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Diffstat (limited to 'libAACdec/src/aacdec_hcr_bit.cpp')
| -rw-r--r-- | libAACdec/src/aacdec_hcr_bit.cpp | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/libAACdec/src/aacdec_hcr_bit.cpp b/libAACdec/src/aacdec_hcr_bit.cpp new file mode 100644 index 0000000..ab82ca3 --- /dev/null +++ b/libAACdec/src/aacdec_hcr_bit.cpp @@ -0,0 +1,165 @@ + +/* ----------------------------------------------------------------------------------------------------------- +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-4 AAC Decoder *************************** + + Author(s): Robert Weidner (DSP Solutions) + Description: HCR Decoder: Bitstream reading + +*******************************************************************************/ + +#include "aacdec_hcr_bit.h" + + +/*--------------------------------------------------------------------------------------------- + description: This function toggles the read direction. +----------------------------------------------------------------------------------------------- + input: current read direction +----------------------------------------------------------------------------------------------- + return: new read direction +-------------------------------------------------------------------------------------------- */ +UCHAR ToggleReadDirection(UCHAR readDirection) +{ + if ( readDirection == FROM_LEFT_TO_RIGHT ) { + return FROM_RIGHT_TO_LEFT; + } + else { + return FROM_LEFT_TO_RIGHT; + } +} + + +/*--------------------------------------------------------------------------------------------- + description: This function returns a bit from the bitstream according to read direction. + It is called very often, therefore it makes sense to inline it (runtime). +----------------------------------------------------------------------------------------------- + input: - handle to FDK bitstream + - reference value marking start of bitfield + - pLeftStartOfSegment + - pRightStartOfSegment + - readDirection +----------------------------------------------------------------------------------------------- + return: - bit from bitstream +-------------------------------------------------------------------------------------------- */ +UINT HcrGetABitFromBitstream(HANDLE_FDK_BITSTREAM bs, + USHORT *pLeftStartOfSegment, + USHORT *pRightStartOfSegment, + UCHAR readDirection) +{ + UINT bit; + INT readBitOffset; + + if (readDirection == FROM_LEFT_TO_RIGHT) { + readBitOffset = *pLeftStartOfSegment-FDKgetBitCnt(bs); + if( readBitOffset ) { + FDKpushBiDirectional(bs, readBitOffset); + } + + bit = FDKreadBits(bs, 1); + + *pLeftStartOfSegment += 1; + } + else { + readBitOffset = *pRightStartOfSegment-FDKgetBitCnt(bs); + if( readBitOffset ) { + FDKpushBiDirectional(bs, readBitOffset); + } + + /* to be replaced with a brother function of FDKreadBits() */ + bit = FDKreadBits(bs, 1); + FDKpushBack(bs, 2); + + *pRightStartOfSegment -= 1; + } + + +#if ERROR_GENERATOR_BIT_STREAM_HCR + static int a; + if ((++a % MODULO_DIVISOR_HCR) == 0) { + bit = (bit == 0) ? 1 : 0; + } +#endif + + return (bit); +} + |