WebRtc_Word16 wr, wi;
WebRtc_Word32 tr32, ti32, qr32, qi32;
WebRtc_Word32 tmp32, round2;
/* The 1024-value is a constant given from the size of WebRtcSpl_kSinTable1024[],
* and should not be changed depending on the input parameter 'stages'
*/
n = 1 << stages;
if (n > 1024)
return -1;
scale = 0;
l = 1;
k = 10 - 1; /* Constant for given WebRtcSpl_kSinTable1024[]. Do not change
depending on the input parameter 'stages' */
while (l < n)
{
// variable scaling, depending upon data
shift = 0;
round2 = 8192;
tmp32 = (WebRtc_Word32)WebRtcSpl_MaxAbsValueW16(frfi, 2 * n);
if (tmp32 > 13573)
{
shift++;
scale++;
round2 <<= 1;
}
if (tmp32 > 27146)
{
shift++;
scale++;
round2 <<= 1;
}
istep = l << 1;
if (mode == 0)
{
// mode==0: Low-complexity and Low-accuracy mode
for (m = 0; m < l; ++m)
{
j = m << k;
/* The 256-value is a constant given as 1/4 of the size of
* WebRtcSpl_kSinTable1024[], and should not be changed depending on the input
* parameter 'stages'. It will result in 0 <= j < N_SINE_WAVE/2
*/
wr = WebRtcSpl_kSinTable1024[j + 256];
wi = WebRtcSpl_kSinTable1024[j];
for (i = m; i < n; i += istep)
{
j = i + l;
tr32 = WEBRTC_SPL_RSHIFT_W32((WEBRTC_SPL_MUL_16_16_RSFT(wr, frfi[2 * j], 0)
- WEBRTC_SPL_MUL_16_16_RSFT(wi, frfi[2 * j + 1], 0)), 15);
ti32 = WEBRTC_SPL_RSHIFT_W32(
(WEBRTC_SPL_MUL_16_16_RSFT(wr, frfi[2 * j + 1], 0)
+ WEBRTC_SPL_MUL_16_16_RSFT(wi,frfi[2*j],0)), 15);
qr32 = (WebRtc_Word32)frfi[2 * i];
qi32 = (WebRtc_Word32)frfi[2 * i + 1];
frfi[2 * j] = (WebRtc_Word16)WEBRTC_SPL_RSHIFT_W32(qr32 - tr32, shift);
frfi[2 * j + 1] = (WebRtc_Word16)WEBRTC_SPL_RSHIFT_W32(qi32 - ti32, shift);
frfi[2 * i] = (WebRtc_Word16)WEBRTC_SPL_RSHIFT_W32(qr32 + tr32, shift);
frfi[2 * i + 1] = (WebRtc_Word16)WEBRTC_SPL_RSHIFT_W32(qi32 + ti32, shift);
}
}
} else
{
// mode==1: High-complexity and High-accuracy mode
for (m = 0; m < l; ++m)
{
j = m << k;
/* The 256-value is a constant given as 1/4 of the size of
* WebRtcSpl_kSinTable1024[], and should not be changed depending on the input
* parameter 'stages'. It will result in 0 <= j < N_SINE_WAVE/2
*/
wr = WebRtcSpl_kSinTable1024[j + 256];
wi = WebRtcSpl_kSinTable1024[j];
for (i = m; i < n; i += istep)
{
j = i + l;
tr32 = WEBRTC_SPL_RSHIFT_W32((WEBRTC_SPL_MUL_16_16_RSFT(wr, frfi[2 * j], 0)
- WEBRTC_SPL_MUL_16_16_RSFT(wi, frfi[2 * j + 1], 0) + CIFFTRND),
15 - CIFFTSFT);
ti32 = WEBRTC_SPL_RSHIFT_W32(
(WEBRTC_SPL_MUL_16_16_RSFT(wr, frfi[2 * j + 1], 0)
+ WEBRTC_SPL_MUL_16_16_RSFT(wi, frfi[2 * j], 0)
+ CIFFTRND), 15 - CIFFTSFT);
qr32 = ((WebRtc_Word32)frfi[2 * i]) << CIFFTSFT;
qi32 = ((WebRtc_Word32)frfi[2 * i + 1]) << CIFFTSFT;
frfi[2 * j] = (WebRtc_Word16)WEBRTC_SPL_RSHIFT_W32((qr32 - tr32+round2),
shift+CIFFTSFT);
frfi[2 * j + 1] = (WebRtc_Word16)WEBRTC_SPL_RSHIFT_W32(
(qi32 - ti32 + round2), shift + CIFFTSFT);
frfi[2 * i] = (WebRtc_Word16)WEBRTC_SPL_RSHIFT_W32((qr32 + tr32 + round2),
shift + CIFFTSFT);
frfi[2 * i + 1] = (WebRtc_Word16)WEBRTC_SPL_RSHIFT_W32(
(qi32 + ti32 + round2), shift + CIFFTSFT);
}
}
}
--k;
l = istep;
}
return scale;
}
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