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Diffstat (limited to 'media/openmax_dl/dl/sp/src/omxSP_FFTInit_R_F32.c')
| -rw-r--r-- | media/openmax_dl/dl/sp/src/omxSP_FFTInit_R_F32.c | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/media/openmax_dl/dl/sp/src/omxSP_FFTInit_R_F32.c b/media/openmax_dl/dl/sp/src/omxSP_FFTInit_R_F32.c new file mode 100644 index 0000000000..32d22230ed --- /dev/null +++ b/media/openmax_dl/dl/sp/src/omxSP_FFTInit_R_F32.c @@ -0,0 +1,210 @@ +/* + * Copyright (c) 2013 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 is a modification of omxSP_FFTInit_R_S32.c to support float + * instead of S32. + */ + +#include "dl/api/armOMX.h" +#include "dl/api/omxtypes.h" +#include "dl/sp/api/armSP.h" +#include "dl/sp/api/omxSP.h" + +/** + * Function: omxSP_FFTInit_R_F32 + * + * Description: + * Initialize the real forward-FFT specification information struct. + * + * Remarks: + * This function is used to initialize the specification structures + * for functions <ippsFFTFwd_RToCCS_F32_Sfs> and + * <ippsFFTInv_CCSToR_F32_Sfs>. Memory for *pFFTSpec must be + * allocated prior to calling this function. The number of bytes + * required for *pFFTSpec can be determined using + * <FFTGetBufSize_R_F32>. + * + * Parameters: + * [in] order base-2 logarithm of the desired block length; + * valid in the range [1,12]. ([1,15] if + * BIG_FFT_TABLE is defined.) + * [out] pFFTFwdSpec pointer to the initialized specification structure. + * + * Return Value: + * Standard omxError result. See enumeration for possible result codes. + * + */ +OMXResult omxSP_FFTInit_R_F32(OMXFFTSpec_R_F32* pFFTSpec, OMX_INT order) { + OMX_INT i; + OMX_INT j; + OMX_FC32* pTwiddle; + OMX_FC32* pTwiddle1; + OMX_FC32* pTwiddle2; + OMX_FC32* pTwiddle3; + OMX_FC32* pTwiddle4; + OMX_F32* pBuf; + OMX_U16* pBitRev; + OMX_U32 pTmp; + OMX_INT Nby2; + OMX_INT N; + OMX_INT M; + OMX_INT diff; + OMX_INT step; + OMX_F32 x; + OMX_F32 y; + OMX_F32 xNeg; + ARMsFFTSpec_R_FC32* pFFTStruct = 0; + + pFFTStruct = (ARMsFFTSpec_R_FC32 *) pFFTSpec; + + /* Validate args */ + if (!pFFTSpec || (order < 1) || (order > TWIDDLE_TABLE_ORDER)) + return OMX_Sts_BadArgErr; + + /* Do the initializations */ + Nby2 = 1 << (order - 1); + N = Nby2 << 1; + + /* optimized implementations don't use bitreversal */ + pBitRev = NULL; + + pTwiddle = (OMX_FC32 *) (sizeof(ARMsFFTSpec_R_SC32) + (OMX_S8*) pFFTSpec); + + /* Align to 32 byte boundary */ + pTmp = ((OMX_U32)pTwiddle) & 31; + if (pTmp) + pTwiddle = (OMX_FC32*) ((OMX_S8*)pTwiddle + (32 - pTmp)); + + pBuf = (OMX_F32*) (sizeof(OMX_FC32)*(5*N/8) + (OMX_S8*) pTwiddle); + + /* Align to 32 byte boundary */ + pTmp = ((OMX_U32)pBuf)&31; /* (OMX_U32)pBuf % 32 */ + if (pTmp) + pBuf = (OMX_F32*) ((OMX_S8*)pBuf + (32 - pTmp)); + + /* + * Filling Twiddle factors : + * + * exp^(-j*2*PI*k/ (N/2) ) ; k=0,1,2,...,3/4(N/2) + * + * N/2 point complex FFT is used to compute N point real FFT The + * original twiddle table "armSP_FFT_F32TwiddleTable" is of size + * (MaxSize/8 + 1) Rest of the values i.e., upto MaxSize are + * calculated using the symmetries of sin and cos The max size of + * the twiddle table needed is 3/4(N/2) for a radix-4 stage + * + * W = (-2 * PI) / N + * N = 1 << order + * W = -PI >> (order - 1) + */ + + M = Nby2 >> 3; + diff = TWIDDLE_TABLE_ORDER - (order - 1); + /* step into the twiddle table for the current order */ + step = 1 << diff; + + x = armSP_FFT_F32TwiddleTable[0]; + y = armSP_FFT_F32TwiddleTable[1]; + xNeg = 1; + + if ((order - 1) >= 3) { + /* i = 0 case */ + pTwiddle[0].Re = x; + pTwiddle[0].Im = y; + pTwiddle[2*M].Re = -y; + pTwiddle[2*M].Im = xNeg; + pTwiddle[4*M].Re = xNeg; + pTwiddle[4*M].Im = y; + + for (i = 1; i <= M; i++) { + j = i*step; + + x = armSP_FFT_F32TwiddleTable[2*j]; + y = armSP_FFT_F32TwiddleTable[2*j+1]; + + pTwiddle[i].Re = x; + pTwiddle[i].Im = y; + pTwiddle[2*M-i].Re = -y; + pTwiddle[2*M-i].Im = -x; + pTwiddle[2*M+i].Re = y; + pTwiddle[2*M+i].Im = -x; + pTwiddle[4*M-i].Re = -x; + pTwiddle[4*M-i].Im = y; + pTwiddle[4*M+i].Re = -x; + pTwiddle[4*M+i].Im = -y; + pTwiddle[6*M-i].Re = y; + pTwiddle[6*M-i].Im = x; + } + } else if ((order - 1) == 2) { + pTwiddle[0].Re = x; + pTwiddle[0].Im = y; + pTwiddle[1].Re = -y; + pTwiddle[1].Im = xNeg; + pTwiddle[2].Re = xNeg; + pTwiddle[2].Im = y; + } else if ((order-1) == 1) { + pTwiddle[0].Re = x; + pTwiddle[0].Im = y; + } + + /* + * Now fill the last N/4 values : exp^(-j*2*PI*k/N) ; + * k=1,3,5,...,N/2-1 These are used for the final twiddle fix-up for + * converting complex to real FFT + */ + + M = N >> 3; + diff = TWIDDLE_TABLE_ORDER - order; + step = 1 << diff; + + pTwiddle1 = pTwiddle + 3*N/8; + pTwiddle4 = pTwiddle1 + (N/4 - 1); + pTwiddle3 = pTwiddle1 + N/8; + pTwiddle2 = pTwiddle1 + (N/8 - 1); + + x = armSP_FFT_F32TwiddleTable[0]; + y = armSP_FFT_F32TwiddleTable[1]; + xNeg = 1; + + if (order >=3) { + for (i = 1; i <= M; i += 2) { + j = i*step; + + x = armSP_FFT_F32TwiddleTable[2*j]; + y = armSP_FFT_F32TwiddleTable[2*j+1]; + + pTwiddle1[0].Re = x; + pTwiddle1[0].Im = y; + pTwiddle1 += 1; + pTwiddle2[0].Re = -y; + pTwiddle2[0].Im = -x; + pTwiddle2 -= 1; + pTwiddle3[0].Re = y; + pTwiddle3[0].Im = -x; + pTwiddle3 += 1; + pTwiddle4[0].Re = -x; + pTwiddle4[0].Im = y; + pTwiddle4 -= 1; + } + } else { + if (order == 2) { + pTwiddle1[0].Re = -y; + pTwiddle1[0].Im = xNeg; + } + } + + + /* Update the structure */ + pFFTStruct->N = N; + pFFTStruct->pTwiddle = pTwiddle; + pFFTStruct->pBitRev = pBitRev; + pFFTStruct->pBuf = pBuf; + + return OMX_Sts_NoErr; +} |