| |
| /* ----------------------------------------------------------------------------------------------------------- |
| 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: Pre echo control |
| |
| ******************************************************************************/ |
| |
| #include "pre_echo_control.h" |
| #include "psy_configuration.h" |
| |
| void FDKaacEnc_InitPreEchoControl(FIXP_DBL *RESTRICT pbThresholdNm1, |
| INT *calcPreEcho, |
| INT numPb, |
| FIXP_DBL *RESTRICT sfbPcmQuantThreshold, |
| INT *mdctScalenm1) |
| { |
| *mdctScalenm1 = PCM_QUANT_THR_SCALE>>1; |
| |
| FDKmemcpy(pbThresholdNm1, sfbPcmQuantThreshold, numPb*sizeof(FIXP_DBL)); |
| |
| *calcPreEcho = 1; |
| } |
| |
| |
| void FDKaacEnc_PreEchoControl(FIXP_DBL *RESTRICT pbThresholdNm1, |
| INT calcPreEcho, |
| INT numPb, |
| INT maxAllowedIncreaseFactor, |
| FIXP_SGL minRemainingThresholdFactor, |
| FIXP_DBL *RESTRICT pbThreshold, |
| INT mdctScale, |
| INT *mdctScalenm1) |
| { |
| int i; |
| FIXP_DBL tmpThreshold1, tmpThreshold2; |
| int scaling; |
| |
| /* If lastWindowSequence in previous frame was start- or stop-window, |
| skip preechocontrol calculation */ |
| if (calcPreEcho==0) { |
| /* copy thresholds to internal memory */ |
| FDKmemcpy(pbThresholdNm1, pbThreshold, numPb*sizeof(FIXP_DBL)); |
| *mdctScalenm1 = mdctScale; |
| return; |
| } |
| |
| if ( mdctScale > *mdctScalenm1 ) { |
| /* if current thresholds are downscaled more than the ones from the last block */ |
| scaling = 2*(mdctScale-*mdctScalenm1); |
| for(i = 0; i < numPb; i++) { |
| |
| /* multiplication with return data type fract ist equivalent to int multiplication */ |
| FDK_ASSERT(scaling>=0); |
| tmpThreshold1 = maxAllowedIncreaseFactor * (pbThresholdNm1[i]>>scaling); |
| tmpThreshold2 = fMult(minRemainingThresholdFactor, pbThreshold[i]); |
| |
| FIXP_DBL tmp = pbThreshold[i]; |
| |
| /* copy thresholds to internal memory */ |
| pbThresholdNm1[i] = tmp; |
| |
| tmp = fixMin(tmp, tmpThreshold1); |
| pbThreshold[i] = fixMax(tmp, tmpThreshold2); |
| } |
| } |
| else { |
| /* if thresholds of last block are more downscaled than the current ones */ |
| scaling = 2*(*mdctScalenm1-mdctScale); |
| for(i = 0; i < numPb; i++) { |
| |
| /* multiplication with return data type fract ist equivalent to int multiplication */ |
| tmpThreshold1 = (maxAllowedIncreaseFactor>>1) * pbThresholdNm1[i]; |
| tmpThreshold2 = fMult(minRemainingThresholdFactor, pbThreshold[i]); |
| |
| /* copy thresholds to internal memory */ |
| pbThresholdNm1[i] = pbThreshold[i]; |
| |
| FDK_ASSERT(scaling>=0); |
| if((pbThreshold[i]>>(scaling+1)) > tmpThreshold1) { |
| pbThreshold[i] = tmpThreshold1<<(scaling+1); |
| } |
| pbThreshold[i] = fixMax(pbThreshold[i], tmpThreshold2); |
| } |
| } |
| |
| *mdctScalenm1 = mdctScale; |
| } |
