diff options
Diffstat (limited to 'media/libstagefright/codecs/aacdec/pns_left.cpp')
| -rw-r--r-- | media/libstagefright/codecs/aacdec/pns_left.cpp | 431 |
1 files changed, 431 insertions, 0 deletions
diff --git a/media/libstagefright/codecs/aacdec/pns_left.cpp b/media/libstagefright/codecs/aacdec/pns_left.cpp new file mode 100644 index 0000000..2446de2 --- /dev/null +++ b/media/libstagefright/codecs/aacdec/pns_left.cpp @@ -0,0 +1,431 @@ +/* ------------------------------------------------------------------ + * 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: pns_left.c + +------------------------------------------------------------------------------ + REVISION HISTORY + + Description: Modified from original shareware code + + Description: Brought code in-line with PV standards. + Merged PNS and Intensity blocks into one function. + Modified routine to interface with a fixed-point implementation. + Modified variable names for clarity. + Improved for-loop structure that was previously checking + the codebook used in each scale factor band multiple times. + + Description: Added some comments for clarity. + + Description: Changed strategy for q-format. Q-format for SFBs should not + be grouped. + + Description: Function had to be modified to obey new interpretation of the + sfb_prediction_used flag. LTP takes precedence, and PNS should not be + executed when a collision occurs between these two tools. + + Description: + (1) Added flag "ltp_data_present" + (2) Where feasible, I updated the code to resemble right_ch_sfb_tools_ms.c + Just for conformance, readability. + + Description: Added include file - "e_huffmanconst.h" + + Description: The same "Factors" pointer indexing problem that existed in + right_ch_sfb_tools_ms also existed here in pns_left.c + + Description: Modified how groups and windows are handled, as the multigroup + case was not correct + + Who: Date: + Description: +------------------------------------------------------------------------------ + INPUT AND OUTPUT DEFINITIONS + + Inputs: + + const FrameInfo *pFrameInfo = Pointer to structure that holds + information about each group. + (long block flag, + number of windows, + scalefactor bands per group, etc.) + + const Int group[] = Array that contains indexes of the + the first window in the next group. + + const Int codebook_map[] = Array that denotes which Huffman + codebook was used for the encoding + of each scalefactor band. + + const Int factors[] = Array of scalefactors + + Int sfb_prediction_used[] = Flag that denotes the activation + of long term prediction on a sfb + basis. + + Bool ltp_data_present = Flag that denotes whether LTP + is active for the entire frame. If + this flag is FALSE, + sfb_prediction_used is garbage. + + Int32 spectral_coef[] = Array of pointers pointing to the + spectral coef's for the LEFT channel. + + Int q_format[] = Q-format for the information + pointed to by spectral_coef. + Indexed by scalefactor band. + + Int32 *pCurrentSeed = Pointer to the current seed for the + random number generator. + (gen_rand_vector) + + Local Stores/Buffers/Pointers Needed: + + Global Stores/Buffers/Pointers Needed: + + Outputs: + + Pointers and Buffers Modified: + Int32 spectral_coef[] = Contains the new spectral information + + Local Stores Modified: + + Global Stores Modified: + +------------------------------------------------------------------------------ + FUNCTION DESCRIPTION + + The function steps through each scalefactor band in the group, and + checks for the use of Huffman codebook NOISE_HCB. + + When a SFB utilizing NOISE_HCB is detected, the band in every window in the + group has its spectral information filled with scaled random data. + + The scaled random data is generated by the function gen_rand_vector. + +------------------------------------------------------------------------------ + REQUIREMENTS + + This module shall replace bands that were encoded with the Huffman codebook + NOISE_HCB with random noise as returned from gen_rand_vector(). The result + shall be perceptually indistinguishable from the result obtained by the + ISO decoder. + +------------------------------------------------------------------------------ + REFERENCES + + (1) ISO/IEC 14496-3:1999(E) + Part 3 + Subpart 4.5.5 Figures + Subpart 4.6.2 ScaleFactors + Subpart 4.6.12 Perceptual Noise Substituion (PNS) + + (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 + + pFirst_Window_Coefs = spectral_coef; + + window_start = 0; + + tot_sfb = 0; + + DO + + num_bands = pFrameInfo->sfb_per_win[window_start]; + pBand = pFrameInfo->win_sfb_top[window_start]; + + partition = *(pGroup); + pGroup = pGroup + 1; + + band_start = 0; + + coef_per_win = pFrameInfo->coef_per_win[window_start]; + + wins_in_group = (partition - window_start); + + FOR (sfb = num_bands; sfb > 0; sfb--) + + band_stop = *pBand; + pBand = pBand + 1; + + IF (*(pCodebookMap++) == NOISE_HCB ) + + tempInt = sfb_prediction_used[tot_sfb] AND ltp_data_present; + + IF (tempInt == FALSE) + + pWindow_Coef = pFirst_Window_Coefs + band_start; + + band_length = (band_stop - band_start); + + start_indx = tot_sfb; + + tempInt = *(pFactors); + + FOR (win_indx = wins_in_group; win_indx > 0; win_indx--) + + CALL gen_rand_vector( pWindow_CoefR, + band_length, + pCurrentSeed, + tempInt); + + MODIFYING pWindow_CoefR = scaled random noise + pCurrentSeed = current state of the random + noise generator. + + RETURNING q_format[start_indx] = q-format for this sfb. + + pWindow_Coef = pWindow_Coef + coef_per_win; + + start_indx = start_indx + + pFrameInfo->sfb_per_win[win_indx]; + + ENDFOR + + ENDIF + + ENDIF + + band_start = band_stop; + + tot_sfb = tot_sfb + 1; + + pFactors = pFactors + 1; + + ENDFOR + + coef_per_win = coef_per_win * wins_in_group; + wins_in_group = wins_in_group - 1; + + tot_sfb = tot_sfb + num_bands * wins_in_group; + pFactors = pFactors + num_bands * wins_in_group; + + pFirst_Window_Coefs = pFirst_Window_Coefs + coef_per_win; + + window_start = partition; + + WHILE (partition < pFrameInfo->num_win); + +------------------------------------------------------------------------------ + 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 "pns_left.h" +#include "e_huffmanconst.h" +#include "gen_rand_vector.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 pns_left( + const FrameInfo *pFrameInfo, + const Int group[], + const Int codebook_map[], + const Int factors[], + const Int sfb_prediction_used[], + const Bool ltp_data_present, + Int32 spectral_coef[], + Int q_format[], + Int32 *pCurrentSeed) +{ + + Int tot_sfb; + Int start_indx; + + Int sfb; + Int band_stop; + + const Int16 *pBand; + + const Int *pCodebookMap = &(codebook_map[0]); + const Int *pGroup = &(group[0]); + const Int *pFactors = &(factors[0]); + + Int tempInt; + Int32 *pWindow_Coef; + + + Int32 *spec; + + Int partition; + Int win_indx; + + tot_sfb = 0; + + spec = spectral_coef; + + /* PNS goes by group */ + win_indx = 0; + partition = 0; + do + { + Int num_bands = pFrameInfo->sfb_per_win[partition]; + pBand = pFrameInfo->win_sfb_top[partition]; + + /*---------------------------------------------------------- + Partition is equal to the first window in the next group + + { Group 0 }{ Group 1 }{ Group 2 }{Group 3} + [win 0][win 1][win 2][win 3][win 4][win 5][win 6][win 7] + + pGroup[0] = 2 + pGroup[1] = 5 + pGroup[2] = 7 + pGroup[3] = 8 + -----------------------------------------------------------*/ + + partition = *pGroup++; /* partition = index of last sbk in group */ + + do + { + Int band_start = 0; + for (sfb = 0; sfb < num_bands; sfb++) + { + band_stop = pBand[sfb]; /* band is offset table, band_stop is last coef in band */ + + Int band_length = band_stop - band_start; + if (pCodebookMap[sfb] == NOISE_HCB) + { + + tempInt = sfb_prediction_used[tot_sfb] & ltp_data_present; + + if (tempInt == FALSE) + { + /* generate random noise */ + pWindow_Coef = spec + band_start; + + tempInt = pFactors[sfb]; + + start_indx = tot_sfb++; + + /* reconstruct noise substituted values */ + /* generate random noise */ + + q_format[start_indx] = gen_rand_vector(pWindow_Coef, + band_length, + pCurrentSeed, + tempInt); + + } /* if (sfb_prediction_used[tot_sfb] == FALSE) */ + + } /* if (*(pCodebookMap++) == NOISE_HCB) */ + else + { + tot_sfb ++; /* update absolute sfb counter */ + } + + band_start = band_stop; + + } /* for (sfb) */ + + spec += pFrameInfo->coef_per_win[win_indx++]; + pFactors += num_bands; + + } + while (win_indx < partition); + + pCodebookMap += pFrameInfo->sfb_per_win[win_indx-1]; + + } + while (partition < pFrameInfo->num_win); + + + return; + +} /* pns */ |