| /* ----------------------------------------------------------------------------- |
| Software License for The Fraunhofer FDK AAC Codec Library for Android |
| |
| © Copyright 1995 - 2018 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 |
| ----------------------------------------------------------------------------- */ |
| |
| /******************* Library for basic calculation routines ******************** |
| |
| Author(s): Josef Hoepfl, DSP Solutions |
| |
| Description: Fix point FFT |
| |
| *******************************************************************************/ |
| |
| #ifndef FFT_H |
| #define FFT_H |
| |
| #include "common_fix.h" |
| |
| /** |
| * \brief Perform an inplace complex valued FFT of length 2^n |
| * |
| * \param length Length of the FFT to be calculated. |
| * \param pInput Input/Output data buffer. The input data must have at least 1 |
| * bit scale headroom. The values are interleaved, real/imag pairs. |
| * \param scalefactor Pointer to an INT, which contains the current scale of the |
| * input data, which is updated according to the FFT scale. |
| */ |
| void fft(int length, FIXP_DBL *pInput, INT *scalefactor); |
| |
| /** |
| * \brief Perform an inplace complex valued IFFT of length 2^n |
| * |
| * \param length Length of the FFT to be calculated. |
| * \param pInput Input/Output data buffer. The input data must have at least 1 |
| * bit scale headroom. The values are interleaved, real/imag pairs. |
| * \param scalefactor Pointer to an INT, which contains the current scale of the |
| * input data, which is updated according to the IFFT scale. |
| */ |
| void ifft(int length, FIXP_DBL *pInput, INT *scalefactor); |
| |
| /* |
| * Frequently used and fixed short length FFTs. |
| */ |
| |
| #ifndef FUNCTION_fft_4 |
| /** |
| * \brief Perform an inplace complex valued FFT of length 4 |
| * |
| * \param pInput Input/Output data buffer. The input data must have at least 1 |
| * bit scale headroom. The values are interleaved, real/imag pairs. |
| */ |
| LNK_SECTION_CODE_L1 |
| static void FDK_FORCEINLINE fft_4(FIXP_DBL *x) { |
| FIXP_DBL a00, a10, a20, a30, tmp0, tmp1; |
| |
| a00 = (x[0] + x[4]) >> 1; /* Re A + Re B */ |
| a10 = (x[2] + x[6]) >> 1; /* Re C + Re D */ |
| a20 = (x[1] + x[5]) >> 1; /* Im A + Im B */ |
| a30 = (x[3] + x[7]) >> 1; /* Im C + Im D */ |
| |
| x[0] = a00 + a10; /* Re A' = Re A + Re B + Re C + Re D */ |
| x[1] = a20 + a30; /* Im A' = Im A + Im B + Im C + Im D */ |
| |
| tmp0 = a00 - x[4]; /* Re A - Re B */ |
| tmp1 = a20 - x[5]; /* Im A - Im B */ |
| |
| x[4] = a00 - a10; /* Re C' = Re A + Re B - Re C - Re D */ |
| x[5] = a20 - a30; /* Im C' = Im A + Im B - Im C - Im D */ |
| |
| a10 = a10 - x[6]; /* Re C - Re D */ |
| a30 = a30 - x[7]; /* Im C - Im D */ |
| |
| x[2] = tmp0 + a30; /* Re B' = Re A - Re B + Im C - Im D */ |
| x[6] = tmp0 - a30; /* Re D' = Re A - Re B - Im C + Im D */ |
| x[3] = tmp1 - a10; /* Im B' = Im A - Im B - Re C + Re D */ |
| x[7] = tmp1 + a10; /* Im D' = Im A - Im B + Re C - Re D */ |
| } |
| #endif /* FUNCTION_fft_4 */ |
| |
| #ifndef FUNCTION_fft_8 |
| LNK_SECTION_CODE_L1 |
| static void FDK_FORCEINLINE fft_8(FIXP_DBL *x) { |
| FIXP_SPK w_PiFOURTH = {{FIXP_SGL(0x5A82), FIXP_SGL(0x5A82)}}; |
| |
| FIXP_DBL a00, a10, a20, a30; |
| FIXP_DBL y[16]; |
| |
| a00 = (x[0] + x[8]) >> 1; |
| a10 = x[4] + x[12]; |
| a20 = (x[1] + x[9]) >> 1; |
| a30 = x[5] + x[13]; |
| |
| y[0] = a00 + (a10 >> 1); |
| y[4] = a00 - (a10 >> 1); |
| y[1] = a20 + (a30 >> 1); |
| y[5] = a20 - (a30 >> 1); |
| |
| a00 = a00 - x[8]; |
| a10 = (a10 >> 1) - x[12]; |
| a20 = a20 - x[9]; |
| a30 = (a30 >> 1) - x[13]; |
| |
| y[2] = a00 + a30; |
| y[6] = a00 - a30; |
| y[3] = a20 - a10; |
| y[7] = a20 + a10; |
| |
| a00 = (x[2] + x[10]) >> 1; |
| a10 = x[6] + x[14]; |
| a20 = (x[3] + x[11]) >> 1; |
| a30 = x[7] + x[15]; |
| |
| y[8] = a00 + (a10 >> 1); |
| y[12] = a00 - (a10 >> 1); |
| y[9] = a20 + (a30 >> 1); |
| y[13] = a20 - (a30 >> 1); |
| |
| a00 = a00 - x[10]; |
| a10 = (a10 >> 1) - x[14]; |
| a20 = a20 - x[11]; |
| a30 = (a30 >> 1) - x[15]; |
| |
| y[10] = a00 + a30; |
| y[14] = a00 - a30; |
| y[11] = a20 - a10; |
| y[15] = a20 + a10; |
| |
| FIXP_DBL vr, vi, ur, ui; |
| |
| ur = y[0] >> 1; |
| ui = y[1] >> 1; |
| vr = y[8]; |
| vi = y[9]; |
| x[0] = ur + (vr >> 1); |
| x[1] = ui + (vi >> 1); |
| x[8] = ur - (vr >> 1); |
| x[9] = ui - (vi >> 1); |
| |
| ur = y[4] >> 1; |
| ui = y[5] >> 1; |
| vi = y[12]; |
| vr = y[13]; |
| x[4] = ur + (vr >> 1); |
| x[5] = ui - (vi >> 1); |
| x[12] = ur - (vr >> 1); |
| x[13] = ui + (vi >> 1); |
| |
| ur = y[10]; |
| ui = y[11]; |
| |
| cplxMultDiv2(&vi, &vr, ui, ur, w_PiFOURTH); |
| |
| ur = y[2]; |
| ui = y[3]; |
| x[2] = (ur >> 1) + vr; |
| x[3] = (ui >> 1) + vi; |
| x[10] = (ur >> 1) - vr; |
| x[11] = (ui >> 1) - vi; |
| |
| ur = y[14]; |
| ui = y[15]; |
| |
| cplxMultDiv2(&vr, &vi, ui, ur, w_PiFOURTH); |
| |
| ur = y[6]; |
| ui = y[7]; |
| x[6] = (ur >> 1) + vr; |
| x[7] = (ui >> 1) - vi; |
| x[14] = (ur >> 1) - vr; |
| x[15] = (ui >> 1) + vi; |
| } |
| #endif /* FUNCTION_fft_8 */ |
| |
| #endif |