| /* ------------------------------------------------------------------ |
| * 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 */ |
