/*
(c) Copyright 1998-2000 - Tord Jansson
======================================
This file is part of the BladeEnc MP3 Encoder, based on
ISO's reference code for MPEG Layer 3 compression, and might
contain smaller or larger sections that are directly taken
from ISO's reference code.
All changes to the ISO reference code herein are either
copyrighted by Tord Jansson ([email protected])
or sublicensed to Tord Jansson by a third party.
BladeEnc is free software; you can redistribute this file
and/or modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
------------ Changes ------------
2000-12-04 Andre Piotrowski
- redesigned, reformatted, slightly optimized
*/
#include <stdlib.h>
#include <assert.h>
#include "system.h"
#include "common.h"
#include "l3psy.h"
#include "loop.h"
#include "formatbitstream2.h"
#include "huffman.h"
#include "l3bitstream.h" /* the public interface */
#include "l3bitstream-pvt.h"
static int stereo = 1;
static frame_params *fr_ps = NULL;
static int PartHoldersInitialized = 0;
static BitHolder *headerPH;
static BitHolder *frameSIPH;
static BitHolder *channelSIPH[MAX_CHANNELS];
static BitHolder *spectrumSIPH[MAX_GRANULES][MAX_CHANNELS];
static BitHolder *scaleFactorsPH[MAX_GRANULES][MAX_CHANNELS];
static BitHolder *codedDataPH[MAX_GRANULES][MAX_CHANNELS];
static BitHolder *userSpectrumPH[MAX_GRANULES][MAX_CHANNELS];
static BitHolder *userFrameDataPH;
static BF_FrameData sFrameData;
static BF_FrameResults sFrameResults;
/*
III_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).
*/
void III_format_bitstream
(
int bitsPerFrame,
frame_params *in_fr_ps,
int l3_enc[2][2][576],
III_side_info_t *l3_side,
III_scalefac_t *scalefac,
double (*xr)[2][576],
char *ancillary,
int ancillary_bits
)
{
int gr, ch, i, mode_gr;
fr_ps = in_fr_ps;
stereo = fr_ps->stereo;
mode_gr = 2;
if (!PartHoldersInitialized)
{
headerPH = initBitHolder (&sFrameData.header, 16*2);
frameSIPH = initBitHolder (&sFrameData.frameSI, 4*2);
for (ch = 0; ch < MAX_CHANNELS; ch++)
channelSIPH[ch] = initBitHolder (&sFrameData.channelSI[ch], 8*2);
for (gr = 0; gr < MAX_GRANULES; gr++)
{
for (ch = 0; ch < MAX_CHANNELS; ch++)
{
spectrumSIPH[gr][ch] = initBitHolder (&sFrameData. spectrumSI[gr][ch], 32*2);
scaleFactorsPH[gr][ch] = initBitHolder (&sFrameData.scaleFactors[gr][ch], 64*2);
codedDataPH[gr][ch] = initBitHolder (&sFrameData. codedData[gr][ch], 576*2);
userSpectrumPH[gr][ch] = initBitHolder (&sFrameData.userSpectrum[gr][ch], 4*2);
}
}
userFrameDataPH = initBitHolder (&sFrameData.userFrameData, 8*2);
PartHoldersInitialized = 1;
}
#if 1
for (gr = 0; gr < mode_gr; gr++)
{
for (ch = 0; ch < stereo; ch++)
{
int *pi = &l3_enc[gr][ch][0];
double *pr = &xr[gr][ch][0];
for (i = 0; i < 576; i++, pr++, pi++)
if (*pr < 0 && *pi > 0)
*pi *= -1;
}
}
#endif
encodeSideInfo (l3_side);
encodeMainData (l3_enc, l3_side, scalefac);
write_ancillary_data (ancillary, ancillary_bits);
if (l3_side->resvDrain)
drain_into_ancillary_data (l3_side->resvDrain);
sFrameData.frameLength = bitsPerFrame;
sFrameData.nGranules = mode_gr;
sFrameData.nChannels = stereo;
writeFrame (&sFrameData, &sFrameResults);
/* we set this here -- it will be tested in the next loops iteration */
l3_side->main_data_begin = sFrameResults.nextBackPtr;
}
void III_FlushBitstream (void)
{
int gr, ch;
if (PartHoldersInitialized)
{
exitBitHolder (&sFrameData.header);
exitBitHolder (&sFrameData.frameSI);
for (ch = 0; ch < MAX_CHANNELS; ch++)
exitBitHolder (&sFrameData.channelSI[ch]);
for (gr = 0; gr < MAX_GRANULES; gr++)
{
for (ch = 0; ch < MAX_CHANNELS; ch++)
{
exitBitHolder (&sFrameData. spectrumSI[gr][ch]);
exitBitHolder (&sFrameData.scaleFactors[gr][ch]);
exitBitHolder (&sFrameData. codedData[gr][ch]);
exitBitHolder (&sFrameData.userSpectrum[gr][ch]);
}
}
exitBitHolder (&sFrameData.userFrameData);
PartHoldersInitialized = 0;
}
/* BF_FlushBitstream (frameData, frameResults); */
}
static unsigned slen1_tab[16] = { 0, 0, 0, 0, 3, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4 };
static unsigned slen2_tab[16] = { 0, 1, 2, 3, 0, 1, 2, 3, 1, 2, 3, 1, 2, 3, 2, 3 };
static void encodeMainData
(
int l3_enc[2][2][576],
III_side_info_t *side_info,
III_scalefac_t *scalefac
)
{
int gr, ch, sfb, b, mode_gr;
mode_gr = 2;
for (gr = 0; gr < mode_gr; gr++)
for (ch = 0; ch < stereo; ch++)
scaleFactorsPH[gr][ch]->nrEntries = 0;
for (gr = 0; gr < mode_gr; gr++)
for (ch = 0; ch < stereo; ch++)
codedDataPH[gr][ch]->nrEntries = 0;
for (gr = 0; gr < 2; gr++)
{
for (ch = 0; ch < stereo; ch++)
{
BitHolder *ph = scaleFactorsPH[gr][ch];
gr_info *cod_info = &side_info->gr[gr].ch[ch].tt;
unsigned slen1 = slen1_tab[cod_info->scalefac_compress];
unsigned slen2 = slen2_tab[cod_info->scalefac_compress];
int *ix = &l3_enc[gr][ch][0];
if (cod_info->window_switching_flag && cod_info->block_type == SHORT_TYPE)
{
if (cod_info->mixed_block_flag)
{
for (sfb = 0; sfb < 8; sfb++)
addBits (ph, scalefac->l[gr][ch][sfb], slen1);
for (sfb = 3; sfb < 6; sfb++)
for (b = 0; b < 3; b++)
addBits (ph, scalefac->s[gr][ch][sfb][b], slen1);
}
else
{
for (sfb = 0; sfb < 6; sfb++)
for (b = 0; b < 3; b++)
addBits (ph, scalefac->s[gr][ch][sfb][b], slen1);
}
for (sfb = 6; sfb < 12; sfb++)
for (b = 0; b < 3; b++)
addBits (ph, scalefac->s[gr][ch][sfb][b], slen2);
}
else if (gr == 0)
{
for (sfb = 0; sfb < 11; sfb++)
addBits (ph, scalefac->l[gr][ch][sfb], slen1);
for (sfb = 11; sfb < 21; sfb++)
addBits (ph, scalefac->l[gr][ch][sfb], slen2);
}
else
{
if (!side_info->scfsi[ch][0])
for (sfb = 0; sfb < 6; sfb++)
addBits (ph, scalefac->l[gr][ch][sfb], slen1);
if (!side_info->scfsi[ch][1])
for (sfb = 6; sfb < 11; sfb++)
addBits (ph, scalefac->l[gr][ch][sfb], slen1);
if (!side_info->scfsi[ch][2])
for (sfb = 11; sfb < 16; sfb++)
addBits (ph, scalefac->l[gr][ch][sfb], slen2);
if (!side_info->scfsi[ch][3])
for (sfb = 16; sfb < 21; sfb++)
addBits (ph, scalefac->l[gr][ch][sfb], slen2);
}
Huffmancodebits (codedDataPH[gr][ch], ix, cod_info);
} /* for ch */
} /* for gr */
} /* main_data */
/*____ encodeSideInfo() _____________________________________________________*/
static int encodeSideInfo (III_side_info_t *side_info)
{
int gr, ch, scfsi_band, region, b, bits_sent, mode_gr;
layer *info = fr_ps->header;
mode_gr = 2;
headerPH->nrEntries = 0;
addBits (headerPH, 0xfff , 12);
addBits (headerPH, 1 , 1);
addBits (headerPH, 4 - 3 , 2); /* 4 - Layer */
addBits (headerPH, !info->error_protection , 1);
addBits (headerPH, info->bitrate_index , 4);
addBits (headerPH, info->sampling_frequency, 2);
addBits (headerPH, info->padding , 1);
addBits (headerPH, info->extension , 1);
addBits (headerPH, info->mode , 2);
addBits (headerPH, info->mode_ext , 2);
addBits (headerPH, info->copyright , 1);
addBits (headerPH, info->original , 1);
addBits (headerPH, info->emphasis , 2);
bits_sent = 32;
if (info->error_protection)
{
addBits (headerPH, 0, 16); /* Just a dummy add. Real CRC calculated & inserted in writeSideInfo() */
bits_sent += 16;
}
frameSIPH->nrEntries = 0;
addBits (frameSIPH, side_info->main_data_begin, 9);
if (stereo == 2)
addBits (frameSIPH, side_info->private_bits, 3);
else
addBits (frameSIPH, side_info->private_bits, 5);
for (ch = 0; ch < stereo; ch++)
{
BitHolder *ph = channelSIPH[ch];
ph->nrEntries = 0;
for (scfsi_band = 0; scfsi_band < 4; scfsi_band++)
addBits (ph, side_info->scfsi[ch][scfsi_band], 1);
}
for (gr = 0; gr < 2; gr++)
{
for (ch = 0; ch < stereo; ch++)
{
BitHolder *ph = spectrumSIPH[gr][ch];
gr_info *cod_info = &side_info->gr[gr].ch[ch].tt;
ph->nrEntries = 0;
addBits (ph, cod_info->part2_3_length , 12);
addBits (ph, cod_info->big_values , 9);
addBits (ph, cod_info->global_gain , 8);
addBits (ph, cod_info->scalefac_compress , 4);
addBits (ph, cod_info->window_switching_flag, 1);
if (cod_info->window_switching_flag)
{
addBits (ph, cod_info->block_type , 2);
addBits (ph, cod_info->mixed_block_flag, 1);
for (region = 0; region < 2; region++)
addBits (ph, cod_info->table_select[region], 5);
for (b = 0; b < 3; b++)
addBits (ph, cod_info->subblock_gain[b], 3);
}
else
{
for (region = 0; region < 3; region++)
addBits (ph, cod_info->table_select[region], 5);
addBits (ph, cod_info->region0_count, 4);
addBits (ph, cod_info->region1_count, 3);
}
addBits (ph, cod_info->preflag , 1);
addBits (ph, cod_info->scalefac_scale , 1);
addBits (ph, cod_info->count1table_select, 1);
}
}
if (stereo == 2)
bits_sent += 256;
else
bits_sent += 136;
return bits_sent;
}
/*____ write_ancillary_data() _______________________________________________*/
static void write_ancillary_data
(
char *theData,
int lengthInBits
)
{
int bytesToSend = lengthInBits / 8;
int remainingBits = lengthInBits % 8;
unsigned wrd;
userFrameDataPH->nrEntries = 0;
while (bytesToSend--)
{
wrd = *theData++;
addBits (userFrameDataPH, wrd, 8);
}
if (remainingBits)
{
/* right-justify remaining bits */
wrd = *theData >> (8 - remainingBits);
addBits (userFrameDataPH, wrd, remainingBits);
}
}
/*
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_data (int lengthInBits)
{
int wordsToSend = lengthInBits / 32;
int remainingBits = lengthInBits % 32;
/*
userFrameDataPH->part->nrEntries set by call to write_ancillary_data()
*/
while (wordsToSend--)
addBits (userFrameDataPH, 0, 32);
if (remainingBits)
addBits (userFrameDataPH, 0, remainingBits);
}
/*
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 void Huffmancodebits
(
BitHolder *ph,
int *ix,
gr_info *cod_info
)
{
int sfb, window, line, start, end;
int stuffingBits, table;
int bitsWritten = 0;
int bigvalues = cod_info->big_values * 2;
/*
Within each scalefactor band, data is given for successive time windows,
beginning with window 0 and ending with window 2 (in case of short blocks!
--- there is only one long block window). Within each window, the quantized
values are then arranged in order of increasing frequency...
*/
/* 1: Write the bigvalues */
if (bigvalues)
{
if (cod_info->window_switching_flag && (cod_info->block_type == SHORT_TYPE))
{
int (*ix_s)[3] = (int (*)[3]) ix;
int *scalefac = &sfBandIndex[fr_ps->header->sampling_frequency].s[0];
table = cod_info->table_select[0];
if (table)
{
if (cod_info->mixed_block_flag) /* Mixed blocks long, short */
{
for (line=0; line<36; line+=2) /* cod_info->address1 = 36 */
bitsWritten += writeHuffmanCode (ph, table, ix[line], ix[line+1]);
}
else
{
for (sfb=0; sfb<3; sfb++) /* (cod_info->region0_count + 1) / 3 = 3 */
{
start = scalefac[sfb];
end = scalefac[sfb+1];
for (window=0; window<3; window++)
for (line=start; line<end; line+=2)
bitsWritten += writeHuffmanCode (ph, table, ix_s[line][window], ix_s[line+1][window]);
}
}
}
table = cod_info->table_select[1];
if (table)
{
for (sfb=3; sfb<SFB_SMAX; sfb++) /* scalefac[3] = 12 --- 12*3 = 36 */
{
start = scalefac[sfb];
end = scalefac[sfb+1];
for (window=0; window<3; window++)
for (line=start; line<end; line+=2)
bitsWritten += writeHuffmanCode (ph, table, ix_s[line][window], ix_s[line+1][window]);
}
}
}
else /* Long blocks */
{
int region1Start = (cod_info->address1 > bigvalues) ? bigvalues : cod_info->address1;
int region2Start = (cod_info->address2 > bigvalues) ? bigvalues : cod_info->address2;
table = cod_info->table_select[0];
if (table)
for (line=0; line<region1Start; line+=2)
bitsWritten += writeHuffmanCode (ph, table, ix[line], ix[line+1]);
table = cod_info->table_select[1];
if (table)
for (line=region1Start; line<region2Start; line+=2)
bitsWritten += writeHuffmanCode (ph, table, ix[line], ix[line+1]);
table = cod_info->table_select[2];
if (table)
for (line=region2Start; line<bigvalues; line+=2)
bitsWritten += writeHuffmanCode (ph, table, ix[line], ix[line+1]);
}
}
/* 2: Write count1 area */
if (cod_info->count1)
{
struct huffcodetab *h = ht + (cod_info->count1table_select + 32);
int *pos = ix + bigvalues;
int *end = ix + bigvalues + (cod_info->count1 * 4);
while (pos < end)
{
int len, v, w, x, y;
int bits = 0;
int p = 0;
v = *pos++; if (v) bits++, p |= 1;
w = *pos++; if (w) bits++, p |= 2;
x = *pos++; if (x) bits++, p |= 4;
y = *pos++; if (y) bits++, p |= 8;
addBits (ph, h->table[p], len = h->hlen[p]);
if (v) addBits (ph, v<0, 1);
if (w) addBits (ph, w<0, 1);
if (x) addBits (ph, x<0, 1);
if (y) addBits (ph, y<0, 1);
bitsWritten += bits+len;
}
}
stuffingBits = cod_info->part2_3_length - cod_info->part2_length - bitsWritten;
if (stuffingBits)
{
int stuffingWords = stuffingBits / 32;
int remainingBits = stuffingBits % 32;
/*
Due to the nature of the Huffman code
tables, we will pad with ones
*/
while (stuffingWords--)
addBits (ph, ~0, 32);
if (remainingBits)
addBits (ph, ~0, remainingBits);
bitsWritten += stuffingBits;
}
}
/*
Implements the pseudocode of page 98 of the IS
aaaaaaaaaaaaaaargh --- why don� write the code immediately?
*/
static int writeHuffmanCode
(
BitHolder *ph,
int table,
int x,
int y
)
{
struct huffcodetab *h = ht + table;
unsigned signx = (x <= 0) ? (x = -x, 1) : 0;
unsigned signy = (y <= 0) ? (y = -y, 1) : 0;
unsigned code, cbits, idx;
assert (table);
/*
if (table == 0)
return 0;
*/
if (table > 15) /* ESC-table is used */
{
unsigned linbits = h->linbits;
unsigned ext = 0;
unsigned xbits = 0;
if (x) {if (x > 14) {ext = (x-15); xbits += linbits; x = 15;} ext = (ext << 1) | signx; xbits++;}
if (y) {if (y > 14) {ext = (ext << linbits) | (y-15); xbits += linbits; y = 15;} ext = (ext << 1) | signy; xbits++;}
idx = x * h->ylen + y;
code = h->table[idx];
cbits = h->hlen[idx];
addBits (ph, code, cbits);
addBits (ph, ext , xbits);
return cbits + xbits;
}
else /* No ESC-words */
{
idx = x * h->ylen + y;
code = h->table[idx];
cbits = h->hlen[idx];
if (x) {code = (code << 1) | signx; cbits++;}
if (y) {code = (code << 1) | signy; cbits++;}
addBits (ph, code, cbits);
return cbits;
}
}
|
