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Diffstat (limited to 'libFDK/src/FDK_hybrid.cpp')
| -rw-r--r-- | libFDK/src/FDK_hybrid.cpp | 215 |
1 files changed, 79 insertions, 136 deletions
diff --git a/libFDK/src/FDK_hybrid.cpp b/libFDK/src/FDK_hybrid.cpp index d66e534..3d3ab7b 100644 --- a/libFDK/src/FDK_hybrid.cpp +++ b/libFDK/src/FDK_hybrid.cpp @@ -1,29 +1,91 @@ -/*************************** Fraunhofer IIS FDK Tools ********************** - (C) Copyright Fraunhofer IIS (2011) - All Rights Reserved +/* ----------------------------------------------------------------------------------------------------------- +Software License for The Fraunhofer FDK AAC Codec Library for Android + +© Copyright 1995 - 2012 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. - Please be advised that this software and/or program delivery is - Confidential Information of Fraunhofer and subject to and covered by the +You may not charge copyright license fees for anyone to use, copy or distribute the FDK AAC Codec +software or your modifications thereto. - Fraunhofer IIS Software Evaluation Agreement - between Google Inc. and Fraunhofer - effective and in full force since March 1, 2012. +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." - You may use this software and/or program only under the terms and - conditions described in the above mentioned Fraunhofer IIS Software - Evaluation Agreement. Any other and/or further use requires a separate agreement. +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 +----------------------------------------------------------------------------------------------------------- */ + +/*************************** Fraunhofer IIS FDK Tools ********************** - $Id$ Author(s): Markus Lohwasser Description: FDK Tools Hybrid Filterbank - This software and/or program is protected by copyright law and international - treaties. Any reproduction or distribution of this software and/or program, - or any portion of it, may result in severe civil and criminal penalties, and - will be prosecuted to the maximum extent possible under law. - ******************************************************************************/ #include "FDK_hybrid.h" @@ -386,33 +448,6 @@ INT FDKhybridSynthesisApply( return err; } -/*****************************************************************************/ -/* **** FILTERBANK **** */ - -/* - 2 channel filter - Filter Coefs: - 0.0, - 0.01899487526049, - 0.0, - -0.07293139167538, - 0.0, - 0.30596630545168, - 0.5, - 0.30596630545168, - 0.0, - -0.07293139167538, - 0.0, - 0.01899487526049, - 0.0 - - - Filter design: - h[q,n] = g[n] * cos(2pi/2 * q * (n-6) ); n = 0..12, q = 0,1; - - -> h[0,n] = g[n] * 1; - -> h[1,n] = g[n] * pow(-1,n); -*/ static void dualChannelFiltering( const FIXP_DBL *const pQmfReal, const FIXP_DBL *const pQmfImag, @@ -554,98 +589,6 @@ static void fourChannelFiltering( } - -/* - 8 channel filter - - Implementation using a FFT of length 8 - - prototype filter coefficients: - 0.00746082949812 0.02270420949825 0.04546865930473 0.07266113929591 0.09885108575264 0.11793710567217 - 0.125 - 0.11793710567217 0.09885108575264 0.07266113929591 0.04546865930473 0.02270420949825 0.00746082949812 - - Filter design: - N = 13; Q = 8; - h[q,n] = g[n] * exp(j * 2 * pi / Q * (q + .5) * (n - 6)); n = 0..(N-1), q = 0..(Q-1); - - Time Signal: x[t]; - Filter Bank Output - y[q,t] = conv(x[t],h[q,t]) = conv(h[q,t],x[t]) = sum(x[k] * h[q, t - k] ) = sum(h[q, k] * x[t - k] ); k = 0..(N-1); - - y[q,t] = x[t - 12]*h[q, 12] + x[t - 11]*h[q, 11] + x[t - 10]*h[q, 10] + x[t - 9]*h[q, 9] - + x[t - 8]*h[q, 8] + x[t - 7]*h[q, 7] - + x[t - 6]*h[q, 6] - + x[t - 5]*h[q, 5] + x[t - 4]*h[q, 4] - + x[t - 3]*h[q, 3] + x[t - 2]*h[q, 2] + x[t - 1]*h[q, 1] + x[t - 0]*h[q, 0]; - - h'[q, n] = h[q,(N-1)-n] = g[n] * exp(j * 2 * pi / Q * (q + .5) * (6 - n)); n = 0..(N-1), q = 0..(Q-1); - - y[q,t] = x[t - 12]*h'[q, 0] + x[t - 11]*h'[q, 1] + x[t - 10]*h'[q, 2] + x[t - 9]*h'[q, 3] - + x[t - 8]*h'[q, 4] + x[t - 7]*h'[q, 5] - + x[t - 6]*h'[q, 6] - + x[t - 5]*h'[q, 7] + x[t - 4]*h'[q, 8] - + x[t - 3]*h'[q, 9] + x[t - 2]*h'[q, 10] + x[t - 1]*h'[q, 11] + x[t - 0]*h'[q, 12]; - - Try to split off FFT Modulation Term: - FFT(x[t], q) = sum(x[t+k]*exp(-j*2*pi/N *q * k)) - c m - Step 1: h'[q,n] = g[n] * ( exp(j * 2 * pi / 8 * .5 * (6 - n)) ) * ( exp (j * 2 * pi / 8 * q * (6 - n)) ); - - h'[q,n] = g[n] *c[n] * m[q,n]; (see above) - c[n] = exp( j * 2 * pi / 8 * .5 * (6 - n) ); - m[q,n] = exp( j * 2 * pi / 8 * q * (6 - n) ); - - y[q,t] = x[t - 0]*g[0]*c[0]*m[q,0] + x[t - 1]*g[1]*c[ 1]*m[q, 1] + ... - ... + x[t - 12]*g[2]*c[12]*m[q,12]; - - | - n m *exp(-j*2*pi) | n' fft -------------------------------------------------------------------------------------------------------------------------- - 0 exp( j * 2 * pi / 8 * q * 6) -> exp(-j * 2 * pi / 8 * q * 2) | 2 exp(-j * 2 * pi / 8 * q * 0) - 1 exp( j * 2 * pi / 8 * q * 5) -> exp(-j * 2 * pi / 8 * q * 3) | 3 exp(-j * 2 * pi / 8 * q * 1) - 2 exp( j * 2 * pi / 8 * q * 4) -> exp(-j * 2 * pi / 8 * q * 4) | 4 exp(-j * 2 * pi / 8 * q * 2) - 3 exp( j * 2 * pi / 8 * q * 3) -> exp(-j * 2 * pi / 8 * q * 5) | 5 exp(-j * 2 * pi / 8 * q * 3) - 4 exp( j * 2 * pi / 8 * q * 2) -> exp(-j * 2 * pi / 8 * q * 6) | 6 exp(-j * 2 * pi / 8 * q * 4) - 5 exp( j * 2 * pi / 8 * q * 1) -> exp(-j * 2 * pi / 8 * q * 7) | 7 exp(-j * 2 * pi / 8 * q * 5) - 6 exp( j * 2 * pi / 8 * q * 0) | 0 exp(-j * 2 * pi / 8 * q * 6) - 7 exp(-j * 2 * pi / 8 * q * 1) | 1 exp(-j * 2 * pi / 8 * q * 7) - 8 exp(-j * 2 * pi / 8 * q * 2) | 2 - 9 exp(-j * 2 * pi / 8 * q * 3) | 3 - 10 exp(-j * 2 * pi / 8 * q * 4) | 4 - 11 exp(-j * 2 * pi / 8 * q * 5) | 5 - 12 exp(-j * 2 * pi / 8 * q * 6) | 6 - - - now use fft modulation coefficients - m[6] = = fft[0] - m[7] = = fft[1] - m[8] = m[ 0] = fft[2] - m[9] = m[ 1] = fft[3] - m[10] = m[ 2] = fft[4] - m[11] = m[ 3] = fft[5] - m[12] = m[ 4] = fft[6] - m[ 5] = fft[7] - - y[q,t] = ( x[t- 6]*g[ 6]*c[ 6] ) * fft[q,0] + - ( x[t- 7]*g[ 7]*c[ 7] ) * fft[q,1] + - ( x[t- 0]*g[ 0]*c[ 0] + x[t- 8]*g[ 8]*c[ 8] ) * fft[q,2] + - ( x[t- 1]*g[ 1]*c[ 1] + x[t- 9]*g[ 9]*c[ 9] ) * fft[q,3] + - ( x[t- 2]*g[ 2]*c[ 2] + x[t-10]*g[10]*c[10] ) * fft[q,4] + - ( x[t- 3]*g[ 3]*c[ 3] + x[t-11]*g[11]*c[11] ) * fft[q,5] + - ( x[t- 4]*g[ 4]*c[ 4] + x[t-12]*g[12]*c[12] ) * fft[q,6] + - ( x[t- 5]*g[ 5]*c[ 5] ) * fft[q,7]; - - pre twiddle factors c[n] = exp(j * 2 * pi / 8 * .5 * (6 - n)); - n c] | n c[n] | n c[n] ---------------------------------------------------------------------------------------------------- - 0 exp( j * 6 * pi / 8) | 1 exp( j * 5 * pi / 8) | 2 exp( j * 4 * pi / 8) - 3 exp( j * 3 * pi / 8) | 4 exp( j * 2 * pi / 8) | 5 exp( j * 1 * pi / 8) - 6 exp( j * 0 * pi / 8) | 7 exp(-j * 1 * pi / 8) | 8 exp(-j * 2 * pi / 8) - 9 exp(-j * 3 * pi / 8) | 10 exp(-j * 4 * pi / 8) | 11 exp(-j * 5 * pi / 8) - 12 exp(-j * 6 * pi / 8) | | - -*/ static void eightChannelFiltering( const FIXP_DBL *const pQmfReal, const FIXP_DBL *const pQmfImag, |