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Diffstat (limited to 'media/libstagefright/codecs/aacdec/pulse_nc.cpp')
| -rw-r--r-- | media/libstagefright/codecs/aacdec/pulse_nc.cpp | 298 |
1 files changed, 298 insertions, 0 deletions
diff --git a/media/libstagefright/codecs/aacdec/pulse_nc.cpp b/media/libstagefright/codecs/aacdec/pulse_nc.cpp new file mode 100644 index 0000000..87b264d --- /dev/null +++ b/media/libstagefright/codecs/aacdec/pulse_nc.cpp @@ -0,0 +1,298 @@ +/* ------------------------------------------------------------------ + * Copyright (C) 1998-2009 PacketVideo + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either + * express or implied. + * See the License for the specific language governing permissions + * and limitations under the License. + * ------------------------------------------------------------------- + */ +/* + + Pathname: pulse_nc.c + +------------------------------------------------------------------------------ + REVISION HISTORY + + Description: Modified from original shareware code + + Description: Modified to pass variables by reference to eliminate use + of global variables. + + Description: Modified to bring code in-line with PV standards. + + Description: Pass in max as input argument. + + Description: Went back to the if-statement to check for max. + + Who: Date: + Description: + +------------------------------------------------------------------------------ + INPUT AND OUTPUT DEFINITIONS + + Inputs: + coef[] = Array of quantized spectral coefficents. + (Int []) + + pPulseInfo = Pointer to structure which contains noiseless + encoding info, includes information about the pulse data, + pulse amplitude, etc. + (const PulseInfo *) + + pLongFrameInfo = Pointer to structure that holds information about + each group. (long block flag, number of windows, + scalefactor bands per group, etc.) + + Variable is named (pLongFrameInfo) because this function + is only used for LONG windows. + (FrameInfo *) + max = Pointer to the maximum value of coef[] + + Local Stores/Buffers/Pointers Needed: + None + + Global Stores/Buffers/Pointers Needed: + None + + Outputs: + None + + Pointers and Buffers Modified: + coef[] = coefficient contents are modified by the encoded pulse + + Local Stores Modified: + + Global Stores Modified: + +------------------------------------------------------------------------------ + FUNCTION DESCRIPTION + + This function adds pulses to defined ranges of coefficients in the window, + for the case of LONG windows. The pulses are unsigned, so + negative coefficients subtract the pulse, and positive coefficients add it. + (The ampltiude of the coefficient is always increased by the pulse) + + A maximum of 4 coefficients may be modified by a pulse, and these + coefficients must all occur in the same scalefactor band. + + The number of pulse-encoded coefficients to be processed by this function + is communicated to this function via pPulseInfo->number_pulse + + This value is equal to the actual number of pulses - 1. + (e.g if pPulseInfo->number_pulse == 0, one pulse is assumed) + This function must not be called if no pulse encoded data exists. + The function assumes that at least one pulse exists. +------------------------------------------------------------------------------ + REQUIREMENTS + + This module shall correctly add transmitted pulse(s) to the correct + coefficients in a LONG window. + +------------------------------------------------------------------------------ + REFERENCES + (1) ISO/IEC 14496-3:1999(E) + Part 3 + Subpart 4.6.3.3 Decoding Process + + (2) MPEG-2 NBC Audio Decoder + "This software module was originally developed by AT&T, Dolby + Laboratories, Fraunhofer Gesellschaft IIS in the course of development + of the MPEG-2 NBC/MPEG-4 Audio standard ISO/IEC 13818-7, 14496-1,2 and + 3. This software module is an implementation of a part of one or more + MPEG-2 NBC/MPEG-4 Audio tools as specified by the MPEG-2 NBC/MPEG-4 + Audio standard. ISO/IEC gives users of the MPEG-2 NBC/MPEG-4 Audio + standards free license to this software module or modifications thereof + for use in hardware or software products claiming conformance to the + MPEG-2 NBC/MPEG-4 Audio standards. Those intending to use this software + module in hardware or software products are advised that this use may + infringe existing patents. The original developer of this software + module and his/her company, the subsequent editors and their companies, + and ISO/IEC have no liability for use of this software module or + modifications thereof in an implementation. Copyright is not released + for non MPEG-2 NBC/MPEG-4 Audio conforming products.The original + developer retains full right to use the code for his/her own purpose, + assign or donate the code to a third party and to inhibit third party + from using the code for non MPEG-2 NBC/MPEG-4 Audio conforming products. + This copyright notice must be included in all copies or derivative + works." + Copyright(c)1996. + +------------------------------------------------------------------------------ + PSEUDO-CODE + + index = pLongFrameInfo->win_sfb_top[0][pPulseInfo->pulse_start_sfb]; + + pPulseOffset = &(pPulseInfo->pulse_offset[0]); + + pPulseAmp = &(pPulseInfo->pulse_amp[0]); + + pCoef = &(Coef[index]); + + FOR (index = pPulseInfo->number_pulse; index >= 0; index--) + + pCoef = pCoef + *(pPulseOffset); + pPulseOffset = pPulseOffset + 1; + + IF (*pCoef > 0) + *(pCoef) = *(pCoef) + *(pPulseAmp); + pPulseAmp = pPulseAmp + 1; + ELSE + *(pCoef) = *(pCoef) - *(pPulseAmp); + pPulseAmp = pPulseAmp + 1; + ENDIF + + ENDFOR + +------------------------------------------------------------------------------ + RESOURCES USED + When the code is written for a specific target processor the + the resources used should be documented below. + + STACK USAGE: [stack count for this module] + [variable to represent + stack usage for each subroutine called] + + where: [stack usage variable] = stack usage for [subroutine + name] (see [filename].ext) + + DATA MEMORY USED: x words + + PROGRAM MEMORY USED: x words + + CLOCK CYCLES: [cycle count equation for this module] + [variable + used to represent cycle count for each subroutine + called] + + where: [cycle count variable] = cycle count for [subroutine + name] (see [filename].ext) + +------------------------------------------------------------------------------ +*/ + + +/*---------------------------------------------------------------------------- +; INCLUDES +----------------------------------------------------------------------------*/ +#include "pv_audio_type_defs.h" +#include "s_frameinfo.h" +#include "s_pulseinfo.h" +#include "pulse_nc.h" + +/*---------------------------------------------------------------------------- +; MACROS +; Define module specific macros here +----------------------------------------------------------------------------*/ + +/*--------------------------------------------------------------------------- +; DEFINES +; Include all pre-processor statements here. Include conditional +; compile variables also. +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; LOCAL FUNCTION DEFINITIONS +; Function Prototype declaration +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; LOCAL STORE/BUFFER/POINTER DEFINITIONS +; Variable declaration - defined here and used outside this module +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; EXTERNAL FUNCTION REFERENCES +; Declare functions defined elsewhere and referenced in this module +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES +; Declare variables used in this module but defined elsewhere +----------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------- +; FUNCTION CODE +----------------------------------------------------------------------------*/ + +void pulse_nc( + Int16 coef[], + const PulseInfo *pPulseInfo, + const FrameInfo *pLongFrameInfo, + Int *max) +{ + Int index; + + Int16 *pCoef; + Int temp; + + const Int *pPulseOffset; + const Int *pPulseAmp; + + /*--- Find the scalefactor band where pulse-encoded data starts ---*/ + + if (pPulseInfo->pulse_start_sfb > 0) + { + index = pLongFrameInfo->win_sfb_top[0][pPulseInfo->pulse_start_sfb - 1]; + } + else + { + index = 0; + } + + /*------------------------------------------------------------------------- + Each pulse index is stored as an offset from the previous pulse + + Example - here we have a sfb that is 20 coefficients in length: + + [0][1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] + [ ][ ][ ][ ][ ][P][P][ ][ ][ ][ ][ ][ ][ ][ ][ P][ ][ ][ ][ P] + + The array pointed to by pPulseOffset == [5][1][9][4] + + pPulseAmp is of the same length as pPulseOffset, and contains + an individual pulse amplitude for each coefficient. + --------------------------------------------------------------------------*/ + + pCoef = &(coef[index]); + + pPulseOffset = &(pPulseInfo->pulse_offset[0]); + + pPulseAmp = &(pPulseInfo->pulse_amp[0]); + + for (index = pPulseInfo->number_pulse; index > 0; index--) + { + pCoef += *pPulseOffset++; + + temp = *pCoef; + + if (temp > 0) + { + temp += *(pPulseAmp++); + *pCoef = (Int16)temp; + if (temp > *max) + { + *max = temp; + } + } + else + { + temp -= *(pPulseAmp++); + *pCoef = (Int16)temp; + if (-temp > *max) + { + *max = -temp; + } + } + + } /* for() */ + + return; + +} /* pulse_nc */ |