/* ------------------------------------------------------------------ * 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: ./src/hufffac.c Funtions: hufffac ------------------------------------------------------------------------------ REVISION HISTORY Description: Modified from original shareware code Description: Modified to pass variables by reference to eliminate use of global variables. Description: (1) Modified with new templates, (2) Modified variable names for clarity (3) adjusted variables of "for loop" (4) eliminated multiple returns, use return valid Description: (1) Change return logic: 0 if success, 1 if error (2) Define SectInfo structure to store section codebook index and section boundary (3) Substitute "switch" with "if- else if" (4) move BITS *pInputStream to second pass-in parameter (5) pass in huffBookUsed[] to save stack size Description: (1) Remove pass in parameter Hcb pBook Description: Use binary tree search in decode_huff_cw_binary Description: Use decode_huff_scl function. Who: Date: MM/DD/YYYY Description: ------------------------------------------------------------------------------ INPUT AND OUTPUT DEFINITIONS Inputs: *pFrameInfo = pointer to structure that holds information of each Frame. type FrameInfo *pInputStream = pointer to input bitstream. type BITS *pGroup = pointer to array that contains the index of the first window in each group, type UChar nsect = number of sections to be decoded. type Int *pSect = pointer to structure array that contains the huffman codebook index and section boundary for each section, type SectInfo global_gain = initial value for "DPCM encoded" scalefactors and noise energy, type Int *pFactors = pointer to array that stores the decoded scalefactors, intensity position or noise energy, type Int huffBookUsed = array that will hold the huffman codebook index for each sfb, type Int *pBook = pointer to structure that contains the huffman codebook information, such as dimension, Largest Absolute Value (LAV) of each huffman codebook, etc. type Hcb Local Stores/Buffers/Pointers Needed: None Global Stores/Buffers/Pointers Needed: None Outputs: 0 if success 1 if error Pointers and Buffers Modified: Int *pFactors contains the newly decoded scalefactors and/or intensity position and/or noise energy level Local Stores Modified: Global Stores Modified: ------------------------------------------------------------------------------ FUNCTION DESCRIPTION This function first reads the Huffman codebook index of all sections within one Frame. Then, depending on the huffman codebook index of each section, the function decodes the scalefactors, and/or intensity positions (INTENSITY_HCB, INTENSITY_HCB2), and/or noise energy (NOISE_HCB) for every scalefactor band in each section. The function returns 0 upon successful decoding, returns 1 if error. ------------------------------------------------------------------------------ REQUIREMENTS This function should replace the content of the array pFactors with the decoded scalefactors and/or intensity positions and/or noise energy ------------------------------------------------------------------------------ REFERENCES (1) 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. (2) ISO/IEC 14496-3: 1999(E) Subpart 4 p72-73 (scalefactors) p76 (decoding) p78 (Table 4.6.1, Table 4.6.2) p93-94 (INTENSITY_HCB) p123 (NOISE_HCB) ------------------------------------------------------------------------------ PSEUDO-CODE status = SUCCESS; CALL pv_memset(pHuffBookUsed, ZERO_HCB, MAXBANDS*sizeof(*pHuffBookUsed)); CALL pv_memset(pFactors, ZERO_HCB, MAXBANDS*sizeof(*pFactors)); sect_start = 0; FOR(sect_idx = nsect; sect_idx > 0; sect_idx--) { sect_cb = pSect->sect_cb; sect_end = pSect->sect_end; pSect++; CALL pv_memset( &pHuffBookUsed[sect_start], sect_cb, (sect_end - sect_start)); } ENDFOR fac = global_gain; is_pos = 0; noise_nrg = global_gain - NOISE_OFFSET; pTable = pBook[BOOKSCL].pTable; group_win = 0; group_end = 0; WHILE((group_end < pFrameInfo->num_win)&&(status == SUCCESS)) { nsfb_win = pFrameInfo->sfb_per_win[group_end]; group_end = *pGroup++; FOR(sfb = 0; sfb < nsfb_win; sfb++) { IF ((pHuffBookUsed[sfb] > 0)&&(pHuffBookUsed[sfb] < BOOKSCL)) { cw_index = CALL decode_huff_cw_binary(pTable, pInputStream); fac += cw_index - MIDFAC; IF((fac >= 2*TEXP) || (fac < 0)) { status = 1; } ELSE { pFactors[sfb] = fac; } ENDIF (fac) } ELSE IF (pHuffBookUsed[sfb] == ZERO_HCB) { do nothing; } ELSE IF ((pHuffBookUsed[sfb] == INTENSITY_HCB)|| (pHuffBookUsed[sfb] == INTENSITY_HCB2)) { cw_index = CALL decode_huff_cw_binary(pTable, pInputStream); is_pos += cw_index - MIDFAC; pFactors[sfb] = is_pos; } ELSE IF (pHuffBookUsed[sfb] == NOISE_HCB) { IF (noise_pcm_flag == TRUE) { noise_pcm_flag = FALSE; dpcm_noise_nrg = CALL getbits( NOISE_PCM_BITS, pInputStream); dpcm_noise_nrg -= NOISE_PCM_OFFSET; } ELSE { dpcm_noise_nrg = CALL decode_huff_cw_binary( pTable, pInputStream); dpcm_noise_nrg -= MIDFAC; } ENDIF (noise_pcm_flag) noise_nrg += dpcm_noise_nrg; pFactors[sfb] = noise_nrg; } ELSE IF (pHuffBookUsed[sfb] == BOOKSCL) { status = 1; } ENDIF (pHuffBookUsed[sfb]) } ENDFOR (sfb) IF (pFrameInfo->islong == FALSE) { FOR(group_win++; group_win < group_end; group_win++) { FOR (sfb=0; sfb < nsfb_win; sfb++) { pFactors[sfb + nsfb_win] = pFactors[sfb]; } ENDFOR pFactors += nsfb_win; } ENDFOR } ENDIF (pFrameInfo) pHuffBookUsed += nsfb_win; pFactors += nsfb_win; } ENDWHILE (group_end) return status; ------------------------------------------------------------------------------ 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 "aac_mem_funcs.h" /* pv_memset */ #include "s_frameinfo.h" #include "s_bits.h" #include "s_sectinfo.h" #include "s_huffman.h" #include "ibstream.h" #include "hcbtables.h" #include "e_huffmanconst.h" #include "e_infoinitconst.h" #include "huffman.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 ----------------------------------------------------------------------------*/ Int hufffac( FrameInfo *pFrameInfo, BITS *pInputStream, Int *pGroup, /* may be changed to Int */ Int nsect, SectInfo *pSect, /* may be changed to Int */ Int global_gain, Int *pFactors, Int huffBookUsed[]) { Int sect_idx; Int group_end; /* index of 1st window in next group */ Int group_win; /* window index within group */ Int cw_index; /* huff codeword index */ Int nsfb_win; /* # of scfbands per window */ Int sfb; /* scalefactor band index */ Int sect_cb; /* huff codebook # for each section */ Int fac; /* decoded scf */ Int is_pos; /* intensity stereo position */ Int noise_pcm_flag = TRUE; /* first PNS sfb */ Int dpcm_noise_nrg; /* dpcm noise energy */ Int noise_nrg; /* noise energy */ Int status = SUCCESS; /* status of decoding */ Int *pHuffBookUsed = &huffBookUsed[0]; pv_memset(pFactors, ZERO_HCB, MAXBANDS*sizeof(*pFactors)); if (nsect) { /* read section length and codebook */ if (nsect == 1) /* long window */ { sect_cb = pSect->sect_cb; /* codebook for this section */ /* all sfbs in one section share the same codebook */ for (sfb = pSect->sect_end >> 2; sfb != 0; sfb--) { *(pHuffBookUsed++) = sect_cb; *(pHuffBookUsed++) = sect_cb; *(pHuffBookUsed++) = sect_cb; *(pHuffBookUsed++) = sect_cb; } for (sfb = pSect->sect_end & 3; sfb != 0; sfb--) { *(pHuffBookUsed++) = sect_cb; } } else /* short */ { Int sect_start = 0; /* start index of sfb for each section */ for (sect_idx = nsect; sect_idx > 0; sect_idx--) { sect_cb = pSect->sect_cb; /* codebook for this section */ /* all sfbs in one section share the same codebook */ for (sfb = sect_start; sfb < pSect->sect_end; sfb++) { pHuffBookUsed[sfb] = sect_cb; } pSect++; sect_start = sfb; } /* for (sect_idx) */ } } else { /* clear array for the case of max_sfb == 0 */ pv_memset(pHuffBookUsed, ZERO_HCB, MAXBANDS*sizeof(*pHuffBookUsed)); } pHuffBookUsed = &huffBookUsed[0]; /* scale factors and noise energy are dpcm relative to global gain * intensity positions are dpcm relative to zero */ fac = global_gain; is_pos = 0; noise_nrg = global_gain - NOISE_OFFSET; /* get scale factors, * use reserved Table entry = 12, see reference (2) p78 Table 4.6.2 */ group_win = 0; group_end = 0; /* group by group decoding scalefactors and/or noise energy * and/or intensity position */ while ((group_end < pFrameInfo->num_win) && (status == SUCCESS)) { nsfb_win = pFrameInfo->sfb_per_win[group_end]; group_end = *pGroup++; /* index of 1st window in next group */ /* decode scf in first window of each group */ for (sfb = 0; sfb < nsfb_win; sfb++) { switch (pHuffBookUsed[sfb]) { case ZERO_HCB: break; case INTENSITY_HCB: case INTENSITY_HCB2: /* intensity books */ /* decode intensity position */ cw_index = decode_huff_scl(pInputStream); is_pos += cw_index - MIDFAC; pFactors[sfb] = is_pos; break; case NOISE_HCB: /* noise books */ /* decode noise energy */ if (noise_pcm_flag == TRUE) { noise_pcm_flag = FALSE; dpcm_noise_nrg = get9_n_lessbits(NOISE_PCM_BITS, pInputStream); dpcm_noise_nrg -= NOISE_PCM_OFFSET; } else { dpcm_noise_nrg = decode_huff_scl(pInputStream); dpcm_noise_nrg -= MIDFAC; } /* if (noise_pcm_flag) */ noise_nrg += dpcm_noise_nrg; pFactors[sfb] = noise_nrg; break; case BOOKSCL: status = 1; /* invalid books */ sfb = nsfb_win; /* force out */ break; default: /* spectral books */ /* decode scale factors */ cw_index = decode_huff_scl(pInputStream); fac += cw_index - MIDFAC; /* 1.5 dB */ if ((fac >= 2*TEXP) || (fac < 0)) { status = 1; /* error, MUST 0<=scf<256, Ref. p73 */ } else { pFactors[sfb] = fac; /* store scf */ } /* if (fac) */ } } /* for (sfb=0), first window decode ends */ /* expand scf to other windows in the same group */ if (pFrameInfo->islong == FALSE) { for (group_win++; group_win < group_end; group_win++) { for (sfb = 0; sfb < nsfb_win; sfb++) { pFactors[sfb + nsfb_win] = pFactors[sfb]; } pFactors += nsfb_win; } } /* if (pFrameInfo->islong), one group decode ends */ /* points to next group */ pHuffBookUsed += nsfb_win; pFactors += nsfb_win; } /* while (group_end), all groups decode end */ return status; } /* hufffac */