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ffmpeg/libavcodec/mpegaudiodec.c

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/*
* MPEG Audio decoder
* Copyright (c) 2001, 2002 Gerard Lantau.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
//#define DEBUG
#include "avcodec.h"
#include "mpegaudio.h"
/*
* TODO:
* - in low precision mode, use more 16 bit multiplies in synth filter
* - test lsf / mpeg25 extensively.
*/
/* define USE_HIGHPRECISION to have a bit exact (but slower) mpeg
audio decoder */
//#define USE_HIGHPRECISION
#ifdef USE_HIGHPRECISION
#define FRAC_BITS 23 /* fractional bits for sb_samples and dct */
#define WFRAC_BITS 16 /* fractional bits for window */
#else
#define FRAC_BITS 15 /* fractional bits for sb_samples and dct */
#define WFRAC_BITS 14 /* fractional bits for window */
#endif
#define FRAC_ONE (1 << FRAC_BITS)
#define MULL(a,b) (((INT64)(a) * (INT64)(b)) >> FRAC_BITS)
#define MUL64(a,b) ((INT64)(a) * (INT64)(b))
#define FIX(a) ((int)((a) * FRAC_ONE))
/* WARNING: only correct for posititive numbers */
#define FIXR(a) ((int)((a) * FRAC_ONE + 0.5))
#define FRAC_RND(a) (((a) + (FRAC_ONE/2)) >> FRAC_BITS)
#if FRAC_BITS <= 15
typedef INT16 MPA_INT;
#else
typedef INT32 MPA_INT;
#endif
/****************/
#define HEADER_SIZE 4
#define BACKSTEP_SIZE 512
typedef struct MPADecodeContext {
UINT8 inbuf1[2][MPA_MAX_CODED_FRAME_SIZE + BACKSTEP_SIZE]; /* input buffer */
int inbuf_index;
UINT8 *inbuf_ptr, *inbuf;
int frame_size;
int free_format_frame_size; /* frame size in case of free format
(zero if currently unknown) */
/* next header (used in free format parsing) */
UINT32 free_format_next_header;
int error_protection;
int layer;
int sample_rate;
int sample_rate_index; /* between 0 and 8 */
int bit_rate;
int old_frame_size;
GetBitContext gb;
int nb_channels;
int mode;
int mode_ext;
int lsf;
MPA_INT synth_buf[MPA_MAX_CHANNELS][512 * 2];
int synth_buf_offset[MPA_MAX_CHANNELS];
INT32 sb_samples[MPA_MAX_CHANNELS][36][SBLIMIT];
INT32 mdct_buf[MPA_MAX_CHANNELS][SBLIMIT * 18]; /* previous samples, for layer 3 MDCT */
#ifdef DEBUG
int frame_count;
#endif
} MPADecodeContext;
/* layer 3 "granule" */
typedef struct GranuleDef {
UINT8 scfsi;
int part2_3_length;
int big_values;
int global_gain;
int scalefac_compress;
UINT8 block_type;
UINT8 switch_point;
int table_select[3];
int subblock_gain[3];
UINT8 scalefac_scale;
UINT8 count1table_select;
int region_size[3]; /* number of huffman codes in each region */
int preflag;
int short_start, long_end; /* long/short band indexes */
UINT8 scale_factors[40];
INT32 sb_hybrid[SBLIMIT * 18]; /* 576 samples */
} GranuleDef;
#define MODE_EXT_MS_STEREO 2
#define MODE_EXT_I_STEREO 1
/* layer 3 huffman tables */
typedef struct HuffTable {
int xsize;
const UINT8 *bits;
const UINT16 *codes;
} HuffTable;
#include "mpegaudiodectab.h"
/* vlc structure for decoding layer 3 huffman tables */
static VLC huff_vlc[16];
static UINT8 *huff_code_table[16];
static VLC huff_quad_vlc[2];
/* computed from band_size_long */
static UINT16 band_index_long[9][23];
/* XXX: free when all decoders are closed */
#define TABLE_4_3_SIZE (8191 + 16)
static INT8 *table_4_3_exp;
#if FRAC_BITS <= 15
static UINT16 *table_4_3_value;
#else
static UINT32 *table_4_3_value;
#endif
/* intensity stereo coef table */
static INT32 is_table[2][16];
static INT32 is_table_lsf[2][2][16];
static INT32 csa_table[8][2];
static INT32 mdct_win[8][36];
/* lower 2 bits: modulo 3, higher bits: shift */
static UINT16 scale_factor_modshift[64];
/* [i][j]: 2^(-j/3) * FRAC_ONE * 2^(i+2) / (2^(i+2) - 1) */
static INT32 scale_factor_mult[15][3];
/* mult table for layer 2 group quantization */
#define SCALE_GEN(v) \
{ FIXR(1.0 * (v)), FIXR(0.7937005259 * (v)), FIXR(0.6299605249 * (v)) }
static INT32 scale_factor_mult2[3][3] = {
SCALE_GEN(1.0 / 3.0), /* 3 steps */
SCALE_GEN(1.0 / 5.0), /* 5 steps */
SCALE_GEN(1.0 / 9.0), /* 9 steps */
};
/* 2^(n/4) */
static UINT32 scale_factor_mult3[4] = {
FIXR(1.0),
FIXR(1.18920711500272106671),
FIXR(1.41421356237309504880),
FIXR(1.68179283050742908605),
};
static MPA_INT window[512];
/* layer 1 unscaling */
/* n = number of bits of the mantissa minus 1 */
static inline int l1_unscale(int n, int mant, int scale_factor)
{
int shift, mod;
INT64 val;
shift = scale_factor_modshift[scale_factor];
mod = shift & 3;
shift >>= 2;
val = MUL64(mant + (-1 << n) + 1, scale_factor_mult[n-1][mod]);
shift += n;
return (int)((val + (1 << (shift - 1))) >> shift);
}
static inline int l2_unscale_group(int steps, int mant, int scale_factor)
{
int shift, mod, val;
shift = scale_factor_modshift[scale_factor];
mod = shift & 3;
shift >>= 2;
/* XXX: store the result directly */
val = (2 * (mant - (steps >> 1))) * scale_factor_mult2[steps >> 2][mod];
return (val + (1 << (shift - 1))) >> shift;
}
/* compute value^(4/3) * 2^(exponent/4). It normalized to FRAC_BITS */
static inline int l3_unscale(int value, int exponent)
{
#if FRAC_BITS <= 15
unsigned int m;
#else
UINT64 m;
#endif
int e;
e = table_4_3_exp[value];
e += (exponent >> 2);
e = FRAC_BITS - e;
#if FRAC_BITS <= 15
if (e > 31)
e = 31;
#endif
m = table_4_3_value[value];
#if FRAC_BITS <= 15
m = (m * scale_factor_mult3[exponent & 3]);
m = (m + (1 << (e-1))) >> e;
return m;
#else
m = MUL64(m, scale_factor_mult3[exponent & 3]);
m = (m + (UINT64_C(1) << (e-1))) >> e;
return m;
#endif
}
/* all integer n^(4/3) computation code */
#define DEV_ORDER 13
#define POW_FRAC_BITS 24
#define POW_FRAC_ONE (1 << POW_FRAC_BITS)
#define POW_FIX(a) ((int)((a) * POW_FRAC_ONE))
#define POW_MULL(a,b) (((INT64)(a) * (INT64)(b)) >> POW_FRAC_BITS)
static int dev_4_3_coefs[DEV_ORDER];
static int pow_mult3[3] = {
POW_FIX(1.0),
POW_FIX(1.25992104989487316476),
POW_FIX(1.58740105196819947474),
};
static void int_pow_init(void)
{
int i, a;
a = POW_FIX(1.0);
for(i=0;i<DEV_ORDER;i++) {
a = POW_MULL(a, POW_FIX(4.0 / 3.0) - i * POW_FIX(1.0)) / (i + 1);
dev_4_3_coefs[i] = a;
}
}
/* return the mantissa and the binary exponent */
static int int_pow(int i, int *exp_ptr)
{
int e, er, eq, j;
int a, a1;
/* renormalize */
a = i;
e = POW_FRAC_BITS;
while (a < (1 << (POW_FRAC_BITS - 1))) {
a = a << 1;
e--;
}
a -= (1 << POW_FRAC_BITS);
a1 = 0;
for(j = DEV_ORDER - 1; j >= 0; j--)
a1 = POW_MULL(a, dev_4_3_coefs[j] + a1);
a = (1 << POW_FRAC_BITS) + a1;
/* exponent compute (exact) */
e = e * 4;
er = e % 3;
eq = e / 3;
a = POW_MULL(a, pow_mult3[er]);
while (a >= 2 * POW_FRAC_ONE) {
a = a >> 1;
eq++;
}
/* convert to float */
while (a < POW_FRAC_ONE) {
a = a << 1;
eq--;
}
/* now POW_FRAC_ONE <= a < 2 * POW_FRAC_ONE */
#if (POW_FRAC_BITS - 1) > FRAC_BITS
a = (a + (1 << (POW_FRAC_BITS - FRAC_BITS - 1))) >> (POW_FRAC_BITS - FRAC_BITS);
/* correct overflow */
if (a >= 2 * (1 << FRAC_BITS)) {
a = a >> 1;
eq++;
}
#endif
*exp_ptr = eq;
return a;
}
static int decode_init(AVCodecContext * avctx)
{
MPADecodeContext *s = avctx->priv_data;
static int init;
int i, j, k;
if(!init) {
/* scale factors table for layer 1/2 */
for(i=0;i<64;i++) {
int shift, mod;
/* 1.0 (i = 3) is normalized to 2 ^ FRAC_BITS */
shift = (i / 3) - 1;
mod = i % 3;
#if FRAC_BITS <= 15
if (shift > 31)
shift = 31;
#endif
scale_factor_modshift[i] = mod | (shift << 2);
}
/* scale factor multiply for layer 1 */
for(i=0;i<15;i++) {
int n, norm;
n = i + 2;
norm = ((INT64_C(1) << n) * FRAC_ONE) / ((1 << n) - 1);
scale_factor_mult[i][0] = MULL(FIXR(1.0), norm);
scale_factor_mult[i][1] = MULL(FIXR(0.7937005259), norm);
scale_factor_mult[i][2] = MULL(FIXR(0.6299605249), norm);
dprintf("%d: norm=%x s=%x %x %x\n",
i, norm,
scale_factor_mult[i][0],
scale_factor_mult[i][1],
scale_factor_mult[i][2]);
}
/* window */
/* max = 18760, max sum over all 16 coefs : 44736 */
for(i=0;i<257;i++) {
int v;
v = mpa_enwindow[i];
#if WFRAC_BITS < 16
v = (v + (1 << (16 - WFRAC_BITS - 1))) >> (16 - WFRAC_BITS);
#endif
window[i] = v;
if ((i & 63) != 0)
v = -v;
if (i != 0)
window[512 - i] = v;
}
/* huffman decode tables */
huff_code_table[0] = NULL;
for(i=1;i<16;i++) {
const HuffTable *h = &mpa_huff_tables[i];
int xsize, n, x, y;
UINT8 *code_table;
xsize = h->xsize;
n = xsize * xsize;
/* XXX: fail test */
init_vlc(&huff_vlc[i], 8, n,
h->bits, 1, 1, h->codes, 2, 2);
code_table = av_mallocz(n);
j = 0;
for(x=0;x<xsize;x++) {
for(y=0;y<xsize;y++)
code_table[j++] = (x << 4) | y;
}
huff_code_table[i] = code_table;
}
for(i=0;i<2;i++) {
init_vlc(&huff_quad_vlc[i], i == 0 ? 7 : 4, 16,
mpa_quad_bits[i], 1, 1, mpa_quad_codes[i], 1, 1);
}
for(i=0;i<9;i++) {
k = 0;
for(j=0;j<22;j++) {
band_index_long[i][j] = k;
k += band_size_long[i][j];
}
band_index_long[i][22] = k;
}
/* compute n ^ (4/3) and store it in mantissa/exp format */
table_4_3_exp = av_mallocz(TABLE_4_3_SIZE *
sizeof(table_4_3_exp[0]));
if (!table_4_3_exp)
return -1;
table_4_3_value = av_mallocz(TABLE_4_3_SIZE *
sizeof(table_4_3_value[0]));
if (!table_4_3_value) {
av_free(table_4_3_exp);
return -1;
}
int_pow_init();
for(i=1;i<TABLE_4_3_SIZE;i++) {
int e, m;
m = int_pow(i, &e);
#if 0
/* test code */
{
double f, fm;
int e1, m1;
f = pow((double)i, 4.0 / 3.0);
fm = frexp(f, &e1);
m1 = FIXR(2 * fm);
#if FRAC_BITS <= 15
if ((unsigned short)m1 != m1) {
m1 = m1 >> 1;
e1++;
}
#endif
e1--;
if (m != m1 || e != e1) {
printf("%4d: m=%x m1=%x e=%d e1=%d\n",
i, m, m1, e, e1);
}
}
#endif
/* normalized to FRAC_BITS */
table_4_3_value[i] = m;
table_4_3_exp[i] = e;
}
for(i=0;i<7;i++) {
float f;
int v;
if (i != 6) {
f = tan((double)i * M_PI / 12.0);
v = FIXR(f / (1.0 + f));
} else {
v = FIXR(1.0);
}
is_table[0][i] = v;
is_table[1][6 - i] = v;
}
/* invalid values */
for(i=7;i<16;i++)
is_table[0][i] = is_table[1][i] = 0.0;
for(i=0;i<16;i++) {
double f;
int e, k;
for(j=0;j<2;j++) {
e = -(j + 1) * ((i + 1) >> 1);
f = pow(2.0, e / 4.0);
k = i & 1;
is_table_lsf[j][k ^ 1][i] = FIXR(f);
is_table_lsf[j][k][i] = FIXR(1.0);
dprintf("is_table_lsf %d %d: %x %x\n",
i, j, is_table_lsf[j][0][i], is_table_lsf[j][1][i]);
}
}
for(i=0;i<8;i++) {
float ci, cs, ca;
ci = ci_table[i];
cs = 1.0 / sqrt(1.0 + ci * ci);
ca = cs * ci;
csa_table[i][0] = FIX(cs);
csa_table[i][1] = FIX(ca);
}
/* compute mdct windows */
for(i=0;i<36;i++) {
int v;
v = FIXR(sin(M_PI * (i + 0.5) / 36.0));
mdct_win[0][i] = v;
mdct_win[1][i] = v;
mdct_win[3][i] = v;
}
for(i=0;i<6;i++) {
mdct_win[1][18 + i] = FIXR(1.0);
mdct_win[1][24 + i] = FIXR(sin(M_PI * ((i + 6) + 0.5) / 12.0));
mdct_win[1][30 + i] = FIXR(0.0);
mdct_win[3][i] = FIXR(0.0);
mdct_win[3][6 + i] = FIXR(sin(M_PI * (i + 0.5) / 12.0));
mdct_win[3][12 + i] = FIXR(1.0);
}
for(i=0;i<12;i++)
mdct_win[2][i] = FIXR(sin(M_PI * (i + 0.5) / 12.0));
/* NOTE: we do frequency inversion adter the MDCT by changing
the sign of the right window coefs */
for(j=0;j<4;j++) {
for(i=0;i<36;i+=2) {
mdct_win[j + 4][i] = mdct_win[j][i];
mdct_win[j + 4][i + 1] = -mdct_win[j][i + 1];
}
}
#if defined(DEBUG)
for(j=0;j<8;j++) {
printf("win%d=\n", j);
for(i=0;i<36;i++)
printf("%f, ", (double)mdct_win[j][i] / FRAC_ONE);
printf("\n");
}
#endif
init = 1;
}
s->inbuf_index = 0;
s->inbuf = &s->inbuf1[s->inbuf_index][BACKSTEP_SIZE];
s->inbuf_ptr = s->inbuf;
#ifdef DEBUG
s->frame_count = 0;
#endif
return 0;
}
/* tab[i][j] = 1.0 / (2.0 * cos(pi*(2*k+1) / 2^(6 - j))) */;
/* cos(i*pi/64) */
#define COS0_0 FIXR(0.50060299823519630134)
#define COS0_1 FIXR(0.50547095989754365998)
#define COS0_2 FIXR(0.51544730992262454697)
#define COS0_3 FIXR(0.53104259108978417447)
#define COS0_4 FIXR(0.55310389603444452782)
#define COS0_5 FIXR(0.58293496820613387367)
#define COS0_6 FIXR(0.62250412303566481615)
#define COS0_7 FIXR(0.67480834145500574602)
#define COS0_8 FIXR(0.74453627100229844977)
#define COS0_9 FIXR(0.83934964541552703873)
#define COS0_10 FIXR(0.97256823786196069369)
#define COS0_11 FIXR(1.16943993343288495515)
#define COS0_12 FIXR(1.48416461631416627724)
#define COS0_13 FIXR(2.05778100995341155085)
#define COS0_14 FIXR(3.40760841846871878570)
#define COS0_15 FIXR(10.19000812354805681150)
#define COS1_0 FIXR(0.50241928618815570551)
#define COS1_1 FIXR(0.52249861493968888062)
#define COS1_2 FIXR(0.56694403481635770368)
#define COS1_3 FIXR(0.64682178335999012954)
#define COS1_4 FIXR(0.78815462345125022473)
#define COS1_5 FIXR(1.06067768599034747134)
#define COS1_6 FIXR(1.72244709823833392782)
#define COS1_7 FIXR(5.10114861868916385802)
#define COS2_0 FIXR(0.50979557910415916894)
#define COS2_1 FIXR(0.60134488693504528054)
#define COS2_2 FIXR(0.89997622313641570463)
#define COS2_3 FIXR(2.56291544774150617881)
#define COS3_0 FIXR(0.54119610014619698439)
#define COS3_1 FIXR(1.30656296487637652785)
#define COS4_0 FIXR(0.70710678118654752439)
/* butterfly operator */
#define BF(a, b, c)\
{\
tmp0 = tab[a] + tab[b];\
tmp1 = tab[a] - tab[b];\
tab[a] = tmp0;\
tab[b] = MULL(tmp1, c);\
}
#define BF1(a, b, c, d)\
{\
BF(a, b, COS4_0);\
BF(c, d, -COS4_0);\
tab[c] += tab[d];\
}
#define BF2(a, b, c, d)\
{\
BF(a, b, COS4_0);\
BF(c, d, -COS4_0);\
tab[c] += tab[d];\
tab[a] += tab[c];\
tab[c] += tab[b];\
tab[b] += tab[d];\
}
#define ADD(a, b) tab[a] += tab[b]
/* DCT32 without 1/sqrt(2) coef zero scaling. */
static void dct32(INT32 *out, INT32 *tab)
{
int tmp0, tmp1;
/* pass 1 */
BF(0, 31, COS0_0);
BF(1, 30, COS0_1);
BF(2, 29, COS0_2);
BF(3, 28, COS0_3);
BF(4, 27, COS0_4);
BF(5, 26, COS0_5);
BF(6, 25, COS0_6);
BF(7, 24, COS0_7);
BF(8, 23, COS0_8);
BF(9, 22, COS0_9);
BF(10, 21, COS0_10);
BF(11, 20, COS0_11);
BF(12, 19, COS0_12);
BF(13, 18, COS0_13);
BF(14, 17, COS0_14);
BF(15, 16, COS0_15);
/* pass 2 */
BF(0, 15, COS1_0);
BF(1, 14, COS1_1);
BF(2, 13, COS1_2);
BF(3, 12, COS1_3);
BF(4, 11, COS1_4);
BF(5, 10, COS1_5);
BF(6, 9, COS1_6);
BF(7, 8, COS1_7);
BF(16, 31, -COS1_0);
BF(17, 30, -COS1_1);
BF(18, 29, -COS1_2);
BF(19, 28, -COS1_3);
BF(20, 27, -COS1_4);
BF(21, 26, -COS1_5);
BF(22, 25, -COS1_6);
BF(23, 24, -COS1_7);
/* pass 3 */
BF(0, 7, COS2_0);
BF(1, 6, COS2_1);
BF(2, 5, COS2_2);
BF(3, 4, COS2_3);
BF(8, 15, -COS2_0);
BF(9, 14, -COS2_1);
BF(10, 13, -COS2_2);
BF(11, 12, -COS2_3);
BF(16, 23, COS2_0);
BF(17, 22, COS2_1);
BF(18, 21, COS2_2);
BF(19, 20, COS2_3);
BF(24, 31, -COS2_0);
BF(25, 30, -COS2_1);
BF(26, 29, -COS2_2);
BF(27, 28, -COS2_3);
/* pass 4 */
BF(0, 3, COS3_0);
BF(1, 2, COS3_1);
BF(4, 7, -COS3_0);
BF(5, 6, -COS3_1);
BF(8, 11, COS3_0);
BF(9, 10, COS3_1);
BF(12, 15, -COS3_0);
BF(13, 14, -COS3_1);
BF(16, 19, COS3_0);
BF(17, 18, COS3_1);
BF(20, 23, -COS3_0);
BF(21, 22, -COS3_1);
BF(24, 27, COS3_0);
BF(25, 26, COS3_1);
BF(28, 31, -COS3_0);
BF(29, 30, -COS3_1);
/* pass 5 */
BF1(0, 1, 2, 3);
BF2(4, 5, 6, 7);
BF1(8, 9, 10, 11);
BF2(12, 13, 14, 15);
BF1(16, 17, 18, 19);
BF2(20, 21, 22, 23);
BF1(24, 25, 26, 27);
BF2(28, 29, 30, 31);
/* pass 6 */
ADD( 8, 12);
ADD(12, 10);
ADD(10, 14);
ADD(14, 9);
ADD( 9, 13);
ADD(13, 11);
ADD(11, 15);
out[ 0] = tab[0];
out[16] = tab[1];
out[ 8] = tab[2];
out[24] = tab[3];
out[ 4] = tab[4];
out[20] = tab[5];
out[12] = tab[6];
out[28] = tab[7];
out[ 2] = tab[8];
out[18] = tab[9];
out[10] = tab[10];
out[26] = tab[11];
out[ 6] = tab[12];
out[22] = tab[13];
out[14] = tab[14];
out[30] = tab[15];
ADD(24, 28);
ADD(28, 26);
ADD(26, 30);
ADD(30, 25);
ADD(25, 29);
ADD(29, 27);
ADD(27, 31);
out[ 1] = tab[16] + tab[24];
out[17] = tab[17] + tab[25];
out[ 9] = tab[18] + tab[26];
out[25] = tab[19] + tab[27];
out[ 5] = tab[20] + tab[28];
out[21] = tab[21] + tab[29];
out[13] = tab[22] + tab[30];
out[29] = tab[23] + tab[31];
out[ 3] = tab[24] + tab[20];
out[19] = tab[25] + tab[21];
out[11] = tab[26] + tab[22];
out[27] = tab[27] + tab[23];
out[ 7] = tab[28] + tab[18];
out[23] = tab[29] + tab[19];
out[15] = tab[30] + tab[17];
out[31] = tab[31];
}
#define OUT_SHIFT (WFRAC_BITS + FRAC_BITS - 15)
#if FRAC_BITS <= 15
#define OUT_SAMPLE(sum)\
{\
int sum1;\
sum1 = (sum + (1 << (OUT_SHIFT - 1))) >> OUT_SHIFT;\
if (sum1 < -32768)\
sum1 = -32768;\
else if (sum1 > 32767)\
sum1 = 32767;\
*samples = sum1;\
samples += incr;\
}
#define SUM8(off, op) \
{ \
sum op w[0 * 64 + off] * p[0 * 64];\
sum op w[1 * 64 + off] * p[1 * 64];\
sum op w[2 * 64 + off] * p[2 * 64];\
sum op w[3 * 64 + off] * p[3 * 64];\
sum op w[4 * 64 + off] * p[4 * 64];\
sum op w[5 * 64 + off] * p[5 * 64];\
sum op w[6 * 64 + off] * p[6 * 64];\
sum op w[7 * 64 + off] * p[7 * 64];\
}
#else
#define OUT_SAMPLE(sum)\
{\
int sum1;\
sum1 = (int)((sum + (INT64_C(1) << (OUT_SHIFT - 1))) >> OUT_SHIFT);\
if (sum1 < -32768)\
sum1 = -32768;\
else if (sum1 > 32767)\
sum1 = 32767;\
*samples = sum1;\
samples += incr;\
}
#define SUM8(off, op) \
{ \
sum op MUL64(w[0 * 64 + off], p[0 * 64]);\
sum op MUL64(w[1 * 64 + off], p[1 * 64]);\
sum op MUL64(w[2 * 64 + off], p[2 * 64]);\
sum op MUL64(w[3 * 64 + off], p[3 * 64]);\
sum op MUL64(w[4 * 64 + off], p[4 * 64]);\
sum op MUL64(w[5 * 64 + off], p[5 * 64]);\
sum op MUL64(w[6 * 64 + off], p[6 * 64]);\
sum op MUL64(w[7 * 64 + off], p[7 * 64]);\
}
#endif
/* 32 sub band synthesis filter. Input: 32 sub band samples, Output:
32 samples. */
/* XXX: optimize by avoiding ring buffer usage */
static void synth_filter(MPADecodeContext *s1,
int ch, INT16 *samples, int incr,
INT32 sb_samples[SBLIMIT])
{
INT32 tmp[32];
register MPA_INT *synth_buf, *p;
register MPA_INT *w;
int j, offset, v;
#if FRAC_BITS <= 15
int sum;
#else
INT64 sum;
#endif
dct32(tmp, sb_samples);
offset = s1->synth_buf_offset[ch];
synth_buf = s1->synth_buf[ch] + offset;
for(j=0;j<32;j++) {
v = tmp[j];
#if FRAC_BITS <= 15
if (v > 32767)
v = 32767;
else if (v < -32768)
v = -32768;
#endif
synth_buf[j] = v;
}
/* copy to avoid wrap */
memcpy(synth_buf + 512, synth_buf, 32 * sizeof(MPA_INT));
w = window;
for(j=0;j<16;j++) {
sum = 0;
p = synth_buf + 16 + j; /* 0-15 */
SUM8(0, +=);
p = synth_buf + 48 - j; /* 32-47 */
SUM8(32, -=);
OUT_SAMPLE(sum);
w++;
}
p = synth_buf + 32; /* 48 */
sum = 0;
SUM8(32, -=);
OUT_SAMPLE(sum);
w++;
for(j=17;j<32;j++) {
sum = 0;
p = synth_buf + 48 - j; /* 17-31 */
SUM8(0, -=);
p = synth_buf + 16 + j; /* 49-63 */
SUM8(32, -=);
OUT_SAMPLE(sum);
w++;
}
offset = (offset - 32) & 511;
s1->synth_buf_offset[ch] = offset;
}
/* cos(pi*i/24) */
#define C1 FIXR(0.99144486137381041114)
#define C3 FIXR(0.92387953251128675612)
#define C5 FIXR(0.79335334029123516458)
#define C7 FIXR(0.60876142900872063941)
#define C9 FIXR(0.38268343236508977173)
#define C11 FIXR(0.13052619222005159154)
/* 12 points IMDCT. We compute it "by hand" by factorizing obvious
cases. */
static void imdct12(int *out, int *in)
{
int tmp;
INT64 in1_3, in1_9, in4_3, in4_9;
in1_3 = MUL64(in[1], C3);
in1_9 = MUL64(in[1], C9);
in4_3 = MUL64(in[4], C3);
in4_9 = MUL64(in[4], C9);
tmp = FRAC_RND(MUL64(in[0], C7) - in1_3 - MUL64(in[2], C11) +
MUL64(in[3], C1) - in4_9 - MUL64(in[5], C5));
out[0] = tmp;
out[5] = -tmp;
tmp = FRAC_RND(MUL64(in[0] - in[3], C9) - in1_3 +
MUL64(in[2] + in[5], C3) - in4_9);
out[1] = tmp;
out[4] = -tmp;
tmp = FRAC_RND(MUL64(in[0], C11) - in1_9 + MUL64(in[2], C7) -
MUL64(in[3], C5) + in4_3 - MUL64(in[5], C1));
out[2] = tmp;
out[3] = -tmp;
tmp = FRAC_RND(MUL64(-in[0], C5) + in1_9 + MUL64(in[2], C1) +
MUL64(in[3], C11) - in4_3 - MUL64(in[5], C7));
out[6] = tmp;
out[11] = tmp;
tmp = FRAC_RND(MUL64(-in[0] + in[3], C3) - in1_9 +
MUL64(in[2] + in[5], C9) + in4_3);
out[7] = tmp;
out[10] = tmp;
tmp = FRAC_RND(-MUL64(in[0], C1) - in1_3 - MUL64(in[2], C5) -
MUL64(in[3], C7) - in4_9 - MUL64(in[5], C11));
out[8] = tmp;
out[9] = tmp;
}
#undef C1
#undef C3
#undef C5
#undef C7
#undef C9
#undef C11
/* cos(pi*i/18) */
#define C1 FIXR(0.98480775301220805936)
#define C2 FIXR(0.93969262078590838405)
#define C3 FIXR(0.86602540378443864676)
#define C4 FIXR(0.76604444311897803520)
#define C5 FIXR(0.64278760968653932632)
#define C6 FIXR(0.5)
#define C7 FIXR(0.34202014332566873304)
#define C8 FIXR(0.17364817766693034885)
/* 0.5 / cos(pi*(2*i+1)/36) */
static const int icos36[9] = {
FIXR(0.50190991877167369479),
FIXR(0.51763809020504152469),
FIXR(0.55168895948124587824),
FIXR(0.61038729438072803416),
FIXR(0.70710678118654752439),
FIXR(0.87172339781054900991),
FIXR(1.18310079157624925896),
FIXR(1.93185165257813657349),
FIXR(5.73685662283492756461),
};
static const int icos72[18] = {
/* 0.5 / cos(pi*(2*i+19)/72) */
FIXR(0.74009361646113053152),
FIXR(0.82133981585229078570),
FIXR(0.93057949835178895673),
FIXR(1.08284028510010010928),
FIXR(1.30656296487637652785),
FIXR(1.66275476171152078719),
FIXR(2.31011315767264929558),
FIXR(3.83064878777019433457),
FIXR(11.46279281302667383546),
/* 0.5 / cos(pi*(2*(i + 18) +19)/72) */
FIXR(-0.67817085245462840086),
FIXR(-0.63023620700513223342),
FIXR(-0.59284452371708034528),
FIXR(-0.56369097343317117734),
FIXR(-0.54119610014619698439),
FIXR(-0.52426456257040533932),
FIXR(-0.51213975715725461845),
FIXR(-0.50431448029007636036),
FIXR(-0.50047634258165998492),
};
/* using Lee like decomposition followed by hand coded 9 points DCT */
static void imdct36(int *out, int *in)
{
int i, j, t0, t1, t2, t3, s0, s1, s2, s3;
int tmp[18], *tmp1, *in1;
INT64 in3_3, in6_6;
for(i=17;i>=1;i--)
in[i] += in[i-1];
for(i=17;i>=3;i-=2)
in[i] += in[i-2];
for(j=0;j<2;j++) {
tmp1 = tmp + j;
in1 = in + j;
in3_3 = MUL64(in1[2*3], C3);
in6_6 = MUL64(in1[2*6], C6);
tmp1[0] = FRAC_RND(MUL64(in1[2*1], C1) + in3_3 +
MUL64(in1[2*5], C5) + MUL64(in1[2*7], C7));
tmp1[2] = in1[2*0] + FRAC_RND(MUL64(in1[2*2], C2) +
MUL64(in1[2*4], C4) + in6_6 +
MUL64(in1[2*8], C8));
tmp1[4] = FRAC_RND(MUL64(in1[2*1] - in1[2*5] - in1[2*7], C3));
tmp1[6] = FRAC_RND(MUL64(in1[2*2] - in1[2*4] - in1[2*8], C6)) -
in1[2*6] + in1[2*0];
tmp1[8] = FRAC_RND(MUL64(in1[2*1], C5) - in3_3 -
MUL64(in1[2*5], C7) + MUL64(in1[2*7], C1));
tmp1[10] = in1[2*0] + FRAC_RND(MUL64(-in1[2*2], C8) -
MUL64(in1[2*4], C2) + in6_6 +
MUL64(in1[2*8], C4));
tmp1[12] = FRAC_RND(MUL64(in1[2*1], C7) - in3_3 +
MUL64(in1[2*5], C1) -
MUL64(in1[2*7], C5));
tmp1[14] = in1[2*0] + FRAC_RND(MUL64(-in1[2*2], C4) +
MUL64(in1[2*4], C8) + in6_6 -
MUL64(in1[2*8], C2));
tmp1[16] = in1[2*0] - in1[2*2] + in1[2*4] - in1[2*6] + in1[2*8];
}
i = 0;
for(j=0;j<4;j++) {
t0 = tmp[i];
t1 = tmp[i + 2];
s0 = t1 + t0;
s2 = t1 - t0;
t2 = tmp[i + 1];
t3 = tmp[i + 3];
s1 = MULL(t3 + t2, icos36[j]);
s3 = MULL(t3 - t2, icos36[8 - j]);
t0 = MULL(s0 + s1, icos72[9 + 8 - j]);
t1 = MULL(s0 - s1, icos72[8 - j]);
out[18 + 9 + j] = t0;
out[18 + 8 - j] = t0;
out[9 + j] = -t1;
out[8 - j] = t1;
t0 = MULL(s2 + s3, icos72[9+j]);
t1 = MULL(s2 - s3, icos72[j]);
out[18 + 9 + (8 - j)] = t0;
out[18 + j] = t0;
out[9 + (8 - j)] = -t1;
out[j] = t1;
i += 4;
}
s0 = tmp[16];
s1 = MULL(tmp[17], icos36[4]);
t0 = MULL(s0 + s1, icos72[9 + 4]);
t1 = MULL(s0 - s1, icos72[4]);
out[18 + 9 + 4] = t0;
out[18 + 8 - 4] = t0;
out[9 + 4] = -t1;
out[8 - 4] = t1;
}
/* fast header check for resync */
static int check_header(UINT32 header)
{
/* header */
if ((header & 0xffe00000) != 0xffe00000)
return -1;
/* layer check */
if (((header >> 17) & 3) == 0)
return -1;
/* bit rate */
if (((header >> 12) & 0xf) == 0xf)
return -1;
/* frequency */
if (((header >> 10) & 3) == 3)
return -1;
return 0;
}
/* header + layer + bitrate + freq + lsf/mpeg25 */
#define SAME_HEADER_MASK \
(0xffe00000 | (3 << 17) | (0xf << 12) | (3 << 10) | (3 << 19))
/* header decoding. MUST check the header before because no
consistency check is done there. Return 1 if free format found and
that the frame size must be computed externally */
static int decode_header(MPADecodeContext *s, UINT32 header)
{
int sample_rate, frame_size, mpeg25, padding;
int sample_rate_index, bitrate_index;
if (header & (1<<20)) {
s->lsf = (header & (1<<19)) ? 0 : 1;
mpeg25 = 0;
} else {
s->lsf = 1;
mpeg25 = 1;
}
s->layer = 4 - ((header >> 17) & 3);
/* extract frequency */
sample_rate_index = (header >> 10) & 3;
sample_rate = mpa_freq_tab[sample_rate_index] >> (s->lsf + mpeg25);
if (sample_rate == 0)
return 1;
sample_rate_index += 3 * (s->lsf + mpeg25);
s->sample_rate_index = sample_rate_index;
s->error_protection = ((header >> 16) & 1) ^ 1;
bitrate_index = (header >> 12) & 0xf;
padding = (header >> 9) & 1;
//extension = (header >> 8) & 1;
s->mode = (header >> 6) & 3;
s->mode_ext = (header >> 4) & 3;
//copyright = (header >> 3) & 1;
//original = (header >> 2) & 1;
//emphasis = header & 3;
if (s->mode == MPA_MONO)
s->nb_channels = 1;
else
s->nb_channels = 2;
if (bitrate_index != 0) {
frame_size = mpa_bitrate_tab[s->lsf][s->layer - 1][bitrate_index];
s->bit_rate = frame_size * 1000;
switch(s->layer) {
case 1:
frame_size = (frame_size * 12000) / sample_rate;
frame_size = (frame_size + padding) * 4;
break;
case 2:
frame_size = (frame_size * 144000) / sample_rate;
frame_size += padding;
break;
default:
case 3:
frame_size = (frame_size * 144000) / (sample_rate << s->lsf);
frame_size += padding;
break;
}
s->frame_size = frame_size;
} else {
/* if no frame size computed, signal it */
if (!s->free_format_frame_size)
return 1;
/* free format: compute bitrate and real frame size from the
frame size we extracted by reading the bitstream */
s->frame_size = s->free_format_frame_size;
switch(s->layer) {
case 1:
s->frame_size += padding * 4;
s->bit_rate = (s->frame_size * sample_rate) / 48000;
break;
case 2:
s->frame_size += padding;
s->bit_rate = (s->frame_size * sample_rate) / 144000;
break;
default:
case 3:
s->frame_size += padding;
s->bit_rate = (s->frame_size * (sample_rate << s->lsf)) / 144000;
break;
}
}
s->sample_rate = sample_rate;
#ifdef DEBUG
printf("layer%d, %d Hz, %d kbits/s, ",
s->layer, s->sample_rate, s->bit_rate);
if (s->nb_channels == 2) {
if (s->layer == 3) {
if (s->mode_ext & MODE_EXT_MS_STEREO)
printf("ms-");
if (s->mode_ext & MODE_EXT_I_STEREO)
printf("i-");
}
printf("stereo");
} else {
printf("mono");
}
printf("\n");
#endif
return 0;
}
/* return the number of decoded frames */
static int mp_decode_layer1(MPADecodeContext *s)
{
int bound, i, v, n, ch, j, mant;
UINT8 allocation[MPA_MAX_CHANNELS][SBLIMIT];
UINT8 scale_factors[MPA_MAX_CHANNELS][SBLIMIT];
if (s->mode == MPA_JSTEREO)
bound = (s->mode_ext + 1) * 4;
else
bound = SBLIMIT;
/* allocation bits */
for(i=0;i<bound;i++) {
for(ch=0;ch<s->nb_channels;ch++) {
allocation[ch][i] = get_bits(&s->gb, 4);
}
}
for(i=bound;i<SBLIMIT;i++) {
allocation[0][i] = get_bits(&s->gb, 4);
}
/* scale factors */
for(i=0;i<bound;i++) {
for(ch=0;ch<s->nb_channels;ch++) {
if (allocation[ch][i])
scale_factors[ch][i] = get_bits(&s->gb, 6);
}
}
for(i=bound;i<SBLIMIT;i++) {
if (allocation[0][i]) {
scale_factors[0][i] = get_bits(&s->gb, 6);
scale_factors[1][i] = get_bits(&s->gb, 6);
}
}
/* compute samples */
for(j=0;j<12;j++) {
for(i=0;i<bound;i++) {
for(ch=0;ch<s->nb_channels;ch++) {
n = allocation[ch][i];
if (n) {
mant = get_bits(&s->gb, n + 1);
v = l1_unscale(n, mant, scale_factors[ch][i]);
} else {
v = 0;
}
s->sb_samples[ch][j][i] = v;
}
}
for(i=bound;i<SBLIMIT;i++) {
n = allocation[0][i];
if (n) {
mant = get_bits(&s->gb, n + 1);
v = l1_unscale(n, mant, scale_factors[0][i]);
s->sb_samples[0][j][i] = v;
v = l1_unscale(n, mant, scale_factors[1][i]);
s->sb_samples[1][j][i] = v;
} else {
s->sb_samples[0][j][i] = 0;
s->sb_samples[1][j][i] = 0;
}
}
}
return 12;
}
/* bitrate is in kb/s */
int l2_select_table(int bitrate, int nb_channels, int freq, int lsf)
{
int ch_bitrate, table;
ch_bitrate = bitrate / nb_channels;
if (!lsf) {
if ((freq == 48000 && ch_bitrate >= 56) ||
(ch_bitrate >= 56 && ch_bitrate <= 80))
table = 0;
else if (freq != 48000 && ch_bitrate >= 96)
table = 1;
else if (freq != 32000 && ch_bitrate <= 48)
table = 2;
else
table = 3;
} else {
table = 4;
}
return table;
}
static int mp_decode_layer2(MPADecodeContext *s)
{
int sblimit; /* number of used subbands */
const unsigned char *alloc_table;
int table, bit_alloc_bits, i, j, ch, bound, v;
unsigned char bit_alloc[MPA_MAX_CHANNELS][SBLIMIT];
unsigned char scale_code[MPA_MAX_CHANNELS][SBLIMIT];
unsigned char scale_factors[MPA_MAX_CHANNELS][SBLIMIT][3], *sf;
int scale, qindex, bits, steps, k, l, m, b;
/* select decoding table */
table = l2_select_table(s->bit_rate / 1000, s->nb_channels,
s->sample_rate, s->lsf);
sblimit = sblimit_table[table];
alloc_table = alloc_tables[table];
if (s->mode == MPA_JSTEREO)
bound = (s->mode_ext + 1) * 4;
else
bound = sblimit;
dprintf("bound=%d sblimit=%d\n", bound, sblimit);
/* parse bit allocation */
j = 0;
for(i=0;i<bound;i++) {
bit_alloc_bits = alloc_table[j];
for(ch=0;ch<s->nb_channels;ch++) {
bit_alloc[ch][i] = get_bits(&s->gb, bit_alloc_bits);
}
j += 1 << bit_alloc_bits;
}
for(i=bound;i<sblimit;i++) {
bit_alloc_bits = alloc_table[j];
v = get_bits(&s->gb, bit_alloc_bits);
bit_alloc[0][i] = v;
bit_alloc[1][i] = v;
j += 1 << bit_alloc_bits;
}
#ifdef DEBUG
{
for(ch=0;ch<s->nb_channels;ch++) {
for(i=0;i<sblimit;i++)
printf(" %d", bit_alloc[ch][i]);
printf("\n");
}
}
#endif
/* scale codes */
for(i=0;i<sblimit;i++) {
for(ch=0;ch<s->nb_channels;ch++) {
if (bit_alloc[ch][i])
scale_code[ch][i] = get_bits(&s->gb, 2);
}
}
/* scale factors */
for(i=0;i<sblimit;i++) {
for(ch=0;ch<s->nb_channels;ch++) {
if (bit_alloc[ch][i]) {
sf = scale_factors[ch][i];
switch(scale_code[ch][i]) {
default:
case 0:
sf[0] = get_bits(&s->gb, 6);
sf[1] = get_bits(&s->gb, 6);
sf[2] = get_bits(&s->gb, 6);
break;
case 2:
sf[0] = get_bits(&s->gb, 6);
sf[1] = sf[0];
sf[2] = sf[0];
break;
case 1:
sf[0] = get_bits(&s->gb, 6);
sf[2] = get_bits(&s->gb, 6);
sf[1] = sf[0];
break;
case 3:
sf[0] = get_bits(&s->gb, 6);
sf[2] = get_bits(&s->gb, 6);
sf[1] = sf[2];
break;
}
}
}
}
#ifdef DEBUG
for(ch=0;ch<s->nb_channels;ch++) {
for(i=0;i<sblimit;i++) {
if (bit_alloc[ch][i]) {
sf = scale_factors[ch][i];
printf(" %d %d %d", sf[0], sf[1], sf[2]);
} else {
printf(" -");
}
}
printf("\n");
}
#endif
/* samples */
for(k=0;k<3;k++) {
for(l=0;l<12;l+=3) {
j = 0;
for(i=0;i<bound;i++) {
bit_alloc_bits = alloc_table[j];
for(ch=0;ch<s->nb_channels;ch++) {
b = bit_alloc[ch][i];
if (b) {
scale = scale_factors[ch][i][k];
qindex = alloc_table[j+b];
bits = quant_bits[qindex];
if (bits < 0) {
/* 3 values at the same time */
v = get_bits(&s->gb, -bits);
steps = quant_steps[qindex];
s->sb_samples[ch][k * 12 + l + 0][i] =
l2_unscale_group(steps, v % steps, scale);
v = v / steps;
s->sb_samples[ch][k * 12 + l + 1][i] =
l2_unscale_group(steps, v % steps, scale);
v = v / steps;
s->sb_samples[ch][k * 12 + l + 2][i] =
l2_unscale_group(steps, v, scale);
} else {
for(m=0;m<3;m++) {
v = get_bits(&s->gb, bits);
v = l1_unscale(bits - 1, v, scale);
s->sb_samples[ch][k * 12 + l + m][i] = v;
}
}
} else {
s->sb_samples[ch][k * 12 + l + 0][i] = 0;
s->sb_samples[ch][k * 12 + l + 1][i] = 0;
s->sb_samples[ch][k * 12 + l + 2][i] = 0;
}
}
/* next subband in alloc table */
j += 1 << bit_alloc_bits;
}
/* XXX: find a way to avoid this duplication of code */
for(i=bound;i<sblimit;i++) {
bit_alloc_bits = alloc_table[j];
b = bit_alloc[0][i];
if (b) {
int mant, scale0, scale1;
scale0 = scale_factors[0][i][k];
scale1 = scale_factors[1][i][k];
qindex = alloc_table[j+b];
bits = quant_bits[qindex];
if (bits < 0) {
/* 3 values at the same time */
v = get_bits(&s->gb, -bits);
steps = quant_steps[qindex];
mant = v % steps;
v = v / steps;
s->sb_samples[0][k * 12 + l + 0][i] =
l2_unscale_group(steps, mant, scale0);
s->sb_samples[1][k * 12 + l + 0][i] =
l2_unscale_group(steps, mant, scale1);
mant = v % steps;
v = v / steps;
s->sb_samples[0][k * 12 + l + 1][i] =
l2_unscale_group(steps, mant, scale0);
s->sb_samples[1][k * 12 + l + 1][i] =
l2_unscale_group(steps, mant, scale1);
s->sb_samples[0][k * 12 + l + 2][i] =
l2_unscale_group(steps, v, scale0);
s->sb_samples[1][k * 12 + l + 2][i] =
l2_unscale_group(steps, v, scale1);
} else {
for(m=0;m<3;m++) {
mant = get_bits(&s->gb, bits);
s->sb_samples[0][k * 12 + l + m][i] =
l1_unscale(bits - 1, mant, scale0);
s->sb_samples[1][k * 12 + l + m][i] =
l1_unscale(bits - 1, mant, scale1);
}
}
} else {
s->sb_samples[0][k * 12 + l + 0][i] = 0;
s->sb_samples[0][k * 12 + l + 1][i] = 0;
s->sb_samples[0][k * 12 + l + 2][i] = 0;
s->sb_samples[1][k * 12 + l + 0][i] = 0;
s->sb_samples[1][k * 12 + l + 1][i] = 0;
s->sb_samples[1][k * 12 + l + 2][i] = 0;
}
/* next subband in alloc table */
j += 1 << bit_alloc_bits;
}
/* fill remaining samples to zero */
for(i=sblimit;i<SBLIMIT;i++) {
for(ch=0;ch<s->nb_channels;ch++) {
s->sb_samples[ch][k * 12 + l + 0][i] = 0;
s->sb_samples[ch][k * 12 + l + 1][i] = 0;
s->sb_samples[ch][k * 12 + l + 2][i] = 0;
}
}
}
}
return 3 * 12;
}
/*
* Seek back in the stream for backstep bytes (at most 511 bytes)
*/
static void seek_to_maindata(MPADecodeContext *s, long backstep)
{
UINT8 *ptr;
/* compute current position in stream */
#ifdef ALT_BITSTREAM_READER
ptr = s->gb.buffer + (s->gb.index>>3);
#else
ptr = s->gb.buf_ptr - (s->gb.bit_cnt >> 3);
#endif
/* copy old data before current one */
ptr -= backstep;
memcpy(ptr, s->inbuf1[s->inbuf_index ^ 1] +
BACKSTEP_SIZE + s->old_frame_size - backstep, backstep);
/* init get bits again */
init_get_bits(&s->gb, ptr, s->frame_size + backstep);
/* prepare next buffer */
s->inbuf_index ^= 1;
s->inbuf = &s->inbuf1[s->inbuf_index][BACKSTEP_SIZE];
s->old_frame_size = s->frame_size;
}
static inline void lsf_sf_expand(int *slen,
int sf, int n1, int n2, int n3)
{
if (n3) {
slen[3] = sf % n3;
sf /= n3;
} else {
slen[3] = 0;
}
if (n2) {
slen[2] = sf % n2;
sf /= n2;
} else {
slen[2] = 0;
}
slen[1] = sf % n1;
sf /= n1;
slen[0] = sf;
}
static void exponents_from_scale_factors(MPADecodeContext *s,
GranuleDef *g,
INT16 *exponents)
{
const UINT8 *bstab, *pretab;
int len, i, j, k, l, v0, shift, gain, gains[3];
INT16 *exp_ptr;
exp_ptr = exponents;
gain = g->global_gain - 210;
shift = g->scalefac_scale + 1;
bstab = band_size_long[s->sample_rate_index];
pretab = mpa_pretab[g->preflag];
for(i=0;i<g->long_end;i++) {
v0 = gain - ((g->scale_factors[i] + pretab[i]) << shift);
len = bstab[i];
for(j=len;j>0;j--)
*exp_ptr++ = v0;
}
if (g->short_start < 13) {
bstab = band_size_short[s->sample_rate_index];
gains[0] = gain - (g->subblock_gain[0] << 3);
gains[1] = gain - (g->subblock_gain[1] << 3);
gains[2] = gain - (g->subblock_gain[2] << 3);
k = g->long_end;
for(i=g->short_start;i<13;i++) {
len = bstab[i];
for(l=0;l<3;l++) {
v0 = gains[l] - (g->scale_factors[k++] << shift);
for(j=len;j>0;j--)
*exp_ptr++ = v0;
}
}
}
}
/* handle n = 0 too */
static inline int get_bitsz(GetBitContext *s, int n)
{
if (n == 0)
return 0;
else
return get_bits(s, n);
}
static int huffman_decode(MPADecodeContext *s, GranuleDef *g,
INT16 *exponents, int end_pos)
{
int s_index;
int linbits, code, x, y, l, v, i, j, k, pos;
UINT8 *last_buf_ptr;
UINT32 last_bit_buf;
int last_bit_cnt;
VLC *vlc;
UINT8 *code_table;
/* low frequencies (called big values) */
s_index = 0;
for(i=0;i<3;i++) {
j = g->region_size[i];
if (j == 0)
continue;
/* select vlc table */
k = g->table_select[i];
l = mpa_huff_data[k][0];
linbits = mpa_huff_data[k][1];
vlc = &huff_vlc[l];
code_table = huff_code_table[l];
/* read huffcode and compute each couple */
for(;j>0;j--) {
if (get_bits_count(&s->gb) >= end_pos)
break;
if (code_table) {
code = get_vlc(&s->gb, vlc);
if (code < 0)
return -1;
y = code_table[code];
x = y >> 4;
y = y & 0x0f;
} else {
x = 0;
y = 0;
}
dprintf("region=%d n=%d x=%d y=%d exp=%d\n",
i, g->region_size[i] - j, x, y, exponents[s_index]);
if (x) {
if (x == 15)
x += get_bitsz(&s->gb, linbits);
v = l3_unscale(x, exponents[s_index]);
if (get_bits1(&s->gb))
v = -v;
} else {
v = 0;
}
g->sb_hybrid[s_index++] = v;
if (y) {
if (y == 15)
y += get_bitsz(&s->gb, linbits);
v = l3_unscale(y, exponents[s_index]);
if (get_bits1(&s->gb))
v = -v;
} else {
v = 0;
}
g->sb_hybrid[s_index++] = v;
}
}
/* high frequencies */
vlc = &huff_quad_vlc[g->count1table_select];
last_buf_ptr = NULL;
last_bit_buf = 0;
last_bit_cnt = 0;
while (s_index <= 572) {
pos = get_bits_count(&s->gb);
if (pos >= end_pos) {
if (pos > end_pos && last_buf_ptr != NULL) {
/* some encoders generate an incorrect size for this
part. We must go back into the data */
s_index -= 4;
#ifdef ALT_BITSTREAM_READER
s->gb.buffer = last_buf_ptr;
s->gb.index = last_bit_cnt;
#else
s->gb.buf_ptr = last_buf_ptr;
s->gb.bit_buf = last_bit_buf;
s->gb.bit_cnt = last_bit_cnt;
#endif
}
break;
}
#ifdef ALT_BITSTREAM_READER
last_buf_ptr = s->gb.buffer;
last_bit_cnt = s->gb.index;
#else
last_buf_ptr = s->gb.buf_ptr;
last_bit_buf = s->gb.bit_buf;
last_bit_cnt = s->gb.bit_cnt;
#endif
code = get_vlc(&s->gb, vlc);
dprintf("t=%d code=%d\n", g->count1table_select, code);
if (code < 0)
return -1;
for(i=0;i<4;i++) {
if (code & (8 >> i)) {
/* non zero value. Could use a hand coded function for
'one' value */
v = l3_unscale(1, exponents[s_index]);
if(get_bits1(&s->gb))
v = -v;
} else {
v = 0;
}
g->sb_hybrid[s_index++] = v;
}
}
while (s_index < 576)
g->sb_hybrid[s_index++] = 0;
return 0;
}
/* Reorder short blocks from bitstream order to interleaved order. It
would be faster to do it in parsing, but the code would be far more
complicated */
static void reorder_block(MPADecodeContext *s, GranuleDef *g)
{
int i, j, k, len;
INT32 *ptr, *dst, *ptr1;
INT32 tmp[576];
if (g->block_type != 2)
return;
if (g->switch_point) {
if (s->sample_rate_index != 8) {
ptr = g->sb_hybrid + 36;
} else {
ptr = g->sb_hybrid + 48;
}
} else {
ptr = g->sb_hybrid;
}
for(i=g->short_start;i<13;i++) {
len = band_size_short[s->sample_rate_index][i];
ptr1 = ptr;
for(k=0;k<3;k++) {
dst = tmp + k;
for(j=len;j>0;j--) {
*dst = *ptr++;
dst += 3;
}
}
memcpy(ptr1, tmp, len * 3 * sizeof(INT32));
}
}
#define ISQRT2 FIXR(0.70710678118654752440)
static void compute_stereo(MPADecodeContext *s,
GranuleDef *g0, GranuleDef *g1)
{
int i, j, k, l;
INT32 v1, v2;
int sf_max, tmp0, tmp1, sf, len, non_zero_found;
INT32 (*is_tab)[16];
INT32 *tab0, *tab1;
int non_zero_found_short[3];
/* intensity stereo */
if (s->mode_ext & MODE_EXT_I_STEREO) {
if (!s->lsf) {
is_tab = is_table;
sf_max = 7;
} else {
is_tab = is_table_lsf[g1->scalefac_compress & 1];
sf_max = 16;
}
tab0 = g0->sb_hybrid + 576;
tab1 = g1->sb_hybrid + 576;
non_zero_found_short[0] = 0;
non_zero_found_short[1] = 0;
non_zero_found_short[2] = 0;
k = (13 - g1->short_start) * 3 + g1->long_end - 3;
for(i = 12;i >= g1->short_start;i--) {
/* for last band, use previous scale factor */
if (i != 11)
k -= 3;
len = band_size_short[s->sample_rate_index][i];
for(l=2;l>=0;l--) {
tab0 -= len;
tab1 -= len;
if (!non_zero_found_short[l]) {
/* test if non zero band. if so, stop doing i-stereo */
for(j=0;j<len;j++) {
if (tab1[j] != 0) {
non_zero_found_short[l] = 1;
goto found1;
}
}
sf = g1->scale_factors[k + l];
if (sf >= sf_max)
goto found1;
v1 = is_tab[0][sf];
v2 = is_tab[1][sf];
for(j=0;j<len;j++) {
tmp0 = tab0[j];
tab0[j] = MULL(tmp0, v1);
tab1[j] = MULL(tmp0, v2);
}
} else {
found1:
if (s->mode_ext & MODE_EXT_MS_STEREO) {
/* lower part of the spectrum : do ms stereo
if enabled */
for(j=0;j<len;j++) {
tmp0 = tab0[j];
tmp1 = tab1[j];
tab0[j] = MULL(tmp0 + tmp1, ISQRT2);
tab1[j] = MULL(tmp0 - tmp1, ISQRT2);
}
}
}
}
}
non_zero_found = non_zero_found_short[0] |
non_zero_found_short[1] |
non_zero_found_short[2];
for(i = g1->long_end - 1;i >= 0;i--) {
len = band_size_long[s->sample_rate_index][i];
tab0 -= len;
tab1 -= len;
/* test if non zero band. if so, stop doing i-stereo */
if (!non_zero_found) {
for(j=0;j<len;j++) {
if (tab1[j] != 0) {
non_zero_found = 1;
goto found2;
}
}
/* for last band, use previous scale factor */
k = (i == 21) ? 20 : i;
sf = g1->scale_factors[k];
if (sf >= sf_max)
goto found2;
v1 = is_tab[0][sf];
v2 = is_tab[1][sf];
for(j=0;j<len;j++) {
tmp0 = tab0[j];
tab0[j] = MULL(tmp0, v1);
tab1[j] = MULL(tmp0, v2);
}
} else {
found2:
if (s->mode_ext & MODE_EXT_MS_STEREO) {
/* lower part of the spectrum : do ms stereo
if enabled */
for(j=0;j<len;j++) {
tmp0 = tab0[j];
tmp1 = tab1[j];
tab0[j] = MULL(tmp0 + tmp1, ISQRT2);
tab1[j] = MULL(tmp0 - tmp1, ISQRT2);
}
}
}
}
} else if (s->mode_ext & MODE_EXT_MS_STEREO) {
/* ms stereo ONLY */
/* NOTE: the 1/sqrt(2) normalization factor is included in the
global gain */
tab0 = g0->sb_hybrid;
tab1 = g1->sb_hybrid;
for(i=0;i<576;i++) {
tmp0 = tab0[i];
tmp1 = tab1[i];
tab0[i] = tmp0 + tmp1;
tab1[i] = tmp0 - tmp1;
}
}
}
static void compute_antialias(MPADecodeContext *s,
GranuleDef *g)
{
INT32 *ptr, *p0, *p1, *csa;
int n, tmp0, tmp1, i, j;
/* we antialias only "long" bands */
if (g->block_type == 2) {
if (!g->switch_point)
return;
/* XXX: check this for 8000Hz case */
n = 1;
} else {
n = SBLIMIT - 1;
}
ptr = g->sb_hybrid + 18;
for(i = n;i > 0;i--) {
p0 = ptr - 1;
p1 = ptr;
csa = &csa_table[0][0];
for(j=0;j<8;j++) {
tmp0 = *p0;
tmp1 = *p1;
*p0 = FRAC_RND(MUL64(tmp0, csa[0]) - MUL64(tmp1, csa[1]));
*p1 = FRAC_RND(MUL64(tmp0, csa[1]) + MUL64(tmp1, csa[0]));
p0--;
p1++;
csa += 2;
}
ptr += 18;
}
}
static void compute_imdct(MPADecodeContext *s,
GranuleDef *g,
INT32 *sb_samples,
INT32 *mdct_buf)
{
INT32 *ptr, *win, *win1, *buf, *buf2, *out_ptr, *ptr1;
INT32 in[6];
INT32 out[36];
INT32 out2[12];
int i, j, k, mdct_long_end, v, sblimit;
/* find last non zero block */
ptr = g->sb_hybrid + 576;
ptr1 = g->sb_hybrid + 2 * 18;
while (ptr >= ptr1) {
ptr -= 6;
v = ptr[0] | ptr[1] | ptr[2] | ptr[3] | ptr[4] | ptr[5];
if (v != 0)
break;
}
sblimit = ((ptr - g->sb_hybrid) / 18) + 1;
if (g->block_type == 2) {
/* XXX: check for 8000 Hz */
if (g->switch_point)
mdct_long_end = 2;
else
mdct_long_end = 0;
} else {
mdct_long_end = sblimit;
}
buf = mdct_buf;
ptr = g->sb_hybrid;
for(j=0;j<mdct_long_end;j++) {
imdct36(out, ptr);
/* apply window & overlap with previous buffer */
out_ptr = sb_samples + j;
/* select window */
if (g->switch_point && j < 2)
win1 = mdct_win[0];
else
win1 = mdct_win[g->block_type];
/* select frequency inversion */
win = win1 + ((4 * 36) & -(j & 1));
for(i=0;i<18;i++) {
*out_ptr = MULL(out[i], win[i]) + buf[i];
buf[i] = MULL(out[i + 18], win[i + 18]);
out_ptr += SBLIMIT;
}
ptr += 18;
buf += 18;
}
for(j=mdct_long_end;j<sblimit;j++) {
for(i=0;i<6;i++) {
out[i] = 0;
out[6 + i] = 0;
out[30+i] = 0;
}
/* select frequency inversion */
win = mdct_win[2] + ((4 * 36) & -(j & 1));
buf2 = out + 6;
for(k=0;k<3;k++) {
/* reorder input for short mdct */
ptr1 = ptr + k;
for(i=0;i<6;i++) {
in[i] = *ptr1;
ptr1 += 3;
}
imdct12(out2, in);
/* apply 12 point window and do small overlap */
for(i=0;i<6;i++) {
buf2[i] = MULL(out2[i], win[i]) + buf2[i];
buf2[i + 6] = MULL(out2[i + 6], win[i + 6]);
}
buf2 += 6;
}
/* overlap */
out_ptr = sb_samples + j;
for(i=0;i<18;i++) {
*out_ptr = out[i] + buf[i];
buf[i] = out[i + 18];
out_ptr += SBLIMIT;
}
ptr += 18;
buf += 18;
}
/* zero bands */
for(j=sblimit;j<SBLIMIT;j++) {
/* overlap */
out_ptr = sb_samples + j;
for(i=0;i<18;i++) {
*out_ptr = buf[i];
buf[i] = 0;
out_ptr += SBLIMIT;
}
buf += 18;
}
}
#if defined(DEBUG)
void sample_dump(int fnum, INT32 *tab, int n)
{
static FILE *files[16], *f;
char buf[512];
f = files[fnum];
if (!f) {
sprintf(buf, "/tmp/out%d.pcm", fnum);
f = fopen(buf, "w");
if (!f)
return;
files[fnum] = f;
}
if (fnum == 0) {
int i;
static int pos = 0;
printf("pos=%d\n", pos);
for(i=0;i<n;i++) {
printf(" %f", (double)tab[i] / 32768.0);
if ((i % 18) == 17)
printf("\n");
}
pos += n;
}
fwrite(tab, 1, n * sizeof(INT32), f);
}
#endif
/* main layer3 decoding function */
static int mp_decode_layer3(MPADecodeContext *s)
{
int nb_granules, main_data_begin, private_bits;
int gr, ch, blocksplit_flag, i, j, k, n, bits_pos, bits_left;
GranuleDef granules[2][2], *g;
INT16 exponents[576];
/* read side info */
if (s->lsf) {
main_data_begin = get_bits(&s->gb, 8);
if (s->nb_channels == 2)
private_bits = get_bits(&s->gb, 2);
else
private_bits = get_bits(&s->gb, 1);
nb_granules = 1;
} else {
main_data_begin = get_bits(&s->gb, 9);
if (s->nb_channels == 2)
private_bits = get_bits(&s->gb, 3);
else
private_bits = get_bits(&s->gb, 5);
nb_granules = 2;
for(ch=0;ch<s->nb_channels;ch++) {
granules[ch][0].scfsi = 0; /* all scale factors are transmitted */
granules[ch][1].scfsi = get_bits(&s->gb, 4);
}
}
for(gr=0;gr<nb_granules;gr++) {
for(ch=0;ch<s->nb_channels;ch++) {
dprintf("gr=%d ch=%d: side_info\n", gr, ch);
g = &granules[ch][gr];
g->part2_3_length = get_bits(&s->gb, 12);
g->big_values = get_bits(&s->gb, 9);
g->global_gain = get_bits(&s->gb, 8);
/* if MS stereo only is selected, we precompute the
1/sqrt(2) renormalization factor */
if ((s->mode_ext & (MODE_EXT_MS_STEREO | MODE_EXT_I_STEREO)) ==
MODE_EXT_MS_STEREO)
g->global_gain -= 2;
if (s->lsf)
g->scalefac_compress = get_bits(&s->gb, 9);
else
g->scalefac_compress = get_bits(&s->gb, 4);
blocksplit_flag = get_bits(&s->gb, 1);
if (blocksplit_flag) {
g->block_type = get_bits(&s->gb, 2);
if (g->block_type == 0)
return -1;
g->switch_point = get_bits(&s->gb, 1);
for(i=0;i<2;i++)
g->table_select[i] = get_bits(&s->gb, 5);
for(i=0;i<3;i++)
g->subblock_gain[i] = get_bits(&s->gb, 3);
/* compute huffman coded region sizes */
if (g->block_type == 2)
g->region_size[0] = (36 / 2);
else {
if (s->sample_rate_index <= 2)
g->region_size[0] = (36 / 2);
else if (s->sample_rate_index != 8)
g->region_size[0] = (54 / 2);
else
g->region_size[0] = (108 / 2);
}
g->region_size[1] = (576 / 2);
} else {
int region_address1, region_address2, l;
g->block_type = 0;
g->switch_point = 0;
for(i=0;i<3;i++)
g->table_select[i] = get_bits(&s->gb, 5);
/* compute huffman coded region sizes */
region_address1 = get_bits(&s->gb, 4);
region_address2 = get_bits(&s->gb, 3);
dprintf("region1=%d region2=%d\n",
region_address1, region_address2);
g->region_size[0] =
band_index_long[s->sample_rate_index][region_address1 + 1] >> 1;
l = region_address1 + region_address2 + 2;
/* should not overflow */
if (l > 22)
l = 22;
g->region_size[1] =
band_index_long[s->sample_rate_index][l] >> 1;
}
/* convert region offsets to region sizes and truncate
size to big_values */
g->region_size[2] = (576 / 2);
j = 0;
for(i=0;i<3;i++) {
k = g->region_size[i];
if (k > g->big_values)
k = g->big_values;
g->region_size[i] = k - j;
j = k;
}
/* compute band indexes */
if (g->block_type == 2) {
if (g->switch_point) {
/* if switched mode, we handle the 36 first samples as
long blocks. For 8000Hz, we handle the 48 first
exponents as long blocks (XXX: check this!) */
if (s->sample_rate_index <= 2)
g->long_end = 8;
else if (s->sample_rate_index != 8)
g->long_end = 6;
else
g->long_end = 4; /* 8000 Hz */
if (s->sample_rate_index != 8)
g->short_start = 3;
else
g->short_start = 2;
} else {
g->long_end = 0;
g->short_start = 0;
}
} else {
g->short_start = 13;
g->long_end = 22;
}
g->preflag = 0;
if (!s->lsf)
g->preflag = get_bits(&s->gb, 1);
g->scalefac_scale = get_bits(&s->gb, 1);
g->count1table_select = get_bits(&s->gb, 1);
dprintf("block_type=%d switch_point=%d\n",
g->block_type, g->switch_point);
}
}
/* now we get bits from the main_data_begin offset */
dprintf("seekback: %d\n", main_data_begin);
seek_to_maindata(s, main_data_begin);
for(gr=0;gr<nb_granules;gr++) {
for(ch=0;ch<s->nb_channels;ch++) {
g = &granules[ch][gr];
bits_pos = get_bits_count(&s->gb);
if (!s->lsf) {
UINT8 *sc;
int slen, slen1, slen2;
/* MPEG1 scale factors */
slen1 = slen_table[0][g->scalefac_compress];
slen2 = slen_table[1][g->scalefac_compress];
dprintf("slen1=%d slen2=%d\n", slen1, slen2);
if (g->block_type == 2) {
n = g->switch_point ? 17 : 18;
j = 0;
for(i=0;i<n;i++)
g->scale_factors[j++] = get_bitsz(&s->gb, slen1);
for(i=0;i<18;i++)
g->scale_factors[j++] = get_bitsz(&s->gb, slen2);
for(i=0;i<3;i++)
g->scale_factors[j++] = 0;
} else {
sc = granules[ch][0].scale_factors;
j = 0;
for(k=0;k<4;k++) {
n = (k == 0 ? 6 : 5);
if ((g->scfsi & (0x8 >> k)) == 0) {
slen = (k < 2) ? slen1 : slen2;
for(i=0;i<n;i++)
g->scale_factors[j++] = get_bitsz(&s->gb, slen);
} else {
/* simply copy from last granule */
for(i=0;i<n;i++) {
g->scale_factors[j] = sc[j];
j++;
}
}
}
g->scale_factors[j++] = 0;
}
#if defined(DEBUG)
{
printf("scfsi=%x gr=%d ch=%d scale_factors:\n",
g->scfsi, gr, ch);
for(i=0;i<j;i++)
printf(" %d", g->scale_factors[i]);
printf("\n");
}
#endif
} else {
int tindex, tindex2, slen[4], sl, sf;
/* LSF scale factors */
if (g->block_type == 2) {
tindex = g->switch_point ? 2 : 1;
} else {
tindex = 0;
}
sf = g->scalefac_compress;
if ((s->mode_ext & MODE_EXT_I_STEREO) && ch == 1) {
/* intensity stereo case */
sf >>= 1;
if (sf < 180) {
lsf_sf_expand(slen, sf, 6, 6, 0);
tindex2 = 3;
} else if (sf < 244) {
lsf_sf_expand(slen, sf - 180, 4, 4, 0);
tindex2 = 4;
} else {
lsf_sf_expand(slen, sf - 244, 3, 0, 0);
tindex2 = 5;
}
} else {
/* normal case */
if (sf < 400) {
lsf_sf_expand(slen, sf, 5, 4, 4);
tindex2 = 0;
} else if (sf < 500) {
lsf_sf_expand(slen, sf - 400, 5, 4, 0);
tindex2 = 1;
} else {
lsf_sf_expand(slen, sf - 500, 3, 0, 0);
tindex2 = 2;
g->preflag = 1;
}
}
j = 0;
for(k=0;k<4;k++) {
n = lsf_nsf_table[tindex2][tindex][k];
sl = slen[k];
for(i=0;i<n;i++)
g->scale_factors[j++] = get_bitsz(&s->gb, sl);
}
/* XXX: should compute exact size */
for(;j<40;j++)
g->scale_factors[j] = 0;
#if defined(DEBUG)
{
printf("gr=%d ch=%d scale_factors:\n",
gr, ch);
for(i=0;i<40;i++)
printf(" %d", g->scale_factors[i]);
printf("\n");
}
#endif
}
exponents_from_scale_factors(s, g, exponents);
/* read Huffman coded residue */
if (huffman_decode(s, g, exponents,
bits_pos + g->part2_3_length) < 0)
return -1;
#if defined(DEBUG)
sample_dump(0, g->sb_hybrid, 576);
#endif
/* skip extension bits */
bits_left = g->part2_3_length - (get_bits_count(&s->gb) - bits_pos);
if (bits_left < 0) {
dprintf("bits_left=%d\n", bits_left);
return -1;
}
while (bits_left >= 16) {
skip_bits(&s->gb, 16);
bits_left -= 16;
}
if (bits_left > 0)
skip_bits(&s->gb, bits_left);
} /* ch */
if (s->nb_channels == 2)
compute_stereo(s, &granules[0][gr], &granules[1][gr]);
for(ch=0;ch<s->nb_channels;ch++) {
g = &granules[ch][gr];
reorder_block(s, g);
#if defined(DEBUG)
sample_dump(0, g->sb_hybrid, 576);
#endif
compute_antialias(s, g);
#ifdef DEBUG
sample_dump(1, g->sb_hybrid, 576);
#endif
compute_imdct(s, g, &s->sb_samples[ch][18 * gr][0], s->mdct_buf[ch]);
#ifdef DEBUG
sample_dump(2, &s->sb_samples[ch][18 * gr][0], 576);
#endif
}
} /* gr */
return nb_granules * 18;
}
static int mp_decode_frame(MPADecodeContext *s,
short *samples)
{
int i, nb_frames, ch;
short *samples_ptr;
init_get_bits(&s->gb, s->inbuf + HEADER_SIZE,
s->inbuf_ptr - s->inbuf - HEADER_SIZE);
/* skip error protection field */
if (s->error_protection)
get_bits(&s->gb, 16);
dprintf("frame %d:\n", s->frame_count);
switch(s->layer) {
case 1:
nb_frames = mp_decode_layer1(s);
break;
case 2:
nb_frames = mp_decode_layer2(s);
break;
case 3:
default:
nb_frames = mp_decode_layer3(s);
break;
}
#if defined(DEBUG)
for(i=0;i<nb_frames;i++) {
for(ch=0;ch<s->nb_channels;ch++) {
int j;
printf("%d-%d:", i, ch);
for(j=0;j<SBLIMIT;j++)
printf(" %0.6f", (double)s->sb_samples[ch][i][j] / FRAC_ONE);
printf("\n");
}
}
#endif
/* apply the synthesis filter */
for(ch=0;ch<s->nb_channels;ch++) {
samples_ptr = samples + ch;
for(i=0;i<nb_frames;i++) {
synth_filter(s, ch, samples_ptr, s->nb_channels,
s->sb_samples[ch][i]);
samples_ptr += 32 * s->nb_channels;
}
}
#ifdef DEBUG
s->frame_count++;
#endif
return nb_frames * 32 * sizeof(short) * s->nb_channels;
}
static int decode_frame(AVCodecContext * avctx,
void *data, int *data_size,
UINT8 * buf, int buf_size)
{
MPADecodeContext *s = avctx->priv_data;
UINT32 header;
UINT8 *buf_ptr;
int len, out_size;
short *out_samples = data;
*data_size = 0;
buf_ptr = buf;
while (buf_size > 0) {
len = s->inbuf_ptr - s->inbuf;
if (s->frame_size == 0) {
/* special case for next header for first frame in free
format case (XXX: find a simpler method) */
if (s->free_format_next_header != 0) {
s->inbuf[0] = s->free_format_next_header >> 24;
s->inbuf[1] = s->free_format_next_header >> 16;
s->inbuf[2] = s->free_format_next_header >> 8;
s->inbuf[3] = s->free_format_next_header;
s->inbuf_ptr = s->inbuf + 4;
s->free_format_next_header = 0;
goto got_header;
}
/* no header seen : find one. We need at least HEADER_SIZE
bytes to parse it */
len = HEADER_SIZE - len;
if (len > buf_size)
len = buf_size;
if (len > 0) {
memcpy(s->inbuf_ptr, buf_ptr, len);
buf_ptr += len;
buf_size -= len;
s->inbuf_ptr += len;
}
if ((s->inbuf_ptr - s->inbuf) >= HEADER_SIZE) {
got_header:
header = (s->inbuf[0] << 24) | (s->inbuf[1] << 16) |
(s->inbuf[2] << 8) | s->inbuf[3];
if (check_header(header) < 0) {
/* no sync found : move by one byte (inefficient, but simple!) */
memcpy(s->inbuf, s->inbuf + 1, s->inbuf_ptr - s->inbuf - 1);
s->inbuf_ptr--;
dprintf("skip %x\n", header);
/* reset free format frame size to give a chance
to get a new bitrate */
s->free_format_frame_size = 0;
} else {
if (decode_header(s, header) == 1) {
/* free format: compute frame size */
s->frame_size = -1;
memcpy(s->inbuf, s->inbuf + 1, s->inbuf_ptr - s->inbuf - 1);
s->inbuf_ptr--;
} else {
/* update codec info */
avctx->sample_rate = s->sample_rate;
avctx->channels = s->nb_channels;
avctx->bit_rate = s->bit_rate;
avctx->frame_size = s->frame_size;
}
}
}
} else if (s->frame_size == -1) {
/* free format : find next sync to compute frame size */
len = MPA_MAX_CODED_FRAME_SIZE - len;
if (len > buf_size)
len = buf_size;
if (len == 0) {
/* frame too long: resync */
s->frame_size = 0;
} else {
UINT8 *p, *pend;
UINT32 header1;
int padding;
memcpy(s->inbuf_ptr, buf_ptr, len);
/* check for header */
p = s->inbuf_ptr - 3;
pend = s->inbuf_ptr + len - 4;
while (p <= pend) {
header = (p[0] << 24) | (p[1] << 16) |
(p[2] << 8) | p[3];
header1 = (s->inbuf[0] << 24) | (s->inbuf[1] << 16) |
(s->inbuf[2] << 8) | s->inbuf[3];
/* check with high probability that we have a
valid header */
if ((header & SAME_HEADER_MASK) ==
(header1 & SAME_HEADER_MASK)) {
/* header found: update pointers */
len = (p + 4) - s->inbuf_ptr;
buf_ptr += len;
buf_size -= len;
s->inbuf_ptr = p;
/* compute frame size */
s->free_format_next_header = header;
s->free_format_frame_size = s->inbuf_ptr - s->inbuf;
padding = (header1 >> 9) & 1;
if (s->layer == 1)
s->free_format_frame_size -= padding * 4;
else
s->free_format_frame_size -= padding;
dprintf("free frame size=%d padding=%d\n",
s->free_format_frame_size, padding);
decode_header(s, header1);
goto next_data;
}
p++;
}
/* not found: simply increase pointers */
buf_ptr += len;
s->inbuf_ptr += len;
buf_size -= len;
}
} else if (len < s->frame_size) {
if (s->frame_size > MPA_MAX_CODED_FRAME_SIZE)
s->frame_size = MPA_MAX_CODED_FRAME_SIZE;
len = s->frame_size - len;
if (len > buf_size)
len = buf_size;
else if (len < 4)
len = buf_size > 4 ? 4 : buf_size;
memcpy(s->inbuf_ptr, buf_ptr, len);
buf_ptr += len;
s->inbuf_ptr += len;
buf_size -= len;
} else {
out_size = mp_decode_frame(s, out_samples);
s->inbuf_ptr = s->inbuf;
s->frame_size = 0;
*data_size = out_size;
break;
}
next_data:
}
return buf_ptr - buf;
}
AVCodec mp2_decoder =
{
"mp2",
CODEC_TYPE_AUDIO,
CODEC_ID_MP2,
sizeof(MPADecodeContext),
decode_init,
NULL,
NULL,
decode_frame,
};
AVCodec mp3_decoder =
{
"mp3",
CODEC_TYPE_AUDIO,
CODEC_ID_MP3LAME,
sizeof(MPADecodeContext),
decode_init,
NULL,
NULL,
decode_frame,
};
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