ffmpeg / libavcodec / mpegaudiodec.c @ bf1f4da0
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1 
/*


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* MPEG Audio decoder

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* Copyright (c) 2001, 2002 Fabrice Bellard.

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*

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* This library is free software; you can redistribute it and/or

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* modify it under the terms of the GNU Lesser General Public

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* License as published by the Free Software Foundation; either

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* version 2 of the License, or (at your option) any later version.

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*

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* This library is distributed in the hope that it will be useful,

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* but WITHOUT ANY WARRANTY; without even the implied warranty of

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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

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* Lesser General Public License for more details.

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*

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* You should have received a copy of the GNU Lesser General Public

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* License along with this library; if not, write to the Free Software

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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 021111307 USA

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*/

19  
20 
/**

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* @file mpegaudiodec.c

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* MPEG Audio decoder.

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*/

24  
25 
//#define DEBUG

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#include "avcodec.h" 
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#include "bitstream.h" 
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#include "mpegaudio.h" 
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#include "dsputil.h" 
30  
31 
/*

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* TODO:

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*  in low precision mode, use more 16 bit multiplies in synth filter

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*  test lsf / mpeg25 extensively.

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*/

36  
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/* define USE_HIGHPRECISION to have a bit exact (but slower) mpeg

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audio decoder */

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#ifdef CONFIG_MPEGAUDIO_HP

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#define USE_HIGHPRECISION

41 
#endif

42  
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#ifdef USE_HIGHPRECISION

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#define FRAC_BITS 23 /* fractional bits for sb_samples and dct */ 
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#define WFRAC_BITS 16 /* fractional bits for window */ 
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#else

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#define FRAC_BITS 15 /* fractional bits for sb_samples and dct */ 
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#define WFRAC_BITS 14 /* fractional bits for window */ 
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#endif

50  
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#define FRAC_ONE (1 << FRAC_BITS) 
52  
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#define MULL(a,b) (((int64_t)(a) * (int64_t)(b)) >> FRAC_BITS)

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#define MUL64(a,b) ((int64_t)(a) * (int64_t)(b))

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#define FIX(a) ((int)((a) * FRAC_ONE)) 
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/* WARNING: only correct for posititive numbers */

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#define FIXR(a) ((int)((a) * FRAC_ONE + 0.5)) 
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#define FRAC_RND(a) (((a) + (FRAC_ONE/2)) >> FRAC_BITS) 
59  
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#if FRAC_BITS <= 15 
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typedef int16_t MPA_INT;

62 
#else

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typedef int32_t MPA_INT;

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#endif

65  
66 
/****************/

67  
68 
#define HEADER_SIZE 4 
69 
#define BACKSTEP_SIZE 512 
70  
71 
struct GranuleDef;

72  
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typedef struct MPADecodeContext { 
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uint8_t inbuf1[2][MPA_MAX_CODED_FRAME_SIZE + BACKSTEP_SIZE]; /* input buffer */ 
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int inbuf_index;

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uint8_t *inbuf_ptr, *inbuf; 
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int frame_size;

78 
int free_format_frame_size; /* frame size in case of free format 
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(zero if currently unknown) */

80 
/* next header (used in free format parsing) */

81 
uint32_t free_format_next_header; 
82 
int error_protection;

83 
int layer;

84 
int sample_rate;

85 
int sample_rate_index; /* between 0 and 8 */ 
86 
int bit_rate;

87 
int old_frame_size;

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GetBitContext gb; 
89 
int nb_channels;

90 
int mode;

91 
int mode_ext;

92 
int lsf;

93 
MPA_INT synth_buf[MPA_MAX_CHANNELS][512 * 2] __attribute__((aligned(16))); 
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int synth_buf_offset[MPA_MAX_CHANNELS];

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int32_t sb_samples[MPA_MAX_CHANNELS][36][SBLIMIT] __attribute__((aligned(16))); 
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int32_t mdct_buf[MPA_MAX_CHANNELS][SBLIMIT * 18]; /* previous samples, for layer 3 MDCT */ 
97 
#ifdef DEBUG

98 
int frame_count;

99 
#endif

100 
void (*compute_antialias)(struct MPADecodeContext *s, struct GranuleDef *g); 
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int adu_mode; ///< 0 for standard mp3, 1 for adu formatted mp3 
102 
} MPADecodeContext; 
103  
104 
/* layer 3 "granule" */

105 
typedef struct GranuleDef { 
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uint8_t scfsi; 
107 
int part2_3_length;

108 
int big_values;

109 
int global_gain;

110 
int scalefac_compress;

111 
uint8_t block_type; 
112 
uint8_t switch_point; 
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int table_select[3]; 
114 
int subblock_gain[3]; 
115 
uint8_t scalefac_scale; 
116 
uint8_t count1table_select; 
117 
int region_size[3]; /* number of huffman codes in each region */ 
118 
int preflag;

119 
int short_start, long_end; /* long/short band indexes */ 
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uint8_t scale_factors[40];

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int32_t sb_hybrid[SBLIMIT * 18]; /* 576 samples */ 
122 
} GranuleDef; 
123  
124 
#define MODE_EXT_MS_STEREO 2 
125 
#define MODE_EXT_I_STEREO 1 
126  
127 
/* layer 3 huffman tables */

128 
typedef struct HuffTable { 
129 
int xsize;

130 
const uint8_t *bits;

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const uint16_t *codes;

132 
} HuffTable; 
133  
134 
#include "mpegaudiodectab.h" 
135  
136 
static void compute_antialias_integer(MPADecodeContext *s, GranuleDef *g); 
137 
static void compute_antialias_float(MPADecodeContext *s, GranuleDef *g); 
138  
139 
/* vlc structure for decoding layer 3 huffman tables */

140 
static VLC huff_vlc[16]; 
141 
static uint8_t *huff_code_table[16]; 
142 
static VLC huff_quad_vlc[2]; 
143 
/* computed from band_size_long */

144 
static uint16_t band_index_long[9][23]; 
145 
/* XXX: free when all decoders are closed */

146 
#define TABLE_4_3_SIZE (8191 + 16) 
147 
static int8_t *table_4_3_exp;

148 
#if FRAC_BITS <= 15 
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static uint16_t *table_4_3_value;

150 
#else

151 
static uint32_t *table_4_3_value;

152 
#endif

153 
/* intensity stereo coef table */

154 
static int32_t is_table[2][16]; 
155 
static int32_t is_table_lsf[2][2][16]; 
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static int32_t csa_table[8][4]; 
157 
static float csa_table_float[8][4]; 
158 
static int32_t mdct_win[8][36]; 
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160 
/* lower 2 bits: modulo 3, higher bits: shift */

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static uint16_t scale_factor_modshift[64]; 
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/* [i][j]: 2^(j/3) * FRAC_ONE * 2^(i+2) / (2^(i+2)  1) */

163 
static int32_t scale_factor_mult[15][3]; 
164 
/* mult table for layer 2 group quantization */

165  
166 
#define SCALE_GEN(v) \

167 
{ FIXR(1.0 * (v)), FIXR(0.7937005259 * (v)), FIXR(0.6299605249 * (v)) } 
168  
169 
static int32_t scale_factor_mult2[3][3] = { 
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SCALE_GEN(4.0 / 3.0), /* 3 steps */ 
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SCALE_GEN(4.0 / 5.0), /* 5 steps */ 
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SCALE_GEN(4.0 / 9.0), /* 9 steps */ 
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}; 
174  
175 
/* 2^(n/4) */

176 
static uint32_t scale_factor_mult3[4] = { 
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FIXR(1.0), 
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FIXR(1.18920711500272106671), 
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FIXR(1.41421356237309504880), 
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FIXR(1.68179283050742908605), 
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}; 
182  
183 
void ff_mpa_synth_init(MPA_INT *window);

184 
static MPA_INT window[512] __attribute__((aligned(16))); 
185 

186 
/* layer 1 unscaling */

187 
/* n = number of bits of the mantissa minus 1 */

188 
static inline int l1_unscale(int n, int mant, int scale_factor) 
189 
{ 
190 
int shift, mod;

191 
int64_t val; 
192  
193 
shift = scale_factor_modshift[scale_factor]; 
194 
mod = shift & 3;

195 
shift >>= 2;

196 
val = MUL64(mant + (1 << n) + 1, scale_factor_mult[n1][mod]); 
197 
shift += n; 
198 
/* NOTE: at this point, 1 <= shift >= 21 + 15 */

199 
return (int)((val + (1LL << (shift  1))) >> shift); 
200 
} 
201  
202 
static inline int l2_unscale_group(int steps, int mant, int scale_factor) 
203 
{ 
204 
int shift, mod, val;

205  
206 
shift = scale_factor_modshift[scale_factor]; 
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mod = shift & 3;

208 
shift >>= 2;

209  
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val = (mant  (steps >> 1)) * scale_factor_mult2[steps >> 2][mod]; 
211 
/* NOTE: at this point, 0 <= shift <= 21 */

212 
if (shift > 0) 
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val = (val + (1 << (shift  1))) >> shift; 
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return val;

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} 
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/* compute value^(4/3) * 2^(exponent/4). It normalized to FRAC_BITS */

218 
static inline int l3_unscale(int value, int exponent) 
219 
{ 
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#if FRAC_BITS <= 15 
221 
unsigned int m; 
222 
#else

223 
uint64_t m; 
224 
#endif

225 
int e;

226  
227 
e = table_4_3_exp[value]; 
228 
e += (exponent >> 2);

229 
e = FRAC_BITS  e; 
230 
#if FRAC_BITS <= 15 
231 
if (e > 31) 
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e = 31;

233 
#endif

234 
m = table_4_3_value[value]; 
235 
#if FRAC_BITS <= 15 
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m = (m * scale_factor_mult3[exponent & 3]);

237 
m = (m + (1 << (e1))) >> e; 
238 
return m;

239 
#else

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m = MUL64(m, scale_factor_mult3[exponent & 3]);

241 
m = (m + (uint64_t_C(1) << (e1))) >> e; 
242 
return m;

243 
#endif

244 
} 
245  
246 
/* all integer n^(4/3) computation code */

247 
#define DEV_ORDER 13 
248  
249 
#define POW_FRAC_BITS 24 
250 
#define POW_FRAC_ONE (1 << POW_FRAC_BITS) 
251 
#define POW_FIX(a) ((int)((a) * POW_FRAC_ONE)) 
252 
#define POW_MULL(a,b) (((int64_t)(a) * (int64_t)(b)) >> POW_FRAC_BITS)

253  
254 
static int dev_4_3_coefs[DEV_ORDER]; 
255  
256 
static int pow_mult3[3] = { 
257 
POW_FIX(1.0), 
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POW_FIX(1.25992104989487316476), 
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POW_FIX(1.58740105196819947474), 
260 
}; 
261  
262 
static void int_pow_init(void) 
263 
{ 
264 
int i, a;

265  
266 
a = POW_FIX(1.0); 
267 
for(i=0;i<DEV_ORDER;i++) { 
268 
a = POW_MULL(a, POW_FIX(4.0 / 3.0)  i * POW_FIX(1.0)) / (i + 1); 
269 
dev_4_3_coefs[i] = a; 
270 
} 
271 
} 
272  
273 
/* return the mantissa and the binary exponent */

274 
static int int_pow(int i, int *exp_ptr) 
275 
{ 
276 
int e, er, eq, j;

277 
int a, a1;

278 

279 
/* renormalize */

280 
a = i; 
281 
e = POW_FRAC_BITS; 
282 
while (a < (1 << (POW_FRAC_BITS  1))) { 
283 
a = a << 1;

284 
e; 
285 
} 
286 
a = (1 << POW_FRAC_BITS);

287 
a1 = 0;

288 
for(j = DEV_ORDER  1; j >= 0; j) 
289 
a1 = POW_MULL(a, dev_4_3_coefs[j] + a1); 
290 
a = (1 << POW_FRAC_BITS) + a1;

291 
/* exponent compute (exact) */

292 
e = e * 4;

293 
er = e % 3;

294 
eq = e / 3;

295 
a = POW_MULL(a, pow_mult3[er]); 
296 
while (a >= 2 * POW_FRAC_ONE) { 
297 
a = a >> 1;

298 
eq++; 
299 
} 
300 
/* convert to float */

301 
while (a < POW_FRAC_ONE) {

302 
a = a << 1;

303 
eq; 
304 
} 
305 
/* now POW_FRAC_ONE <= a < 2 * POW_FRAC_ONE */

306 
#if POW_FRAC_BITS > FRAC_BITS

307 
a = (a + (1 << (POW_FRAC_BITS  FRAC_BITS  1))) >> (POW_FRAC_BITS  FRAC_BITS); 
308 
/* correct overflow */

309 
if (a >= 2 * (1 << FRAC_BITS)) { 
310 
a = a >> 1;

311 
eq++; 
312 
} 
313 
#endif

314 
*exp_ptr = eq; 
315 
return a;

316 
} 
317  
318 
static int decode_init(AVCodecContext * avctx) 
319 
{ 
320 
MPADecodeContext *s = avctx>priv_data; 
321 
static int init=0; 
322 
int i, j, k;

323  
324 
if(avctx>antialias_algo == FF_AA_INT)

325 
s>compute_antialias= compute_antialias_integer; 
326 
else

327 
s>compute_antialias= compute_antialias_float; 
328  
329 
if (!init && !avctx>parse_only) {

330 
/* scale factors table for layer 1/2 */

331 
for(i=0;i<64;i++) { 
332 
int shift, mod;

333 
/* 1.0 (i = 3) is normalized to 2 ^ FRAC_BITS */

334 
shift = (i / 3);

335 
mod = i % 3;

336 
scale_factor_modshift[i] = mod  (shift << 2);

337 
} 
338  
339 
/* scale factor multiply for layer 1 */

340 
for(i=0;i<15;i++) { 
341 
int n, norm;

342 
n = i + 2;

343 
norm = ((int64_t_C(1) << n) * FRAC_ONE) / ((1 << n)  1); 
344 
scale_factor_mult[i][0] = MULL(FIXR(1.0 * 2.0), norm); 
345 
scale_factor_mult[i][1] = MULL(FIXR(0.7937005259 * 2.0), norm); 
346 
scale_factor_mult[i][2] = MULL(FIXR(0.6299605249 * 2.0), norm); 
347 
dprintf("%d: norm=%x s=%x %x %x\n",

348 
i, norm, 
349 
scale_factor_mult[i][0],

350 
scale_factor_mult[i][1],

351 
scale_factor_mult[i][2]);

352 
} 
353 

354 
ff_mpa_synth_init(window); 
355 

356 
/* huffman decode tables */

357 
huff_code_table[0] = NULL; 
358 
for(i=1;i<16;i++) { 
359 
const HuffTable *h = &mpa_huff_tables[i];

360 
int xsize, x, y;

361 
unsigned int n; 
362 
uint8_t *code_table; 
363  
364 
xsize = h>xsize; 
365 
n = xsize * xsize; 
366 
/* XXX: fail test */

367 
init_vlc(&huff_vlc[i], 8, n,

368 
h>bits, 1, 1, h>codes, 2, 2, 1); 
369 

370 
code_table = av_mallocz(n); 
371 
j = 0;

372 
for(x=0;x<xsize;x++) { 
373 
for(y=0;y<xsize;y++) 
374 
code_table[j++] = (x << 4)  y;

375 
} 
376 
huff_code_table[i] = code_table; 
377 
} 
378 
for(i=0;i<2;i++) { 
379 
init_vlc(&huff_quad_vlc[i], i == 0 ? 7 : 4, 16, 
380 
mpa_quad_bits[i], 1, 1, mpa_quad_codes[i], 1, 1, 1); 
381 
} 
382  
383 
for(i=0;i<9;i++) { 
384 
k = 0;

385 
for(j=0;j<22;j++) { 
386 
band_index_long[i][j] = k; 
387 
k += band_size_long[i][j]; 
388 
} 
389 
band_index_long[i][22] = k;

390 
} 
391  
392 
/* compute n ^ (4/3) and store it in mantissa/exp format */

393 
table_4_3_exp= av_mallocz_static(TABLE_4_3_SIZE * sizeof(table_4_3_exp[0])); 
394 
if(!table_4_3_exp)

395 
return 1; 
396 
table_4_3_value= av_mallocz_static(TABLE_4_3_SIZE * sizeof(table_4_3_value[0])); 
397 
if(!table_4_3_value)

398 
return 1; 
399 

400 
int_pow_init(); 
401 
for(i=1;i<TABLE_4_3_SIZE;i++) { 
402 
int e, m;

403 
m = int_pow(i, &e); 
404 
#if 0

405 
/* test code */

406 
{

407 
double f, fm;

408 
int e1, m1;

409 
f = pow((double)i, 4.0 / 3.0);

410 
fm = frexp(f, &e1);

411 
m1 = FIXR(2 * fm);

412 
#if FRAC_BITS <= 15

413 
if ((unsigned short)m1 != m1) {

414 
m1 = m1 >> 1;

415 
e1++;

416 
}

417 
#endif

418 
e1; 
419 
if (m != m1  e != e1) {

420 
printf("%4d: m=%x m1=%x e=%d e1=%d\n",

421 
i, m, m1, e, e1); 
422 
} 
423 
} 
424 
#endif

425 
/* normalized to FRAC_BITS */

426 
table_4_3_value[i] = m; 
427 
table_4_3_exp[i] = e; 
428 
} 
429 

430 
for(i=0;i<7;i++) { 
431 
float f;

432 
int v;

433 
if (i != 6) { 
434 
f = tan((double)i * M_PI / 12.0); 
435 
v = FIXR(f / (1.0 + f)); 
436 
} else {

437 
v = FIXR(1.0); 
438 
} 
439 
is_table[0][i] = v;

440 
is_table[1][6  i] = v; 
441 
} 
442 
/* invalid values */

443 
for(i=7;i<16;i++) 
444 
is_table[0][i] = is_table[1][i] = 0.0; 
445  
446 
for(i=0;i<16;i++) { 
447 
double f;

448 
int e, k;

449  
450 
for(j=0;j<2;j++) { 
451 
e = (j + 1) * ((i + 1) >> 1); 
452 
f = pow(2.0, e / 4.0); 
453 
k = i & 1;

454 
is_table_lsf[j][k ^ 1][i] = FIXR(f);

455 
is_table_lsf[j][k][i] = FIXR(1.0); 
456 
dprintf("is_table_lsf %d %d: %x %x\n",

457 
i, j, is_table_lsf[j][0][i], is_table_lsf[j][1][i]); 
458 
} 
459 
} 
460  
461 
for(i=0;i<8;i++) { 
462 
float ci, cs, ca;

463 
ci = ci_table[i]; 
464 
cs = 1.0 / sqrt(1.0 + ci * ci); 
465 
ca = cs * ci; 
466 
csa_table[i][0] = FIX(cs);

467 
csa_table[i][1] = FIX(ca);

468 
csa_table[i][2] = FIX(ca) + FIX(cs);

469 
csa_table[i][3] = FIX(ca)  FIX(cs);

470 
csa_table_float[i][0] = cs;

471 
csa_table_float[i][1] = ca;

472 
csa_table_float[i][2] = ca + cs;

473 
csa_table_float[i][3] = ca  cs;

474 
// printf("%d %d %d %d\n", FIX(cs), FIX(cs1), FIX(ca), FIX(cs)FIX(ca));

475 
} 
476  
477 
/* compute mdct windows */

478 
for(i=0;i<36;i++) { 
479 
int v;

480 
v = FIXR(sin(M_PI * (i + 0.5) / 36.0)); 
481 
mdct_win[0][i] = v;

482 
mdct_win[1][i] = v;

483 
mdct_win[3][i] = v;

484 
} 
485 
for(i=0;i<6;i++) { 
486 
mdct_win[1][18 + i] = FIXR(1.0); 
487 
mdct_win[1][24 + i] = FIXR(sin(M_PI * ((i + 6) + 0.5) / 12.0)); 
488 
mdct_win[1][30 + i] = FIXR(0.0); 
489  
490 
mdct_win[3][i] = FIXR(0.0); 
491 
mdct_win[3][6 + i] = FIXR(sin(M_PI * (i + 0.5) / 12.0)); 
492 
mdct_win[3][12 + i] = FIXR(1.0); 
493 
} 
494  
495 
for(i=0;i<12;i++) 
496 
mdct_win[2][i] = FIXR(sin(M_PI * (i + 0.5) / 12.0)); 
497 

498 
/* NOTE: we do frequency inversion adter the MDCT by changing

499 
the sign of the right window coefs */

500 
for(j=0;j<4;j++) { 
501 
for(i=0;i<36;i+=2) { 
502 
mdct_win[j + 4][i] = mdct_win[j][i];

503 
mdct_win[j + 4][i + 1] = mdct_win[j][i + 1]; 
504 
} 
505 
} 
506  
507 
#if defined(DEBUG)

508 
for(j=0;j<8;j++) { 
509 
printf("win%d=\n", j);

510 
for(i=0;i<36;i++) 
511 
printf("%f, ", (double)mdct_win[j][i] / FRAC_ONE); 
512 
printf("\n");

513 
} 
514 
#endif

515 
init = 1;

516 
} 
517  
518 
s>inbuf_index = 0;

519 
s>inbuf = &s>inbuf1[s>inbuf_index][BACKSTEP_SIZE]; 
520 
s>inbuf_ptr = s>inbuf; 
521 
#ifdef DEBUG

522 
s>frame_count = 0;

523 
#endif

524 
if (avctx>codec_id == CODEC_ID_MP3ADU)

525 
s>adu_mode = 1;

526 
return 0; 
527 
} 
528  
529 
/* tab[i][j] = 1.0 / (2.0 * cos(pi*(2*k+1) / 2^(6  j))) */

530  
531 
/* cos(i*pi/64) */

532  
533 
#define COS0_0 FIXR(0.50060299823519630134) 
534 
#define COS0_1 FIXR(0.50547095989754365998) 
535 
#define COS0_2 FIXR(0.51544730992262454697) 
536 
#define COS0_3 FIXR(0.53104259108978417447) 
537 
#define COS0_4 FIXR(0.55310389603444452782) 
538 
#define COS0_5 FIXR(0.58293496820613387367) 
539 
#define COS0_6 FIXR(0.62250412303566481615) 
540 
#define COS0_7 FIXR(0.67480834145500574602) 
541 
#define COS0_8 FIXR(0.74453627100229844977) 
542 
#define COS0_9 FIXR(0.83934964541552703873) 
543 
#define COS0_10 FIXR(0.97256823786196069369) 
544 
#define COS0_11 FIXR(1.16943993343288495515) 
545 
#define COS0_12 FIXR(1.48416461631416627724) 
546 
#define COS0_13 FIXR(2.05778100995341155085) 
547 
#define COS0_14 FIXR(3.40760841846871878570) 
548 
#define COS0_15 FIXR(10.19000812354805681150) 
549  
550 
#define COS1_0 FIXR(0.50241928618815570551) 
551 
#define COS1_1 FIXR(0.52249861493968888062) 
552 
#define COS1_2 FIXR(0.56694403481635770368) 
553 
#define COS1_3 FIXR(0.64682178335999012954) 
554 
#define COS1_4 FIXR(0.78815462345125022473) 
555 
#define COS1_5 FIXR(1.06067768599034747134) 
556 
#define COS1_6 FIXR(1.72244709823833392782) 
557 
#define COS1_7 FIXR(5.10114861868916385802) 
558  
559 
#define COS2_0 FIXR(0.50979557910415916894) 
560 
#define COS2_1 FIXR(0.60134488693504528054) 
561 
#define COS2_2 FIXR(0.89997622313641570463) 
562 
#define COS2_3 FIXR(2.56291544774150617881) 
563  
564 
#define COS3_0 FIXR(0.54119610014619698439) 
565 
#define COS3_1 FIXR(1.30656296487637652785) 
566  
567 
#define COS4_0 FIXR(0.70710678118654752439) 
568  
569 
/* butterfly operator */

570 
#define BF(a, b, c)\

571 
{\ 
572 
tmp0 = tab[a] + tab[b];\ 
573 
tmp1 = tab[a]  tab[b];\ 
574 
tab[a] = tmp0;\ 
575 
tab[b] = MULL(tmp1, c);\ 
576 
} 
577  
578 
#define BF1(a, b, c, d)\

579 
{\ 
580 
BF(a, b, COS4_0);\ 
581 
BF(c, d, COS4_0);\ 
582 
tab[c] += tab[d];\ 
583 
} 
584  
585 
#define BF2(a, b, c, d)\

586 
{\ 
587 
BF(a, b, COS4_0);\ 
588 
BF(c, d, COS4_0);\ 
589 
tab[c] += tab[d];\ 
590 
tab[a] += tab[c];\ 
591 
tab[c] += tab[b];\ 
592 
tab[b] += tab[d];\ 
593 
} 
594  
595 
#define ADD(a, b) tab[a] += tab[b]

596  
597 
/* DCT32 without 1/sqrt(2) coef zero scaling. */

598 
static void dct32(int32_t *out, int32_t *tab) 
599 
{ 
600 
int tmp0, tmp1;

601  
602 
/* pass 1 */

603 
BF(0, 31, COS0_0); 
604 
BF(1, 30, COS0_1); 
605 
BF(2, 29, COS0_2); 
606 
BF(3, 28, COS0_3); 
607 
BF(4, 27, COS0_4); 
608 
BF(5, 26, COS0_5); 
609 
BF(6, 25, COS0_6); 
610 
BF(7, 24, COS0_7); 
611 
BF(8, 23, COS0_8); 
612 
BF(9, 22, COS0_9); 
613 
BF(10, 21, COS0_10); 
614 
BF(11, 20, COS0_11); 
615 
BF(12, 19, COS0_12); 
616 
BF(13, 18, COS0_13); 
617 
BF(14, 17, COS0_14); 
618 
BF(15, 16, COS0_15); 
619  
620 
/* pass 2 */

621 
BF(0, 15, COS1_0); 
622 
BF(1, 14, COS1_1); 
623 
BF(2, 13, COS1_2); 
624 
BF(3, 12, COS1_3); 
625 
BF(4, 11, COS1_4); 
626 
BF(5, 10, COS1_5); 
627 
BF(6, 9, COS1_6); 
628 
BF(7, 8, COS1_7); 
629 

630 
BF(16, 31, COS1_0); 
631 
BF(17, 30, COS1_1); 
632 
BF(18, 29, COS1_2); 
633 
BF(19, 28, COS1_3); 
634 
BF(20, 27, COS1_4); 
635 
BF(21, 26, COS1_5); 
636 
BF(22, 25, COS1_6); 
637 
BF(23, 24, COS1_7); 
638 

639 
/* pass 3 */

640 
BF(0, 7, COS2_0); 
641 
BF(1, 6, COS2_1); 
642 
BF(2, 5, COS2_2); 
643 
BF(3, 4, COS2_3); 
644 

645 
BF(8, 15, COS2_0); 
646 
BF(9, 14, COS2_1); 
647 
BF(10, 13, COS2_2); 
648 
BF(11, 12, COS2_3); 
649 

650 
BF(16, 23, COS2_0); 
651 
BF(17, 22, COS2_1); 
652 
BF(18, 21, COS2_2); 
653 
BF(19, 20, COS2_3); 
654 

655 
BF(24, 31, COS2_0); 
656 
BF(25, 30, COS2_1); 
657 
BF(26, 29, COS2_2); 
658 
BF(27, 28, COS2_3); 
659  
660 
/* pass 4 */

661 
BF(0, 3, COS3_0); 
662 
BF(1, 2, COS3_1); 
663 

664 
BF(4, 7, COS3_0); 
665 
BF(5, 6, COS3_1); 
666 

667 
BF(8, 11, COS3_0); 
668 
BF(9, 10, COS3_1); 
669 

670 
BF(12, 15, COS3_0); 
671 
BF(13, 14, COS3_1); 
672 

673 
BF(16, 19, COS3_0); 
674 
BF(17, 18, COS3_1); 
675 

676 
BF(20, 23, COS3_0); 
677 
BF(21, 22, COS3_1); 
678 

679 
BF(24, 27, COS3_0); 
680 
BF(25, 26, COS3_1); 
681 

682 
BF(28, 31, COS3_0); 
683 
BF(29, 30, COS3_1); 
684 

685 
/* pass 5 */

686 
BF1(0, 1, 2, 3); 
687 
BF2(4, 5, 6, 7); 
688 
BF1(8, 9, 10, 11); 
689 
BF2(12, 13, 14, 15); 
690 
BF1(16, 17, 18, 19); 
691 
BF2(20, 21, 22, 23); 
692 
BF1(24, 25, 26, 27); 
693 
BF2(28, 29, 30, 31); 
694 

695 
/* pass 6 */

696 

697 
ADD( 8, 12); 
698 
ADD(12, 10); 
699 
ADD(10, 14); 
700 
ADD(14, 9); 
701 
ADD( 9, 13); 
702 
ADD(13, 11); 
703 
ADD(11, 15); 
704  
705 
out[ 0] = tab[0]; 
706 
out[16] = tab[1]; 
707 
out[ 8] = tab[2]; 
708 
out[24] = tab[3]; 
709 
out[ 4] = tab[4]; 
710 
out[20] = tab[5]; 
711 
out[12] = tab[6]; 
712 
out[28] = tab[7]; 
713 
out[ 2] = tab[8]; 
714 
out[18] = tab[9]; 
715 
out[10] = tab[10]; 
716 
out[26] = tab[11]; 
717 
out[ 6] = tab[12]; 
718 
out[22] = tab[13]; 
719 
out[14] = tab[14]; 
720 
out[30] = tab[15]; 
721 

722 
ADD(24, 28); 
723 
ADD(28, 26); 
724 
ADD(26, 30); 
725 
ADD(30, 25); 
726 
ADD(25, 29); 
727 
ADD(29, 27); 
728 
ADD(27, 31); 
729  
730 
out[ 1] = tab[16] + tab[24]; 
731 
out[17] = tab[17] + tab[25]; 
732 
out[ 9] = tab[18] + tab[26]; 
733 
out[25] = tab[19] + tab[27]; 
734 
out[ 5] = tab[20] + tab[28]; 
735 
out[21] = tab[21] + tab[29]; 
736 
out[13] = tab[22] + tab[30]; 
737 
out[29] = tab[23] + tab[31]; 
738 
out[ 3] = tab[24] + tab[20]; 
739 
out[19] = tab[25] + tab[21]; 
740 
out[11] = tab[26] + tab[22]; 
741 
out[27] = tab[27] + tab[23]; 
742 
out[ 7] = tab[28] + tab[18]; 
743 
out[23] = tab[29] + tab[19]; 
744 
out[15] = tab[30] + tab[17]; 
745 
out[31] = tab[31]; 
746 
} 
747  
748 
#define OUT_SHIFT (WFRAC_BITS + FRAC_BITS  15) 
749  
750 
#if FRAC_BITS <= 15 
751  
752 
static inline int round_sample(int sum) 
753 
{ 
754 
int sum1;

755 
sum1 = (sum + (1 << (OUT_SHIFT  1))) >> OUT_SHIFT; 
756 
if (sum1 < 32768) 
757 
sum1 = 32768;

758 
else if (sum1 > 32767) 
759 
sum1 = 32767;

760 
return sum1;

761 
} 
762  
763 
#if defined(ARCH_POWERPC_405)

764  
765 
/* signed 16x16 > 32 multiply add accumulate */

766 
#define MACS(rt, ra, rb) \

767 
asm ("maclhw %0, %2, %3" : "=r" (rt) : "0" (rt), "r" (ra), "r" (rb)); 
768  
769 
/* signed 16x16 > 32 multiply */

770 
#define MULS(ra, rb) \

771 
({ int __rt; asm ("mullhw %0, %1, %2" : "=r" (__rt) : "r" (ra), "r" (rb)); __rt; }) 
772  
773 
#else

774  
775 
/* signed 16x16 > 32 multiply add accumulate */

776 
#define MACS(rt, ra, rb) rt += (ra) * (rb)

777  
778 
/* signed 16x16 > 32 multiply */

779 
#define MULS(ra, rb) ((ra) * (rb))

780  
781 
#endif

782  
783 
#else

784  
785 
static inline int round_sample(int64_t sum) 
786 
{ 
787 
int sum1;

788 
sum1 = (int)((sum + (int64_t_C(1) << (OUT_SHIFT  1))) >> OUT_SHIFT); 
789 
if (sum1 < 32768) 
790 
sum1 = 32768;

791 
else if (sum1 > 32767) 
792 
sum1 = 32767;

793 
return sum1;

794 
} 
795  
796 
#define MULS(ra, rb) MUL64(ra, rb)

797  
798 
#endif

799  
800 
#define SUM8(sum, op, w, p) \

801 
{ \ 
802 
sum op MULS((w)[0 * 64], p[0 * 64]);\ 
803 
sum op MULS((w)[1 * 64], p[1 * 64]);\ 
804 
sum op MULS((w)[2 * 64], p[2 * 64]);\ 
805 
sum op MULS((w)[3 * 64], p[3 * 64]);\ 
806 
sum op MULS((w)[4 * 64], p[4 * 64]);\ 
807 
sum op MULS((w)[5 * 64], p[5 * 64]);\ 
808 
sum op MULS((w)[6 * 64], p[6 * 64]);\ 
809 
sum op MULS((w)[7 * 64], p[7 * 64]);\ 
810 
} 
811  
812 
#define SUM8P2(sum1, op1, sum2, op2, w1, w2, p) \

813 
{ \ 
814 
int tmp;\

815 
tmp = p[0 * 64];\ 
816 
sum1 op1 MULS((w1)[0 * 64], tmp);\ 
817 
sum2 op2 MULS((w2)[0 * 64], tmp);\ 
818 
tmp = p[1 * 64];\ 
819 
sum1 op1 MULS((w1)[1 * 64], tmp);\ 
820 
sum2 op2 MULS((w2)[1 * 64], tmp);\ 
821 
tmp = p[2 * 64];\ 
822 
sum1 op1 MULS((w1)[2 * 64], tmp);\ 
823 
sum2 op2 MULS((w2)[2 * 64], tmp);\ 
824 
tmp = p[3 * 64];\ 
825 
sum1 op1 MULS((w1)[3 * 64], tmp);\ 
826 
sum2 op2 MULS((w2)[3 * 64], tmp);\ 
827 
tmp = p[4 * 64];\ 
828 
sum1 op1 MULS((w1)[4 * 64], tmp);\ 
829 
sum2 op2 MULS((w2)[4 * 64], tmp);\ 
830 
tmp = p[5 * 64];\ 
831 
sum1 op1 MULS((w1)[5 * 64], tmp);\ 
832 
sum2 op2 MULS((w2)[5 * 64], tmp);\ 
833 
tmp = p[6 * 64];\ 
834 
sum1 op1 MULS((w1)[6 * 64], tmp);\ 
835 
sum2 op2 MULS((w2)[6 * 64], tmp);\ 
836 
tmp = p[7 * 64];\ 
837 
sum1 op1 MULS((w1)[7 * 64], tmp);\ 
838 
sum2 op2 MULS((w2)[7 * 64], tmp);\ 
839 
} 
840  
841 
void ff_mpa_synth_init(MPA_INT *window)

842 
{ 
843 
int i;

844  
845 
/* max = 18760, max sum over all 16 coefs : 44736 */

846 
for(i=0;i<257;i++) { 
847 
int v;

848 
v = mpa_enwindow[i]; 
849 
#if WFRAC_BITS < 16 
850 
v = (v + (1 << (16  WFRAC_BITS  1))) >> (16  WFRAC_BITS); 
851 
#endif

852 
window[i] = v; 
853 
if ((i & 63) != 0) 
854 
v = v; 
855 
if (i != 0) 
856 
window[512  i] = v;

857 
} 
858 
} 
859  
860 
/* 32 sub band synthesis filter. Input: 32 sub band samples, Output:

861 
32 samples. */

862 
/* XXX: optimize by avoiding ring buffer usage */

863 
void ff_mpa_synth_filter(MPA_INT *synth_buf_ptr, int *synth_buf_offset, 
864 
MPA_INT *window, 
865 
int16_t *samples, int incr,

866 
int32_t sb_samples[SBLIMIT]) 
867 
{ 
868 
int32_t tmp[32];

869 
register MPA_INT *synth_buf;

870 
register const MPA_INT *w, *w2, *p; 
871 
int j, offset, v;

872 
int16_t *samples2; 
873 
#if FRAC_BITS <= 15 
874 
int sum, sum2;

875 
#else

876 
int64_t sum, sum2; 
877 
#endif

878  
879 
dct32(tmp, sb_samples); 
880 

881 
offset = *synth_buf_offset; 
882 
synth_buf = synth_buf_ptr + offset; 
883  
884 
for(j=0;j<32;j++) { 
885 
v = tmp[j]; 
886 
#if FRAC_BITS <= 15 
887 
/* NOTE: can cause a loss in precision if very high amplitude

888 
sound */

889 
if (v > 32767) 
890 
v = 32767;

891 
else if (v < 32768) 
892 
v = 32768;

893 
#endif

894 
synth_buf[j] = v; 
895 
} 
896 
/* copy to avoid wrap */

897 
memcpy(synth_buf + 512, synth_buf, 32 * sizeof(MPA_INT)); 
898  
899 
samples2 = samples + 31 * incr;

900 
w = window; 
901 
w2 = window + 31;

902  
903 
sum = 0;

904 
p = synth_buf + 16;

905 
SUM8(sum, +=, w, p); 
906 
p = synth_buf + 48;

907 
SUM8(sum, =, w + 32, p);

908 
*samples = round_sample(sum); 
909 
samples += incr; 
910 
w++; 
911  
912 
/* we calculate two samples at the same time to avoid one memory

913 
access per two sample */

914 
for(j=1;j<16;j++) { 
915 
sum = 0;

916 
sum2 = 0;

917 
p = synth_buf + 16 + j;

918 
SUM8P2(sum, +=, sum2, =, w, w2, p); 
919 
p = synth_buf + 48  j;

920 
SUM8P2(sum, =, sum2, =, w + 32, w2 + 32, p); 
921  
922 
*samples = round_sample(sum); 
923 
samples += incr; 
924 
*samples2 = round_sample(sum2); 
925 
samples2 = incr; 
926 
w++; 
927 
w2; 
928 
} 
929 

930 
p = synth_buf + 32;

931 
sum = 0;

932 
SUM8(sum, =, w + 32, p);

933 
*samples = round_sample(sum); 
934  
935 
offset = (offset  32) & 511; 
936 
*synth_buf_offset = offset; 
937 
} 
938  
939 
/* cos(pi*i/24) */

940 
#define C1 FIXR(0.99144486137381041114) 
941 
#define C3 FIXR(0.92387953251128675612) 
942 
#define C5 FIXR(0.79335334029123516458) 
943 
#define C7 FIXR(0.60876142900872063941) 
944 
#define C9 FIXR(0.38268343236508977173) 
945 
#define C11 FIXR(0.13052619222005159154) 
946  
947 
/* 12 points IMDCT. We compute it "by hand" by factorizing obvious

948 
cases. */

949 
static void imdct12(int *out, int *in) 
950 
{ 
951 
int tmp;

952 
int64_t in1_3, in1_9, in4_3, in4_9; 
953  
954 
in1_3 = MUL64(in[1], C3);

955 
in1_9 = MUL64(in[1], C9);

956 
in4_3 = MUL64(in[4], C3);

957 
in4_9 = MUL64(in[4], C9);

958 

959 
tmp = FRAC_RND(MUL64(in[0], C7)  in1_3  MUL64(in[2], C11) + 
960 
MUL64(in[3], C1)  in4_9  MUL64(in[5], C5)); 
961 
out[0] = tmp;

962 
out[5] = tmp;

963 
tmp = FRAC_RND(MUL64(in[0]  in[3], C9)  in1_3 + 
964 
MUL64(in[2] + in[5], C3)  in4_9); 
965 
out[1] = tmp;

966 
out[4] = tmp;

967 
tmp = FRAC_RND(MUL64(in[0], C11)  in1_9 + MUL64(in[2], C7)  
968 
MUL64(in[3], C5) + in4_3  MUL64(in[5], C1)); 
969 
out[2] = tmp;

970 
out[3] = tmp;

971 
tmp = FRAC_RND(MUL64(in[0], C5) + in1_9 + MUL64(in[2], C1) + 
972 
MUL64(in[3], C11)  in4_3  MUL64(in[5], C7)); 
973 
out[6] = tmp;

974 
out[11] = tmp;

975 
tmp = FRAC_RND(MUL64(in[0] + in[3], C3)  in1_9 + 
976 
MUL64(in[2] + in[5], C9) + in4_3); 
977 
out[7] = tmp;

978 
out[10] = tmp;

979 
tmp = FRAC_RND(MUL64(in[0], C1)  in1_3  MUL64(in[2], C5)  
980 
MUL64(in[3], C7)  in4_9  MUL64(in[5], C11)); 
981 
out[8] = tmp;

982 
out[9] = tmp;

983 
} 
984  
985 
#undef C1

986 
#undef C3

987 
#undef C5

988 
#undef C7

989 
#undef C9

990 
#undef C11

991  
992 
/* cos(pi*i/18) */

993 
#define C1 FIXR(0.98480775301220805936) 
994 
#define C2 FIXR(0.93969262078590838405) 
995 
#define C3 FIXR(0.86602540378443864676) 
996 
#define C4 FIXR(0.76604444311897803520) 
997 
#define C5 FIXR(0.64278760968653932632) 
998 
#define C6 FIXR(0.5) 
999 
#define C7 FIXR(0.34202014332566873304) 
1000 
#define C8 FIXR(0.17364817766693034885) 
1001  
1002 
/* 0.5 / cos(pi*(2*i+1)/36) */

1003 
static const int icos36[9] = { 
1004 
FIXR(0.50190991877167369479), 
1005 
FIXR(0.51763809020504152469), 
1006 
FIXR(0.55168895948124587824), 
1007 
FIXR(0.61038729438072803416), 
1008 
FIXR(0.70710678118654752439), 
1009 
FIXR(0.87172339781054900991), 
1010 
FIXR(1.18310079157624925896), 
1011 
FIXR(1.93185165257813657349), 
1012 
FIXR(5.73685662283492756461), 
1013 
}; 
1014  
1015 
static const int icos72[18] = { 
1016 
/* 0.5 / cos(pi*(2*i+19)/72) */

1017 
FIXR(0.74009361646113053152), 
1018 
FIXR(0.82133981585229078570), 
1019 
FIXR(0.93057949835178895673), 
1020 
FIXR(1.08284028510010010928), 
1021 
FIXR(1.30656296487637652785), 
1022 
FIXR(1.66275476171152078719), 
1023 
FIXR(2.31011315767264929558), 
1024 
FIXR(3.83064878777019433457), 
1025 
FIXR(11.46279281302667383546), 
1026  
1027 
/* 0.5 / cos(pi*(2*(i + 18) +19)/72) */

1028 
FIXR(0.67817085245462840086), 
1029 
FIXR(0.63023620700513223342), 
1030 
FIXR(0.59284452371708034528), 
1031 
FIXR(0.56369097343317117734), 
1032 
FIXR(0.54119610014619698439), 
1033 
FIXR(0.52426456257040533932), 
1034 
FIXR(0.51213975715725461845), 
1035 
FIXR(0.50431448029007636036), 
1036 
FIXR(0.50047634258165998492), 
1037 
}; 
1038  
1039 
/* using Lee like decomposition followed by hand coded 9 points DCT */

1040 
static void imdct36(int *out, int *in) 
1041 
{ 
1042 
int i, j, t0, t1, t2, t3, s0, s1, s2, s3;

1043 
int tmp[18], *tmp1, *in1; 
1044 
int64_t in3_3, in6_6; 
1045  
1046 
for(i=17;i>=1;i) 
1047 
in[i] += in[i1];

1048 
for(i=17;i>=3;i=2) 
1049 
in[i] += in[i2];

1050  
1051 
for(j=0;j<2;j++) { 
1052 
tmp1 = tmp + j; 
1053 
in1 = in + j; 
1054  
1055 
in3_3 = MUL64(in1[2*3], C3); 
1056 
in6_6 = MUL64(in1[2*6], C6); 
1057  
1058 
tmp1[0] = FRAC_RND(MUL64(in1[2*1], C1) + in3_3 + 
1059 
MUL64(in1[2*5], C5) + MUL64(in1[2*7], C7)); 
1060 
tmp1[2] = in1[2*0] + FRAC_RND(MUL64(in1[2*2], C2) + 
1061 
MUL64(in1[2*4], C4) + in6_6 + 
1062 
MUL64(in1[2*8], C8)); 
1063 
tmp1[4] = FRAC_RND(MUL64(in1[2*1]  in1[2*5]  in1[2*7], C3)); 
1064 
tmp1[6] = FRAC_RND(MUL64(in1[2*2]  in1[2*4]  in1[2*8], C6))  
1065 
in1[2*6] + in1[2*0]; 
1066 
tmp1[8] = FRAC_RND(MUL64(in1[2*1], C5)  in3_3  
1067 
MUL64(in1[2*5], C7) + MUL64(in1[2*7], C1)); 
1068 
tmp1[10] = in1[2*0] + FRAC_RND(MUL64(in1[2*2], C8)  
1069 
MUL64(in1[2*4], C2) + in6_6 + 
1070 
MUL64(in1[2*8], C4)); 
1071 
tmp1[12] = FRAC_RND(MUL64(in1[2*1], C7)  in3_3 + 
1072 
MUL64(in1[2*5], C1)  
1073 
MUL64(in1[2*7], C5)); 
1074 
tmp1[14] = in1[2*0] + FRAC_RND(MUL64(in1[2*2], C4) + 
1075 
MUL64(in1[2*4], C8) + in6_6  
1076 
MUL64(in1[2*8], C2)); 
1077 
tmp1[16] = in1[2*0]  in1[2*2] + in1[2*4]  in1[2*6] + in1[2*8]; 
1078 
} 
1079  
1080 
i = 0;

1081 
for(j=0;j<4;j++) { 
1082 
t0 = tmp[i]; 
1083 
t1 = tmp[i + 2];

1084 
s0 = t1 + t0; 
1085 
s2 = t1  t0; 
1086  
1087 
t2 = tmp[i + 1];

1088 
t3 = tmp[i + 3];

1089 
s1 = MULL(t3 + t2, icos36[j]); 
1090 
s3 = MULL(t3  t2, icos36[8  j]);

1091 

1092 
t0 = MULL(s0 + s1, icos72[9 + 8  j]); 
1093 
t1 = MULL(s0  s1, icos72[8  j]);

1094 
out[18 + 9 + j] = t0; 
1095 
out[18 + 8  j] = t0; 
1096 
out[9 + j] = t1;

1097 
out[8  j] = t1;

1098 

1099 
t0 = MULL(s2 + s3, icos72[9+j]);

1100 
t1 = MULL(s2  s3, icos72[j]); 
1101 
out[18 + 9 + (8  j)] = t0; 
1102 
out[18 + j] = t0;

1103 
out[9 + (8  j)] = t1; 
1104 
out[j] = t1; 
1105 
i += 4;

1106 
} 
1107  
1108 
s0 = tmp[16];

1109 
s1 = MULL(tmp[17], icos36[4]); 
1110 
t0 = MULL(s0 + s1, icos72[9 + 4]); 
1111 
t1 = MULL(s0  s1, icos72[4]);

1112 
out[18 + 9 + 4] = t0; 
1113 
out[18 + 8  4] = t0; 
1114 
out[9 + 4] = t1; 
1115 
out[8  4] = t1; 
1116 
} 
1117  
1118 
/* fast header check for resync */

1119 
static int check_header(uint32_t header) 
1120 
{ 
1121 
/* header */

1122 
if ((header & 0xffe00000) != 0xffe00000) 
1123 
return 1; 
1124 
/* layer check */

1125 
if (((header >> 17) & 3) == 0) 
1126 
return 1; 
1127 
/* bit rate */

1128 
if (((header >> 12) & 0xf) == 0xf) 
1129 
return 1; 
1130 
/* frequency */

1131 
if (((header >> 10) & 3) == 3) 
1132 
return 1; 
1133 
return 0; 
1134 
} 
1135  
1136 
/* header + layer + bitrate + freq + lsf/mpeg25 */

1137 
#define SAME_HEADER_MASK \

1138 
(0xffe00000  (3 << 17)  (0xf << 12)  (3 << 10)  (3 << 19)) 
1139  
1140 
/* header decoding. MUST check the header before because no

1141 
consistency check is done there. Return 1 if free format found and

1142 
that the frame size must be computed externally */

1143 
static int decode_header(MPADecodeContext *s, uint32_t header) 
1144 
{ 
1145 
int sample_rate, frame_size, mpeg25, padding;

1146 
int sample_rate_index, bitrate_index;

1147 
if (header & (1<<20)) { 
1148 
s>lsf = (header & (1<<19)) ? 0 : 1; 
1149 
mpeg25 = 0;

1150 
} else {

1151 
s>lsf = 1;

1152 
mpeg25 = 1;

1153 
} 
1154 

1155 
s>layer = 4  ((header >> 17) & 3); 
1156 
/* extract frequency */

1157 
sample_rate_index = (header >> 10) & 3; 
1158 
sample_rate = mpa_freq_tab[sample_rate_index] >> (s>lsf + mpeg25); 
1159 
sample_rate_index += 3 * (s>lsf + mpeg25);

1160 
s>sample_rate_index = sample_rate_index; 
1161 
s>error_protection = ((header >> 16) & 1) ^ 1; 
1162 
s>sample_rate = sample_rate; 
1163  
1164 
bitrate_index = (header >> 12) & 0xf; 
1165 
padding = (header >> 9) & 1; 
1166 
//extension = (header >> 8) & 1;

1167 
s>mode = (header >> 6) & 3; 
1168 
s>mode_ext = (header >> 4) & 3; 
1169 
//copyright = (header >> 3) & 1;

1170 
//original = (header >> 2) & 1;

1171 
//emphasis = header & 3;

1172  
1173 
if (s>mode == MPA_MONO)

1174 
s>nb_channels = 1;

1175 
else

1176 
s>nb_channels = 2;

1177 

1178 
if (bitrate_index != 0) { 
1179 
frame_size = mpa_bitrate_tab[s>lsf][s>layer  1][bitrate_index];

1180 
s>bit_rate = frame_size * 1000;

1181 
switch(s>layer) {

1182 
case 1: 
1183 
frame_size = (frame_size * 12000) / sample_rate;

1184 
frame_size = (frame_size + padding) * 4;

1185 
break;

1186 
case 2: 
1187 
frame_size = (frame_size * 144000) / sample_rate;

1188 
frame_size += padding; 
1189 
break;

1190 
default:

1191 
case 3: 
1192 
frame_size = (frame_size * 144000) / (sample_rate << s>lsf);

1193 
frame_size += padding; 
1194 
break;

1195 
} 
1196 
s>frame_size = frame_size; 
1197 
} else {

1198 
/* if no frame size computed, signal it */

1199 
if (!s>free_format_frame_size)

1200 
return 1; 
1201 
/* free format: compute bitrate and real frame size from the

1202 
frame size we extracted by reading the bitstream */

1203 
s>frame_size = s>free_format_frame_size; 
1204 
switch(s>layer) {

1205 
case 1: 
1206 
s>frame_size += padding * 4;

1207 
s>bit_rate = (s>frame_size * sample_rate) / 48000;

1208 
break;

1209 
case 2: 
1210 
s>frame_size += padding; 
1211 
s>bit_rate = (s>frame_size * sample_rate) / 144000;

1212 
break;

1213 
default:

1214 
case 3: 
1215 
s>frame_size += padding; 
1216 
s>bit_rate = (s>frame_size * (sample_rate << s>lsf)) / 144000;

1217 
break;

1218 
} 
1219 
} 
1220 

1221 
#if defined(DEBUG)

1222 
printf("layer%d, %d Hz, %d kbits/s, ",

1223 
s>layer, s>sample_rate, s>bit_rate); 
1224 
if (s>nb_channels == 2) { 
1225 
if (s>layer == 3) { 
1226 
if (s>mode_ext & MODE_EXT_MS_STEREO)

1227 
printf("ms");

1228 
if (s>mode_ext & MODE_EXT_I_STEREO)

1229 
printf("i");

1230 
} 
1231 
printf("stereo");

1232 
} else {

1233 
printf("mono");

1234 
} 
1235 
printf("\n");

1236 
#endif

1237 
return 0; 
1238 
} 
1239  
1240 
/* useful helper to get mpeg audio stream infos. Return 1 if error in

1241 
header, otherwise the coded frame size in bytes */

1242 
int mpa_decode_header(AVCodecContext *avctx, uint32_t head)

1243 
{ 
1244 
MPADecodeContext s1, *s = &s1; 
1245 
memset( s, 0, sizeof(MPADecodeContext) ); 
1246  
1247 
if (check_header(head) != 0) 
1248 
return 1; 
1249  
1250 
if (decode_header(s, head) != 0) { 
1251 
return 1; 
1252 
} 
1253  
1254 
switch(s>layer) {

1255 
case 1: 
1256 
avctx>frame_size = 384;

1257 
break;

1258 
case 2: 
1259 
avctx>frame_size = 1152;

1260 
break;

1261 
default:

1262 
case 3: 
1263 
if (s>lsf)

1264 
avctx>frame_size = 576;

1265 
else

1266 
avctx>frame_size = 1152;

1267 
break;

1268 
} 
1269  
1270 
avctx>sample_rate = s>sample_rate; 
1271 
avctx>channels = s>nb_channels; 
1272 
avctx>bit_rate = s>bit_rate; 
1273 
avctx>sub_id = s>layer; 
1274 
return s>frame_size;

1275 
} 
1276  
1277 
/* return the number of decoded frames */

1278 
static int mp_decode_layer1(MPADecodeContext *s) 
1279 
{ 
1280 
int bound, i, v, n, ch, j, mant;

1281 
uint8_t allocation[MPA_MAX_CHANNELS][SBLIMIT]; 
1282 
uint8_t scale_factors[MPA_MAX_CHANNELS][SBLIMIT]; 
1283  
1284 
if (s>mode == MPA_JSTEREO)

1285 
bound = (s>mode_ext + 1) * 4; 
1286 
else

1287 
bound = SBLIMIT; 
1288  
1289 
/* allocation bits */

1290 
for(i=0;i<bound;i++) { 
1291 
for(ch=0;ch<s>nb_channels;ch++) { 
1292 
allocation[ch][i] = get_bits(&s>gb, 4);

1293 
} 
1294 
} 
1295 
for(i=bound;i<SBLIMIT;i++) {

1296 
allocation[0][i] = get_bits(&s>gb, 4); 
1297 
} 
1298  
1299 
/* scale factors */

1300 
for(i=0;i<bound;i++) { 
1301 
for(ch=0;ch<s>nb_channels;ch++) { 
1302 
if (allocation[ch][i])

1303 
scale_factors[ch][i] = get_bits(&s>gb, 6);

1304 
} 
1305 
} 
1306 
for(i=bound;i<SBLIMIT;i++) {

1307 
if (allocation[0][i]) { 
1308 
scale_factors[0][i] = get_bits(&s>gb, 6); 
1309 
scale_factors[1][i] = get_bits(&s>gb, 6); 
1310 
} 
1311 
} 
1312 

1313 
/* compute samples */

1314 
for(j=0;j<12;j++) { 
1315 
for(i=0;i<bound;i++) { 
1316 
for(ch=0;ch<s>nb_channels;ch++) { 
1317 
n = allocation[ch][i]; 
1318 
if (n) {

1319 
mant = get_bits(&s>gb, n + 1);

1320 
v = l1_unscale(n, mant, scale_factors[ch][i]); 
1321 
} else {

1322 
v = 0;

1323 
} 
1324 
s>sb_samples[ch][j][i] = v; 
1325 
} 
1326 
} 
1327 
for(i=bound;i<SBLIMIT;i++) {

1328 
n = allocation[0][i];

1329 
if (n) {

1330 
mant = get_bits(&s>gb, n + 1);

1331 
v = l1_unscale(n, mant, scale_factors[0][i]);

1332 
s>sb_samples[0][j][i] = v;

1333 
v = l1_unscale(n, mant, scale_factors[1][i]);

1334 
s>sb_samples[1][j][i] = v;

1335 
} else {

1336 
s>sb_samples[0][j][i] = 0; 
1337 
s>sb_samples[1][j][i] = 0; 
1338 
} 
1339 
} 
1340 
} 
1341 
return 12; 
1342 
} 
1343  
1344 
/* bitrate is in kb/s */

1345 
int l2_select_table(int bitrate, int nb_channels, int freq, int lsf) 
1346 
{ 
1347 
int ch_bitrate, table;

1348 

1349 
ch_bitrate = bitrate / nb_channels; 
1350 
if (!lsf) {

1351 
if ((freq == 48000 && ch_bitrate >= 56)  
1352 
(ch_bitrate >= 56 && ch_bitrate <= 80)) 
1353 
table = 0;

1354 
else if (freq != 48000 && ch_bitrate >= 96) 
1355 
table = 1;

1356 
else if (freq != 32000 && ch_bitrate <= 48) 
1357 
table = 2;

1358 
else

1359 
table = 3;

1360 
} else {

1361 
table = 4;

1362 
} 
1363 
return table;

1364 
} 
1365  
1366 
static int mp_decode_layer2(MPADecodeContext *s) 
1367 
{ 
1368 
int sblimit; /* number of used subbands */ 
1369 
const unsigned char *alloc_table; 
1370 
int table, bit_alloc_bits, i, j, ch, bound, v;

1371 
unsigned char bit_alloc[MPA_MAX_CHANNELS][SBLIMIT]; 
1372 
unsigned char scale_code[MPA_MAX_CHANNELS][SBLIMIT]; 
1373 
unsigned char scale_factors[MPA_MAX_CHANNELS][SBLIMIT][3], *sf; 
1374 
int scale, qindex, bits, steps, k, l, m, b;

1375  
1376 
/* select decoding table */

1377 
table = l2_select_table(s>bit_rate / 1000, s>nb_channels,

1378 
s>sample_rate, s>lsf); 
1379 
sblimit = sblimit_table[table]; 
1380 
alloc_table = alloc_tables[table]; 
1381  
1382 
if (s>mode == MPA_JSTEREO)

1383 
bound = (s>mode_ext + 1) * 4; 
1384 
else

1385 
bound = sblimit; 
1386  
1387 
dprintf("bound=%d sblimit=%d\n", bound, sblimit);

1388  
1389 
/* sanity check */

1390 
if( bound > sblimit ) bound = sblimit;

1391  
1392 
/* parse bit allocation */

1393 
j = 0;

1394 
for(i=0;i<bound;i++) { 
1395 
bit_alloc_bits = alloc_table[j]; 
1396 
for(ch=0;ch<s>nb_channels;ch++) { 
1397 
bit_alloc[ch][i] = get_bits(&s>gb, bit_alloc_bits); 
1398 
} 
1399 
j += 1 << bit_alloc_bits;

1400 
} 
1401 
for(i=bound;i<sblimit;i++) {

1402 
bit_alloc_bits = alloc_table[j]; 
1403 
v = get_bits(&s>gb, bit_alloc_bits); 
1404 
bit_alloc[0][i] = v;

1405 
bit_alloc[1][i] = v;

1406 
j += 1 << bit_alloc_bits;

1407 
} 
1408  
1409 
#ifdef DEBUG

1410 
{ 
1411 
for(ch=0;ch<s>nb_channels;ch++) { 
1412 
for(i=0;i<sblimit;i++) 
1413 
printf(" %d", bit_alloc[ch][i]);

1414 
printf("\n");

1415 
} 
1416 
} 
1417 
#endif

1418  
1419 
/* scale codes */

1420 
for(i=0;i<sblimit;i++) { 
1421 
for(ch=0;ch<s>nb_channels;ch++) { 
1422 
if (bit_alloc[ch][i])

1423 
scale_code[ch][i] = get_bits(&s>gb, 2);

1424 
} 
1425 
} 
1426 

1427 
/* scale factors */

1428 
for(i=0;i<sblimit;i++) { 
1429 
for(ch=0;ch<s>nb_channels;ch++) { 
1430 
if (bit_alloc[ch][i]) {

1431 
sf = scale_factors[ch][i]; 
1432 
switch(scale_code[ch][i]) {

1433 
default:

1434 
case 0: 
1435 
sf[0] = get_bits(&s>gb, 6); 
1436 
sf[1] = get_bits(&s>gb, 6); 
1437 
sf[2] = get_bits(&s>gb, 6); 
1438 
break;

1439 
case 2: 
1440 
sf[0] = get_bits(&s>gb, 6); 
1441 
sf[1] = sf[0]; 
1442 
sf[2] = sf[0]; 
1443 
break;

1444 
case 1: 
1445 
sf[0] = get_bits(&s>gb, 6); 
1446 
sf[2] = get_bits(&s>gb, 6); 
1447 
sf[1] = sf[0]; 
1448 
break;

1449 
case 3: 
1450 
sf[0] = get_bits(&s>gb, 6); 
1451 
sf[2] = get_bits(&s>gb, 6); 
1452 
sf[1] = sf[2]; 
1453 
break;

1454 
} 
1455 
} 
1456 
} 
1457 
} 
1458  
1459 
#ifdef DEBUG

1460 
for(ch=0;ch<s>nb_channels;ch++) { 
1461 
for(i=0;i<sblimit;i++) { 
1462 
if (bit_alloc[ch][i]) {

1463 
sf = scale_factors[ch][i]; 
1464 
printf(" %d %d %d", sf[0], sf[1], sf[2]); 
1465 
} else {

1466 
printf(" ");

1467 
} 
1468 
} 
1469 
printf("\n");

1470 
} 
1471 
#endif

1472  
1473 
/* samples */

1474 
for(k=0;k<3;k++) { 
1475 
for(l=0;l<12;l+=3) { 
1476 
j = 0;

1477 
for(i=0;i<bound;i++) { 
1478 
bit_alloc_bits = alloc_table[j]; 
1479 
for(ch=0;ch<s>nb_channels;ch++) { 
1480 
b = bit_alloc[ch][i]; 
1481 
if (b) {

1482 
scale = scale_factors[ch][i][k]; 
1483 
qindex = alloc_table[j+b]; 
1484 
bits = quant_bits[qindex]; 
1485 
if (bits < 0) { 
1486 
/* 3 values at the same time */

1487 
v = get_bits(&s>gb, bits); 
1488 
steps = quant_steps[qindex]; 
1489 
s>sb_samples[ch][k * 12 + l + 0][i] = 
1490 
l2_unscale_group(steps, v % steps, scale); 
1491 
v = v / steps; 
1492 
s>sb_samples[ch][k * 12 + l + 1][i] = 
1493 
l2_unscale_group(steps, v % steps, scale); 
1494 
v = v / steps; 
1495 
s>sb_samples[ch][k * 12 + l + 2][i] = 
1496 
l2_unscale_group(steps, v, scale); 
1497 
} else {

1498 
for(m=0;m<3;m++) { 
1499 
v = get_bits(&s>gb, bits); 
1500 
v = l1_unscale(bits  1, v, scale);

1501 
s>sb_samples[ch][k * 12 + l + m][i] = v;

1502 
} 
1503 
} 
1504 
} else {

1505 
s>sb_samples[ch][k * 12 + l + 0][i] = 0; 
1506 
s>sb_samples[ch][k * 12 + l + 1][i] = 0; 
1507 
s>sb_samples[ch][k * 12 + l + 2][i] = 0; 
1508 
} 
1509 
} 
1510 
/* next subband in alloc table */

1511 
j += 1 << bit_alloc_bits;

1512 
} 
1513 
/* XXX: find a way to avoid this duplication of code */

1514 
for(i=bound;i<sblimit;i++) {

1515 
bit_alloc_bits = alloc_table[j]; 
1516 
b = bit_alloc[0][i];

1517 
if (b) {

1518 
int mant, scale0, scale1;

1519 
scale0 = scale_factors[0][i][k];

1520 
scale1 = scale_factors[1][i][k];

1521 
qindex = alloc_table[j+b]; 
1522 
bits = quant_bits[qindex]; 
1523 
if (bits < 0) { 
1524 
/* 3 values at the same time */

1525 
v = get_bits(&s>gb, bits); 
1526 
steps = quant_steps[qindex]; 
1527 
mant = v % steps; 
1528 
v = v / steps; 
1529 
s>sb_samples[0][k * 12 + l + 0][i] = 
1530 
l2_unscale_group(steps, mant, scale0); 
1531 
s>sb_samples[1][k * 12 + l + 0][i] = 
1532 
l2_unscale_group(steps, mant, scale1); 
1533 
mant = v % steps; 
1534 
v = v / steps; 
1535 
s>sb_samples[0][k * 12 + l + 1][i] = 
1536 
l2_unscale_group(steps, mant, scale0); 
1537 
s>sb_samples[1][k * 12 + l + 1][i] = 
1538 
l2_unscale_group(steps, mant, scale1); 
1539 
s>sb_samples[0][k * 12 + l + 2][i] = 
1540 
l2_unscale_group(steps, v, scale0); 
1541 
s>sb_samples[1][k * 12 + l + 2][i] = 
1542 
l2_unscale_group(steps, v, scale1); 
1543 
} else {

1544 
for(m=0;m<3;m++) { 
1545 
mant = get_bits(&s>gb, bits); 
1546 
s>sb_samples[0][k * 12 + l + m][i] = 
1547 
l1_unscale(bits  1, mant, scale0);

1548 
s>sb_samples[1][k * 12 + l + m][i] = 
1549 
l1_unscale(bits  1, mant, scale1);

1550 
} 
1551 
} 
1552 
} else {

1553 
s>sb_samples[0][k * 12 + l + 0][i] = 0; 
1554 
s>sb_samples[0][k * 12 + l + 1][i] = 0; 
1555 
s>sb_samples[0][k * 12 + l + 2][i] = 0; 
1556 
s>sb_samples[1][k * 12 + l + 0][i] = 0; 
1557 
s>sb_samples[1][k * 12 + l + 1][i] = 0; 
1558 
s>sb_samples[1][k * 12 + l + 2][i] = 0; 
1559 
} 
1560 
/* next subband in alloc table */

1561 
j += 1 << bit_alloc_bits;

1562 
} 
1563 
/* fill remaining samples to zero */

1564 
for(i=sblimit;i<SBLIMIT;i++) {

1565 
for(ch=0;ch<s>nb_channels;ch++) { 
1566 
s>sb_samples[ch][k * 12 + l + 0][i] = 0; 
1567 
s>sb_samples[ch][k * 12 + l + 1][i] = 0; 
1568 
s>sb_samples[ch][k * 12 + l + 2][i] = 0; 
1569 
} 
1570 
} 
1571 
} 
1572 
} 
1573 
return 3 * 12; 
1574 
} 
1575  
1576 
/*

1577 
* Seek back in the stream for backstep bytes (at most 511 bytes)

1578 
*/

1579 
static void seek_to_maindata(MPADecodeContext *s, unsigned int backstep) 
1580 
{ 
1581 
uint8_t *ptr; 
1582  
1583 
/* compute current position in stream */

1584 
ptr = (uint8_t *)(s>gb.buffer + (get_bits_count(&s>gb)>>3));

1585  
1586 
/* copy old data before current one */

1587 
ptr = backstep; 
1588 
memcpy(ptr, s>inbuf1[s>inbuf_index ^ 1] +

1589 
BACKSTEP_SIZE + s>old_frame_size  backstep, backstep); 
1590 
/* init get bits again */

1591 
init_get_bits(&s>gb, ptr, (s>frame_size + backstep)*8);

1592  
1593 
/* prepare next buffer */

1594 
s>inbuf_index ^= 1;

1595 
s>inbuf = &s>inbuf1[s>inbuf_index][BACKSTEP_SIZE]; 
1596 
s>old_frame_size = s>frame_size; 
1597 
} 
1598  
1599 
static inline void lsf_sf_expand(int *slen, 
1600 
int sf, int n1, int n2, int n3) 
1601 
{ 
1602 
if (n3) {

1603 
slen[3] = sf % n3;

1604 
sf /= n3; 
1605 
} else {

1606 
slen[3] = 0; 
1607 
} 
1608 
if (n2) {

1609 
slen[2] = sf % n2;

1610 
sf /= n2; 
1611 
} else {

1612 
slen[2] = 0; 
1613 
} 
1614 
slen[1] = sf % n1;

1615 
sf /= n1; 
1616 
slen[0] = sf;

1617 
} 
1618  
1619 
static void exponents_from_scale_factors(MPADecodeContext *s, 
1620 
GranuleDef *g, 
1621 
int16_t *exponents) 
1622 
{ 
1623 
const uint8_t *bstab, *pretab;

1624 
int len, i, j, k, l, v0, shift, gain, gains[3]; 
1625 
int16_t *exp_ptr; 
1626  
1627 
exp_ptr = exponents; 
1628 
gain = g>global_gain  210;

1629 
shift = g>scalefac_scale + 1;

1630  
1631 
bstab = band_size_long[s>sample_rate_index]; 
1632 
pretab = mpa_pretab[g>preflag]; 
1633 
for(i=0;i<g>long_end;i++) { 
1634 
v0 = gain  ((g>scale_factors[i] + pretab[i]) << shift); 
1635 
len = bstab[i]; 
1636 
for(j=len;j>0;j) 
1637 
*exp_ptr++ = v0; 
1638 
} 
1639  
1640 
if (g>short_start < 13) { 
1641 
bstab = band_size_short[s>sample_rate_index]; 
1642 
gains[0] = gain  (g>subblock_gain[0] << 3); 
1643 
gains[1] = gain  (g>subblock_gain[1] << 3); 
1644 
gains[2] = gain  (g>subblock_gain[2] << 3); 
1645 
k = g>long_end; 
1646 
for(i=g>short_start;i<13;i++) { 
1647 
len = bstab[i]; 
1648 
for(l=0;l<3;l++) { 
1649 
v0 = gains[l]  (g>scale_factors[k++] << shift); 
1650 
for(j=len;j>0;j) 
1651 
*exp_ptr++ = v0; 
1652 
} 
1653 
} 
1654 
} 
1655 
} 
1656  
1657 
/* handle n = 0 too */

1658 
static inline int get_bitsz(GetBitContext *s, int n) 
1659 
{ 
1660 
if (n == 0) 
1661 
return 0; 
1662 
else

1663 
return get_bits(s, n);

1664 
} 
1665  
1666 
static int huffman_decode(MPADecodeContext *s, GranuleDef *g, 
1667 
int16_t *exponents, int end_pos)

1668 
{ 
1669 
int s_index;

1670 
int linbits, code, x, y, l, v, i, j, k, pos;

1671 
GetBitContext last_gb; 
1672 
VLC *vlc; 
1673 
uint8_t *code_table; 
1674  
1675 
/* low frequencies (called big values) */

1676 
s_index = 0;

1677 
for(i=0;i<3;i++) { 
1678 
j = g>region_size[i]; 
1679 
if (j == 0) 
1680 
continue;

1681 
/* select vlc table */

1682 
k = g>table_select[i]; 
1683 
l = mpa_huff_data[k][0];

1684 
linbits = mpa_huff_data[k][1];

1685 
vlc = &huff_vlc[l]; 
1686 
code_table = huff_code_table[l]; 
1687  
1688 
/* read huffcode and compute each couple */

1689 
for(;j>0;j) { 
1690 
if (get_bits_count(&s>gb) >= end_pos)

1691 
break;

1692 
if (code_table) {

1693 
code = get_vlc(&s>gb, vlc); 
1694 
if (code < 0) 
1695 
return 1; 
1696 
y = code_table[code]; 
1697 
x = y >> 4;

1698 
y = y & 0x0f;

1699 
} else {

1700 
x = 0;

1701 
y = 0;

1702 
} 
1703 
dprintf("region=%d n=%d x=%d y=%d exp=%d\n",

1704 
i, g>region_size[i]  j, x, y, exponents[s_index]); 
1705 
if (x) {

1706 
if (x == 15) 
1707 
x += get_bitsz(&s>gb, linbits); 
1708 
v = l3_unscale(x, exponents[s_index]); 
1709 
if (get_bits1(&s>gb))

1710 
v = v; 
1711 
} else {

1712 
v = 0;

1713 
} 
1714 
g>sb_hybrid[s_index++] = v; 
1715 
if (y) {

1716 
if (y == 15) 
1717 
y += get_bitsz(&s>gb, linbits); 
1718 
v = l3_unscale(y, exponents[s_index]); 
1719 
if (get_bits1(&s>gb))

1720 
v = v; 
1721 
} else {

1722 
v = 0;

1723 
} 
1724 
g>sb_hybrid[s_index++] = v; 
1725 
} 
1726 
} 
1727 

1728 
/* high frequencies */

1729 
vlc = &huff_quad_vlc[g>count1table_select]; 
1730 
last_gb.buffer = NULL;

1731 
while (s_index <= 572) { 
1732 
pos = get_bits_count(&s>gb); 
1733 
if (pos >= end_pos) {

1734 
if (pos > end_pos && last_gb.buffer != NULL) { 
1735 
/* some encoders generate an incorrect size for this

1736 
part. We must go back into the data */

1737 
s_index = 4;

1738 
s>gb = last_gb; 
1739 
} 
1740 
break;

1741 
} 
1742 
last_gb= s>gb; 
1743  
1744 
code = get_vlc(&s>gb, vlc); 
1745 
dprintf("t=%d code=%d\n", g>count1table_select, code);

1746 
if (code < 0) 
1747 
return 1; 
1748 
for(i=0;i<4;i++) { 
1749 
if (code & (8 >> i)) { 
1750 
/* non zero value. Could use a hand coded function for

1751 
'one' value */

1752 
v = l3_unscale(1, exponents[s_index]);

1753 
if(get_bits1(&s>gb))

1754 
v = v; 
1755 
} else {

1756 
v = 0;

1757 
} 
1758 
g>sb_hybrid[s_index++] = v; 
1759 
} 
1760 
} 
1761 
while (s_index < 576) 
1762 
g>sb_hybrid[s_index++] = 0;

1763 
return 0; 
1764 
} 
1765  
1766 
/* Reorder short blocks from bitstream order to interleaved order. It

1767 
would be faster to do it in parsing, but the code would be far more

1768 
complicated */

1769 
static void reorder_block(MPADecodeContext *s, GranuleDef *g) 
1770 
{ 
1771 
int i, j, k, len;

1772 
int32_t *ptr, *dst, *ptr1; 
1773 
int32_t tmp[576];

1774  
1775 
if (g>block_type != 2) 
1776 
return;

1777  
1778 
if (g>switch_point) {

1779 
if (s>sample_rate_index != 8) { 
1780 
ptr = g>sb_hybrid + 36;

1781 
} else {

1782 
ptr = g>sb_hybrid + 48;

1783 
} 
1784 
} else {

1785 
ptr = g>sb_hybrid; 
1786 
} 
1787 

1788 
for(i=g>short_start;i<13;i++) { 
1789 
len = band_size_short[s>sample_rate_index][i]; 
1790 
ptr1 = ptr; 
1791 
for(k=0;k<3;k++) { 
1792 
dst = tmp + k; 
1793 
for(j=len;j>0;j) { 
1794 
*dst = *ptr++; 
1795 
dst += 3;

1796 
} 
1797 
} 
1798 
memcpy(ptr1, tmp, len * 3 * sizeof(int32_t)); 
1799 
} 
1800 
} 
1801  
1802 
#define ISQRT2 FIXR(0.70710678118654752440) 
1803  
1804 
static void compute_stereo(MPADecodeContext *s, 
1805 
GranuleDef *g0, GranuleDef *g1) 
1806 
{ 
1807 
int i, j, k, l;

1808 
int32_t v1, v2; 
1809 
int sf_max, tmp0, tmp1, sf, len, non_zero_found;

1810 
int32_t (*is_tab)[16];

1811 
int32_t *tab0, *tab1; 
1812 
int non_zero_found_short[3]; 
1813  
1814 
/* intensity stereo */

1815 
if (s>mode_ext & MODE_EXT_I_STEREO) {

1816 
if (!s>lsf) {

1817 
is_tab = is_table; 
1818 
sf_max = 7;

1819 
} else {

1820 
is_tab = is_table_lsf[g1>scalefac_compress & 1];

1821 
sf_max = 16;

1822 
} 
1823 

1824 
tab0 = g0>sb_hybrid + 576;

1825 
tab1 = g1>sb_hybrid + 576;

1826  
1827 
non_zero_found_short[0] = 0; 
1828 
non_zero_found_short[1] = 0; 
1829 
non_zero_found_short[2] = 0; 
1830 
k = (13  g1>short_start) * 3 + g1>long_end  3; 
1831 
for(i = 12;i >= g1>short_start;i) { 
1832 
/* for last band, use previous scale factor */

1833 
if (i != 11) 
1834 
k = 3;

1835 
len = band_size_short[s>sample_rate_index][i]; 
1836 
for(l=2;l>=0;l) { 
1837 
tab0 = len; 
1838 
tab1 = len; 
1839 
if (!non_zero_found_short[l]) {

1840 
/* test if non zero band. if so, stop doing istereo */

1841 
for(j=0;j<len;j++) { 
1842 
if (tab1[j] != 0) { 
1843 
non_zero_found_short[l] = 1;

1844 
goto found1;

1845 
} 
1846 
} 
1847 
sf = g1>scale_factors[k + l]; 
1848 
if (sf >= sf_max)

1849 
goto found1;

1850  
1851 
v1 = is_tab[0][sf];

1852 
v2 = is_tab[1][sf];

1853 
for(j=0;j<len;j++) { 
1854 
tmp0 = tab0[j]; 
1855 
tab0[j] = MULL(tmp0, v1); 
1856 
tab1[j] = MULL(tmp0, v2); 
1857 
} 
1858 
} else {

1859 
found1:

1860 
if (s>mode_ext & MODE_EXT_MS_STEREO) {

1861 
/* lower part of the spectrum : do ms stereo

1862 
if enabled */

1863 
for(j=0;j<len;j++) { 
1864 
tmp0 = tab0[j]; 
1865 
tmp1 = tab1[j]; 
1866 
tab0[j] = MULL(tmp0 + tmp1, ISQRT2); 
1867 
tab1[j] = MULL(tmp0  tmp1, ISQRT2); 
1868 
} 
1869 
} 
1870 
} 
1871 
} 
1872 
} 
1873  
1874 
non_zero_found = non_zero_found_short[0] 

1875 
non_zero_found_short[1] 

1876 
non_zero_found_short[2];

1877  
1878 
for(i = g1>long_end  1;i >= 0;i) { 
1879 
len = band_size_long[s>sample_rate_index][i]; 
1880 
tab0 = len; 
1881 
tab1 = len; 
1882 
/* test if non zero band. if so, stop doing istereo */

1883 
if (!non_zero_found) {

1884 
for(j=0;j<len;j++) { 
1885 
if (tab1[j] != 0) { 
1886 
non_zero_found = 1;

1887 
goto found2;

1888 
} 
1889 
} 
1890 
/* for last band, use previous scale factor */

1891 
k = (i == 21) ? 20 : i; 
1892 
sf = g1>scale_factors[k]; 
1893 
if (sf >= sf_max)

1894 
goto found2;

1895 
v1 = is_tab[0][sf];

1896 
v2 = is_tab[1][sf];

1897 
for(j=0;j<len;j++) { 
1898 
tmp0 = tab0[j]; 
1899 
tab0[j] = MULL(tmp0, v1); 
1900 
tab1[j] = MULL(tmp0, v2); 
1901 
} 
1902 
} else {

1903 
found2:

1904 
if (s>mode_ext & MODE_EXT_MS_STEREO) {

1905 
/* lower part of the spectrum : do ms stereo

1906 
if enabled */

1907 
for(j=0;j<len;j++) { 
1908 
tmp0 = tab0[j]; 
1909 
tmp1 = tab1[j]; 
1910 
tab0[j] = MULL(tmp0 + tmp1, ISQRT2); 
1911 
tab1[j] = MULL(tmp0  tmp1, ISQRT2); 
1912 
} 
1913 
} 
1914 
} 
1915 
} 
1916 
} else if (s>mode_ext & MODE_EXT_MS_STEREO) { 
1917 
/* ms stereo ONLY */

1918 
/* NOTE: the 1/sqrt(2) normalization factor is included in the

1919 
global gain */

1920 
tab0 = g0>sb_hybrid; 
1921 
tab1 = g1>sb_hybrid; 
1922 
for(i=0;i<576;i++) { 
1923 
tmp0 = tab0[i]; 
1924 
tmp1 = tab1[i]; 
1925 
tab0[i] = tmp0 + tmp1; 
1926 
tab1[i] = tmp0  tmp1; 
1927 
} 
1928 
} 
1929 
} 
1930  
1931 
static void compute_antialias_integer(MPADecodeContext *s, 
1932 
GranuleDef *g) 
1933 
{ 
1934 
int32_t *ptr, *p0, *p1, *csa; 
1935 
int n, i, j;

1936  
1937 
/* we antialias only "long" bands */

1938 
if (g>block_type == 2) { 
1939 
if (!g>switch_point)

1940 
return;

1941 
/* XXX: check this for 8000Hz case */

1942 
n = 1;

1943 
} else {

1944 
n = SBLIMIT  1;

1945 
} 
1946 

1947 
ptr = g>sb_hybrid + 18;

1948 
for(i = n;i > 0;i) { 
1949 
p0 = ptr  1;

1950 
p1 = ptr; 
1951 
csa = &csa_table[0][0]; 
1952 
for(j=0;j<4;j++) { 
1953 
int tmp0 = *p0;

1954 
int tmp1 = *p1;

1955 
#if 0

1956 
*p0 = FRAC_RND(MUL64(tmp0, csa[0])  MUL64(tmp1, csa[1]));

1957 
*p1 = FRAC_RND(MUL64(tmp0, csa[1]) + MUL64(tmp1, csa[0]));

1958 
#else

1959 
int64_t tmp2= MUL64(tmp0 + tmp1, csa[0]);

1960 
*p0 = FRAC_RND(tmp2  MUL64(tmp1, csa[2]));

1961 
*p1 = FRAC_RND(tmp2 + MUL64(tmp0, csa[3]));

1962 
#endif

1963 
p0; p1++; 
1964 
csa += 4;

1965 
tmp0 = *p0; 
1966 
tmp1 = *p1; 
1967 
#if 0

1968 
*p0 = FRAC_RND(MUL64(tmp0, csa[0])  MUL64(tmp1, csa[1]));

1969 
*p1 = FRAC_RND(MUL64(tmp0, csa[1]) + MUL64(tmp1, csa[0]));

1970 
#else

1971 
tmp2= MUL64(tmp0 + tmp1, csa[0]);

1972 
*p0 = FRAC_RND(tmp2  MUL64(tmp1, csa[2]));

1973 
*p1 = FRAC_RND(tmp2 + MUL64(tmp0, csa[3]));

1974 
#endif

1975 
p0; p1++; 
1976 
csa += 4;

1977 
} 
1978 
ptr += 18;

1979 
} 
1980 
} 
1981  
1982 
static void compute_antialias_float(MPADecodeContext *s, 
1983 
GranuleDef *g) 
1984 
{ 
1985 
int32_t *ptr, *p0, *p1; 
1986 
int n, i, j;

1987  
1988 
/* we antialias only "long" bands */

1989 
if (g>block_type == 2) { 
1990 
if (!g>switch_point)

1991 
return;

1992 
/* XXX: check this for 8000Hz case */

1993 
n = 1;

1994 
} else {

1995 
n = SBLIMIT  1;

1996 
} 
1997 

1998 
ptr = g>sb_hybrid + 18;

1999 
for(i = n;i > 0;i) { 
2000 
float *csa = &csa_table_float[0][0]; 
2001 
p0 = ptr  1;

2002 
p1 = ptr; 
2003 
for(j=0;j<4;j++) { 
2004 
float tmp0 = *p0;

2005 
float tmp1 = *p1;

2006 
#if 1 
2007 
*p0 = lrintf(tmp0 * csa[0]  tmp1 * csa[1]); 
2008 
*p1 = lrintf(tmp0 * csa[1] + tmp1 * csa[0]); 
2009 
#else

2010 
float tmp2= (tmp0 + tmp1) * csa[0]; 
2011 
*p0 = lrintf(tmp2  tmp1 * csa[2]);

2012 
*p1 = lrintf(tmp2 + tmp0 * csa[3]);

2013 
#endif

2014 
p0; p1++; 
2015 
csa += 4;

2016 
tmp0 = *p0; 
2017 
tmp1 = *p1; 
2018 
#if 1 
2019 
*p0 = lrintf(tmp0 * csa[0]  tmp1 * csa[1]); 
2020 
*p1 = lrintf(tmp0 * csa[1] + tmp1 * csa[0]); 
2021 
#else

2022 
tmp2= (tmp0 + tmp1) * csa[0];

2023 
*p0 = lrintf(tmp2  tmp1 * csa[2]);

2024 
*p1 = lrintf(tmp2 + tmp0 * csa[3]);

2025 
#endif

2026 
p0; p1++; 
2027 
csa += 4;

2028 
} 
2029 
ptr += 18;

2030 
} 
2031 
} 
2032  
2033 
static void compute_imdct(MPADecodeContext *s, 
2034 
GranuleDef *g, 
2035 
int32_t *sb_samples, 
2036 
int32_t *mdct_buf) 
2037 
{ 
2038 
int32_t *ptr, *win, *win1, *buf, *buf2, *out_ptr, *ptr1; 
2039 
int32_t in[6];

2040 
int32_t out[36];

2041 
int32_t out2[12];

2042 
int i, j, k, mdct_long_end, v, sblimit;

2043  
2044 
/* find last non zero block */

2045 
ptr = g>sb_hybrid + 576;

2046 
ptr1 = g>sb_hybrid + 2 * 18; 
2047 
while (ptr >= ptr1) {

2048 
ptr = 6;

2049 
v = ptr[0]  ptr[1]  ptr[2]  ptr[3]  ptr[4]  ptr[5]; 
2050 
if (v != 0) 
2051 
break;

2052 
} 
2053 
sblimit = ((ptr  g>sb_hybrid) / 18) + 1; 
2054  
2055 
if (g>block_type == 2) { 
2056 
/* XXX: check for 8000 Hz */

2057 
if (g>switch_point)

2058 
mdct_long_end = 2;

2059 
else

2060 
mdct_long_end = 0;

2061 
} else {

2062 
mdct_long_end = sblimit; 
2063 
} 
2064  
2065 
buf = mdct_buf; 
2066 
ptr = g>sb_hybrid; 
2067 
for(j=0;j<mdct_long_end;j++) { 
2068 
imdct36(out, ptr); 
2069 
/* apply window & overlap with previous buffer */

2070 
out_ptr = sb_samples + j; 
2071 
/* select window */

2072 
if (g>switch_point && j < 2) 
2073 
win1 = mdct_win[0];

2074 
else

2075 
win1 = mdct_win[g>block_type]; 
2076 
/* select frequency inversion */

2077 
win = win1 + ((4 * 36) & (j & 1)); 
2078 
for(i=0;i<18;i++) { 
2079 
*out_ptr = MULL(out[i], win[i]) + buf[i]; 
2080 
buf[i] = MULL(out[i + 18], win[i + 18]); 
2081 
out_ptr += SBLIMIT; 
2082 
} 
2083 
ptr += 18;

2084 
buf += 18;

2085 
} 
2086 
for(j=mdct_long_end;j<sblimit;j++) {

2087 
for(i=0;i<6;i++) { 
2088 
out[i] = 0;

2089 
out[6 + i] = 0; 
2090 
out[30+i] = 0; 
2091 
} 
2092 
/* select frequency inversion */

2093 
win = mdct_win[2] + ((4 * 36) & (j & 1)); 
2094 
buf2 = out + 6;

2095 
for(k=0;k<3;k++) { 
2096 
/* reorder input for short mdct */

2097 
ptr1 = ptr + k; 
2098 
for(i=0;i<6;i++) { 
2099 
in[i] = *ptr1; 
2100 
ptr1 += 3;

2101 
} 
2102 
imdct12(out2, in); 
2103 
/* apply 12 point window and do small overlap */

2104 
for(i=0;i<6;i++) { 
2105 
buf2[i] = MULL(out2[i], win[i]) + buf2[i]; 
2106 
buf2[i + 6] = MULL(out2[i + 6], win[i + 6]); 
2107 
} 
2108 
buf2 += 6;

2109 
} 
2110 
/* overlap */

2111 
out_ptr = sb_samples + j; 
2112 
for(i=0;i<18;i++) { 
2113 
*out_ptr = out[i] + buf[i]; 
2114 
buf[i] = out[i + 18];

2115 
out_ptr += SBLIMIT; 
2116 
} 
2117 
ptr += 18;

2118 
buf += 18;

2119 
} 
2120 
/* zero bands */

2121 
for(j=sblimit;j<SBLIMIT;j++) {

2122 
/* overlap */

2123 
out_ptr = sb_samples + j; 
2124 
for(i=0;i<18;i++) { 
2125 
*out_ptr = buf[i]; 
2126 
buf[i] = 0;

2127 
out_ptr += SBLIMIT; 
2128 
} 
2129 
buf += 18;

2130 
} 
2131 
} 
2132  
2133 
#if defined(DEBUG)

2134 
void sample_dump(int fnum, int32_t *tab, int n) 
2135 
{ 
2136 
static FILE *files[16], *f; 
2137 
char buf[512]; 
2138 
int i;

2139 
int32_t v; 
2140 

2141 
f = files[fnum]; 
2142 
if (!f) {

2143 
snprintf(buf, sizeof(buf), "/tmp/out%d.%s.pcm", 
2144 
fnum, 
2145 
#ifdef USE_HIGHPRECISION

2146 
"hp"

2147 
#else

2148 
"lp"

2149 
#endif

2150 
); 
2151 
f = fopen(buf, "w");

2152 
if (!f)

2153 
return;

2154 
files[fnum] = f; 
2155 
} 
2156 

2157 
if (fnum == 0) { 
2158 
static int pos = 0; 
2159 
printf("pos=%d\n", pos);

2160 
for(i=0;i<n;i++) { 
2161 
printf(" %0.4f", (double)tab[i] / FRAC_ONE); 
2162 
if ((i % 18) == 17) 
2163 
printf("\n");

2164 
} 
2165 
pos += n; 
2166 
} 
2167 
for(i=0;i<n;i++) { 
2168 
/* normalize to 23 frac bits */

2169 
v = tab[i] << (23  FRAC_BITS);

2170 
fwrite(&v, 1, sizeof(int32_t), f); 
2171 
} 
2172 
} 
2173 
#endif

2174  
2175  
2176 
/* main layer3 decoding function */

2177 
static int mp_decode_layer3(MPADecodeContext *s) 
2178 
{ 
2179 
int nb_granules, main_data_begin, private_bits;

2180 
int gr, ch, blocksplit_flag, i, j, k, n, bits_pos, bits_left;

2181 
GranuleDef granules[2][2], *g; 
2182 
int16_t exponents[576];

2183  
2184 
/* read side info */

2185 
if (s>lsf) {

2186 
main_data_begin = get_bits(&s>gb, 8);

2187 
if (s>nb_channels == 2) 
2188 
private_bits = get_bits(&s>gb, 2);

2189 
else

2190 
private_bits = get_bits(&s>gb, 1);

2191 
nb_granules = 1;

2192 
} else {

2193 
main_data_begin = get_bits(&s>gb, 9);

2194 
if (s>nb_channels == 2) 
2195 
private_bits = get_bits(&s>gb, 3);

2196 
else

2197 
private_bits = get_bits(&s>gb, 5);

2198 
nb_granules = 2;

2199 
for(ch=0;ch<s>nb_channels;ch++) { 
2200 
granules[ch][0].scfsi = 0; /* all scale factors are transmitted */ 
2201 
granules[ch][1].scfsi = get_bits(&s>gb, 4); 
2202 
} 
2203 
} 
2204 

2205 
for(gr=0;gr<nb_granules;gr++) { 
2206 
for(ch=0;ch<s>nb_channels;ch++) { 
2207 
dprintf("gr=%d ch=%d: side_info\n", gr, ch);

2208 
g = &granules[ch][gr]; 
2209 
g>part2_3_length = get_bits(&s>gb, 12);

2210 
g>big_values = get_bits(&s>gb, 9);

2211 
g>global_gain = get_bits(&s>gb, 8);

2212 
/* if MS stereo only is selected, we precompute the

2213 
1/sqrt(2) renormalization factor */

2214 
if ((s>mode_ext & (MODE_EXT_MS_STEREO  MODE_EXT_I_STEREO)) ==

2215 
MODE_EXT_MS_STEREO) 
2216 
g>global_gain = 2;

2217 
if (s>lsf)

2218 
g>scalefac_compress = get_bits(&s>gb, 9);

2219 
else

2220 
g>scalefac_compress = get_bits(&s>gb, 4);

2221 
blocksplit_flag = get_bits(&s>gb, 1);

2222 
if (blocksplit_flag) {

2223 
g>block_type = get_bits(&s>gb, 2);

2224 
if (g>block_type == 0) 
2225 
return 1; 
2226 
g>switch_point = get_bits(&s>gb, 1);

2227 
for(i=0;i<2;i++) 
2228 
g>table_select[i] = get_bits(&s>gb, 5);

2229 
for(i=0;i<3;i++) 
2230 
g>subblock_gain[i] = get_bits(&s>gb, 3);

2231 
/* compute huffman coded region sizes */

2232 
if (g>block_type == 2) 
2233 
g>region_size[0] = (36 / 2); 
2234 
else {

2235 
if (s>sample_rate_index <= 2) 
2236 
g>region_size[0] = (36 / 2); 
2237 
else if (s>sample_rate_index != 8) 
2238 
g>region_size[0] = (54 / 2); 
2239 
else

2240 
g>region_size[0] = (108 / 2); 
2241 
} 
2242 
g>region_size[1] = (576 / 2); 
2243 
} else {

2244 
int region_address1, region_address2, l;

2245 
g>block_type = 0;

2246 
g>switch_point = 0;

2247 
for(i=0;i<3;i++) 
2248 
g>table_select[i] = get_bits(&s>gb, 5);

2249 
/* compute huffman coded region sizes */

2250 
region_address1 = get_bits(&s>gb, 4);

2251 
region_address2 = get_bits(&s>gb, 3);

2252 
dprintf("region1=%d region2=%d\n",

2253 
region_address1, region_address2); 
2254 
g>region_size[0] =

2255 
band_index_long[s>sample_rate_index][region_address1 + 1] >> 1; 
2256 
l = region_address1 + region_address2 + 2;

2257 
/* should not overflow */

2258 
if (l > 22) 
2259 
l = 22;

2260 
g>region_size[1] =

2261 
band_index_long[s>sample_rate_index][l] >> 1;

2262 
} 
2263 
/* convert region offsets to region sizes and truncate

2264 
size to big_values */

2265 
g>region_size[2] = (576 / 2); 
2266 
j = 0;

2267 
for(i=0;i<3;i++) { 
2268 
k = g>region_size[i]; 
2269 
if (k > g>big_values)

2270 
k = g>big_values; 
2271 
g>region_size[i] = k  j; 
2272 
j = k; 
2273 
} 
2274  
2275 
/* compute band indexes */

2276 
if (g>block_type == 2) { 
2277 
if (g>switch_point) {

2278 
/* if switched mode, we handle the 36 first samples as

2279 
long blocks. For 8000Hz, we handle the 48 first

2280 
exponents as long blocks (XXX: check this!) */

2281 
if (s>sample_rate_index <= 2) 
2282 
g>long_end = 8;

2283 
else if (s>sample_rate_index != 8) 
2284 
g>long_end = 6;

2285 
else

2286 
g>long_end = 4; /* 8000 Hz */ 
2287 

2288 
if (s>sample_rate_index != 8) 
2289 
g>short_start = 3;

2290 
else

2291 
g>short_start = 2;

2292 
} else {

2293 
g>long_end = 0;

2294 
g>short_start = 0;

2295 
} 
2296 
} else {

2297 
g>short_start = 13;

2298 
g>long_end = 22;

2299 
} 
2300 

2301 
g>preflag = 0;

2302 
if (!s>lsf)

2303 
g>preflag = get_bits(&s>gb, 1);

2304 
g>scalefac_scale = get_bits(&s>gb, 1);

2305 
g>count1table_select = get_bits(&s>gb, 1);

2306 
dprintf("block_type=%d switch_point=%d\n",

2307 
g>block_type, g>switch_point); 
2308 
} 
2309 
} 
2310  
2311 
if (!s>adu_mode) {

2312 
/* now we get bits from the main_data_begin offset */

2313 
dprintf("seekback: %d\n", main_data_begin);

2314 
seek_to_maindata(s, main_data_begin); 
2315 
} 
2316  
2317 
for(gr=0;gr<nb_granules;gr++) { 
2318 
for(ch=0;ch<s>nb_channels;ch++) { 
2319 
g = &granules[ch][gr]; 
2320 

2321 
bits_pos = get_bits_count(&s>gb); 
2322 

2323 
if (!s>lsf) {

2324 
uint8_t *sc; 
2325 
int slen, slen1, slen2;

2326  
2327 
/* MPEG1 scale factors */

2328 
slen1 = slen_table[0][g>scalefac_compress];

2329 
slen2 = slen_table[1][g>scalefac_compress];

2330 
dprintf("slen1=%d slen2=%d\n", slen1, slen2);

2331 
if (g>block_type == 2) { 
2332 
n = g>switch_point ? 17 : 18; 
2333 
j = 0;

2334 
for(i=0;i<n;i++) 
2335 
g>scale_factors[j++] = get_bitsz(&s>gb, slen1); 
2336 
for(i=0;i<18;i++) 
2337 
g>scale_factors[j++] = get_bitsz(&s>gb, slen2); 
2338 
for(i=0;i<3;i++) 
2339 
g>scale_factors[j++] = 0;

2340 
} else {

2341 
sc = granules[ch][0].scale_factors;

2342 
j = 0;

2343 
for(k=0;k<4;k++) { 
2344 
n = (k == 0 ? 6 : 5); 
2345 
if ((g>scfsi & (0x8 >> k)) == 0) { 
2346 
slen = (k < 2) ? slen1 : slen2;

2347 
for(i=0;i<n;i++) 
2348 
g>scale_factors[j++] = get_bitsz(&s>gb, slen); 
2349 
} else {

2350 
/* simply copy from last granule */

2351 
for(i=0;i<n;i++) { 
2352 
g>scale_factors[j] = sc[j]; 
2353 
j++; 
2354 
} 
2355 
} 
2356 
} 
2357 
g>scale_factors[j++] = 0;

2358 
} 
2359 
#if defined(DEBUG)

2360 
{ 
2361 
printf("scfsi=%x gr=%d ch=%d scale_factors:\n",

2362 
g>scfsi, gr, ch); 
2363 
for(i=0;i<j;i++) 
2364 
printf(" %d", g>scale_factors[i]);

2365 
printf("\n");

2366 
} 
2367 
#endif

2368 
} else {

2369 
int tindex, tindex2, slen[4], sl, sf; 
2370  
2371 
/* LSF scale factors */

2372 
if (g>block_type == 2) { 
2373 
tindex = g>switch_point ? 2 : 1; 
2374 
} else {

2375 
tindex = 0;

2376 
} 
2377 
sf = g>scalefac_compress; 
2378 
if ((s>mode_ext & MODE_EXT_I_STEREO) && ch == 1) { 
2379 
/* intensity stereo case */

2380 
sf >>= 1;

2381 
if (sf < 180) { 
2382 
lsf_sf_expand(slen, sf, 6, 6, 0); 
2383 
tindex2 = 3;

2384 
} else if (sf < 244) { 
2385 
lsf_sf_expand(slen, sf  180, 4, 4, 0); 
2386 
tindex2 = 4;

2387 
} else {

2388 
lsf_sf_expand(slen, sf  244, 3, 0, 0); 
2389 
tindex2 = 5;

2390 
} 
2391 
} else {

2392 
/* normal case */

2393 
if (sf < 400) { 
2394 
lsf_sf_expand(slen, sf, 5, 4, 4); 
2395 
tindex2 = 0;

2396 
} else if (sf < 500) { 
2397 
lsf_sf_expand(slen, sf  400, 5, 4, 0); 
2398 
tindex2 = 1;

2399 
} else {

2400 
lsf_sf_expand(slen, sf  500, 3, 0, 0); 
2401 
tindex2 = 2;

2402 
g>preflag = 1;

2403 
} 
2404 
} 
2405  
2406 
j = 0;

2407 
for(k=0;k<4;k++) { 
2408 
n = lsf_nsf_table[tindex2][tindex][k]; 
2409 
sl = slen[k]; 
2410 
for(i=0;i<n;i++) 
2411 
g>scale_factors[j++] = get_bitsz(&s>gb, sl); 
2412 
} 
2413 
/* XXX: should compute exact size */

2414 
for(;j<40;j++) 
2415 
g>scale_factors[j] = 0;

2416 
#if defined(DEBUG)

2417 
{ 
2418 
printf("gr=%d ch=%d scale_factors:\n",

2419 
gr, ch); 
2420 
for(i=0;i<40;i++) 
2421 
printf(" %d", g>scale_factors[i]);

2422 
printf("\n");

2423 
} 
2424 
#endif

2425 
} 
2426  
2427 
exponents_from_scale_factors(s, g, exponents); 
2428  
2429 
/* read Huffman coded residue */

2430 
if (huffman_decode(s, g, exponents,

2431 
bits_pos + g>part2_3_length) < 0)

2432 
return 1; 
2433 
#if defined(DEBUG)

2434 
sample_dump(0, g>sb_hybrid, 576); 
2435 
#endif

2436  
2437 
/* skip extension bits */

2438 
bits_left = g>part2_3_length  (get_bits_count(&s>gb)  bits_pos); 
2439 
if (bits_left < 0) { 
2440 
dprintf("bits_left=%d\n", bits_left);

2441 
return 1; 
2442 
} 
2443 
while (bits_left >= 16) { 
2444 
skip_bits(&s>gb, 16);

2445 
bits_left = 16;

2446 
} 
2447 
if (bits_left > 0) 
2448 
skip_bits(&s>gb, bits_left); 
2449 
} /* ch */

2450  
2451 
if (s>nb_channels == 2) 
2452 
compute_stereo(s, &granules[0][gr], &granules[1][gr]); 
2453  
2454 
for(ch=0;ch<s>nb_channels;ch++) { 
2455 
g = &granules[ch][gr]; 
2456  
2457 
reorder_block(s, g); 
2458 
#if defined(DEBUG)

2459 
sample_dump(0, g>sb_hybrid, 576); 
2460 
#endif

2461 
s>compute_antialias(s, g); 
2462 
#if defined(DEBUG)

2463 
sample_dump(1, g>sb_hybrid, 576); 
2464 
#endif

2465 
compute_imdct(s, g, &s>sb_samples[ch][18 * gr][0], s>mdct_buf[ch]); 
2466 
#if defined(DEBUG)

2467 
sample_dump(2, &s>sb_samples[ch][18 * gr][0], 576); 
2468 
#endif

2469 
} 
2470 
} /* gr */

2471 
return nb_granules * 18; 
2472 
} 
2473  
2474 
static int mp_decode_frame(MPADecodeContext *s, 
2475 
short *samples)

2476 
{ 
2477 
int i, nb_frames, ch;

2478 
short *samples_ptr;

2479  
2480 
init_get_bits(&s>gb, s>inbuf + HEADER_SIZE, 
2481 
(s>inbuf_ptr  s>inbuf  HEADER_SIZE)*8);

2482 

2483 
/* skip error protection field */

2484 
if (s>error_protection)

2485 
get_bits(&s>gb, 16);

2486  
2487 
dprintf("frame %d:\n", s>frame_count);

2488 
switch(s>layer) {

2489 
case 1: 
2490 
nb_frames = mp_decode_layer1(s); 
2491 
break;

2492 
case 2: 
2493 
nb_frames = mp_decode_layer2(s); 
2494 
break;

2495 
case 3: 
2496 
default:

2497 
nb_frames = mp_decode_layer3(s); 
2498 
break;

2499 
} 
2500 
#if defined(DEBUG)

2501 
for(i=0;i<nb_frames;i++) { 
2502 
for(ch=0;ch<s>nb_channels;ch++) { 
2503 
int j;

2504 
printf("%d%d:", i, ch);

2505 
for(j=0;j<SBLIMIT;j++) 
2506 
printf(" %0.6f", (double)s>sb_samples[ch][i][j] / FRAC_ONE); 
2507 
printf("\n");

2508 
} 
2509 
} 
2510 
#endif

2511 
/* apply the synthesis filter */

2512 
for(ch=0;ch<s>nb_channels;ch++) { 
2513 
samples_ptr = samples + ch; 
2514 
for(i=0;i<nb_frames;i++) { 
2515 
ff_mpa_synth_filter(s>synth_buf[ch], &(s>synth_buf_offset[ch]), 
2516 
window, 
2517 
samples_ptr, s>nb_channels, 
2518 
s>sb_samples[ch][i]); 
2519 
samples_ptr += 32 * s>nb_channels;

2520 
} 
2521 
} 
2522 
#ifdef DEBUG

2523 
s>frame_count++; 
2524 
#endif

2525 
return nb_frames * 32 * sizeof(short) * s>nb_channels; 
2526 
} 
2527  
2528 
static int decode_frame(AVCodecContext * avctx, 
2529 
void *data, int *data_size, 
2530 
uint8_t * buf, int buf_size)

2531 
{ 
2532 
MPADecodeContext *s = avctx>priv_data; 
2533 
uint32_t header; 
2534 
uint8_t *buf_ptr; 
2535 
int len, out_size;

2536 
short *out_samples = data;

2537  
2538 
buf_ptr = buf; 
2539 
while (buf_size > 0) { 
2540 
len = s>inbuf_ptr  s>inbuf; 
2541 
if (s>frame_size == 0) { 
2542 
/* special case for next header for first frame in free

2543 
format case (XXX: find a simpler method) */

2544 
if (s>free_format_next_header != 0) { 
2545 
s>inbuf[0] = s>free_format_next_header >> 24; 
2546 
s>inbuf[1] = s>free_format_next_header >> 16; 
2547 
s>inbuf[2] = s>free_format_next_header >> 8; 
2548 
s>inbuf[3] = s>free_format_next_header;

2549 
s>inbuf_ptr = s>inbuf + 4;

2550 
s>free_format_next_header = 0;

2551 
goto got_header;

2552 
} 
2553 
/* no header seen : find one. We need at least HEADER_SIZE

2554 
bytes to parse it */

2555 
len = HEADER_SIZE  len; 
2556 
if (len > buf_size)

2557 
len = buf_size; 
2558 
if (len > 0) { 
2559 
memcpy(s>inbuf_ptr, buf_ptr, len); 
2560 
buf_ptr += len; 
2561 
buf_size = len; 
2562 
s>inbuf_ptr += len; 
2563 
} 
2564 
if ((s>inbuf_ptr  s>inbuf) >= HEADER_SIZE) {

2565 
got_header:

2566 
header = (s>inbuf[0] << 24)  (s>inbuf[1] << 16)  
2567 
(s>inbuf[2] << 8)  s>inbuf[3]; 
2568  
2569 
if (check_header(header) < 0) { 
2570 
/* no sync found : move by one byte (inefficient, but simple!) */

2571 
memmove(s>inbuf, s>inbuf + 1, s>inbuf_ptr  s>inbuf  1); 
2572 
s>inbuf_ptr; 
2573 
dprintf("skip %x\n", header);

2574 
/* reset free format frame size to give a chance

2575 
to get a new bitrate */

2576 
s>free_format_frame_size = 0;

2577 
} else {

2578 
if (decode_header(s, header) == 1) { 
2579 
/* free format: prepare to compute frame size */

2580 
s>frame_size = 1;

2581 
} 
2582 
/* update codec info */

2583 
avctx>sample_rate = s>sample_rate; 
2584 
avctx>channels = s>nb_channels; 
2585 
avctx>bit_rate = s>bit_rate; 
2586 
avctx>sub_id = s>layer; 
2587 
switch(s>layer) {

2588 
case 1: 
2589 
avctx>frame_size = 384;

2590 
break;

2591 
case 2: 
2592 
avctx>frame_size = 1152;

2593 
break;

2594 
case 3: 
2595 
if (s>lsf)

2596 
avctx>frame_size = 576;

2597 
else

2598 
avctx>frame_size = 1152;

2599 
break;

2600 
} 
2601 
} 
2602 
} 
2603 
} else if (s>frame_size == 1) { 
2604 
/* free format : find next sync to compute frame size */

2605 
len = MPA_MAX_CODED_FRAME_SIZE  len; 
2606 
if (len > buf_size)

2607 
len = buf_size; 
2608 
if (len == 0) { 
2609 
/* frame too long: resync */

2610 
s>frame_size = 0;

2611 
memmove(s>inbuf, s>inbuf + 1, s>inbuf_ptr  s>inbuf  1); 
2612 
s>inbuf_ptr; 
2613 
} else {

2614 
uint8_t *p, *pend; 
2615 
uint32_t header1; 
2616 
int padding;

2617  
2618 
memcpy(s>inbuf_ptr, buf_ptr, len); 
2619 
/* check for header */

2620 
p = s>inbuf_ptr  3;

2621 
pend = s>inbuf_ptr + len  4;

2622 
while (p <= pend) {

2623 
header = (p[0] << 24)  (p[1] << 16)  
2624 
(p[2] << 8)  p[3]; 
2625 
header1 = (s>inbuf[0] << 24)  (s>inbuf[1] << 16)  
2626 
(s>inbuf[2] << 8)  s>inbuf[3]; 
2627 
/* check with high probability that we have a

2628 
valid header */

2629 
if ((header & SAME_HEADER_MASK) ==

2630 
(header1 & SAME_HEADER_MASK)) { 
2631 
/* header found: update pointers */

2632 
len = (p + 4)  s>inbuf_ptr;

2633 
buf_ptr += len; 
2634 
buf_size = len; 
2635 
s>inbuf_ptr = p; 
2636 
/* compute frame size */

2637 
s>free_format_next_header = header; 
2638 
s>free_format_frame_size = s>inbuf_ptr  s>inbuf; 
2639 
padding = (header1 >> 9) & 1; 
2640 
if (s>layer == 1) 
2641 
s>free_format_frame_size = padding * 4;

2642 
else

2643 
s>free_format_frame_size = padding; 
2644 
dprintf("free frame size=%d padding=%d\n",

2645 
s>free_format_frame_size, padding); 
2646 
decode_header(s, header1); 
2647 
goto next_data;

2648 
} 
2649 
p++; 
2650 
} 
2651 
/* not found: simply increase pointers */

2652 
buf_ptr += len; 
2653 
s>inbuf_ptr += len; 
2654 
buf_size = len; 
2655 
} 
2656 
} else if (len < s>frame_size) { 
2657 
if (s>frame_size > MPA_MAX_CODED_FRAME_SIZE)

2658 
s>frame_size = MPA_MAX_CODED_FRAME_SIZE; 
2659 
len = s>frame_size  len; 
2660 
if (len > buf_size)

2661 
len = buf_size; 
2662 
memcpy(s>inbuf_ptr, buf_ptr, len); 
2663 
buf_ptr += len; 
2664 
s>inbuf_ptr += len; 
2665 
buf_size = len; 
2666 
} 
2667 
next_data:

2668 
if (s>frame_size > 0 && 
2669 
(s>inbuf_ptr  s>inbuf) >= s>frame_size) { 
2670 
if (avctx>parse_only) {

2671 
/* simply return the frame data */

2672 
*(uint8_t **)data = s>inbuf; 
2673 
out_size = s>inbuf_ptr  s>inbuf; 
2674 
} else {

2675 
out_size = mp_decode_frame(s, out_samples); 
2676 
} 
2677 
s>inbuf_ptr = s>inbuf; 
2678 
s>frame_size = 0;

2679 
*data_size = out_size; 
2680 
break;

2681 
} 
2682 
} 
2683 
return buf_ptr  buf;

2684 
} 
2685  
2686  
2687 
static int decode_frame_adu(AVCodecContext * avctx, 
2688 
void *data, int *data_size, 
2689 
uint8_t * buf, int buf_size)

2690 
{ 
2691 
MPADecodeContext *s = avctx>priv_data; 
2692 
uint32_t header; 
2693 
int len, out_size;

2694 
short *out_samples = data;

2695  
2696 
len = buf_size; 
2697  
2698 
// Discard too short frames

2699 
if (buf_size < HEADER_SIZE) {

2700 
*data_size = 0;

2701 
return buf_size;

2702 
} 
2703  
2704  
2705 
if (len > MPA_MAX_CODED_FRAME_SIZE)

2706 
len = MPA_MAX_CODED_FRAME_SIZE; 
2707  
2708 
memcpy(s>inbuf, buf, len); 
2709 
s>inbuf_ptr = s>inbuf + len; 
2710  
2711 
// Get header and restore sync word

2712 
header = (s>inbuf[0] << 24)  (s>inbuf[1] << 16)  
2713 
(s>inbuf[2] << 8)  s>inbuf[3]  0xffe00000; 
2714  
2715 
if (check_header(header) < 0) { // Bad header, discard frame 
2716 
*data_size = 0;

2717 
return buf_size;

2718 
} 
2719  
2720 
decode_header(s, header); 
2721 
/* update codec info */

2722 
avctx>sample_rate = s>sample_rate; 
2723 
avctx>channels = s>nb_channels; 
2724 
avctx>bit_rate = s>bit_rate; 
2725 
avctx>sub_id = s>layer; 
2726  
2727 
avctx>frame_size=s>frame_size = len; 
2728  
2729 
if (avctx>parse_only) {

2730 
/* simply return the frame data */

2731 
*(uint8_t **)data = s>inbuf; 
2732 
out_size = s>inbuf_ptr  s>inbuf; 
2733 
} else {

2734 
out_size = mp_decode_frame(s, out_samples); 
2735 
} 
2736  
2737 
*data_size = out_size; 
2738 
return buf_size;

2739 
} 
2740  
2741  
2742 
AVCodec mp2_decoder = 
2743 
{ 
2744 
"mp2",

2745 
CODEC_TYPE_AUDIO, 
2746 
CODEC_ID_MP2, 
2747 
sizeof(MPADecodeContext),

2748 
decode_init, 
2749 
NULL,

2750 
NULL,

2751 
decode_frame, 
2752 
CODEC_CAP_PARSE_ONLY, 
2753 
}; 
2754  
2755 
AVCodec mp3_decoder = 
2756 
{ 
2757 
"mp3",

2758 
CODEC_TYPE_AUDIO, 
2759 
CODEC_ID_MP3, 
2760 
sizeof(MPADecodeContext),

2761 
decode_init, 
2762 
NULL,

2763 
NULL,

2764 
decode_frame, 
2765 
CODEC_CAP_PARSE_ONLY, 
2766 
}; 
2767  
2768 
AVCodec mp3adu_decoder = 
2769 
{ 
2770 
"mp3adu",

2771 
CODEC_TYPE_AUDIO, 
2772 
CODEC_ID_MP3ADU, 
2773 
sizeof(MPADecodeContext),

2774 
decode_init, 
2775 
NULL,

2776 
NULL,

2777 
decode_frame_adu, 
2778 
CODEC_CAP_PARSE_ONLY, 
2779 
}; 