| /* ------------------------------------------------------------------ |
| * 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); |
| |
| } |
| |
