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ed247dfa54
AAC Encoder: Saturate quantizer shift value to prevent undefined behaviour. In very rare cases the shift value 'totalShift = (16-4)-(3*(totalShift>>2))' can be greater than accu data width. If you apply a shift with more then 31 bit the result depends on the architecture and is not defined in C. For certain platforms zeros are shifted in. That would be our desired behaviour. On other platforms the shift will be applied as modulo. For example >>34 would be applied as >>2. To prevent this discrepancy the shift value is limited/saturated to DFRACT_BITS-1. 'accu >>= fixMin(totalShift,DFRACT_BITS-1)'. Bug 9428126 Change-Id: I27177654c4dc22cf899bc35dad9cdd040dccb02d
396 lines
14 KiB
C++
396 lines
14 KiB
C++
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/* -----------------------------------------------------------------------------------------------------------
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Software License for The Fraunhofer FDK AAC Codec Library for Android
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© Copyright 1995 - 2013 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
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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 that implements
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the MPEG Advanced Audio Coding ("AAC") encoding and decoding scheme for digital audio.
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This FDK AAC Codec software is intended to be used on 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 general perceptual
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audio codecs. AAC-ELD is considered the best-performing full-bandwidth communications codec by
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independent studies and is widely deployed. AAC has been standardized by ISO and IEC as part
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of the MPEG specifications.
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Patent licenses for necessary patent claims for the FDK AAC Codec (including those of Fraunhofer)
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may be obtained through Via Licensing (www.vialicensing.com) or through the respective patent owners
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individually for the purpose of encoding or decoding bit streams in products that are compliant with
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the ISO/IEC MPEG audio standards. Please note that most manufacturers of Android devices already license
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these patent claims through Via Licensing or directly from the patent owners, and therefore FDK AAC Codec
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software may already be covered under those patent licenses when it is used for those licensed purposes only.
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Commercially-licensed AAC software libraries, including floating-point versions with enhanced sound quality,
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are also available from Fraunhofer. Users are encouraged to check the Fraunhofer website for additional
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applications 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, are permitted without
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payment of copyright license fees provided that you satisfy the following conditions:
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You must retain the complete text of this software license in redistributions of the FDK AAC Codec or
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your modifications thereto in source code form.
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You must retain the complete text of this software license in the documentation and/or other materials
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provided with redistributions of the FDK AAC Codec or your modifications thereto in binary form.
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You must make available free of 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 from this library without
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prior written permission.
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You may not charge copyright license fees for anyone to use, copy or distribute the FDK AAC Codec
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software or your modifications thereto.
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Your modified versions of the FDK AAC Codec must carry prominent notices stating that you changed the software
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and the date of any change. For modified versions of the FDK AAC Codec, the term
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"Fraunhofer FDK AAC Codec Library for Android" must be replaced by the term
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"Third-Party Modified Version of the Fraunhofer FDK 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 limitation the patents of Fraunhofer,
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ARE GRANTED BY THIS SOFTWARE LICENSE. Fraunhofer provides no warranty of patent non-infringement with
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respect to this software.
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You may use this FDK AAC Codec software or modifications thereto only for purposes that are authorized
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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 holders and contributors
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"AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, including but not limited to the implied warranties
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of merchantability and 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, or consequential damages,
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including but not limited to procurement of substitute goods or services; loss of use, data, or profits,
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or business interruption, 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 this software, even if
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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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/******************************** MPEG Audio Encoder **************************
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Initial author: M.Werner
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contents/description: Quantization
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******************************************************************************/
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#include "quantize.h"
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#include "aacEnc_rom.h"
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/*****************************************************************************
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functionname: FDKaacEnc_quantizeLines
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description: quantizes spectrum lines
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returns:
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input: global gain, number of lines to process, spectral data
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output: quantized spectrum
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*****************************************************************************/
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static void FDKaacEnc_quantizeLines(INT gain,
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INT noOfLines,
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FIXP_DBL *mdctSpectrum,
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SHORT *quaSpectrum)
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{
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int line;
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FIXP_DBL k = FL2FXCONST_DBL(-0.0946f + 0.5f)>>16;
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FIXP_QTD quantizer = FDKaacEnc_quantTableQ[(-gain)&3];
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INT quantizershift = ((-gain)>>2)+1;
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for (line = 0; line < noOfLines; line++)
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{
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FIXP_DBL accu = fMultDiv2(mdctSpectrum[line],quantizer);
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if (accu < FL2FXCONST_DBL(0.0f))
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{
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accu=-accu;
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/* normalize */
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INT accuShift = CntLeadingZeros(accu) - 1; /* CountLeadingBits() is not necessary here since test value is always > 0 */
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accu <<= accuShift;
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INT tabIndex = (INT)(accu>>(DFRACT_BITS-2-MANT_DIGITS))&(~MANT_SIZE);
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INT totalShift = quantizershift-accuShift+1;
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accu = fMultDiv2(FDKaacEnc_mTab_3_4[tabIndex],FDKaacEnc_quantTableE[totalShift&3]);
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totalShift = (16-4)-(3*(totalShift>>2));
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FDK_ASSERT(totalShift >=0); /* MAX_QUANT_VIOLATION */
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accu >>= fixMin(totalShift,DFRACT_BITS-1);
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quaSpectrum[line] = (SHORT)(-((LONG)(k + accu) >> (DFRACT_BITS-1-16)));
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}
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else if(accu > FL2FXCONST_DBL(0.0f))
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{
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/* normalize */
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INT accuShift = CntLeadingZeros(accu) - 1; /* CountLeadingBits() is not necessary here since test value is always > 0 */
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accu <<= accuShift;
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INT tabIndex = (INT)(accu>>(DFRACT_BITS-2-MANT_DIGITS))&(~MANT_SIZE);
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INT totalShift = quantizershift-accuShift+1;
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accu = fMultDiv2(FDKaacEnc_mTab_3_4[tabIndex],FDKaacEnc_quantTableE[totalShift&3]);
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totalShift = (16-4)-(3*(totalShift>>2));
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FDK_ASSERT(totalShift >=0); /* MAX_QUANT_VIOLATION */
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accu >>= fixMin(totalShift,DFRACT_BITS-1);
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quaSpectrum[line] = (SHORT)((LONG)(k + accu) >> (DFRACT_BITS-1-16));
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}
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else
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quaSpectrum[line]=0;
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}
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}
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/*****************************************************************************
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functionname:iFDKaacEnc_quantizeLines
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description: iquantizes spectrum lines
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mdctSpectrum = iquaSpectrum^4/3 *2^(0.25*gain)
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input: global gain, number of lines to process,quantized spectrum
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output: spectral data
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*****************************************************************************/
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static void FDKaacEnc_invQuantizeLines(INT gain,
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INT noOfLines,
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SHORT *quantSpectrum,
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FIXP_DBL *mdctSpectrum)
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{
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INT iquantizermod;
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INT iquantizershift;
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INT line;
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iquantizermod = gain&3;
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iquantizershift = gain>>2;
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for (line = 0; line < noOfLines; line++) {
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if(quantSpectrum[line] < 0) {
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FIXP_DBL accu;
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INT ex,specExp,tabIndex;
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FIXP_DBL s,t;
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accu = (FIXP_DBL) -quantSpectrum[line];
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ex = CountLeadingBits(accu);
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accu <<= ex;
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specExp = (DFRACT_BITS-1) - ex;
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FDK_ASSERT(specExp < 14); /* this fails if abs(value) > 8191 */
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tabIndex = (INT)(accu>>(DFRACT_BITS-2-MANT_DIGITS))&(~MANT_SIZE);
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/* calculate "mantissa" ^4/3 */
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s = FDKaacEnc_mTab_4_3Elc[tabIndex];
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/* get approperiate exponent multiplier for specExp^3/4 combined with scfMod */
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t = FDKaacEnc_specExpMantTableCombElc[iquantizermod][specExp];
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/* multiply "mantissa" ^4/3 with exponent multiplier */
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accu = fMult(s,t);
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/* get approperiate exponent shifter */
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specExp = FDKaacEnc_specExpTableComb[iquantizermod][specExp]-1; /* -1 to avoid overflows in accu */
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if ((-iquantizershift-specExp) < 0)
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accu <<= -(-iquantizershift-specExp);
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else
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accu >>= -iquantizershift-specExp;
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mdctSpectrum[line] = -accu;
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}
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else if (quantSpectrum[line] > 0) {
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FIXP_DBL accu;
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INT ex,specExp,tabIndex;
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FIXP_DBL s,t;
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accu = (FIXP_DBL)(INT)quantSpectrum[line];
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ex = CountLeadingBits(accu);
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accu <<= ex;
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specExp = (DFRACT_BITS-1) - ex;
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FDK_ASSERT(specExp < 14); /* this fails if abs(value) > 8191 */
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tabIndex = (INT)(accu>>(DFRACT_BITS-2-MANT_DIGITS))&(~MANT_SIZE);
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/* calculate "mantissa" ^4/3 */
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s = FDKaacEnc_mTab_4_3Elc[tabIndex];
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/* get approperiate exponent multiplier for specExp^3/4 combined with scfMod */
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t = FDKaacEnc_specExpMantTableCombElc[iquantizermod][specExp];
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/* multiply "mantissa" ^4/3 with exponent multiplier */
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accu = fMult(s,t);
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/* get approperiate exponent shifter */
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specExp = FDKaacEnc_specExpTableComb[iquantizermod][specExp]-1; /* -1 to avoid overflows in accu */
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if (( -iquantizershift-specExp) < 0)
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accu <<= -(-iquantizershift-specExp);
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else
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accu >>= -iquantizershift-specExp;
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mdctSpectrum[line] = accu;
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}
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else {
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mdctSpectrum[line] = FL2FXCONST_DBL(0.0f);
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}
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}
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}
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/*****************************************************************************
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functionname: FDKaacEnc_QuantizeSpectrum
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description: quantizes the entire spectrum
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returns:
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input: number of scalefactor bands to be quantized, ...
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output: quantized spectrum
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*****************************************************************************/
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void FDKaacEnc_QuantizeSpectrum(INT sfbCnt,
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INT maxSfbPerGroup,
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INT sfbPerGroup,
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INT *sfbOffset,
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FIXP_DBL *mdctSpectrum,
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INT globalGain,
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INT *scalefactors,
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SHORT *quantizedSpectrum)
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{
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INT sfbOffs,sfb;
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/* in FDKaacEnc_quantizeLines quaSpectrum is calculated with:
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spec^(3/4) * 2^(-3/16*QSS) * 2^(3/4*scale) + k
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simplify scaling calculation and reduce QSS before:
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spec^(3/4) * 2^(-3/16*(QSS - 4*scale)) */
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for(sfbOffs=0;sfbOffs<sfbCnt;sfbOffs+=sfbPerGroup)
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for (sfb = 0; sfb < maxSfbPerGroup; sfb++)
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{
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INT scalefactor = scalefactors[sfbOffs+sfb] ;
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FDKaacEnc_quantizeLines(globalGain - scalefactor, /* QSS */
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sfbOffset[sfbOffs+sfb+1] - sfbOffset[sfbOffs+sfb],
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mdctSpectrum + sfbOffset[sfbOffs+sfb],
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quantizedSpectrum + sfbOffset[sfbOffs+sfb]);
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}
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}
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/*****************************************************************************
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functionname: FDKaacEnc_calcSfbDist
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description: calculates distortion of quantized values
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returns: distortion
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input: gain, number of lines to process, spectral data
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output:
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*****************************************************************************/
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FIXP_DBL FDKaacEnc_calcSfbDist(FIXP_DBL *mdctSpectrum,
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SHORT *quantSpectrum,
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INT noOfLines,
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INT gain
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)
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{
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INT i,scale;
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FIXP_DBL xfsf;
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FIXP_DBL diff;
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FIXP_DBL invQuantSpec;
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xfsf = FL2FXCONST_DBL(0.0f);
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for (i=0; i<noOfLines; i++) {
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/* quantization */
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FDKaacEnc_quantizeLines(gain,
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1,
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&mdctSpectrum[i],
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&quantSpectrum[i]);
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if (fAbs(quantSpectrum[i])>MAX_QUANT) {
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return FL2FXCONST_DBL(0.0f);
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}
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/* inverse quantization */
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FDKaacEnc_invQuantizeLines(gain,1,&quantSpectrum[i],&invQuantSpec);
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/* dist */
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diff = fixp_abs(fixp_abs(invQuantSpec) - fixp_abs(mdctSpectrum[i]>>1));
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scale = CountLeadingBits(diff);
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diff = scaleValue(diff, scale);
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diff = fPow2(diff);
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scale = fixMin(2*(scale-1), DFRACT_BITS-1);
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diff = scaleValue(diff, -scale);
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xfsf = xfsf + diff;
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}
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xfsf = CalcLdData(xfsf);
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return xfsf;
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}
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/*****************************************************************************
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functionname: FDKaacEnc_calcSfbQuantEnergyAndDist
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description: calculates energy and distortion of quantized values
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returns:
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input: gain, number of lines to process, quantized spectral data,
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spectral data
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output: energy, distortion
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*****************************************************************************/
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void FDKaacEnc_calcSfbQuantEnergyAndDist(FIXP_DBL *mdctSpectrum,
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SHORT *quantSpectrum,
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INT noOfLines,
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INT gain,
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FIXP_DBL *en,
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FIXP_DBL *dist)
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{
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INT i,scale;
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FIXP_DBL invQuantSpec;
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FIXP_DBL diff;
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FIXP_DBL energy = FL2FXCONST_DBL(0.0f);
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FIXP_DBL distortion = FL2FXCONST_DBL(0.0f);
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for (i=0; i<noOfLines; i++) {
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if (fAbs(quantSpectrum[i])>MAX_QUANT) {
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*en = FL2FXCONST_DBL(0.0f);
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*dist = FL2FXCONST_DBL(0.0f);
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return;
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}
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/* inverse quantization */
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FDKaacEnc_invQuantizeLines(gain,1,&quantSpectrum[i],&invQuantSpec);
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/* energy */
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energy += fPow2(invQuantSpec);
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/* dist */
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diff = fixp_abs(fixp_abs(invQuantSpec) - fixp_abs(mdctSpectrum[i]>>1));
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scale = CountLeadingBits(diff);
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diff = scaleValue(diff, scale);
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diff = fPow2(diff);
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scale = fixMin(2*(scale-1), DFRACT_BITS-1);
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diff = scaleValue(diff, -scale);
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distortion += diff;
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}
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*en = CalcLdData(energy)+FL2FXCONST_DBL(0.03125f);
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*dist = CalcLdData(distortion);
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}
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