/* * MP3 bitstream Output interface for LAME * * Copyright (c) 1999 Takehiro TOMINAGA * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Library General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Library General Public License for more details. * * You should have received a copy of the GNU Library General Public * License along with this library; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA. */ #ifdef HAVE_CONFIG_H #include #endif #include #include #include #include "tables.h" #include "bitstream.h" #include "quantize.h" #include "quantize_pvt.h" #include "version.h" #ifdef WITH_DMALLOC #include #endif /* This is the scfsi_band table from 2.4.2.7 of the IS */ const int scfsi_band[5] = { 0, 6, 11, 16, 21 }; /* unsigned int is at least this large: */ /* we work with ints, so when doing bit manipulation, we limit * ourselves to MAX_LENGTH-2 just to be on the safe side */ #define MAX_LENGTH 32 #ifdef DEBUG static int hoge, hogege; #endif void putheader_bits(lame_internal_flags *gfc,int w_ptr) { Bit_stream_struc *bs; bs = &gfc->bs; #ifdef DEBUG hoge += gfc->sideinfo_len * 8; hogege += gfc->sideinfo_len * 8; #endif memcpy(&bs->buf[bs->buf_byte_idx], gfc->header[gfc->w_ptr].buf, gfc->sideinfo_len); bs->buf_byte_idx += gfc->sideinfo_len; bs->totbit += gfc->sideinfo_len * 8; gfc->w_ptr = (gfc->w_ptr + 1) & (MAX_HEADER_BUF - 1); } /*write j bits into the bit stream */ static void putbits2(lame_global_flags *gfp, int val, int j) { lame_internal_flags *gfc=gfp->internal_flags; Bit_stream_struc *bs; bs = &gfc->bs; // assert(j < MAX_LENGTH-2); while (j > 0) { int k; if (bs->buf_bit_idx == 0) { bs->buf_bit_idx = 8; bs->buf_byte_idx++; // assert(bs->buf_byte_idx < BUFFER_SIZE); // assert(gfc->header[gfc->w_ptr].write_timing >= bs->totbit); if (gfc->header[gfc->w_ptr].write_timing == bs->totbit) putheader_bits(gfc, gfc->w_ptr); bs->buf[bs->buf_byte_idx] = 0; } k = Min(j, bs->buf_bit_idx); j -= k; bs->buf_bit_idx -= k; // assert (j < MAX_LENGTH); /* 32 too large on 32 bit machines */ // assert (bs->buf_bit_idx < MAX_LENGTH); bs->buf[bs->buf_byte_idx] |= (val >> j) << bs->buf_bit_idx; bs->totbit += k; } } /*write j bits into the bit stream, ignoring frame headers */ static void putbits_noheaders(lame_global_flags *gfp, int val, int j) { lame_internal_flags *gfc=gfp->internal_flags; Bit_stream_struc *bs; bs = &gfc->bs; // assert(j < MAX_LENGTH-2); while (j > 0) { int k; if (bs->buf_bit_idx == 0) { bs->buf_bit_idx = 8; bs->buf_byte_idx++; // assert(bs->buf_byte_idx < BUFFER_SIZE); bs->buf[bs->buf_byte_idx] = 0; } k = Min(j, bs->buf_bit_idx); j -= k; bs->buf_bit_idx -= k; // assert (j < MAX_LENGTH); /* 32 too large on 32 bit machines */ // assert (bs->buf_bit_idx < MAX_LENGTH); bs->buf[bs->buf_byte_idx] |= (val >> j) << bs->buf_bit_idx; bs->totbit += k; } } /* Some combinations of bitrate, Fs, and stereo make it impossible to stuff out a frame using just main_data, due to the limited number of bits to indicate main_data_length. In these situations, we put stuffing bits into the ancillary data... */ static void drain_into_ancillary(lame_global_flags *gfp,int remainingBits) { lame_internal_flags *gfc=gfp->internal_flags; int i; assert(remainingBits >= 0); if (remainingBits >= 8) { putbits2(gfp,0x4c,8); remainingBits -= 8; } if (remainingBits >= 8) { putbits2(gfp,0x41,8); remainingBits -= 8; } if (remainingBits >= 8) { putbits2(gfp,0x4d,8); remainingBits -= 8; } if (remainingBits >= 8) { putbits2(gfp,0x45,8); remainingBits -= 8; } if (remainingBits >= 32) { const char *version = get_lame_short_version (); if (remainingBits >= 32) for (i=0; i<(int)strlen(version) && remainingBits >=8 ; ++i) { remainingBits -= 8; putbits2(gfp,version[i],8); } } for (; remainingBits >= 1; remainingBits -= 1 ) { putbits2 ( gfp, gfc->ancillary_flag, 1 ); gfc->ancillary_flag ^= 1; } assert (remainingBits == 0); } /*write N bits into the header */ inline static void writeheader(lame_internal_flags *gfc,int val, int j) { int ptr = gfc->header[gfc->h_ptr].ptr; while (j > 0) { int k = Min(j, 8 - (ptr & 7)); j -= k; assert (j < MAX_LENGTH); /* >> 32 too large for 32 bit machines */ gfc->header[gfc->h_ptr].buf[ptr >> 3] |= ((val >> j)) << (8 - (ptr & 7) - k); ptr += k; } gfc->header[gfc->h_ptr].ptr = ptr; } /* (jo) this wrapper function for BF_addEntry() updates also the crc */ static void CRC_writeheader(lame_internal_flags *gfc, int value, int length,int *crc) { int bit = 1 << length; assert(length < MAX_LENGTH-2); while((bit >>= 1)){ *crc <<= 1; if (!(*crc & 0x10000) ^ !(value & bit)) *crc ^= CRC16_POLYNOMIAL; } *crc &= 0xffff; writeheader(gfc,value, length); } void main_CRC_init (void) {} inline static void encodeSideInfo2(lame_global_flags *gfp,int bitsPerFrame) { lame_internal_flags *gfc=gfp->internal_flags; III_side_info_t *l3_side; int gr, ch; int crc; l3_side = &gfc->l3_side; gfc->header[gfc->h_ptr].ptr = 0; memset(gfc->header[gfc->h_ptr].buf, 0, gfc->sideinfo_len); crc = 0xffff; /* (jo) init crc16 for error_protection */ if (gfp->out_samplerate < 16000) writeheader(gfc,0xffe, 12); else writeheader(gfc,0xfff, 12); writeheader(gfc,(gfp->version), 1); writeheader(gfc,4 - 3, 2); writeheader(gfc,(!gfp->error_protection), 1); /* (jo) from now on call the CRC_writeheader() wrapper to update crc */ CRC_writeheader(gfc,(gfc->bitrate_index), 4,&crc); CRC_writeheader(gfc,(gfc->samplerate_index), 2,&crc); CRC_writeheader(gfc,(gfc->padding), 1,&crc); CRC_writeheader(gfc,(gfp->extension), 1,&crc); CRC_writeheader(gfc,(gfp->mode), 2,&crc); CRC_writeheader(gfc,(gfc->mode_ext), 2,&crc); CRC_writeheader(gfc,(gfp->copyright), 1,&crc); CRC_writeheader(gfc,(gfp->original), 1,&crc); CRC_writeheader(gfc,(gfp->emphasis), 2,&crc); if (gfp->error_protection) { writeheader(gfc,0, 16); /* dummy */ } if (gfp->version == 1) { /* MPEG1 */ assert(l3_side->main_data_begin >= 0); CRC_writeheader(gfc,(l3_side->main_data_begin), 9,&crc); if (gfc->channels_out == 2) CRC_writeheader(gfc,l3_side->private_bits, 3,&crc); else CRC_writeheader(gfc,l3_side->private_bits, 5,&crc); for (ch = 0; ch < gfc->channels_out; ch++) { int band; for (band = 0; band < 4; band++) { CRC_writeheader(gfc,l3_side->scfsi[ch][band], 1,&crc); } } for (gr = 0; gr < 2; gr++) { for (ch = 0; ch < gfc->channels_out; ch++) { gr_info *gi = &l3_side->gr[gr].ch[ch].tt; CRC_writeheader(gfc,gi->part2_3_length, 12,&crc); CRC_writeheader(gfc,gi->big_values / 2, 9,&crc); CRC_writeheader(gfc,gi->global_gain, 8,&crc); CRC_writeheader(gfc,gi->scalefac_compress, 4,&crc); CRC_writeheader(gfc,gi->window_switching_flag, 1,&crc); if (gi->window_switching_flag) { CRC_writeheader(gfc,gi->block_type, 2,&crc); CRC_writeheader(gfc,gi->mixed_block_flag, 1,&crc); if (gi->table_select[0] == 14) gi->table_select[0] = 16; CRC_writeheader(gfc,gi->table_select[0], 5,&crc); if (gi->table_select[1] == 14) gi->table_select[1] = 16; CRC_writeheader(gfc,gi->table_select[1], 5,&crc); CRC_writeheader(gfc,gi->subblock_gain[0], 3,&crc); CRC_writeheader(gfc,gi->subblock_gain[1], 3,&crc); CRC_writeheader(gfc,gi->subblock_gain[2], 3,&crc); } else { assert(gi->block_type == NORM_TYPE); if (gi->table_select[0] == 14) gi->table_select[0] = 16; CRC_writeheader(gfc,gi->table_select[0], 5,&crc); if (gi->table_select[1] == 14) gi->table_select[1] = 16; CRC_writeheader(gfc,gi->table_select[1], 5,&crc); if (gi->table_select[2] == 14) gi->table_select[2] = 16; CRC_writeheader(gfc,gi->table_select[2], 5,&crc); assert(gi->region0_count < 16U); assert(gi->region1_count < 8U); CRC_writeheader(gfc,gi->region0_count, 4,&crc); CRC_writeheader(gfc,gi->region1_count, 3,&crc); } CRC_writeheader(gfc,gi->preflag, 1,&crc); CRC_writeheader(gfc,gi->scalefac_scale, 1,&crc); CRC_writeheader(gfc,gi->count1table_select, 1,&crc); } } } else { /* MPEG2 */ assert(l3_side->main_data_begin >= 0); CRC_writeheader(gfc,(l3_side->main_data_begin), 8,&crc); CRC_writeheader(gfc,l3_side->private_bits, gfc->channels_out,&crc); gr = 0; for (ch = 0; ch < gfc->channels_out; ch++) { gr_info *gi = &l3_side->gr[gr].ch[ch].tt; CRC_writeheader(gfc,gi->part2_3_length, 12,&crc); CRC_writeheader(gfc,gi->big_values / 2, 9,&crc); CRC_writeheader(gfc,gi->global_gain, 8,&crc); CRC_writeheader(gfc,gi->scalefac_compress, 9,&crc); CRC_writeheader(gfc,gi->window_switching_flag, 1,&crc); if (gi->window_switching_flag) { CRC_writeheader(gfc,gi->block_type, 2,&crc); CRC_writeheader(gfc,gi->mixed_block_flag, 1,&crc); if (gi->table_select[0] == 14) gi->table_select[0] = 16; CRC_writeheader(gfc,gi->table_select[0], 5,&crc); if (gi->table_select[1] == 14) gi->table_select[1] = 16; CRC_writeheader(gfc,gi->table_select[1], 5,&crc); CRC_writeheader(gfc,gi->subblock_gain[0], 3,&crc); CRC_writeheader(gfc,gi->subblock_gain[1], 3,&crc); CRC_writeheader(gfc,gi->subblock_gain[2], 3,&crc); } else { if (gi->table_select[0] == 14) gi->table_select[0] = 16; CRC_writeheader(gfc,gi->table_select[0], 5,&crc); if (gi->table_select[1] == 14) gi->table_select[1] = 16; CRC_writeheader(gfc,gi->table_select[1], 5,&crc); if (gi->table_select[2] == 14) gi->table_select[2] = 16; CRC_writeheader(gfc,gi->table_select[2], 5,&crc); assert(gi->region0_count < 16U); assert(gi->region1_count < 8U); CRC_writeheader(gfc,gi->region0_count, 4,&crc); CRC_writeheader(gfc,gi->region1_count, 3,&crc); } CRC_writeheader(gfc,gi->scalefac_scale, 1,&crc); CRC_writeheader(gfc,gi->count1table_select, 1,&crc); } } if (gfp->error_protection) { /* (jo) error_protection: add crc16 information to header */ gfc->header[gfc->h_ptr].buf[4] = crc >> 8; gfc->header[gfc->h_ptr].buf[5] = crc & 255; } { int old = gfc->h_ptr; assert(gfc->header[old].ptr == gfc->sideinfo_len * 8); gfc->h_ptr = (old + 1) & (MAX_HEADER_BUF - 1); gfc->header[gfc->h_ptr].write_timing = gfc->header[old].write_timing + bitsPerFrame; if (gfc->h_ptr == gfc->w_ptr) { /* yikes! we are out of header buffer space */ ERRORF(gfc,"Error: MAX_HEADER_BUF too small in bitstream.c \n"); } } } inline static int huffman_coder_count1(lame_global_flags *gfp,int *ix, gr_info *gi) { #ifdef DEBUG lame_internal_flags *gfc = gfp->internal_flags; #endif /* Write count1 area */ const struct huffcodetab *h = &ht[gi->count1table_select + 32]; int i,bits=0; #ifdef DEBUG int gegebo = gfc->bs.totbit; #endif ix += gi->big_values; assert(gi->count1table_select < 2); for (i = (gi->count1 - gi->big_values) / 4; i > 0; --i) { int huffbits = 0; int p = 0, v; v = ix[0]; if (v) { p += 8; if (v < 0) huffbits++; assert(-1 <= v && v <= 1); } v = ix[1]; if (v) { p += 4; huffbits *= 2; if (v < 0) huffbits++; assert(-1 <= v && v <= 1); } v = ix[2]; if (v) { p += 2; huffbits *= 2; if (v < 0) huffbits++; assert(-1 <= v && v <= 1); } v = ix[3]; if (v) { p++; huffbits *= 2; if (v < 0) huffbits++; assert(-1 <= v && v <= 1); } ix += 4; putbits2(gfp,huffbits + h->table[p], h->hlen[p]); bits += h->hlen[p]; } #ifdef DEBUG DEBUGF("%ld %d %d %d\n",gfc->bs.totbit -gegebo, gi->count1bits, gi->big_values, gi->count1); #endif return bits; } /* * Implements the pseudocode of page 98 of the IS */ static int HuffmanCode(lame_global_flags* const gfp, int table_select, int x1, int x2) { struct huffcodetab* h = ht + table_select; int code = 0; int cbits = 0; int xbits = 0; int sgn_x1 = 0; int sgn_x2 = 0; int linbits = h->xlen; int xlen = h->xlen; int ext; // assert ( table_select > 0 ); if (x1 < 0) { sgn_x1++; x1 = -x1; } if (x2 < 0) { sgn_x2++; x2 = -x2; } ext = sgn_x1; if (table_select > 15) { /* use ESC-words */ if (x1 > 14) { int linbits_x1 = x1 - 15; // assert ( linbits_x1 <= h->linmax ); ext |= linbits_x1 << 1; xbits = linbits; x1 = 15; } if (x2 > 14) { int linbits_x2 = x2 - 15; // assert ( linbits_x2 <= h->linmax ); ext <<= linbits; ext |= linbits_x2; xbits += linbits; x2 = 15; } xlen = 16; } if (x1 != 0) { cbits--; } if (x2 != 0) { ext <<= 1; ext |= sgn_x2; cbits--; } xbits -= cbits; // assert ( (x1|x2) < 16u ); x1 = x1 * xlen + x2; code = h->table [x1]; cbits += h->hlen [x1]; // assert ( cbits <= MAX_LENGTH ); // assert ( xbits <= MAX_LENGTH ); putbits2 ( gfp, code, cbits ); putbits2 ( gfp, ext, xbits ); return cbits + xbits; } static int Huffmancodebits(lame_global_flags *gfp, int tableindex, int start, int end, int *ix) { int i,bits; // assert(tableindex < 32); if (!tableindex) return 0; bits=0; for (i = start; i < end; i += 2) { bits += HuffmanCode(gfp,tableindex, ix[i], ix[i + 1]); } return bits; } /* Note the discussion of huffmancodebits() on pages 28 and 29 of the IS, as well as the definitions of the side information on pages 26 and 27. */ static int ShortHuffmancodebits(lame_global_flags *gfp,int *ix, gr_info *gi) { lame_internal_flags *gfc=gfp->internal_flags; int bits; int region1Start; region1Start = 3*gfc->scalefac_band.s[3]; if (region1Start > gi->big_values) region1Start = gi->big_values; /* short blocks do not have a region2 */ bits = Huffmancodebits(gfp,gi->table_select[0], 0, region1Start, ix); bits += Huffmancodebits(gfp,gi->table_select[1], region1Start, gi->big_values, ix); return bits; } static int LongHuffmancodebits(lame_global_flags *gfp,int *ix, gr_info *gi) { lame_internal_flags *gfc=gfp->internal_flags; int i, bigvalues,bits=0; int region1Start, region2Start; bigvalues = gi->big_values; assert(0 <= bigvalues && bigvalues <= 576); i = gi->region0_count + 1; assert(i < 23); region1Start = gfc->scalefac_band.l[i]; i += gi->region1_count + 1; assert(i < 23); region2Start = gfc->scalefac_band.l[i]; if (region1Start > bigvalues) region1Start = bigvalues; if (region2Start > bigvalues) region2Start = bigvalues; bits +=Huffmancodebits(gfp,gi->table_select[0], 0, region1Start, ix); bits +=Huffmancodebits(gfp,gi->table_select[1], region1Start, region2Start, ix); bits +=Huffmancodebits(gfp,gi->table_select[2], region2Start, bigvalues, ix); return bits; } inline static int writeMainData ( lame_global_flags * const gfp, int l3_enc [2] [2] [576], III_scalefac_t scalefac [2] [2] ) { int gr, ch, sfb,data_bits,scale_bits,tot_bits=0; lame_internal_flags *gfc=gfp->internal_flags; III_side_info_t *l3_side; l3_side = &gfc->l3_side; if (gfp->version == 1) { /* MPEG 1 */ for (gr = 0; gr < 2; gr++) { for (ch = 0; ch < gfc->channels_out; ch++) { gr_info *gi = &l3_side->gr[gr].ch[ch].tt; int slen1 = slen1_tab[gi->scalefac_compress]; int slen2 = slen2_tab[gi->scalefac_compress]; data_bits=0; scale_bits=0; #ifdef DEBUG hogege = gfc->bs.totbit; #endif if (gi->block_type == SHORT_TYPE) { for (sfb = 0; sfb < SBPSY_s; sfb++) { int slen = sfb < 6 ? slen1 : slen2; assert(scalefac[gr][ch].s[sfb][0]>=0); assert(scalefac[gr][ch].s[sfb][1]>=0); assert(scalefac[gr][ch].s[sfb][2]>=0); putbits2(gfp,scalefac[gr][ch].s[sfb][0], slen); putbits2(gfp,scalefac[gr][ch].s[sfb][1], slen); putbits2(gfp,scalefac[gr][ch].s[sfb][2], slen); scale_bits += 3*slen; } data_bits += ShortHuffmancodebits(gfp,l3_enc[gr][ch], gi); } else { int i; for (i = 0; i < sizeof(scfsi_band) / sizeof(int) - 1; i++) { if (gr != 0 && l3_side->scfsi[ch][i]) continue; for (sfb = scfsi_band[i]; sfb < scfsi_band[i + 1]; sfb++) { assert(scalefac[gr][ch].l[sfb]>=0); putbits2(gfp,scalefac[gr][ch].l[sfb], sfb < 11 ? slen1 : slen2); scale_bits += sfb < 11 ? slen1 : slen2; } } data_bits +=LongHuffmancodebits(gfp,l3_enc[gr][ch], gi); } data_bits +=huffman_coder_count1(gfp,l3_enc[gr][ch], gi); #ifdef DEBUG DEBUGF("<%ld> ", gfc->bs.totbit-hogege); #endif /* does bitcount in quantize.c agree with actual bit count?*/ assert(data_bits==gi->part2_3_length-gi->part2_length); assert(scale_bits==gi->part2_length); tot_bits += scale_bits + data_bits; } /* for ch */ } /* for gr */ } else { /* MPEG 2 */ gr = 0; for (ch = 0; ch < gfc->channels_out; ch++) { gr_info *gi = &l3_side->gr[gr].ch[ch].tt; int i, sfb_partition; assert(gi->sfb_partition_table); data_bits = 0; scale_bits=0; sfb = 0; sfb_partition = 0; if (gi->block_type == SHORT_TYPE) { for (; sfb_partition < 4; sfb_partition++) { int sfbs = gi->sfb_partition_table[sfb_partition] / 3; int slen = gi->slen[sfb_partition]; for (i = 0; i < sfbs; i++, sfb++) { putbits2(gfp,Max(scalefac[gr][ch].s[sfb][0], 0U), slen); putbits2(gfp,Max(scalefac[gr][ch].s[sfb][1], 0U), slen); putbits2(gfp,Max(scalefac[gr][ch].s[sfb][2], 0U), slen); scale_bits += 3*slen; } } data_bits += ShortHuffmancodebits(gfp,l3_enc[gr][ch], gi); } else { for (; sfb_partition < 4; sfb_partition++) { int sfbs = gi->sfb_partition_table[sfb_partition]; int slen = gi->slen[sfb_partition]; for (i = 0; i < sfbs; i++, sfb++) { putbits2(gfp,Max(scalefac[gr][ch].l[sfb], 0U), slen); scale_bits += slen; } } data_bits +=LongHuffmancodebits(gfp,l3_enc[gr][ch], gi); } data_bits +=huffman_coder_count1(gfp,l3_enc[gr][ch], gi); /* does bitcount in quantize.c agree with actual bit count?*/ assert(data_bits==gi->part2_3_length-gi->part2_length); assert(scale_bits==gi->part2_length); tot_bits += scale_bits + data_bits; } /* for ch */ } /* for gf */ return tot_bits; } /* main_data */ void flush_bitstream(lame_global_flags *gfp) { lame_internal_flags *gfc=gfp->internal_flags; int flushbits,remaining_headers; int bitsPerFrame, mean_bits; int last_ptr,first_ptr; first_ptr=gfc->w_ptr; /* first header to add to bitstream */ last_ptr = gfc->h_ptr - 1; /* last header to add to bitstream */ if (last_ptr==-1) last_ptr=MAX_HEADER_BUF-1; /* add this many bits to bitstream so we can flush all headers */ flushbits = gfc->header[last_ptr].write_timing - gfc->bs.totbit; if (flushbits >= 0) { /* if flushbits >= 0, some headers have not yet been written */ /* reduce flushbits by the size of the headers */ remaining_headers= 1+last_ptr - first_ptr; if (last_ptr < first_ptr) remaining_headers= 1+last_ptr - first_ptr + MAX_HEADER_BUF; flushbits -= remaining_headers*8*gfc->sideinfo_len; } /* finally, add some bits so that the last frame is complete * these bits are not necessary to decode the last frame, but * some decoders will ignore last frame if these bits are missing */ getframebits(gfp,&bitsPerFrame,&mean_bits); flushbits += bitsPerFrame; if (flushbits<0) { #if 0 /* if flushbits < 0, this would mean that the buffer looks like: * (data...) last_header (data...) (extra data that should not be here...) */ DEBUGF("last header write_timing = %i \n",gfc->header[last_ptr].write_timing); DEBUGF("first header write_timing = %i \n",gfc->header[first_ptr].write_timing); DEBUGF("bs.totbit: %i \n",gfc->bs.totbit); DEBUGF("first_ptr, last_ptr %i %i \n",first_ptr,last_ptr); DEBUGF("remaining_headers = %i \n",remaining_headers); DEBUGF("bitsperframe: %i \n",bitsPerFrame); DEBUGF("sidelen: %i \n",gfc->sideinfo_len); #endif ERRORF(gfc,"strange error flushing buffer ... \n"); } else { drain_into_ancillary(gfp,flushbits); } assert (gfc->header[last_ptr].write_timing + bitsPerFrame == gfc->bs.totbit); } void add_dummy_byte ( lame_global_flags* const gfp, unsigned char val ) { lame_internal_flags *gfc = gfp->internal_flags; int i; putbits_noheaders(gfp,val,8); for (i=0 ; i< MAX_HEADER_BUF ; ++i) gfc->header[i].write_timing += 8; } /* format_bitstream() This is called after a frame of audio has been quantized and coded. It will write the encoded audio to the bitstream. Note that from a layer3 encoder's perspective the bit stream is primarily a series of main_data() blocks, with header and side information inserted at the proper locations to maintain framing. (See Figure A.7 in the IS). */ int format_bitstream(lame_global_flags *gfp, int bitsPerFrame, int l3_enc[2][2][576], III_scalefac_t scalefac[2][2] ) { lame_internal_flags *gfc=gfp->internal_flags; int bits; III_side_info_t *l3_side; l3_side = &gfc->l3_side; drain_into_ancillary(gfp,l3_side->resvDrain_pre); encodeSideInfo2(gfp,bitsPerFrame); bits = 8*gfc->sideinfo_len; bits+=writeMainData(gfp,l3_enc,scalefac); drain_into_ancillary(gfp,l3_side->resvDrain_post); bits += l3_side->resvDrain_post; l3_side->main_data_begin += (bitsPerFrame-bits)/8; if ((l3_side->main_data_begin * 8) != gfc->ResvSize ) { ERRORF(gfc,"bit reservoir error: \n" "l3_side->main_data_begin: %i \n" "Resvoir size: %i \n" "resv drain (post) %i \n" "resv drain (pre) %i \n" "header and sideinfo: %i \n" "data bits: %i \n" "total bits: %i (remainder: %i) \n" "bitsperframe: %i \n", 8*l3_side->main_data_begin, gfc->ResvSize, l3_side->resvDrain_post, l3_side->resvDrain_pre, 8*gfc->sideinfo_len, bits-l3_side->resvDrain_post-8*gfc->sideinfo_len, bits, bits % 8, bitsPerFrame ); gfc->ResvSize = l3_side->main_data_begin*8; }; assert(gfc->bs.totbit % 8 == 0); if (gfc->bs.totbit > 1000000000 ) { /* to avoid totbit overflow, (at 8h encoding at 128kbs) lets reset bit counter*/ int i; for (i=0 ; i< MAX_HEADER_BUF ; ++i) gfc->header[i].write_timing -= gfc->bs.totbit; gfc->bs.totbit=0; } return 0; } int copy_buffer(unsigned char *buffer,int size,Bit_stream_struc *bs) { int minimum = bs->buf_byte_idx + 1; if (minimum <= 0) return 0; if (size!=0 && minimum>size) return -1; /* buffer is too small */ memcpy(buffer,bs->buf,minimum); bs->buf_byte_idx = -1; bs->buf_bit_idx = 0; return minimum; } void init_bit_stream_w(lame_internal_flags *gfc) { gfc->bs.buf = (unsigned char *) malloc(BUFFER_SIZE); gfc->bs.buf_size = BUFFER_SIZE; gfc->h_ptr = gfc->w_ptr = 0; gfc->header[gfc->h_ptr].write_timing = 0; gfc->bs.buf_byte_idx = -1; gfc->bs.buf_bit_idx = 0; gfc->bs.totbit = 0; } /* end of bitstream.c */