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| /* ----------------------------------------------------------------------------------------------------------- |
| 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 |
| ----------------------------------------------------------------------------------------------------------- */ |
| |
| /******************************** MPEG Audio Encoder ************************** |
| |
| Initial author: M. Werner |
| contents/description: Chaos measure calculation |
| |
| ******************************************************************************/ |
| |
| #include "chaosmeasure.h" |
| |
| /***************************************************************************** |
| functionname: FDKaacEnc_FDKaacEnc_CalculateChaosMeasurePeakFast |
| description: Eberlein method of chaos measure calculation by high-pass |
| filtering amplitude spectrum |
| A special case of FDKaacEnc_CalculateChaosMeasureTonalGeneric -- |
| highly optimized |
| *****************************************************************************/ |
| static void |
| FDKaacEnc_FDKaacEnc_CalculateChaosMeasurePeakFast( FIXP_DBL *RESTRICT paMDCTDataNM0, |
| INT numberOfLines, |
| FIXP_DBL *RESTRICT chaosMeasure ) |
| { |
| INT i, j; |
| |
| /* calculate chaos measure by "peak filter" */ |
| for (i=0; i<2; i++) { |
| /* make even and odd pass through data */ |
| FIXP_DBL left,center; /* left, center tap of filter */ |
| |
| left = (FIXP_DBL)((LONG)paMDCTDataNM0[i]^((LONG)paMDCTDataNM0[i]>>(DFRACT_BITS-1))); |
| center = (FIXP_DBL)((LONG)paMDCTDataNM0[i+2]^((LONG)paMDCTDataNM0[i+2]>>(DFRACT_BITS-1))); |
| |
| for (j = i+2; j < numberOfLines - 2; j+=2) { |
| FIXP_DBL right = (FIXP_DBL)((LONG)paMDCTDataNM0[j+2]^((LONG)paMDCTDataNM0[j+2]>>(DFRACT_BITS-1))); |
| FIXP_DBL tmp = (left>>1)+(right>>1); |
| |
| if (tmp < center ) { |
| INT leadingBits = CntLeadingZeros(center)-1; |
| tmp = schur_div(tmp<<leadingBits, center<<leadingBits, 8); |
| chaosMeasure[j] = fMult(tmp,tmp); |
| } |
| else { |
| chaosMeasure[j] = (FIXP_DBL)MAXVAL_DBL; |
| } |
| |
| left = center; |
| center = right; |
| } |
| } |
| |
| /* provide chaos measure for first few lines */ |
| chaosMeasure[0] = chaosMeasure[2]; |
| chaosMeasure[1] = chaosMeasure[2]; |
| |
| /* provide chaos measure for last few lines */ |
| for (i = (numberOfLines-3); i < numberOfLines; i++) |
| chaosMeasure[i] = FL2FXCONST_DBL(0.5); |
| } |
| |
| |
| /***************************************************************************** |
| functionname: FDKaacEnc_CalculateChaosMeasure |
| description: calculates a chaosmeasure for every line, different methods |
| are available. 0 means tonal, 1 means noiselike |
| returns: |
| input: MDCT data, number of lines |
| output: chaosMeasure |
| *****************************************************************************/ |
| void |
| FDKaacEnc_CalculateChaosMeasure( FIXP_DBL *paMDCTDataNM0, |
| INT numberOfLines, |
| FIXP_DBL *chaosMeasure ) |
| |
| { |
| FDKaacEnc_FDKaacEnc_CalculateChaosMeasurePeakFast( paMDCTDataNM0, |
| numberOfLines, |
| chaosMeasure ); |
| } |
| |