/* ------------------------------------------------------------------ * 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. * ------------------------------------------------------------------- */ /* ------------------------------------------------------------------------------ PacketVideo Corp. MP3 Decoder Library Filename: pvmp3_huffman_decoding.cpp Funtions: pvmp3_huffman_quad_decoding pvmp3_huffman_pair_decoding pvmp3_huffman_pair_decoding_linbits Date: 09/21/2007 ------------------------------------------------------------------------------ REVISION HISTORY Description: ------------------------------------------------------------------------------ INPUT AND OUTPUT DEFINITIONS Inputs: int32 is[], granuleInfo *grInfo, information for the given channel and granule tmp3dec_file *pVars, decoder state structure int32 part2_start, index to beginning of part 2 data mp3Header *info mp3 header info Outputs: int32 is[], uncompressed data Return: non zero frequency lines ------------------------------------------------------------------------------ FUNCTION DESCRIPTION These functions are used to decode huffman codewords from the input bitstream using combined binary search and look-up table approach. ------------------------------------------------------------------------------ REQUIREMENTS ------------------------------------------------------------------------------ REFERENCES [1] ISO MPEG Audio Subgroup Software Simulation Group (1996) ISO 13818-3 MPEG-2 Audio Decoder - Lower Sampling Frequency Extension ------------------------------------------------------------------------------ PSEUDO-CODE ------------------------------------------------------------------------------ */ /*---------------------------------------------------------------------------- ; INCLUDES ----------------------------------------------------------------------------*/ #include "pv_mp3_huffman.h" #include "s_mp3bits.h" #include "mp3_mem_funcs.h" #include "pvmp3_tables.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 ----------------------------------------------------------------------------*/ int32 pvmp3_huffman_parsing(int32 is[SUBBANDS_NUMBER*FILTERBANK_BANDS], granuleInfo *grInfo, tmp3dec_file *pVars, int32 part2_start, mp3Header *info) { int32 i; int32 region1Start; int32 region2Start; int32 sfreq; uint32 grBits; void(*pt_huff)(struct huffcodetab *, int32 *, tmp3Bits *); struct huffcodetab *h; tmp3Bits *pMainData = &pVars->mainDataStream; /*int32 bt = (*si).ch[ch].gr[gr].window_switching_flag && ((*si).ch[ch].gr[gr].block_type == 2);*/ sfreq = info->sampling_frequency + info->version_x + (info->version_x << 1); /* Find region boundary for short block case. */ if ((grInfo->window_switching_flag) && (grInfo->block_type == 2)) { if (info->version_x == MPEG_1) { /* Region2. */ region1Start = 12; } else { /* Region2. */ i = grInfo->region0_count + 1; region1Start = mp3_sfBandIndex[sfreq].s[i/3]; } region1Start += region1Start << 1; region2Start = 576; /* No Region2 for short block case. */ } else { /* Find region boundary for long block case. */ i = grInfo->region0_count + 1; region1Start = mp3_sfBandIndex[sfreq].l[i]; region2Start = mp3_sfBandIndex[sfreq].l[i + grInfo->region1_count + 1]; } /* Read bigvalues area. */ if (grInfo->big_values > (FILTERBANK_BANDS*SUBBANDS_NUMBER >> 1)) { grInfo->big_values = (FILTERBANK_BANDS * SUBBANDS_NUMBER >> 1); } if ((grInfo->big_values << 1) > (uint32)region2Start) { h = &(pVars->ht[grInfo->table_select[0]]); if (h->linbits) { pt_huff = pvmp3_huffman_pair_decoding_linbits; } else { pt_huff = pvmp3_huffman_pair_decoding; } for (i = 0; i < region1Start; i += 2) { (*pt_huff)(h, &is[i], pMainData); } h = &(pVars->ht[grInfo->table_select[1]]); if (h->linbits) { pt_huff = pvmp3_huffman_pair_decoding_linbits; } else { pt_huff = pvmp3_huffman_pair_decoding; } for (; i < region2Start; i += 2) { (*pt_huff)(h, &is[i], pMainData); } h = &(pVars->ht[grInfo->table_select[2]]); if (h->linbits) { pt_huff = pvmp3_huffman_pair_decoding_linbits; } else { pt_huff = pvmp3_huffman_pair_decoding; } for (; (uint32)i < (grInfo->big_values << 1); i += 2) { (*pt_huff)(h, &is[i], pMainData); } } else if ((grInfo->big_values << 1) > (uint32)region1Start) { h = &(pVars->ht[grInfo->table_select[0]]); if (h->linbits) { pt_huff = pvmp3_huffman_pair_decoding_linbits; } else { pt_huff = pvmp3_huffman_pair_decoding; } for (i = 0; i < region1Start; i += 2) { (*pt_huff)(h, &is[i], pMainData); } h = &(pVars->ht[grInfo->table_select[1]]); if (h->linbits) { pt_huff = pvmp3_huffman_pair_decoding_linbits; } else { pt_huff = pvmp3_huffman_pair_decoding; } for (; (uint32)i < (grInfo->big_values << 1); i += 2) { (*pt_huff)(h, &is[i], pMainData); } } else { h = &(pVars->ht[grInfo->table_select[0]]); if (h->linbits) { pt_huff = pvmp3_huffman_pair_decoding_linbits; } else { pt_huff = pvmp3_huffman_pair_decoding; } for (i = 0; (uint32)i < (grInfo->big_values << 1); i += 2) { (*pt_huff)(h, &is[i], pMainData); } } /* Read count1 area. */ h = &(pVars->ht[grInfo->count1table_select+32]); grBits = part2_start + grInfo->part2_3_length; while ((pMainData->usedBits < grBits) && (i < FILTERBANK_BANDS*SUBBANDS_NUMBER - 4)) { pvmp3_huffman_quad_decoding(h, &is[i], pMainData); i += 4; } if ((pMainData->usedBits < grBits) && (i < FILTERBANK_BANDS*SUBBANDS_NUMBER)) { pvmp3_huffman_quad_decoding(h, &is[i], pMainData); i += 4; if ((i - 2) >= FILTERBANK_BANDS*SUBBANDS_NUMBER) { i -= 2; is[i] = 0; is[(i+1)] = 0; } } if (pMainData->usedBits > grBits) { i -= 4; if (i < 0 || i > FILTERBANK_BANDS*SUBBANDS_NUMBER - 4) { /* illegal parameters may cause invalid access, set i to 0 */ i = 0; } is[i] = 0; is[(i+1)] = 0; is[(i+2)] = 0; is[(i+3)] = 0; } pMainData->usedBits = grBits; return (i); }