mirror of https://github.com/mstorsjo/fdk-aac.git
177 lines
7.4 KiB
C++
177 lines
7.4 KiB
C++
/* -----------------------------------------------------------------------------
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Software License for The Fraunhofer FDK AAC Codec Library for Android
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© Copyright 1995 - 2018 Fraunhofer-Gesellschaft zur Förderung der angewandten
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Forschung e.V. All rights reserved.
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1. INTRODUCTION
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The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software
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that implements the MPEG Advanced Audio Coding ("AAC") encoding and decoding
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scheme for digital audio. This FDK AAC Codec software is intended to be used on
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a wide variety of Android devices.
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AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient
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general perceptual audio codecs. AAC-ELD is considered the best-performing
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full-bandwidth communications codec by independent studies and is widely
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deployed. AAC has been standardized by ISO and IEC as part of the MPEG
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specifications.
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Patent licenses for necessary patent claims for the FDK AAC Codec (including
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those of Fraunhofer) may be obtained through Via Licensing
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(www.vialicensing.com) or through the respective patent owners individually for
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the purpose of encoding or decoding bit streams in products that are compliant
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with the ISO/IEC MPEG audio standards. Please note that most manufacturers of
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Android devices already license these patent claims through Via Licensing or
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directly from the patent owners, and therefore FDK AAC Codec software may
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already be covered under those patent licenses when it is used for those
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licensed purposes only.
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Commercially-licensed AAC software libraries, including floating-point versions
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with enhanced sound quality, are also available from Fraunhofer. Users are
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encouraged to check the Fraunhofer website for additional applications
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information and documentation.
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2. COPYRIGHT LICENSE
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Redistribution and use in source and binary forms, with or without modification,
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are permitted without payment of copyright license fees provided that you
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satisfy the following conditions:
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You must retain the complete text of this software license in redistributions of
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the FDK AAC Codec or your modifications thereto in source code form.
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You must retain the complete text of this software license in the documentation
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and/or other materials provided with redistributions of the FDK AAC Codec or
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your modifications thereto in binary form. You must make available free of
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charge copies of the complete source code of the FDK AAC Codec and your
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modifications thereto to recipients of copies in binary form.
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The name of Fraunhofer may not be used to endorse or promote products derived
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from this library without prior written permission.
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You may not charge copyright license fees for anyone to use, copy or distribute
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the FDK AAC Codec software or your modifications thereto.
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Your modified versions of the FDK AAC Codec must carry prominent notices stating
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that you changed the software and the date of any change. For modified versions
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of the FDK AAC Codec, the term "Fraunhofer FDK AAC Codec Library for Android"
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must be replaced by the term "Third-Party Modified Version of the Fraunhofer FDK
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AAC Codec Library for Android."
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3. NO PATENT LICENSE
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NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without
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limitation the patents of Fraunhofer, ARE GRANTED BY THIS SOFTWARE LICENSE.
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Fraunhofer provides no warranty of patent non-infringement with respect to this
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software.
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You may use this FDK AAC Codec software or modifications thereto only for
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purposes that are authorized by appropriate patent licenses.
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4. DISCLAIMER
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This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright
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holders and contributors "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES,
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including but not limited to the implied warranties of merchantability and
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fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
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CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary,
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or consequential damages, including but not limited to procurement of substitute
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goods or services; loss of use, data, or profits, or business interruption,
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however caused and on any theory of liability, whether in contract, strict
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liability, or tort (including negligence), arising in any way out of the use of
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this software, even if advised of the possibility of such damage.
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5. CONTACT INFORMATION
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Fraunhofer Institute for Integrated Circuits IIS
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Attention: Audio and Multimedia Departments - FDK AAC LL
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Am Wolfsmantel 33
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91058 Erlangen, Germany
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www.iis.fraunhofer.de/amm
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amm-info@iis.fraunhofer.de
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----------------------------------------------------------------------------- */
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/**************************** AAC encoder library ******************************
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Author(s): M.Werner
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Description: Pre echo control
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*******************************************************************************/
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#include "pre_echo_control.h"
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#include "psy_configuration.h"
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void FDKaacEnc_InitPreEchoControl(FIXP_DBL *RESTRICT pbThresholdNm1,
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INT *calcPreEcho, INT numPb,
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FIXP_DBL *RESTRICT sfbPcmQuantThreshold,
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INT *mdctScalenm1) {
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*mdctScalenm1 = PCM_QUANT_THR_SCALE >> 1;
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FDKmemcpy(pbThresholdNm1, sfbPcmQuantThreshold, numPb * sizeof(FIXP_DBL));
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*calcPreEcho = 1;
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}
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void FDKaacEnc_PreEchoControl(FIXP_DBL *RESTRICT pbThresholdNm1,
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INT calcPreEcho, INT numPb,
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INT maxAllowedIncreaseFactor,
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FIXP_SGL minRemainingThresholdFactor,
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FIXP_DBL *RESTRICT pbThreshold, INT mdctScale,
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INT *mdctScalenm1) {
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int i;
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FIXP_DBL tmpThreshold1, tmpThreshold2;
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int scaling;
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/* If lastWindowSequence in previous frame was start- or stop-window,
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skip preechocontrol calculation */
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if (calcPreEcho == 0) {
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/* copy thresholds to internal memory */
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FDKmemcpy(pbThresholdNm1, pbThreshold, numPb * sizeof(FIXP_DBL));
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*mdctScalenm1 = mdctScale;
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return;
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}
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if (mdctScale > *mdctScalenm1) {
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/* if current thresholds are downscaled more than the ones from the last
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* block */
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scaling = 2 * (mdctScale - *mdctScalenm1);
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for (i = 0; i < numPb; i++) {
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/* multiplication with return data type fract ist equivalent to int
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* multiplication */
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FDK_ASSERT(scaling >= 0);
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tmpThreshold1 = maxAllowedIncreaseFactor * (pbThresholdNm1[i] >> scaling);
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tmpThreshold2 = fMult(minRemainingThresholdFactor, pbThreshold[i]);
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FIXP_DBL tmp = pbThreshold[i];
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/* copy thresholds to internal memory */
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pbThresholdNm1[i] = tmp;
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tmp = fixMin(tmp, tmpThreshold1);
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pbThreshold[i] = fixMax(tmp, tmpThreshold2);
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}
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} else {
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/* if thresholds of last block are more downscaled than the current ones */
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scaling = 2 * (*mdctScalenm1 - mdctScale);
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for (i = 0; i < numPb; i++) {
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/* multiplication with return data type fract ist equivalent to int
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* multiplication */
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tmpThreshold1 = (maxAllowedIncreaseFactor >> 1) * pbThresholdNm1[i];
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tmpThreshold2 = fMult(minRemainingThresholdFactor, pbThreshold[i]);
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/* copy thresholds to internal memory */
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pbThresholdNm1[i] = pbThreshold[i];
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FDK_ASSERT(scaling >= 0);
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if ((pbThreshold[i] >> (scaling + 1)) > tmpThreshold1) {
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pbThreshold[i] = tmpThreshold1 << (scaling + 1);
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}
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pbThreshold[i] = fixMax(pbThreshold[i], tmpThreshold2);
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}
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}
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*mdctScalenm1 = mdctScale;
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}
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