rockbox/apps/codecs/libwma/wmadeci.c
Michael Giacomelli 54b80471a5 Fix overflow in noise coding. Greatly improves sound quality of some low bitrate files
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@13975 a1c6a512-1295-4272-9138-f99709370657
2007-07-25 02:34:21 +00:00

1795 lines
50 KiB
C

/*
* WMA compatible decoder
* Copyright (c) 2002 The FFmpeg Project.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser 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
*/
/**
* @file wmadec.c
* WMA compatible decoder.
*/
#include <codecs.h>
#include <codecs/lib/codeclib.h>
#include "asf.h"
#include "wmadec.h"
#include "wmafixed.c"
#include "bitstream.h"
#define VLCBITS 9
#define VLCMAX ((22+VLCBITS-1)/VLCBITS)
#define EXPVLCBITS 9
#define EXPMAX ((19+EXPVLCBITS-1)/EXPVLCBITS)
#define HGAINVLCBITS 9
#define HGAINMAX ((13+HGAINVLCBITS-1)/HGAINVLCBITS)
#ifdef CPU_ARM
static inline
void CMUL(fixed32 *x, fixed32 *y,
fixed32 a, fixed32 b,
fixed32 t, fixed32 v)
{
/* This version loses one bit of precision. Could be solved at the cost
* of 2 extra cycles if it becomes an issue. */
int x1, y1, l;
asm(
"smull %[l], %[y1], %[b], %[t] \n"
"smlal %[l], %[y1], %[a], %[v] \n"
"rsb %[b], %[b], #0 \n"
"smull %[l], %[x1], %[a], %[t] \n"
"smlal %[l], %[x1], %[b], %[v] \n"
: [l] "=&r" (l), [x1]"=&r" (x1), [y1]"=&r" (y1), [b] "+r" (b)
: [a] "r" (a), [t] "r" (t), [v] "r" (v)
: "cc"
);
*x = x1 << 1;
*y = y1 << 1;
}
#elif defined CPU_COLDFIRE
static inline
void CMUL(fixed32 *x, fixed32 *y,
fixed32 a, fixed32 b,
fixed32 t, fixed32 v)
{
asm volatile ("mac.l %[a], %[t], %%acc0;"
"msac.l %[b], %[v], %%acc0;"
"mac.l %[b], %[t], %%acc1;"
"mac.l %[a], %[v], %%acc1;"
"movclr.l %%acc0, %[a];"
"move.l %[a], (%[x]);"
"movclr.l %%acc1, %[a];"
"move.l %[a], (%[y]);"
: [a] "+&r" (a)
: [x] "a" (x), [y] "a" (y),
[b] "r" (b), [t] "r" (t), [v] "r" (v)
: "cc", "memory");
}
#else
// PJJ : reinstate macro
void CMUL(fixed32 *pre,
fixed32 *pim,
fixed32 are,
fixed32 aim,
fixed32 bre,
fixed32 bim)
{
//int64_t x,y;
fixed32 _aref = are;
fixed32 _aimf = aim;
fixed32 _bref = bre;
fixed32 _bimf = bim;
fixed32 _r1 = fixmul32b(_bref, _aref);
fixed32 _r2 = fixmul32b(_bimf, _aimf);
fixed32 _r3 = fixmul32b(_bref, _aimf);
fixed32 _r4 = fixmul32b(_bimf, _aref);
*pre = _r1 - _r2;
*pim = _r3 + _r4;
}
#endif
typedef struct CoefVLCTable
{
int n; /* total number of codes */
const uint32_t *huffcodes; /* VLC bit values */
const uint8_t *huffbits; /* VLC bit size */
const uint16_t *levels; /* table to build run/level tables */
}
CoefVLCTable;
static void wma_lsp_to_curve_init(WMADecodeContext *s, int frame_len);
int fft_calc(FFTContext *s, FFTComplex *z);
fixed32 coefsarray[MAX_CHANNELS][BLOCK_MAX_SIZE] IBSS_ATTR;
//static variables that replace malloced stuff
fixed32 stat0[2048], stat1[1024], stat2[512], stat3[256], stat4[128]; //these are the MDCT reconstruction windows
fixed32 *tcosarray[5], *tsinarray[5];
fixed32 tcos0[1024], tcos1[512], tcos2[256], tcos3[128], tcos4[64]; //these are the sin and cos rotations used by the MDCT
fixed32 tsin0[1024], tsin1[512], tsin2[256], tsin3[128], tsin4[64];
FFTComplex *exparray[5]; //these are the fft lookup tables
uint16_t *revarray[5];
FFTComplex exptab0[512] IBSS_ATTR;
uint16_t revtab0[1024];
uint16_t *runtabarray[2], *levtabarray[2]; //these are VLC lookup tables
uint16_t runtab0[1336], runtab1[1336], levtab0[1336], levtab1[1336]; //these could be made smaller since only one can be 1336
FFTComplex mdct_tmp[1] ; /* dummy var */
//may also be too large by ~ 1KB each?
static VLC_TYPE vlcbuf1[6144][2];
static VLC_TYPE vlcbuf2[3584][2];
static VLC_TYPE vlcbuf3[1536][2] IBSS_ATTR; //small so lets try iram
static VLC_TYPE vlcbuf4[540][2];
#include "wmadata.h" // PJJ
/* butter fly op */
#define BF(pre, pim, qre, qim, pre1, pim1, qre1, qim1) \
{\
fixed32 ax, ay, bx, by;\
bx=pre1;\
by=pim1;\
ax=qre1;\
ay=qim1;\
pre = (bx + ax);\
pim = (by + ay);\
qre = (bx - ax);\
qim = (by - ay);\
}
int fft_calc_unscaled(FFTContext *s, FFTComplex *z)
{
int ln = s->nbits;
int j, np, np2;
int nblocks, nloops;
register FFTComplex *p, *q;
// FFTComplex *exptab = s->exptab;
int l;
fixed32 tmp_re, tmp_im;
int tabshift = 10-ln;
np = 1 << ln;
/* pass 0 */
p=&z[0];
j=(np >> 1);
do
{
BF(p[0].re, p[0].im, p[1].re, p[1].im,
p[0].re, p[0].im, p[1].re, p[1].im);
p+=2;
}
while (--j != 0);
/* pass 1 */
p=&z[0];
j=np >> 2;
if (s->inverse)
{
do
{
BF(p[0].re, p[0].im, p[2].re, p[2].im,
p[0].re, p[0].im, p[2].re, p[2].im);
BF(p[1].re, p[1].im, p[3].re, p[3].im,
p[1].re, p[1].im, -p[3].im, p[3].re);
p+=4;
}
while (--j != 0);
}
else
{
do
{
BF(p[0].re, p[0].im, p[2].re, p[2].im,
p[0].re, p[0].im, p[2].re, p[2].im);
BF(p[1].re, p[1].im, p[3].re, p[3].im,
p[1].re, p[1].im, p[3].im, -p[3].re);
p+=4;
}
while (--j != 0);
}
/* pass 2 .. ln-1 */
nblocks = np >> 3;
nloops = 1 << 2;
np2 = np >> 1;
do
{
p = z;
q = z + nloops;
for (j = 0; j < nblocks; ++j)
{
BF(p->re, p->im, q->re, q->im,
p->re, p->im, q->re, q->im);
p++;
q++;
for(l = nblocks; l < np2; l += nblocks)
{
CMUL(&tmp_re, &tmp_im, exptab0[(l<<tabshift)].re, exptab0[(l<<tabshift)].im, q->re, q->im);
//CMUL(&tmp_re, &tmp_im, exptab[l].re, exptab[l].im, q->re, q->im);
BF(p->re, p->im, q->re, q->im,
p->re, p->im, tmp_re, tmp_im);
p++;
q++;
}
p += nloops;
q += nloops;
}
nblocks = nblocks >> 1;
nloops = nloops << 1;
}
while (nblocks != 0);
return 0;
}
/**
* init MDCT or IMDCT computation.
*/
int ff_mdct_init(MDCTContext *s, int nbits, int inverse)
{
int n, n4, i;
// fixed32 alpha;
memset(s, 0, sizeof(*s));
n = 1 << nbits; //nbits ranges from 12 to 8 inclusive
s->nbits = nbits;
s->n = n;
n4 = n >> 2;
s->tcos = tcosarray[12-nbits];
s->tsin = tsinarray[12-nbits];
for(i=0;i<n4;i++)
{
//fixed32 pi2 = fixmul32(0x20000, M_PI_F);
fixed32 ip = itofix32(i) + 0x2000;
ip = ip >> nbits;
//ip = fixdiv32(ip,itofix32(n)); // PJJ optimize
//alpha = fixmul32(TWO_M_PI_F, ip);
//s->tcos[i] = -fixcos32(alpha); //alpha between 0 and pi/2
//s->tsin[i] = -fixsin32(alpha);
s->tsin[i] = - fsincos(ip<<16, &(s->tcos[i])); //I can't remember why this works, but it seems to agree for ~24 bits, maybe more!
s->tcos[i] *=-1;
}
s->fft.nbits = s->nbits - 2;
s->fft.inverse = inverse;
return 0;
}
/**
* Compute inverse MDCT of size N = 2^nbits
* @param output N samples
* @param input N/2 samples
* @param tmp N/2 samples
*/
void ff_imdct_calc(MDCTContext *s,
fixed32 *output,
fixed32 *input)
{
int k, n8, n4, n2, n, j,scale;
const fixed32 *tcos = s->tcos;
const fixed32 *tsin = s->tsin;
const fixed32 *in1, *in2;
FFTComplex *z1 = (FFTComplex *)output;
FFTComplex *z2 = (FFTComplex *)input;
int revtabshift = 12 - s->nbits;
n = 1 << s->nbits;
n2 = n >> 1;
n4 = n >> 2;
n8 = n >> 3;
/* pre rotation */
in1 = input;
in2 = input + n2 - 1;
for(k = 0; k < n4; k++)
{
j=revtab0[k<<revtabshift];
CMUL(&z1[j].re, &z1[j].im, *in2, *in1, tcos[k], tsin[k]);
in1 += 2;
in2 -= 2;
}
scale = fft_calc_unscaled(&s->fft, z1);
/* post rotation + reordering */
for(k = 0; k < n4; k++)
{
CMUL(&z2[k].re, &z2[k].im, (z1[k].re), (z1[k].im), tcos[k], tsin[k]);
}
for(k = 0; k < n8; k++)
{
fixed32 r1,r2,r3,r4,r1n,r2n,r3n;
r1 = z2[n8 + k].im;
r1n = r1 * -1;
r2 = z2[n8-1-k].re;
r2n = r2 * -1;
r3 = z2[k+n8].re;
r3n = r3 * -1;
r4 = z2[n8-k-1].im;
output[2*k] = r1n;
output[n2-1-2*k] = r1;
output[2*k+1] = r2;
output[n2-1-2*k-1] = r2n;
output[n2 + 2*k]= r3n;
output[n-1- 2*k]= r3n;
output[n2 + 2*k+1]= r4;
output[n-2 - 2 * k] = r4;
}
}
/*
* Helper functions for wma_window.
*
*
*/
static inline void vector_fmul_add_add(fixed32 *dst, const fixed32 *src0, const fixed32 *src1, int len){
int i;
for(i=0; i<len; i++)
dst[i] = fixmul32b(src0[i], src1[i]) + dst[i];
}
static inline void vector_fmul_reverse(fixed32 *dst, const fixed32 *src0, const fixed32 *src1, int len){
int i;
src1 += len-1;
for(i=0; i<len; i++)
dst[i] = fixmul32b(src0[i], src1[-i]);
}
/**
* Apply MDCT window and add into output.
*
* We ensure that when the windows overlap their squared sum
* is always 1 (MDCT reconstruction rule).
*/
static void wma_window(WMADecodeContext *s, fixed32 *in, fixed32 *out)
{
//float *in = s->output;
int block_len, bsize, n;
/* left part */
if (s->block_len_bits <= s->prev_block_len_bits) {
block_len = s->block_len;
bsize = s->frame_len_bits - s->block_len_bits;
vector_fmul_add_add(out, in, s->windows[bsize], block_len);
} else {
block_len = 1 << s->prev_block_len_bits;
n = (s->block_len - block_len) / 2;
bsize = s->frame_len_bits - s->prev_block_len_bits;
vector_fmul_add_add(out+n, in+n, s->windows[bsize], block_len);
memcpy(out+n+block_len, in+n+block_len, n*sizeof(fixed32));
}
out += s->block_len;
in += s->block_len;
/* right part */
if (s->block_len_bits <= s->next_block_len_bits) {
block_len = s->block_len;
bsize = s->frame_len_bits - s->block_len_bits;
vector_fmul_reverse(out, in, s->windows[bsize], block_len);
} else {
block_len = 1 << s->next_block_len_bits;
n = (s->block_len - block_len) / 2;
bsize = s->frame_len_bits - s->next_block_len_bits;
memcpy(out, in, n*sizeof(fixed32));
vector_fmul_reverse(out+n, in+n, s->windows[bsize], block_len);
memset(out+n+block_len, 0, n*sizeof(fixed32));
}
}
/* XXX: use same run/length optimization as mpeg decoders */
static void init_coef_vlc(VLC *vlc,
uint16_t **prun_table, uint16_t **plevel_table,
const CoefVLCTable *vlc_table, int tab)
{
int n = vlc_table->n;
const uint8_t *table_bits = vlc_table->huffbits;
const uint32_t *table_codes = vlc_table->huffcodes;
const uint16_t *levels_table = vlc_table->levels;
uint16_t *run_table, *level_table;
const uint16_t *p;
int i, l, j, level;
init_vlc(vlc, VLCBITS, n, table_bits, 1, 1, table_codes, 4, 4, 0);
run_table = runtabarray[tab];
level_table= levtabarray[tab];
p = levels_table;
i = 2;
level = 1;
while (i < n)
{
l = *p++;
for(j=0;j<l;++j)
{
run_table[i] = j;
level_table[i] = level;
++i;
}
++level;
}
*prun_table = run_table;
*plevel_table = level_table;
}
int wma_decode_init(WMADecodeContext* s, asf_waveformatex_t *wfx)
{
//WMADecodeContext *s = avctx->priv_data;
int i, m, j, flags1, flags2;
fixed32 *window;
uint8_t *extradata;
fixed64 bps1;
fixed32 high_freq;
fixed64 bps;
int sample_rate1;
int coef_vlc_table;
// int filehandle;
#ifdef CPU_COLDFIRE
coldfire_set_macsr(EMAC_FRACTIONAL | EMAC_SATURATE);
#endif
s->sample_rate = wfx->rate;
s->nb_channels = wfx->channels;
s->bit_rate = wfx->bitrate;
s->block_align = wfx->blockalign;
s->coefs = &coefsarray;
if (wfx->codec_id == ASF_CODEC_ID_WMAV1) {
s->version = 1;
} else if (wfx->codec_id == ASF_CODEC_ID_WMAV2 ) {
s->version = 2;
} else {
/*one of those other wma flavors that don't have GPLed decoders */
return -1;
}
/* extract flag infos */
flags1 = 0;
flags2 = 0;
extradata = wfx->data;
if (s->version == 1 && wfx->datalen >= 4) {
flags1 = extradata[0] | (extradata[1] << 8);
flags2 = extradata[2] | (extradata[3] << 8);
}else if (s->version == 2 && wfx->datalen >= 6){
flags1 = extradata[0] | (extradata[1] << 8) |
(extradata[2] << 16) | (extradata[3] << 24);
flags2 = extradata[4] | (extradata[5] << 8);
}
s->use_exp_vlc = flags2 & 0x0001;
s->use_bit_reservoir = flags2 & 0x0002;
s->use_variable_block_len = flags2 & 0x0004;
/* compute MDCT block size */
if (s->sample_rate <= 16000){
s->frame_len_bits = 9;
}else if (s->sample_rate <= 22050 ||
(s->sample_rate <= 32000 && s->version == 1)){
s->frame_len_bits = 10;
}else{
s->frame_len_bits = 11;
}
s->frame_len = 1 << s->frame_len_bits;
if (s-> use_variable_block_len)
{
int nb_max, nb;
nb = ((flags2 >> 3) & 3) + 1;
if ((s->bit_rate / s->nb_channels) >= 32000)
{
nb += 2;
}
nb_max = s->frame_len_bits - BLOCK_MIN_BITS; //max is 11-7
if (nb > nb_max)
nb = nb_max;
s->nb_block_sizes = nb + 1;
}
else
{
s->nb_block_sizes = 1;
}
/* init rate dependant parameters */
s->use_noise_coding = 1;
high_freq = itofix64(s->sample_rate) >> 1;
/* if version 2, then the rates are normalized */
sample_rate1 = s->sample_rate;
if (s->version == 2)
{
if (sample_rate1 >= 44100)
sample_rate1 = 44100;
else if (sample_rate1 >= 22050)
sample_rate1 = 22050;
else if (sample_rate1 >= 16000)
sample_rate1 = 16000;
else if (sample_rate1 >= 11025)
sample_rate1 = 11025;
else if (sample_rate1 >= 8000)
sample_rate1 = 8000;
}
fixed64 tmp = itofix64(s->bit_rate);
fixed64 tmp2 = itofix64(s->nb_channels * s->sample_rate);
bps = fixdiv64(tmp, tmp2);
fixed64 tim = bps * s->frame_len;
fixed64 tmpi = fixdiv64(tim,itofix64(8));
s->byte_offset_bits = av_log2(fixtoi64(tmpi+0x8000)) + 2;
/* compute high frequency value and choose if noise coding should
be activated */
bps1 = bps;
if (s->nb_channels == 2)
bps1 = fixmul32(bps,0x1999a);
if (sample_rate1 == 44100)
{
if (bps1 >= 0x9c29)
s->use_noise_coding = 0;
else
high_freq = fixmul32(high_freq,0x6666);
}
else if (sample_rate1 == 22050)
{
if (bps1 >= 0x128f6)
s->use_noise_coding = 0;
else if (bps1 >= 0xb852)
high_freq = fixmul32(high_freq,0xb333);
else
high_freq = fixmul32(high_freq,0x999a);
}
else if (sample_rate1 == 16000)
{
if (bps > 0x8000)
high_freq = fixmul32(high_freq,0x8000);
else
high_freq = fixmul32(high_freq,0x4ccd);
}
else if (sample_rate1 == 11025)
{
high_freq = fixmul32(high_freq,0xb333);
}
else if (sample_rate1 == 8000)
{
if (bps <= 0xa000)
{
high_freq = fixmul32(high_freq,0x8000);
}
else if (bps > 0xc000)
{
s->use_noise_coding = 0;
}
else
{
high_freq = fixmul32(high_freq,0xa666);
}
}
else
{
if (bps >= 0xcccd)
{
high_freq = fixmul32(high_freq,0xc000);
}
else if (bps >= 0x999a)
{
high_freq = fixmul32(high_freq,0x999a);
}
else
{
high_freq = fixmul32(high_freq,0x8000);
}
}
/* compute the scale factor band sizes for each MDCT block size */
{
int a, b, pos, lpos, k, block_len, i, j, n;
const uint8_t *table;
if (s->version == 1)
{
s->coefs_start = 3;
}
else
{
s->coefs_start = 0;
}
for(k = 0; k < s->nb_block_sizes; ++k)
{
block_len = s->frame_len >> k;
if (s->version == 1)
{
lpos = 0;
for(i=0;i<25;++i)
{
a = wma_critical_freqs[i];
b = s->sample_rate;
pos = ((block_len * 2 * a) + (b >> 1)) / b;
if (pos > block_len)
pos = block_len;
s->exponent_bands[0][i] = pos - lpos;
if (pos >= block_len)
{
++i;
break;
}
lpos = pos;
}
s->exponent_sizes[0] = i;
}
else
{
/* hardcoded tables */
table = NULL;
a = s->frame_len_bits - BLOCK_MIN_BITS - k;
if (a < 3)
{
if (s->sample_rate >= 44100)
table = exponent_band_44100[a];
else if (s->sample_rate >= 32000)
table = exponent_band_32000[a];
else if (s->sample_rate >= 22050)
table = exponent_band_22050[a];
}
if (table)
{
n = *table++;
for(i=0;i<n;++i)
s->exponent_bands[k][i] = table[i];
s->exponent_sizes[k] = n;
}
else
{
j = 0;
lpos = 0;
for(i=0;i<25;++i)
{
a = wma_critical_freqs[i];
b = s->sample_rate;
pos = ((block_len * 2 * a) + (b << 1)) / (4 * b);
pos <<= 2;
if (pos > block_len)
pos = block_len;
if (pos > lpos)
s->exponent_bands[k][j++] = pos - lpos;
if (pos >= block_len)
break;
lpos = pos;
}
s->exponent_sizes[k] = j;
}
}
/* max number of coefs */
s->coefs_end[k] = (s->frame_len - ((s->frame_len * 9) / 100)) >> k;
/* high freq computation */
fixed32 tmp = high_freq*2;
s->high_band_start[k] = fixtoi32(fixdiv32(tmp, itofix32(s->sample_rate)) *block_len +0x8000);
/*
s->high_band_start[k] = (int)((block_len * 2 * high_freq) /
s->sample_rate + 0.5);*/
n = s->exponent_sizes[k];
j = 0;
pos = 0;
for(i=0;i<n;++i)
{
int start, end;
start = pos;
pos += s->exponent_bands[k][i];
end = pos;
if (start < s->high_band_start[k])
start = s->high_band_start[k];
if (end > s->coefs_end[k])
end = s->coefs_end[k];
if (end > start)
s->exponent_high_bands[k][j++] = end - start;
}
s->exponent_high_sizes[k] = j;
}
}
/* init MDCT */
/*TODO: figure out how to fold this up into one array*/
tcosarray[0] = tcos0; tcosarray[1] = tcos1; tcosarray[2] = tcos2; tcosarray[3] = tcos3;tcosarray[4] = tcos4;
tsinarray[0] = tsin0; tsinarray[1] = tsin1; tsinarray[2] = tsin2; tsinarray[3] = tsin3;tsinarray[4] = tsin4;
/*these are folded up now*/
exparray[0] = exptab0; //exparray[1] = exptab1; exparray[2] = exptab2; exparray[3] = exptab3; exparray[4] = exptab4;
revarray[0]=revtab0; //revarray[1]=revtab1; revarray[2]=revtab2; revarray[3]=revtab3; revarray[4]=revtab4;
s->mdct_tmp = mdct_tmp; /* temporary storage for imdct */
for(i = 0; i < s->nb_block_sizes; ++i)
{
ff_mdct_init(&s->mdct_ctx[i], s->frame_len_bits - i + 1, 1);
}
{
int i, n;
fixed32 c1, s1, s2;
n=1<<10;
s2 = 1 ? 1 : -1;
for(i=0;i<(n/2);++i)
{
fixed32 ifix = itofix32(i);
fixed32 nfix = itofix32(n);
fixed32 res = fixdiv32(ifix,nfix);
s1 = fsincos(res<<16, &c1);
exptab0[i].re = c1;
exptab0[i].im = s1*s2;
}
}
/* init the MDCT bit reverse table here rather then in fft_init */
for(i=0;i<1024;i++) /*hard coded to a 2048 bit rotation*/
{ /*smaller sizes can reuse the largest*/
m=0;
for(j=0;j<10;j++)
{
m |= ((i >> j) & 1) << (10-j-1);
}
revtab0[i]=m;
}
/*ffmpeg uses malloc to only allocate as many window sizes as needed. However, we're really only interested in the worst case memory usage.
* In the worst case you can have 5 window sizes, 128 doubling up 2048
* Smaller windows are handled differently.
* Since we don't have malloc, just statically allocate this
*/
fixed32 *temp[5];
temp[0] = stat0;
temp[1] = stat1;
temp[2] = stat2;
temp[3] = stat3;
temp[4] = stat4;
/* init MDCT windows : simple sinus window */
for(i = 0; i < s->nb_block_sizes; i++)
{
int n, j;
fixed32 alpha;
n = 1 << (s->frame_len_bits - i);
//window = av_malloc(sizeof(fixed32) * n);
window = temp[i];
//fixed32 n2 = itofix32(n<<1); //2x the window length
//alpha = fixdiv32(M_PI_F, n2); //PI / (2x Window length) == PI<<(s->frame_len_bits - i+1)
//alpha = M_PI_F>>(s->frame_len_bits - i+1);
alpha = (1<<15)>>(s->frame_len_bits - i+1); /* this calculates 0.5/(2*n) */
for(j=0;j<n;++j)
{
fixed32 j2 = itofix32(j) + 0x8000;
window[j] = fsincos(fixmul32(j2,alpha)<<16, 0); //alpha between 0 and pi/2
}
//printf("created window\n");
s->windows[i] = window;
//printf("assigned window\n");
}
s->reset_block_lengths = 1;
if (s->use_noise_coding)
{
/* init the noise generator */
if (s->use_exp_vlc)
{
s->noise_mult = 0x51f;
s->noise_table = noisetable_exp;
}
else
{
s->noise_mult = 0xa3d;
/*LSP values are simply 2x the EXP values*/
for (i=0;i<NOISE_TAB_SIZE;++i)
noisetable_exp[i] = noisetable_exp[i]<< 1;
s->noise_table = noisetable_exp;
}
#if 0
{
unsigned int seed;
fixed32 norm;
seed = 1;
norm = 0; // PJJ: near as makes any diff to 0!
for (i=0;i<NOISE_TAB_SIZE;++i)
{
seed = seed * 314159 + 1;
s->noise_table[i] = itofix32((int)seed) * norm;
}
}
#endif
s->hgain_vlc.table = vlcbuf4;
s->hgain_vlc.table_allocated = 540;
init_vlc(&s->hgain_vlc, 9, sizeof(hgain_huffbits),
hgain_huffbits, 1, 1,
hgain_huffcodes, 2, 2, 0);
}
if (s->use_exp_vlc)
{
s->exp_vlc.table = vlcbuf3;
s->exp_vlc.table_allocated = 1536;
init_vlc(&s->exp_vlc, 9, sizeof(scale_huffbits),
scale_huffbits, 1, 1,
scale_huffcodes, 4, 4, 0);
}
else
{
wma_lsp_to_curve_init(s, s->frame_len);
}
/* choose the VLC tables for the coefficients */
coef_vlc_table = 2;
if (s->sample_rate >= 32000)
{
if (bps1 < 0xb852)
coef_vlc_table = 0;
else if (bps1 < 0x128f6)
coef_vlc_table = 1;
}
runtabarray[0] = runtab0; runtabarray[1] = runtab1;
levtabarray[0] = levtab0; levtabarray[1] = levtab1;
s->coef_vlc[0].table = vlcbuf1;
s->coef_vlc[0].table_allocated = 24576/4;
s->coef_vlc[1].table = vlcbuf2;
s->coef_vlc[1].table_allocated = 14336/4;
init_coef_vlc(&s->coef_vlc[0], &s->run_table[0], &s->level_table[0],
&coef_vlcs[coef_vlc_table * 2], 0);
init_coef_vlc(&s->coef_vlc[1], &s->run_table[1], &s->level_table[1],
&coef_vlcs[coef_vlc_table * 2 + 1], 1);
s->last_superframe_len = 0;
s->last_bitoffset = 0;
return 0;
}
/* compute x^-0.25 with an exponent and mantissa table. We use linear
interpolation to reduce the mantissa table size at a small speed
expense (linear interpolation approximately doubles the number of
bits of precision). */
static inline fixed32 pow_m1_4(WMADecodeContext *s, fixed32 x)
{
union {
fixed64 f;
unsigned int v;
} u, t;
unsigned int e, m;
fixed64 a, b;
u.f = x;
e = u.v >> 23;
m = (u.v >> (23 - LSP_POW_BITS)) & ((1 << LSP_POW_BITS) - 1);
/* build interpolation scale: 1 <= t < 2. */
t.v = ((u.v << LSP_POW_BITS) & ((1 << 23) - 1)) | (127 << 23);
a = s->lsp_pow_m_table1[m];
b = s->lsp_pow_m_table2[m];
return lsp_pow_e_table[e] * (a + b * t.f);
}
static void wma_lsp_to_curve_init(WMADecodeContext *s, int frame_len)
{
fixed32 wdel, a, b;
int i, m;
wdel = fixdiv32(M_PI_F, itofix32(frame_len));
for (i=0; i<frame_len; ++i)
{
s->lsp_cos_table[i] = 0x20000 * fixcos32(wdel * i); //wdel*i between 0 and pi
}
/* NOTE: these two tables are needed to avoid two operations in
pow_m1_4 */
b = itofix32(1);
int ix = 0;
for(i=(1 << LSP_POW_BITS) - 1;i>=0;i--)
{
m = (1 << LSP_POW_BITS) + i;
a = m * (0x8000 / (1 << LSP_POW_BITS)); //PJJ
a = pow_a_table[ix++]; // PJJ : further refinement
s->lsp_pow_m_table1[i] = 2 * a - b;
s->lsp_pow_m_table2[i] = b - a;
b = a;
}
}
/* NOTE: We use the same code as Vorbis here */
/* XXX: optimize it further with SSE/3Dnow */
static void wma_lsp_to_curve(WMADecodeContext *s,
fixed32 *out,
fixed32 *val_max_ptr,
int n,
fixed32 *lsp)
{
int i, j;
fixed32 p, q, w, v, val_max;
val_max = 0;
for(i=0;i<n;++i)
{
p = 0x8000;
q = 0x8000;
w = s->lsp_cos_table[i];
for (j=1;j<NB_LSP_COEFS;j+=2)
{
q *= w - lsp[j - 1];
p *= w - lsp[j];
}
p *= p * (0x20000 - w);
q *= q * (0x20000 + w);
v = p + q;
v = pow_m1_4(s, v); // PJJ
if (v > val_max)
val_max = v;
out[i] = v;
}
*val_max_ptr = val_max;
}
/* decode exponents coded with LSP coefficients (same idea as Vorbis) */
static void decode_exp_lsp(WMADecodeContext *s, int ch)
{
fixed32 lsp_coefs[NB_LSP_COEFS];
int val, i;
for (i = 0; i < NB_LSP_COEFS; ++i)
{
if (i == 0 || i >= 8)
val = get_bits(&s->gb, 3);
else
val = get_bits(&s->gb, 4);
lsp_coefs[i] = lsp_codebook[i][val];
}
wma_lsp_to_curve(s,
s->exponents[ch],
&s->max_exponent[ch],
s->block_len,
lsp_coefs);
}
/* decode exponents coded with VLC codes */
static int decode_exp_vlc(WMADecodeContext *s, int ch)
{
int last_exp, n, code;
const uint16_t *ptr, *band_ptr;
fixed32 v, max_scale;
fixed32 *q,*q_end;
band_ptr = s->exponent_bands[s->frame_len_bits - s->block_len_bits];
ptr = band_ptr;
q = s->exponents[ch];
q_end = q + s->block_len;
max_scale = 0;
if (s->version == 1) //wmav1 only
{
last_exp = get_bits(&s->gb, 5) + 10;
/* XXX: use a table */
v = pow_10_to_yover16[last_exp];
max_scale = v;
n = *ptr++;
do
{
*q++ = v;
}
while (--n);
}
last_exp = 36;
while (q < q_end)
{
code = get_vlc2(&s->gb, s->exp_vlc.table, EXPVLCBITS, EXPMAX);
if (code < 0)
{
return -1;
}
/* NOTE: this offset is the same as MPEG4 AAC ! */
last_exp += code - 60;
/* XXX: use a table */
v = pow_10_to_yover16[last_exp];
if (v > max_scale)
{
max_scale = v;
}
n = *ptr++;
do
{
*q++ = v;
}
while (--n);
}
s->max_exponent[ch] = max_scale;
return 0;
}
/* return 0 if OK. return 1 if last block of frame. return -1 if
unrecorrable error. */
static int wma_decode_block(WMADecodeContext *s)
{
int n, v, a, ch, code, bsize;
int coef_nb_bits, total_gain;
int nb_coefs[MAX_CHANNELS];
fixed32 mdct_norm;
// printf("***decode_block: %d:%d (%d)\n", s->frame_count - 1, s->block_num, s->block_len);
/* compute current block length */
if (s->use_variable_block_len)
{
n = av_log2(s->nb_block_sizes - 1) + 1;
if (s->reset_block_lengths)
{
s->reset_block_lengths = 0;
v = get_bits(&s->gb, n);
if (v >= s->nb_block_sizes)
{
return -2;
}
s->prev_block_len_bits = s->frame_len_bits - v;
v = get_bits(&s->gb, n);
if (v >= s->nb_block_sizes)
{
return -3;
}
s->block_len_bits = s->frame_len_bits - v;
}
else
{
/* update block lengths */
s->prev_block_len_bits = s->block_len_bits;
s->block_len_bits = s->next_block_len_bits;
}
v = get_bits(&s->gb, n);
if (v >= s->nb_block_sizes)
{
// rb->splash(HZ*4, "v was %d", v); //5, 7
return -4; //this is it
}
else{
//rb->splash(HZ, "passed v block (%d)!", v);
}
s->next_block_len_bits = s->frame_len_bits - v;
}
else
{
/* fixed block len */
s->next_block_len_bits = s->frame_len_bits;
s->prev_block_len_bits = s->frame_len_bits;
s->block_len_bits = s->frame_len_bits;
}
/* now check if the block length is coherent with the frame length */
s->block_len = 1 << s->block_len_bits;
if ((s->block_pos + s->block_len) > s->frame_len)
{
return -5;
}
if (s->nb_channels == 2)
{
s->ms_stereo = get_bits(&s->gb, 1);
}
v = 0;
for (ch = 0; ch < s->nb_channels; ++ch)
{
a = get_bits(&s->gb, 1);
s->channel_coded[ch] = a;
v |= a;
}
/* if no channel coded, no need to go further */
/* XXX: fix potential framing problems */
if (!v)
{
goto next;
}
bsize = s->frame_len_bits - s->block_len_bits;
/* read total gain and extract corresponding number of bits for
coef escape coding */
total_gain = 1;
for(;;)
{
a = get_bits(&s->gb, 7);
total_gain += a;
if (a != 127)
{
break;
}
}
if (total_gain < 15)
coef_nb_bits = 13;
else if (total_gain < 32)
coef_nb_bits = 12;
else if (total_gain < 40)
coef_nb_bits = 11;
else if (total_gain < 45)
coef_nb_bits = 10;
else
coef_nb_bits = 9;
/* compute number of coefficients */
n = s->coefs_end[bsize] - s->coefs_start;
for(ch = 0; ch < s->nb_channels; ++ch)
{
nb_coefs[ch] = n;
}
/* complex coding */
if (s->use_noise_coding)
{
for(ch = 0; ch < s->nb_channels; ++ch)
{
if (s->channel_coded[ch])
{
int i, n, a;
n = s->exponent_high_sizes[bsize];
for(i=0;i<n;++i)
{
a = get_bits(&s->gb, 1);
s->high_band_coded[ch][i] = a;
/* if noise coding, the coefficients are not transmitted */
if (a)
nb_coefs[ch] -= s->exponent_high_bands[bsize][i];
}
}
}
for(ch = 0; ch < s->nb_channels; ++ch)
{
if (s->channel_coded[ch])
{
int i, n, val, code;
n = s->exponent_high_sizes[bsize];
val = (int)0x80000000;
for(i=0;i<n;++i)
{
if (s->high_band_coded[ch][i])
{
if (val == (int)0x80000000)
{
val = get_bits(&s->gb, 7) - 19;
}
else
{
//code = get_vlc(&s->gb, &s->hgain_vlc);
code = get_vlc2(&s->gb, s->hgain_vlc.table, HGAINVLCBITS, HGAINMAX);
if (code < 0)
{
return -6;
}
val += code - 18;
}
s->high_band_values[ch][i] = val;
}
}
}
}
}
/* exponents can be reused in short blocks. */
if ((s->block_len_bits == s->frame_len_bits) || get_bits(&s->gb, 1)) {
for(ch = 0; ch < s->nb_channels; ++ch)
{
if (s->channel_coded[ch])
{
if (s->use_exp_vlc)
{
if (decode_exp_vlc(s, ch) < 0)
{
return -7;
}
}
else
{
decode_exp_lsp(s, ch);
}
s->exponents_bsize[ch] = bsize;
}
}
}
/* parse spectral coefficients : just RLE encoding */
for(ch = 0; ch < s->nb_channels; ++ch)
{
if (s->channel_coded[ch])
{
VLC *coef_vlc;
int level, run, sign, tindex;
int16_t *ptr, *eptr;
const int16_t *level_table, *run_table;
/* special VLC tables are used for ms stereo because
there is potentially less energy there */
tindex = (ch == 1 && s->ms_stereo);
coef_vlc = &s->coef_vlc[tindex];
run_table = s->run_table[tindex];
level_table = s->level_table[tindex];
/* XXX: optimize */
ptr = &s->coefs1[ch][0];
eptr = ptr + nb_coefs[ch];
memset(ptr, 0, s->block_len * sizeof(int16_t));
for(;;)
{
code = get_vlc2(&s->gb, coef_vlc->table, VLCBITS, VLCMAX);
//code = get_vlc(&s->gb, coef_vlc);
if (code < 0)
{
return -8;
}
if (code == 1)
{
/* EOB */
break;
}
else if (code == 0)
{
/* escape */
level = get_bits(&s->gb, coef_nb_bits);
/* NOTE: this is rather suboptimal. reading
block_len_bits would be better */
run = get_bits(&s->gb, s->frame_len_bits);
}
else
{
/* normal code */
run = run_table[code];
level = level_table[code];
}
sign = get_bits(&s->gb, 1);
if (!sign)
level = -level;
ptr += run;
if (ptr >= eptr)
{
return -9;
}
*ptr++ = level;
/* NOTE: EOB can be omitted */
if (ptr >= eptr)
break;
}
}
if (s->version == 1 && s->nb_channels >= 2)
{
align_get_bits(&s->gb);
}
}
{
int n4 = s->block_len >> 1;
//mdct_norm = 0x10000;
//mdct_norm = fixdiv32(mdct_norm,itofix32(n4));
mdct_norm = 0x10000>>(s->block_len_bits-1); //theres no reason to do a divide by two in fixed precision ...
if (s->version == 1)
{
fixed32 tmp = fixsqrt32(itofix32(n4));
mdct_norm *= tmp; // PJJ : exercise this path
}
}
/* finally compute the MDCT coefficients */
for(ch = 0; ch < s->nb_channels; ++ch)
{
if (s->channel_coded[ch])
{
int16_t *coefs1;
fixed32 *exponents, *exp_ptr;
fixed32 *coefs, atemp;
fixed64 mult;
fixed64 mult1;
fixed32 noise, temp1, temp2, mult2;
int i, j, n, n1, last_high_band, esize;
fixed32 exp_power[HIGH_BAND_MAX_SIZE];
//total_gain, coefs1, mdctnorm are lossless
coefs1 = s->coefs1[ch];
exponents = s->exponents[ch];
esize = s->exponents_bsize[ch];
mult = fixdiv64(pow_table[total_gain],Fixed32To64(s->max_exponent[ch]));
// mul = fixtof64(pow_table[total_gain])/(s->block_len/2)/fixtof64(s->max_exponent[ch]);
mult = fixmul64byfixed(mult, mdct_norm); //what the hell? This is actually fixed64*2^16!
coefs = (*(s->coefs))[ch]; //VLC exponenents are used to get MDCT coef here!
n=0;
if (s->use_noise_coding)
{
mult1 = mult;
/* very low freqs : noise */
for(i = 0;i < s->coefs_start; ++i)
{
*coefs++ = fixmul32( (fixmul32(s->noise_table[s->noise_index],(*exponents++))>>4),Fixed32From64(mult1)) >>1;
s->noise_index = (s->noise_index + 1) & (NOISE_TAB_SIZE - 1);
}
n1 = s->exponent_high_sizes[bsize];
/* compute power of high bands */
exp_ptr = exponents +
s->high_band_start[bsize] -
s->coefs_start;
last_high_band = 0; /* avoid warning */
for (j=0;j<n1;++j)
{
n = s->exponent_high_bands[s->frame_len_bits -
s->block_len_bits][j];
if (s->high_band_coded[ch][j])
{
fixed32 e2, v;
e2 = 0;
for(i = 0;i < n; ++i)
{
v = exp_ptr[i]>>5; /*v is noramlized later on so its fixed format is irrelevant*/
e2 += fixmul32(v, v);
}
exp_power[j] = e2/n; /*n is an int...*/
last_high_band = j;
}
exp_ptr += n;
}
/* main freqs and high freqs */
for(j=-1;j<n1;++j)
{
if (j < 0)
{
n = s->high_band_start[bsize] -
s->coefs_start;
}
else
{
n = s->exponent_high_bands[s->frame_len_bits -
s->block_len_bits][j];
}
if (j >= 0 && s->high_band_coded[ch][j])
{
/* use noise with specified power */
fixed32 tmp = fixdiv32(exp_power[j],exp_power[last_high_band]);
mult1 = (fixed64)fixsqrt32(tmp);
/* XXX: use a table */
mult1 = mult1 * pow_table[s->high_band_values[ch][j]] >> PRECISION;
/*this step has a fairly high degree of error for some reason*/
mult1 = fixdiv64(mult1,fixmul32(s->max_exponent[ch],s->noise_mult));
mult1 = mult1*mdct_norm>>PRECISION;
for(i = 0;i < n; ++i)
{
noise = s->noise_table[s->noise_index];
s->noise_index = (s->noise_index + 1) & (NOISE_TAB_SIZE - 1);
*coefs++ = fixmul32((fixmul32(*exponents,noise)>>4),Fixed32From64(mult1)) >>1;
++exponents;
}
}
else
{
/* coded values + small noise */
for(i = 0;i < n; ++i)
{
// PJJ: check code path
noise = s->noise_table[s->noise_index];
s->noise_index = (s->noise_index + 1) & (NOISE_TAB_SIZE - 1);
/*don't forget to renormalize the noise*/
temp1 = (((int32_t)*coefs1++)<<16) + (noise>>4);
temp2 = fixmul32(*exponents, mult>>16);
*coefs++ = fixmul32(temp1, temp2)>>1;
++exponents;
}
}
}
/* very high freqs : noise */
n = s->block_len - s->coefs_end[bsize];
mult2 = fixmul32(mult>>16,exponents[-1]) ; /*the work around for 32.32 vars are getting stupid*/
for (i = 0; i < n; ++i)
{
/*renormalize the noise product and then reduce to 17.15 precison*/
*coefs++ = fixmul32(s->noise_table[s->noise_index],mult2) >>5;
s->noise_index = (s->noise_index + 1) & (NOISE_TAB_SIZE - 1);
}
}
else
{
/* XXX: optimize more */
n = nb_coefs[ch];
for(i = 0;i < n; ++i)
{
/*
* Previously the IMDCT was run in 17.15 precision to avoid overflow. However rare files could
* overflow here as well, so switch to 17.15 now. As a bonus, this saves us a shift later on.
*/
atemp = (fixed32)(coefs1[i]*mult>>17);
//this "works" in the sense that the mdcts converge
//atemp= ftofix32(coefs1[i] * fixtof64(exponents[i]) * fixtof64(mult>>16));
*coefs++=fixmul32(atemp,exponents[i<<bsize>>esize]);
}
n = s->block_len - s->coefs_end[bsize];
for(i = 0;i < n; ++i)
*coefs++ = 0;
}
}
}
if (s->ms_stereo && s->channel_coded[1])
{
fixed32 a, b;
int i;
fixed32 (*coefs)[MAX_CHANNELS][BLOCK_MAX_SIZE] = (s->coefs);
/* nominal case for ms stereo: we do it before mdct */
/* no need to optimize this case because it should almost
never happen */
if (!s->channel_coded[0])
{
memset((*(s->coefs))[0], 0, sizeof(fixed32) * s->block_len);
s->channel_coded[0] = 1;
}
for(i = 0; i < s->block_len; ++i)
{
a = (*coefs)[0][i];
b = (*coefs)[1][i];
(*coefs)[0][i] = a + b;
(*coefs)[1][i] = a - b;
}
}
for(ch = 0; ch < s->nb_channels; ++ch)
{
if (s->channel_coded[ch])
{
static fixed32 output[BLOCK_MAX_SIZE * 2] IBSS_ATTR;
int n4, index, n;
n = s->block_len;
n4 = s->block_len >>1;
ff_imdct_calc(&s->mdct_ctx[bsize],
output,
(*(s->coefs))[ch]);
/* add in the frame */
index = (s->frame_len / 2) + s->block_pos - n4;
wma_window(s, output, &s->frame_out[ch][index]);
/* specific fast case for ms-stereo : add to second
channel if it is not coded */
if (s->ms_stereo && !s->channel_coded[1])
{
wma_window(s, output, &s->frame_out[1][index]);
}
}
}
next:
/* update block number */
++s->block_num;
s->block_pos += s->block_len;
if (s->block_pos >= s->frame_len)
{
return 1;
}
else
{
return 0;
}
}
/* decode a frame of frame_len samples */
static int wma_decode_frame(WMADecodeContext *s, int16_t *samples)
{
int ret, i, n, a, ch, incr;
int16_t *ptr;
fixed32 *iptr;
// rb->splash(HZ, "in wma_decode_frame");
/* read each block */
s->block_num = 0;
s->block_pos = 0;
for(;;)
{
ret = wma_decode_block(s);
if (ret < 0)
{
//rb->splash(HZ*4, "wma_decode_block failed with ret %d", ret);
return -1;
}
if (ret)
{
break;
}
}
/* convert frame to integer */
n = s->frame_len;
incr = s->nb_channels;
for(ch = 0; ch < s->nb_channels; ++ch)
{
ptr = samples + ch;
iptr = s->frame_out[ch];
for (i=0;i<n;++i)
{
a = fixtoi32(*iptr++)<<1; //ugly but good enough for now
if (a > 32767)
{
a = 32767;
}
else if (a < -32768)
{
a = -32768;
}
*ptr = a;
ptr += incr;
}
/* prepare for next block */
memmove(&s->frame_out[ch][0], &s->frame_out[ch][s->frame_len],
s->frame_len * sizeof(fixed32));
}
return 0;
}
/* Initialise the superframe decoding */
int wma_decode_superframe_init(WMADecodeContext* s,
uint8_t *buf, /*input*/
int buf_size)
{
if (buf_size==0)
{
s->last_superframe_len = 0;
return 0;
}
s->current_frame = 0;
init_get_bits(&s->gb, buf, buf_size*8);
if (s->use_bit_reservoir)
{
/* read super frame header */
get_bits(&s->gb, 4); /* super frame index */
s->nb_frames = get_bits(&s->gb, 4);
if (s->last_superframe_len == 0)
s->nb_frames --;
else if (s->nb_frames == 0)
s->nb_frames++;
s->bit_offset = get_bits(&s->gb, s->byte_offset_bits + 3);
} else {
s->nb_frames = 1;
}
return 1;
}
/* Decode a single frame in the current superframe - return -1 if
there was a decoding error, or the number of samples decoded.
*/
int wma_decode_superframe_frame(WMADecodeContext* s,
int16_t* samples, /*output*/
uint8_t *buf, /*input*/
int buf_size)
{
int pos, len;
uint8_t *q;
int done = 0;
if ((s->use_bit_reservoir) && (s->current_frame == 0))
{
if (s->last_superframe_len > 0)
{
/* add s->bit_offset bits to last frame */
if ((s->last_superframe_len + ((s->bit_offset + 7) >> 3)) >
MAX_CODED_SUPERFRAME_SIZE)
{
goto fail;
}
q = s->last_superframe + s->last_superframe_len;
len = s->bit_offset;
while (len > 0)
{
*q++ = (get_bits)(&s->gb, 8);
len -= 8;
}
if (len > 0)
{
*q++ = (get_bits)(&s->gb, len) << (8 - len);
}
/* XXX: s->bit_offset bits into last frame */
init_get_bits(&s->gb, s->last_superframe, MAX_CODED_SUPERFRAME_SIZE*8);
/* skip unused bits */
if (s->last_bitoffset > 0)
skip_bits(&s->gb, s->last_bitoffset);
/* this frame is stored in the last superframe and in the
current one */
if (wma_decode_frame(s, samples) < 0)
{
goto fail;
}
done = 1;
}
/* read each frame starting from s->bit_offset */
pos = s->bit_offset + 4 + 4 + s->byte_offset_bits + 3;
init_get_bits(&s->gb, buf + (pos >> 3), (MAX_CODED_SUPERFRAME_SIZE - (pos >> 3))*8);
len = pos & 7;
if (len > 0)
skip_bits(&s->gb, len);
s->reset_block_lengths = 1;
}
/* If we haven't decoded a frame yet, do it now */
if (!done)
{
if (wma_decode_frame(s, samples) < 0)
{
goto fail;
}
}
s->current_frame++;
if ((s->use_bit_reservoir) && (s->current_frame == s->nb_frames))
{
/* we copy the end of the frame in the last frame buffer */
pos = get_bits_count(&s->gb) + ((s->bit_offset + 4 + 4 + s->byte_offset_bits + 3) & ~7);
s->last_bitoffset = pos & 7;
pos >>= 3;
len = buf_size - pos;
if (len > MAX_CODED_SUPERFRAME_SIZE || len < 0)
{
goto fail;
}
s->last_superframe_len = len;
memcpy(s->last_superframe, buf + pos, len);
}
return s->frame_len;
fail:
/* when error, we reset the bit reservoir */
s->last_superframe_len = 0;
return -1;
}