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Diffstat (limited to 'libAACdec/src/ldfiltbank.cpp')
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diff --git a/libAACdec/src/ldfiltbank.cpp b/libAACdec/src/ldfiltbank.cpp new file mode 100644 index 0000000..8f719c8 --- /dev/null +++ b/libAACdec/src/ldfiltbank.cpp @@ -0,0 +1,208 @@ + +/* ----------------------------------------------------------------------------------------------------------- +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. + +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 +----------------------------------------------------------------------------------------------------------- */ + +/***************************************************************************\ +* + * filename: ldfiltbank.c + * project : MPEG-4 Audio Decoder + * contents/description: low delay filterbank + * +\***************************************************************************/ + +#include "ldfiltbank.h" + + +#include "aac_rom.h" +#include "dct.h" +#include "FDK_tools_rom.h" +#include "mdct.h" + +#define LDFB_HEADROOM 2 + +static void multE2_DinvF_fdk(INT_PCM *output, FIXP_DBL* x, const FIXP_WTB* fb, FIXP_DBL* z, const int N, const int stride) +{ + int i, scale; + + /* scale for FIXP_DBL -> INT_PCM conversion. */ + scale = (DFRACT_BITS - SAMPLE_BITS) - LDFB_HEADROOM; + + for(i=0;i<N/4;i++) + { + FIXP_DBL z0, z2, tmp; + + z2 = x[N/2+i]; + z0 = z2 + ( fMultDiv2(z[N/2+i], fb[2*N + i]) >> (-WTS2-1) ); + + z[N/2+i] = x[N/2-1-i] + ( fMultDiv2(z[N + i], fb[2*N + N/2 + i]) >> (-WTS2-1) ); + + tmp = ( fMultDiv2(z[N/2+i], fb[N+N/2-1-i]) + fMultDiv2(z[i], fb[N+N/2+i]) ) ; + +#if (SAMPLE_BITS <= 16) + FDK_ASSERT( (-WTS1-1 + scale) >= 0); + output[(N*3/4-1-i)*stride] = (INT_PCM)SATURATE_RIGHT_SHIFT(tmp, -WTS1-1 + scale, SAMPLE_BITS); +#else + FDK_ASSERT( (WTS1+1 - scale) >= 0); + output[(N*3/4-1-i)*stride] = (INT_PCM)SATURATE_LEFT_SHIFT(tmp, WTS1+1 - scale, SAMPLE_BITS); +#endif + + z[i] = z0; + z[N + i] = z2; + } + + for(i=N/4;i<N/2;i++) + { + FIXP_DBL z0, z2, tmp0, tmp1; + + z2 = x[N/2+i]; + z0 = z2 + ( fMultDiv2(z[N/2+i], fb[2*N + i]) >> (-WTS2-1) ); + + z[N/2+i] = x[N/2-1-i] + ( fMultDiv2(z[N + i], fb[2*N + N/2 + i]) >> (-WTS2-1) ); + + tmp0 = ( fMultDiv2(z[N/2+i], fb[N/2-1-i]) + fMultDiv2(z[i], fb[N/2+i]) ) ; + tmp1 = ( fMultDiv2(z[N/2+i], fb[N+N/2-1-i]) + fMultDiv2(z[i], fb[N+N/2+i]) ) ; + +#if (SAMPLE_BITS <= 16) + FDK_ASSERT( (-WTS0-1 + scale) >= 0); + output[(i-N/4)*stride] = (INT_PCM)SATURATE_RIGHT_SHIFT(tmp0, -WTS0-1 + scale, SAMPLE_BITS); + output[(N*3/4-1-i)*stride] = (INT_PCM)SATURATE_RIGHT_SHIFT(tmp1, -WTS1-1 + scale, SAMPLE_BITS); +#else + FDK_ASSERT( (WTS0+1 - scale) >= 0); + output[(i-N/4)*stride] = (INT_PCM)SATURATE_LEFT_SHIFT(tmp0, WTS0+1 - scale, SAMPLE_BITS); + output[(N*3/4-1-i)*stride] = (INT_PCM)SATURATE_LEFT_SHIFT(tmp1, WTS1+1 - scale, SAMPLE_BITS); +#endif + z[i] = z0; + z[N + i] = z2; + } + + /* Exchange quarter parts of x to bring them in the "right" order */ + for(i=0;i<N/4;i++) + { + FIXP_DBL tmp0 = fMultDiv2(z[i], fb[N/2+i]); + +#if (SAMPLE_BITS <= 16) + FDK_ASSERT( (-WTS0-1 + scale) >= 0); + output[(N*3/4 + i)*stride] = (INT_PCM)SATURATE_RIGHT_SHIFT(tmp0, -WTS0-1 + scale, SAMPLE_BITS); +#else + FDK_ASSERT( (WTS0+1 - scale) >= 0); + output[(N*3/4 + i)*stride] = (INT_PCM)SATURATE_LEFT_SHIFT(tmp0, WTS0+1 - scale, SAMPLE_BITS); +#endif + } +} + +int InvMdctTransformLowDelay_fdk (FIXP_DBL *mdctData, const int mdctData_e, INT_PCM *output, FIXP_DBL *fs_buffer, const int stride, const int N) { + + const FIXP_WTB *coef; + FIXP_DBL gain = (FIXP_DBL)0; + int scale = mdctData_e + MDCT_OUT_HEADROOM - LDFB_HEADROOM; /* The LDFB_HEADROOM is compensated inside multE2_DinvF_fdk() below */ + + /* Select LD window slope */ + if (N == 512) + coef = (FIXP_WTB*)LowDelaySynthesis512; + else + coef = (FIXP_WTB*)LowDelaySynthesis480; + + /* + Apply exponent and 1/N factor. + Note: "scale" is off by one because for LD_MDCT the window length is twice + the window length of a regular MDCT. This is corrected inside multE2_DinvF_fdk(). + Refer to ISO/IEC 14496-3:2009 page 277, chapter 4.6.20.2 "Low Delay Window". + */ + imdct_gain(&gain, &scale, N); + + dct_IV(mdctData, N, &scale); + + if (gain != (FIXP_DBL)0) { + scaleValuesWithFactor(mdctData, gain, N, scale); + } else { + scaleValues(mdctData, N, scale); + } + + /* Since all exponent and factors have been applied, current exponent is zero. */ + multE2_DinvF_fdk(output, mdctData, coef, fs_buffer, N, stride); + + return (1); +} + + + + |