| 1 | /* |
| 2 | * WMA compatible decoder |
| 3 | * Copyright (c) 2002 The FFmpeg Project |
| 4 | * |
| 5 | * This file is part of FFmpeg. |
| 6 | * |
| 7 | * FFmpeg is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU Lesser General Public |
| 9 | * License as published by the Free Software Foundation; either |
| 10 | * version 2.1 of the License, or (at your option) any later version. |
| 11 | * |
| 12 | * FFmpeg is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 15 | * Lesser General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU Lesser General Public |
| 18 | * License along with FFmpeg; if not, write to the Free Software |
| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 20 | */ |
| 21 | |
| 22 | /** |
| 23 | * @file |
| 24 | * WMA compatible decoder. |
| 25 | * This decoder handles Microsoft Windows Media Audio data, versions 1 & 2. |
| 26 | * WMA v1 is identified by audio format 0x160 in Microsoft media files |
| 27 | * (ASF/AVI/WAV). WMA v2 is identified by audio format 0x161. |
| 28 | * |
| 29 | * To use this decoder, a calling application must supply the extra data |
| 30 | * bytes provided with the WMA data. These are the extra, codec-specific |
| 31 | * bytes at the end of a WAVEFORMATEX data structure. Transmit these bytes |
| 32 | * to the decoder using the extradata[_size] fields in AVCodecContext. There |
| 33 | * should be 4 extra bytes for v1 data and 6 extra bytes for v2 data. |
| 34 | */ |
| 35 | |
| 36 | #include "libavutil/attributes.h" |
| 37 | |
| 38 | #include "avcodec.h" |
| 39 | #include "internal.h" |
| 40 | #include "wma.h" |
| 41 | |
| 42 | #undef NDEBUG |
| 43 | #include <assert.h> |
| 44 | |
| 45 | #define EXPVLCBITS 8 |
| 46 | #define EXPMAX ((19 + EXPVLCBITS - 1) / EXPVLCBITS) |
| 47 | |
| 48 | #define HGAINVLCBITS 9 |
| 49 | #define HGAINMAX ((13 + HGAINVLCBITS - 1) / HGAINVLCBITS) |
| 50 | |
| 51 | static void wma_lsp_to_curve_init(WMACodecContext *s, int frame_len); |
| 52 | |
| 53 | #ifdef TRACE |
| 54 | static void dump_floats(WMACodecContext *s, const char *name, |
| 55 | int prec, const float *tab, int n) |
| 56 | { |
| 57 | int i; |
| 58 | |
| 59 | tprintf(s->avctx, "%s[%d]:\n", name, n); |
| 60 | for (i = 0; i < n; i++) { |
| 61 | if ((i & 7) == 0) |
| 62 | tprintf(s->avctx, "%4d: ", i); |
| 63 | tprintf(s->avctx, " %8.*f", prec, tab[i]); |
| 64 | if ((i & 7) == 7) |
| 65 | tprintf(s->avctx, "\n"); |
| 66 | } |
| 67 | if ((i & 7) != 0) |
| 68 | tprintf(s->avctx, "\n"); |
| 69 | } |
| 70 | #endif /* TRACE */ |
| 71 | |
| 72 | static av_cold int wma_decode_init(AVCodecContext *avctx) |
| 73 | { |
| 74 | WMACodecContext *s = avctx->priv_data; |
| 75 | int i, flags2; |
| 76 | uint8_t *extradata; |
| 77 | |
| 78 | if (!avctx->block_align) { |
| 79 | av_log(avctx, AV_LOG_ERROR, "block_align is not set\n"); |
| 80 | return AVERROR(EINVAL); |
| 81 | } |
| 82 | |
| 83 | s->avctx = avctx; |
| 84 | |
| 85 | /* extract flag infos */ |
| 86 | flags2 = 0; |
| 87 | extradata = avctx->extradata; |
| 88 | if (avctx->codec->id == AV_CODEC_ID_WMAV1 && avctx->extradata_size >= 4) |
| 89 | flags2 = AV_RL16(extradata + 2); |
| 90 | else if (avctx->codec->id == AV_CODEC_ID_WMAV2 && avctx->extradata_size >= 6) |
| 91 | flags2 = AV_RL16(extradata + 4); |
| 92 | |
| 93 | s->use_exp_vlc = flags2 & 0x0001; |
| 94 | s->use_bit_reservoir = flags2 & 0x0002; |
| 95 | s->use_variable_block_len = flags2 & 0x0004; |
| 96 | |
| 97 | if (avctx->codec->id == AV_CODEC_ID_WMAV2 && avctx->extradata_size >= 8){ |
| 98 | if (AV_RL16(extradata+4)==0xd && s->use_variable_block_len){ |
| 99 | av_log(avctx, AV_LOG_WARNING, "Disabling use_variable_block_len, if this fails contact the ffmpeg developers and send us the file\n"); |
| 100 | s->use_variable_block_len= 0; // this fixes issue1503 |
| 101 | } |
| 102 | } |
| 103 | |
| 104 | for (i=0; i<MAX_CHANNELS; i++) |
| 105 | s->max_exponent[i] = 1.0; |
| 106 | |
| 107 | if (ff_wma_init(avctx, flags2) < 0) |
| 108 | return -1; |
| 109 | |
| 110 | /* init MDCT */ |
| 111 | for (i = 0; i < s->nb_block_sizes; i++) |
| 112 | ff_mdct_init(&s->mdct_ctx[i], s->frame_len_bits - i + 1, 1, 1.0 / 32768.0); |
| 113 | |
| 114 | if (s->use_noise_coding) { |
| 115 | init_vlc(&s->hgain_vlc, HGAINVLCBITS, sizeof(ff_wma_hgain_huffbits), |
| 116 | ff_wma_hgain_huffbits, 1, 1, |
| 117 | ff_wma_hgain_huffcodes, 2, 2, 0); |
| 118 | } |
| 119 | |
| 120 | if (s->use_exp_vlc) |
| 121 | init_vlc(&s->exp_vlc, EXPVLCBITS, sizeof(ff_aac_scalefactor_bits), // FIXME move out of context |
| 122 | ff_aac_scalefactor_bits, 1, 1, |
| 123 | ff_aac_scalefactor_code, 4, 4, 0); |
| 124 | else |
| 125 | wma_lsp_to_curve_init(s, s->frame_len); |
| 126 | |
| 127 | avctx->sample_fmt = AV_SAMPLE_FMT_FLTP; |
| 128 | |
| 129 | return 0; |
| 130 | } |
| 131 | |
| 132 | /** |
| 133 | * compute x^-0.25 with an exponent and mantissa table. We use linear |
| 134 | * interpolation to reduce the mantissa table size at a small speed |
| 135 | * expense (linear interpolation approximately doubles the number of |
| 136 | * bits of precision). |
| 137 | */ |
| 138 | static inline float pow_m1_4(WMACodecContext *s, float x) |
| 139 | { |
| 140 | union { |
| 141 | float f; |
| 142 | unsigned int v; |
| 143 | } u, t; |
| 144 | unsigned int e, m; |
| 145 | float a, b; |
| 146 | |
| 147 | u.f = x; |
| 148 | e = u.v >> 23; |
| 149 | m = (u.v >> (23 - LSP_POW_BITS)) & ((1 << LSP_POW_BITS) - 1); |
| 150 | /* build interpolation scale: 1 <= t < 2. */ |
| 151 | t.v = ((u.v << LSP_POW_BITS) & ((1 << 23) - 1)) | (127 << 23); |
| 152 | a = s->lsp_pow_m_table1[m]; |
| 153 | b = s->lsp_pow_m_table2[m]; |
| 154 | return s->lsp_pow_e_table[e] * (a + b * t.f); |
| 155 | } |
| 156 | |
| 157 | static av_cold void wma_lsp_to_curve_init(WMACodecContext *s, int frame_len) |
| 158 | { |
| 159 | float wdel, a, b; |
| 160 | int i, e, m; |
| 161 | |
| 162 | wdel = M_PI / frame_len; |
| 163 | for (i = 0; i < frame_len; i++) |
| 164 | s->lsp_cos_table[i] = 2.0f * cos(wdel * i); |
| 165 | |
| 166 | /* tables for x^-0.25 computation */ |
| 167 | for (i = 0; i < 256; i++) { |
| 168 | e = i - 126; |
| 169 | s->lsp_pow_e_table[i] = pow(2.0, e * -0.25); |
| 170 | } |
| 171 | |
| 172 | /* NOTE: these two tables are needed to avoid two operations in |
| 173 | * pow_m1_4 */ |
| 174 | b = 1.0; |
| 175 | for (i = (1 << LSP_POW_BITS) - 1; i >= 0; i--) { |
| 176 | m = (1 << LSP_POW_BITS) + i; |
| 177 | a = (float) m * (0.5 / (1 << LSP_POW_BITS)); |
| 178 | a = pow(a, -0.25); |
| 179 | s->lsp_pow_m_table1[i] = 2 * a - b; |
| 180 | s->lsp_pow_m_table2[i] = b - a; |
| 181 | b = a; |
| 182 | } |
| 183 | } |
| 184 | |
| 185 | /** |
| 186 | * NOTE: We use the same code as Vorbis here |
| 187 | * @todo optimize it further with SSE/3Dnow |
| 188 | */ |
| 189 | static void wma_lsp_to_curve(WMACodecContext *s, float *out, float *val_max_ptr, |
| 190 | int n, float *lsp) |
| 191 | { |
| 192 | int i, j; |
| 193 | float p, q, w, v, val_max; |
| 194 | |
| 195 | val_max = 0; |
| 196 | for (i = 0; i < n; i++) { |
| 197 | p = 0.5f; |
| 198 | q = 0.5f; |
| 199 | w = s->lsp_cos_table[i]; |
| 200 | for (j = 1; j < NB_LSP_COEFS; j += 2) { |
| 201 | q *= w - lsp[j - 1]; |
| 202 | p *= w - lsp[j]; |
| 203 | } |
| 204 | p *= p * (2.0f - w); |
| 205 | q *= q * (2.0f + w); |
| 206 | v = p + q; |
| 207 | v = pow_m1_4(s, v); |
| 208 | if (v > val_max) |
| 209 | val_max = v; |
| 210 | out[i] = v; |
| 211 | } |
| 212 | *val_max_ptr = val_max; |
| 213 | } |
| 214 | |
| 215 | /** |
| 216 | * decode exponents coded with LSP coefficients (same idea as Vorbis) |
| 217 | */ |
| 218 | static void decode_exp_lsp(WMACodecContext *s, int ch) |
| 219 | { |
| 220 | float lsp_coefs[NB_LSP_COEFS]; |
| 221 | int val, i; |
| 222 | |
| 223 | for (i = 0; i < NB_LSP_COEFS; i++) { |
| 224 | if (i == 0 || i >= 8) |
| 225 | val = get_bits(&s->gb, 3); |
| 226 | else |
| 227 | val = get_bits(&s->gb, 4); |
| 228 | lsp_coefs[i] = ff_wma_lsp_codebook[i][val]; |
| 229 | } |
| 230 | |
| 231 | wma_lsp_to_curve(s, s->exponents[ch], &s->max_exponent[ch], |
| 232 | s->block_len, lsp_coefs); |
| 233 | } |
| 234 | |
| 235 | /** pow(10, i / 16.0) for i in -60..95 */ |
| 236 | static const float pow_tab[] = { |
| 237 | 1.7782794100389e-04, 2.0535250264571e-04, |
| 238 | 2.3713737056617e-04, 2.7384196342644e-04, |
| 239 | 3.1622776601684e-04, 3.6517412725484e-04, |
| 240 | 4.2169650342858e-04, 4.8696752516586e-04, |
| 241 | 5.6234132519035e-04, 6.4938163157621e-04, |
| 242 | 7.4989420933246e-04, 8.6596432336006e-04, |
| 243 | 1.0000000000000e-03, 1.1547819846895e-03, |
| 244 | 1.3335214321633e-03, 1.5399265260595e-03, |
| 245 | 1.7782794100389e-03, 2.0535250264571e-03, |
| 246 | 2.3713737056617e-03, 2.7384196342644e-03, |
| 247 | 3.1622776601684e-03, 3.6517412725484e-03, |
| 248 | 4.2169650342858e-03, 4.8696752516586e-03, |
| 249 | 5.6234132519035e-03, 6.4938163157621e-03, |
| 250 | 7.4989420933246e-03, 8.6596432336006e-03, |
| 251 | 1.0000000000000e-02, 1.1547819846895e-02, |
| 252 | 1.3335214321633e-02, 1.5399265260595e-02, |
| 253 | 1.7782794100389e-02, 2.0535250264571e-02, |
| 254 | 2.3713737056617e-02, 2.7384196342644e-02, |
| 255 | 3.1622776601684e-02, 3.6517412725484e-02, |
| 256 | 4.2169650342858e-02, 4.8696752516586e-02, |
| 257 | 5.6234132519035e-02, 6.4938163157621e-02, |
| 258 | 7.4989420933246e-02, 8.6596432336007e-02, |
| 259 | 1.0000000000000e-01, 1.1547819846895e-01, |
| 260 | 1.3335214321633e-01, 1.5399265260595e-01, |
| 261 | 1.7782794100389e-01, 2.0535250264571e-01, |
| 262 | 2.3713737056617e-01, 2.7384196342644e-01, |
| 263 | 3.1622776601684e-01, 3.6517412725484e-01, |
| 264 | 4.2169650342858e-01, 4.8696752516586e-01, |
| 265 | 5.6234132519035e-01, 6.4938163157621e-01, |
| 266 | 7.4989420933246e-01, 8.6596432336007e-01, |
| 267 | 1.0000000000000e+00, 1.1547819846895e+00, |
| 268 | 1.3335214321633e+00, 1.5399265260595e+00, |
| 269 | 1.7782794100389e+00, 2.0535250264571e+00, |
| 270 | 2.3713737056617e+00, 2.7384196342644e+00, |
| 271 | 3.1622776601684e+00, 3.6517412725484e+00, |
| 272 | 4.2169650342858e+00, 4.8696752516586e+00, |
| 273 | 5.6234132519035e+00, 6.4938163157621e+00, |
| 274 | 7.4989420933246e+00, 8.6596432336007e+00, |
| 275 | 1.0000000000000e+01, 1.1547819846895e+01, |
| 276 | 1.3335214321633e+01, 1.5399265260595e+01, |
| 277 | 1.7782794100389e+01, 2.0535250264571e+01, |
| 278 | 2.3713737056617e+01, 2.7384196342644e+01, |
| 279 | 3.1622776601684e+01, 3.6517412725484e+01, |
| 280 | 4.2169650342858e+01, 4.8696752516586e+01, |
| 281 | 5.6234132519035e+01, 6.4938163157621e+01, |
| 282 | 7.4989420933246e+01, 8.6596432336007e+01, |
| 283 | 1.0000000000000e+02, 1.1547819846895e+02, |
| 284 | 1.3335214321633e+02, 1.5399265260595e+02, |
| 285 | 1.7782794100389e+02, 2.0535250264571e+02, |
| 286 | 2.3713737056617e+02, 2.7384196342644e+02, |
| 287 | 3.1622776601684e+02, 3.6517412725484e+02, |
| 288 | 4.2169650342858e+02, 4.8696752516586e+02, |
| 289 | 5.6234132519035e+02, 6.4938163157621e+02, |
| 290 | 7.4989420933246e+02, 8.6596432336007e+02, |
| 291 | 1.0000000000000e+03, 1.1547819846895e+03, |
| 292 | 1.3335214321633e+03, 1.5399265260595e+03, |
| 293 | 1.7782794100389e+03, 2.0535250264571e+03, |
| 294 | 2.3713737056617e+03, 2.7384196342644e+03, |
| 295 | 3.1622776601684e+03, 3.6517412725484e+03, |
| 296 | 4.2169650342858e+03, 4.8696752516586e+03, |
| 297 | 5.6234132519035e+03, 6.4938163157621e+03, |
| 298 | 7.4989420933246e+03, 8.6596432336007e+03, |
| 299 | 1.0000000000000e+04, 1.1547819846895e+04, |
| 300 | 1.3335214321633e+04, 1.5399265260595e+04, |
| 301 | 1.7782794100389e+04, 2.0535250264571e+04, |
| 302 | 2.3713737056617e+04, 2.7384196342644e+04, |
| 303 | 3.1622776601684e+04, 3.6517412725484e+04, |
| 304 | 4.2169650342858e+04, 4.8696752516586e+04, |
| 305 | 5.6234132519035e+04, 6.4938163157621e+04, |
| 306 | 7.4989420933246e+04, 8.6596432336007e+04, |
| 307 | 1.0000000000000e+05, 1.1547819846895e+05, |
| 308 | 1.3335214321633e+05, 1.5399265260595e+05, |
| 309 | 1.7782794100389e+05, 2.0535250264571e+05, |
| 310 | 2.3713737056617e+05, 2.7384196342644e+05, |
| 311 | 3.1622776601684e+05, 3.6517412725484e+05, |
| 312 | 4.2169650342858e+05, 4.8696752516586e+05, |
| 313 | 5.6234132519035e+05, 6.4938163157621e+05, |
| 314 | 7.4989420933246e+05, 8.6596432336007e+05, |
| 315 | }; |
| 316 | |
| 317 | /** |
| 318 | * decode exponents coded with VLC codes |
| 319 | */ |
| 320 | static int decode_exp_vlc(WMACodecContext *s, int ch) |
| 321 | { |
| 322 | int last_exp, n, code; |
| 323 | const uint16_t *ptr; |
| 324 | float v, max_scale; |
| 325 | uint32_t *q, *q_end, iv; |
| 326 | const float *ptab = pow_tab + 60; |
| 327 | const uint32_t *iptab = (const uint32_t *) ptab; |
| 328 | |
| 329 | ptr = s->exponent_bands[s->frame_len_bits - s->block_len_bits]; |
| 330 | q = (uint32_t *) s->exponents[ch]; |
| 331 | q_end = q + s->block_len; |
| 332 | max_scale = 0; |
| 333 | if (s->version == 1) { |
| 334 | last_exp = get_bits(&s->gb, 5) + 10; |
| 335 | v = ptab[last_exp]; |
| 336 | iv = iptab[last_exp]; |
| 337 | max_scale = v; |
| 338 | n = *ptr++; |
| 339 | switch (n & 3) do { |
| 340 | case 0: *q++ = iv; |
| 341 | case 3: *q++ = iv; |
| 342 | case 2: *q++ = iv; |
| 343 | case 1: *q++ = iv; |
| 344 | } while ((n -= 4) > 0); |
| 345 | } else |
| 346 | last_exp = 36; |
| 347 | |
| 348 | while (q < q_end) { |
| 349 | code = get_vlc2(&s->gb, s->exp_vlc.table, EXPVLCBITS, EXPMAX); |
| 350 | if (code < 0) { |
| 351 | av_log(s->avctx, AV_LOG_ERROR, "Exponent vlc invalid\n"); |
| 352 | return -1; |
| 353 | } |
| 354 | /* NOTE: this offset is the same as MPEG4 AAC ! */ |
| 355 | last_exp += code - 60; |
| 356 | if ((unsigned) last_exp + 60 >= FF_ARRAY_ELEMS(pow_tab)) { |
| 357 | av_log(s->avctx, AV_LOG_ERROR, "Exponent out of range: %d\n", |
| 358 | last_exp); |
| 359 | return -1; |
| 360 | } |
| 361 | v = ptab[last_exp]; |
| 362 | iv = iptab[last_exp]; |
| 363 | if (v > max_scale) |
| 364 | max_scale = v; |
| 365 | n = *ptr++; |
| 366 | switch (n & 3) do { |
| 367 | case 0: *q++ = iv; |
| 368 | case 3: *q++ = iv; |
| 369 | case 2: *q++ = iv; |
| 370 | case 1: *q++ = iv; |
| 371 | } while ((n -= 4) > 0); |
| 372 | } |
| 373 | s->max_exponent[ch] = max_scale; |
| 374 | return 0; |
| 375 | } |
| 376 | |
| 377 | /** |
| 378 | * Apply MDCT window and add into output. |
| 379 | * |
| 380 | * We ensure that when the windows overlap their squared sum |
| 381 | * is always 1 (MDCT reconstruction rule). |
| 382 | */ |
| 383 | static void wma_window(WMACodecContext *s, float *out) |
| 384 | { |
| 385 | float *in = s->output; |
| 386 | int block_len, bsize, n; |
| 387 | |
| 388 | /* left part */ |
| 389 | if (s->block_len_bits <= s->prev_block_len_bits) { |
| 390 | block_len = s->block_len; |
| 391 | bsize = s->frame_len_bits - s->block_len_bits; |
| 392 | |
| 393 | s->fdsp->vector_fmul_add(out, in, s->windows[bsize], |
| 394 | out, block_len); |
| 395 | } else { |
| 396 | block_len = 1 << s->prev_block_len_bits; |
| 397 | n = (s->block_len - block_len) / 2; |
| 398 | bsize = s->frame_len_bits - s->prev_block_len_bits; |
| 399 | |
| 400 | s->fdsp->vector_fmul_add(out + n, in + n, s->windows[bsize], |
| 401 | out + n, block_len); |
| 402 | |
| 403 | memcpy(out + n + block_len, in + n + block_len, n * sizeof(float)); |
| 404 | } |
| 405 | |
| 406 | out += s->block_len; |
| 407 | in += s->block_len; |
| 408 | |
| 409 | /* right part */ |
| 410 | if (s->block_len_bits <= s->next_block_len_bits) { |
| 411 | block_len = s->block_len; |
| 412 | bsize = s->frame_len_bits - s->block_len_bits; |
| 413 | |
| 414 | s->fdsp->vector_fmul_reverse(out, in, s->windows[bsize], block_len); |
| 415 | } else { |
| 416 | block_len = 1 << s->next_block_len_bits; |
| 417 | n = (s->block_len - block_len) / 2; |
| 418 | bsize = s->frame_len_bits - s->next_block_len_bits; |
| 419 | |
| 420 | memcpy(out, in, n * sizeof(float)); |
| 421 | |
| 422 | s->fdsp->vector_fmul_reverse(out + n, in + n, s->windows[bsize], |
| 423 | block_len); |
| 424 | |
| 425 | memset(out + n + block_len, 0, n * sizeof(float)); |
| 426 | } |
| 427 | } |
| 428 | |
| 429 | /** |
| 430 | * @return 0 if OK. 1 if last block of frame. return -1 if |
| 431 | * unrecorrable error. |
| 432 | */ |
| 433 | static int wma_decode_block(WMACodecContext *s) |
| 434 | { |
| 435 | int n, v, a, ch, bsize; |
| 436 | int coef_nb_bits, total_gain; |
| 437 | int nb_coefs[MAX_CHANNELS]; |
| 438 | float mdct_norm; |
| 439 | FFTContext *mdct; |
| 440 | |
| 441 | #ifdef TRACE |
| 442 | tprintf(s->avctx, "***decode_block: %d:%d\n", |
| 443 | s->frame_count - 1, s->block_num); |
| 444 | #endif /* TRACE */ |
| 445 | |
| 446 | /* compute current block length */ |
| 447 | if (s->use_variable_block_len) { |
| 448 | n = av_log2(s->nb_block_sizes - 1) + 1; |
| 449 | |
| 450 | if (s->reset_block_lengths) { |
| 451 | s->reset_block_lengths = 0; |
| 452 | v = get_bits(&s->gb, n); |
| 453 | if (v >= s->nb_block_sizes) { |
| 454 | av_log(s->avctx, AV_LOG_ERROR, |
| 455 | "prev_block_len_bits %d out of range\n", |
| 456 | s->frame_len_bits - v); |
| 457 | return -1; |
| 458 | } |
| 459 | s->prev_block_len_bits = s->frame_len_bits - v; |
| 460 | v = get_bits(&s->gb, n); |
| 461 | if (v >= s->nb_block_sizes) { |
| 462 | av_log(s->avctx, AV_LOG_ERROR, |
| 463 | "block_len_bits %d out of range\n", |
| 464 | s->frame_len_bits - v); |
| 465 | return -1; |
| 466 | } |
| 467 | s->block_len_bits = s->frame_len_bits - v; |
| 468 | } else { |
| 469 | /* update block lengths */ |
| 470 | s->prev_block_len_bits = s->block_len_bits; |
| 471 | s->block_len_bits = s->next_block_len_bits; |
| 472 | } |
| 473 | v = get_bits(&s->gb, n); |
| 474 | if (v >= s->nb_block_sizes) { |
| 475 | av_log(s->avctx, AV_LOG_ERROR, |
| 476 | "next_block_len_bits %d out of range\n", |
| 477 | s->frame_len_bits - v); |
| 478 | return -1; |
| 479 | } |
| 480 | s->next_block_len_bits = s->frame_len_bits - v; |
| 481 | } else { |
| 482 | /* fixed block len */ |
| 483 | s->next_block_len_bits = s->frame_len_bits; |
| 484 | s->prev_block_len_bits = s->frame_len_bits; |
| 485 | s->block_len_bits = s->frame_len_bits; |
| 486 | } |
| 487 | |
| 488 | if (s->frame_len_bits - s->block_len_bits >= s->nb_block_sizes){ |
| 489 | av_log(s->avctx, AV_LOG_ERROR, "block_len_bits not initialized to a valid value\n"); |
| 490 | return -1; |
| 491 | } |
| 492 | |
| 493 | /* now check if the block length is coherent with the frame length */ |
| 494 | s->block_len = 1 << s->block_len_bits; |
| 495 | if ((s->block_pos + s->block_len) > s->frame_len) { |
| 496 | av_log(s->avctx, AV_LOG_ERROR, "frame_len overflow\n"); |
| 497 | return -1; |
| 498 | } |
| 499 | |
| 500 | if (s->avctx->channels == 2) |
| 501 | s->ms_stereo = get_bits1(&s->gb); |
| 502 | v = 0; |
| 503 | for (ch = 0; ch < s->avctx->channels; ch++) { |
| 504 | a = get_bits1(&s->gb); |
| 505 | s->channel_coded[ch] = a; |
| 506 | v |= a; |
| 507 | } |
| 508 | |
| 509 | bsize = s->frame_len_bits - s->block_len_bits; |
| 510 | |
| 511 | /* if no channel coded, no need to go further */ |
| 512 | /* XXX: fix potential framing problems */ |
| 513 | if (!v) |
| 514 | goto next; |
| 515 | |
| 516 | /* read total gain and extract corresponding number of bits for |
| 517 | * coef escape coding */ |
| 518 | total_gain = 1; |
| 519 | for (;;) { |
| 520 | if (get_bits_left(&s->gb) < 7) { |
| 521 | av_log(s->avctx, AV_LOG_ERROR, "total_gain overread\n"); |
| 522 | return AVERROR_INVALIDDATA; |
| 523 | } |
| 524 | a = get_bits(&s->gb, 7); |
| 525 | total_gain += a; |
| 526 | if (a != 127) |
| 527 | break; |
| 528 | } |
| 529 | |
| 530 | coef_nb_bits = ff_wma_total_gain_to_bits(total_gain); |
| 531 | |
| 532 | /* compute number of coefficients */ |
| 533 | n = s->coefs_end[bsize] - s->coefs_start; |
| 534 | for (ch = 0; ch < s->avctx->channels; ch++) |
| 535 | nb_coefs[ch] = n; |
| 536 | |
| 537 | /* complex coding */ |
| 538 | if (s->use_noise_coding) { |
| 539 | for (ch = 0; ch < s->avctx->channels; ch++) { |
| 540 | if (s->channel_coded[ch]) { |
| 541 | int i, n, a; |
| 542 | n = s->exponent_high_sizes[bsize]; |
| 543 | for (i = 0; i < n; i++) { |
| 544 | a = get_bits1(&s->gb); |
| 545 | s->high_band_coded[ch][i] = a; |
| 546 | /* if noise coding, the coefficients are not transmitted */ |
| 547 | if (a) |
| 548 | nb_coefs[ch] -= s->exponent_high_bands[bsize][i]; |
| 549 | } |
| 550 | } |
| 551 | } |
| 552 | for (ch = 0; ch < s->avctx->channels; ch++) { |
| 553 | if (s->channel_coded[ch]) { |
| 554 | int i, n, val, code; |
| 555 | |
| 556 | n = s->exponent_high_sizes[bsize]; |
| 557 | val = (int) 0x80000000; |
| 558 | for (i = 0; i < n; i++) { |
| 559 | if (s->high_band_coded[ch][i]) { |
| 560 | if (val == (int) 0x80000000) { |
| 561 | val = get_bits(&s->gb, 7) - 19; |
| 562 | } else { |
| 563 | code = get_vlc2(&s->gb, s->hgain_vlc.table, |
| 564 | HGAINVLCBITS, HGAINMAX); |
| 565 | if (code < 0) { |
| 566 | av_log(s->avctx, AV_LOG_ERROR, |
| 567 | "hgain vlc invalid\n"); |
| 568 | return -1; |
| 569 | } |
| 570 | val += code - 18; |
| 571 | } |
| 572 | s->high_band_values[ch][i] = val; |
| 573 | } |
| 574 | } |
| 575 | } |
| 576 | } |
| 577 | } |
| 578 | |
| 579 | /* exponents can be reused in short blocks. */ |
| 580 | if ((s->block_len_bits == s->frame_len_bits) || get_bits1(&s->gb)) { |
| 581 | for (ch = 0; ch < s->avctx->channels; ch++) { |
| 582 | if (s->channel_coded[ch]) { |
| 583 | if (s->use_exp_vlc) { |
| 584 | if (decode_exp_vlc(s, ch) < 0) |
| 585 | return -1; |
| 586 | } else { |
| 587 | decode_exp_lsp(s, ch); |
| 588 | } |
| 589 | s->exponents_bsize[ch] = bsize; |
| 590 | } |
| 591 | } |
| 592 | } |
| 593 | |
| 594 | /* parse spectral coefficients : just RLE encoding */ |
| 595 | for (ch = 0; ch < s->avctx->channels; ch++) { |
| 596 | if (s->channel_coded[ch]) { |
| 597 | int tindex; |
| 598 | WMACoef *ptr = &s->coefs1[ch][0]; |
| 599 | |
| 600 | /* special VLC tables are used for ms stereo because |
| 601 | * there is potentially less energy there */ |
| 602 | tindex = (ch == 1 && s->ms_stereo); |
| 603 | memset(ptr, 0, s->block_len * sizeof(WMACoef)); |
| 604 | ff_wma_run_level_decode(s->avctx, &s->gb, &s->coef_vlc[tindex], |
| 605 | s->level_table[tindex], s->run_table[tindex], |
| 606 | 0, ptr, 0, nb_coefs[ch], |
| 607 | s->block_len, s->frame_len_bits, coef_nb_bits); |
| 608 | } |
| 609 | if (s->version == 1 && s->avctx->channels >= 2) |
| 610 | align_get_bits(&s->gb); |
| 611 | } |
| 612 | |
| 613 | /* normalize */ |
| 614 | { |
| 615 | int n4 = s->block_len / 2; |
| 616 | mdct_norm = 1.0 / (float) n4; |
| 617 | if (s->version == 1) |
| 618 | mdct_norm *= sqrt(n4); |
| 619 | } |
| 620 | |
| 621 | /* finally compute the MDCT coefficients */ |
| 622 | for (ch = 0; ch < s->avctx->channels; ch++) { |
| 623 | if (s->channel_coded[ch]) { |
| 624 | WMACoef *coefs1; |
| 625 | float *coefs, *exponents, mult, mult1, noise; |
| 626 | int i, j, n, n1, last_high_band, esize; |
| 627 | float exp_power[HIGH_BAND_MAX_SIZE]; |
| 628 | |
| 629 | coefs1 = s->coefs1[ch]; |
| 630 | exponents = s->exponents[ch]; |
| 631 | esize = s->exponents_bsize[ch]; |
| 632 | mult = pow(10, total_gain * 0.05) / s->max_exponent[ch]; |
| 633 | mult *= mdct_norm; |
| 634 | coefs = s->coefs[ch]; |
| 635 | if (s->use_noise_coding) { |
| 636 | mult1 = mult; |
| 637 | /* very low freqs : noise */ |
| 638 | for (i = 0; i < s->coefs_start; i++) { |
| 639 | *coefs++ = s->noise_table[s->noise_index] * |
| 640 | exponents[i << bsize >> esize] * mult1; |
| 641 | s->noise_index = (s->noise_index + 1) & |
| 642 | (NOISE_TAB_SIZE - 1); |
| 643 | } |
| 644 | |
| 645 | n1 = s->exponent_high_sizes[bsize]; |
| 646 | |
| 647 | /* compute power of high bands */ |
| 648 | exponents = s->exponents[ch] + |
| 649 | (s->high_band_start[bsize] << bsize >> esize); |
| 650 | last_high_band = 0; /* avoid warning */ |
| 651 | for (j = 0; j < n1; j++) { |
| 652 | n = s->exponent_high_bands[s->frame_len_bits - |
| 653 | s->block_len_bits][j]; |
| 654 | if (s->high_band_coded[ch][j]) { |
| 655 | float e2, v; |
| 656 | e2 = 0; |
| 657 | for (i = 0; i < n; i++) { |
| 658 | v = exponents[i << bsize >> esize]; |
| 659 | e2 += v * v; |
| 660 | } |
| 661 | exp_power[j] = e2 / n; |
| 662 | last_high_band = j; |
| 663 | tprintf(s->avctx, "%d: power=%f (%d)\n", j, exp_power[j], n); |
| 664 | } |
| 665 | exponents += n << bsize >> esize; |
| 666 | } |
| 667 | |
| 668 | /* main freqs and high freqs */ |
| 669 | exponents = s->exponents[ch] + (s->coefs_start << bsize >> esize); |
| 670 | for (j = -1; j < n1; j++) { |
| 671 | if (j < 0) |
| 672 | n = s->high_band_start[bsize] - s->coefs_start; |
| 673 | else |
| 674 | n = s->exponent_high_bands[s->frame_len_bits - |
| 675 | s->block_len_bits][j]; |
| 676 | if (j >= 0 && s->high_band_coded[ch][j]) { |
| 677 | /* use noise with specified power */ |
| 678 | mult1 = sqrt(exp_power[j] / exp_power[last_high_band]); |
| 679 | /* XXX: use a table */ |
| 680 | mult1 = mult1 * pow(10, s->high_band_values[ch][j] * 0.05); |
| 681 | mult1 = mult1 / (s->max_exponent[ch] * s->noise_mult); |
| 682 | mult1 *= mdct_norm; |
| 683 | for (i = 0; i < n; i++) { |
| 684 | noise = s->noise_table[s->noise_index]; |
| 685 | s->noise_index = (s->noise_index + 1) & (NOISE_TAB_SIZE - 1); |
| 686 | *coefs++ = noise * exponents[i << bsize >> esize] * mult1; |
| 687 | } |
| 688 | exponents += n << bsize >> esize; |
| 689 | } else { |
| 690 | /* coded values + small noise */ |
| 691 | for (i = 0; i < n; i++) { |
| 692 | noise = s->noise_table[s->noise_index]; |
| 693 | s->noise_index = (s->noise_index + 1) & (NOISE_TAB_SIZE - 1); |
| 694 | *coefs++ = ((*coefs1++) + noise) * |
| 695 | exponents[i << bsize >> esize] * mult; |
| 696 | } |
| 697 | exponents += n << bsize >> esize; |
| 698 | } |
| 699 | } |
| 700 | |
| 701 | /* very high freqs : noise */ |
| 702 | n = s->block_len - s->coefs_end[bsize]; |
| 703 | mult1 = mult * exponents[((-1 << bsize)) >> esize]; |
| 704 | for (i = 0; i < n; i++) { |
| 705 | *coefs++ = s->noise_table[s->noise_index] * mult1; |
| 706 | s->noise_index = (s->noise_index + 1) & (NOISE_TAB_SIZE - 1); |
| 707 | } |
| 708 | } else { |
| 709 | /* XXX: optimize more */ |
| 710 | for (i = 0; i < s->coefs_start; i++) |
| 711 | *coefs++ = 0.0; |
| 712 | n = nb_coefs[ch]; |
| 713 | for (i = 0; i < n; i++) |
| 714 | *coefs++ = coefs1[i] * exponents[i << bsize >> esize] * mult; |
| 715 | n = s->block_len - s->coefs_end[bsize]; |
| 716 | for (i = 0; i < n; i++) |
| 717 | *coefs++ = 0.0; |
| 718 | } |
| 719 | } |
| 720 | } |
| 721 | |
| 722 | #ifdef TRACE |
| 723 | for (ch = 0; ch < s->avctx->channels; ch++) { |
| 724 | if (s->channel_coded[ch]) { |
| 725 | dump_floats(s, "exponents", 3, s->exponents[ch], s->block_len); |
| 726 | dump_floats(s, "coefs", 1, s->coefs[ch], s->block_len); |
| 727 | } |
| 728 | } |
| 729 | #endif /* TRACE */ |
| 730 | |
| 731 | if (s->ms_stereo && s->channel_coded[1]) { |
| 732 | /* nominal case for ms stereo: we do it before mdct */ |
| 733 | /* no need to optimize this case because it should almost |
| 734 | * never happen */ |
| 735 | if (!s->channel_coded[0]) { |
| 736 | tprintf(s->avctx, "rare ms-stereo case happened\n"); |
| 737 | memset(s->coefs[0], 0, sizeof(float) * s->block_len); |
| 738 | s->channel_coded[0] = 1; |
| 739 | } |
| 740 | |
| 741 | s->fdsp->butterflies_float(s->coefs[0], s->coefs[1], s->block_len); |
| 742 | } |
| 743 | |
| 744 | next: |
| 745 | mdct = &s->mdct_ctx[bsize]; |
| 746 | |
| 747 | for (ch = 0; ch < s->avctx->channels; ch++) { |
| 748 | int n4, index; |
| 749 | |
| 750 | n4 = s->block_len / 2; |
| 751 | if (s->channel_coded[ch]) |
| 752 | mdct->imdct_calc(mdct, s->output, s->coefs[ch]); |
| 753 | else if (!(s->ms_stereo && ch == 1)) |
| 754 | memset(s->output, 0, sizeof(s->output)); |
| 755 | |
| 756 | /* multiply by the window and add in the frame */ |
| 757 | index = (s->frame_len / 2) + s->block_pos - n4; |
| 758 | wma_window(s, &s->frame_out[ch][index]); |
| 759 | } |
| 760 | |
| 761 | /* update block number */ |
| 762 | s->block_num++; |
| 763 | s->block_pos += s->block_len; |
| 764 | if (s->block_pos >= s->frame_len) |
| 765 | return 1; |
| 766 | else |
| 767 | return 0; |
| 768 | } |
| 769 | |
| 770 | /* decode a frame of frame_len samples */ |
| 771 | static int wma_decode_frame(WMACodecContext *s, float **samples, |
| 772 | int samples_offset) |
| 773 | { |
| 774 | int ret, ch; |
| 775 | |
| 776 | #ifdef TRACE |
| 777 | tprintf(s->avctx, "***decode_frame: %d size=%d\n", |
| 778 | s->frame_count++, s->frame_len); |
| 779 | #endif /* TRACE */ |
| 780 | |
| 781 | /* read each block */ |
| 782 | s->block_num = 0; |
| 783 | s->block_pos = 0; |
| 784 | for (;;) { |
| 785 | ret = wma_decode_block(s); |
| 786 | if (ret < 0) |
| 787 | return -1; |
| 788 | if (ret) |
| 789 | break; |
| 790 | } |
| 791 | |
| 792 | for (ch = 0; ch < s->avctx->channels; ch++) { |
| 793 | /* copy current block to output */ |
| 794 | memcpy(samples[ch] + samples_offset, s->frame_out[ch], |
| 795 | s->frame_len * sizeof(*s->frame_out[ch])); |
| 796 | /* prepare for next block */ |
| 797 | memmove(&s->frame_out[ch][0], &s->frame_out[ch][s->frame_len], |
| 798 | s->frame_len * sizeof(*s->frame_out[ch])); |
| 799 | |
| 800 | #ifdef TRACE |
| 801 | dump_floats(s, "samples", 6, samples[ch] + samples_offset, |
| 802 | s->frame_len); |
| 803 | #endif /* TRACE */ |
| 804 | } |
| 805 | |
| 806 | return 0; |
| 807 | } |
| 808 | |
| 809 | static int wma_decode_superframe(AVCodecContext *avctx, void *data, |
| 810 | int *got_frame_ptr, AVPacket *avpkt) |
| 811 | { |
| 812 | AVFrame *frame = data; |
| 813 | const uint8_t *buf = avpkt->data; |
| 814 | int buf_size = avpkt->size; |
| 815 | WMACodecContext *s = avctx->priv_data; |
| 816 | int nb_frames, bit_offset, i, pos, len, ret; |
| 817 | uint8_t *q; |
| 818 | float **samples; |
| 819 | int samples_offset; |
| 820 | |
| 821 | tprintf(avctx, "***decode_superframe:\n"); |
| 822 | |
| 823 | if (buf_size == 0) { |
| 824 | s->last_superframe_len = 0; |
| 825 | return 0; |
| 826 | } |
| 827 | if (buf_size < avctx->block_align) { |
| 828 | av_log(avctx, AV_LOG_ERROR, |
| 829 | "Input packet size too small (%d < %d)\n", |
| 830 | buf_size, avctx->block_align); |
| 831 | return AVERROR_INVALIDDATA; |
| 832 | } |
| 833 | if (avctx->block_align) |
| 834 | buf_size = avctx->block_align; |
| 835 | |
| 836 | init_get_bits(&s->gb, buf, buf_size * 8); |
| 837 | |
| 838 | if (s->use_bit_reservoir) { |
| 839 | /* read super frame header */ |
| 840 | skip_bits(&s->gb, 4); /* super frame index */ |
| 841 | nb_frames = get_bits(&s->gb, 4) - (s->last_superframe_len <= 0); |
| 842 | if (nb_frames <= 0) { |
| 843 | av_log(avctx, AV_LOG_ERROR, "nb_frames is %d\n", nb_frames); |
| 844 | return AVERROR_INVALIDDATA; |
| 845 | } |
| 846 | } else |
| 847 | nb_frames = 1; |
| 848 | |
| 849 | /* get output buffer */ |
| 850 | frame->nb_samples = nb_frames * s->frame_len; |
| 851 | if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) |
| 852 | return ret; |
| 853 | samples = (float **) frame->extended_data; |
| 854 | samples_offset = 0; |
| 855 | |
| 856 | if (s->use_bit_reservoir) { |
| 857 | bit_offset = get_bits(&s->gb, s->byte_offset_bits + 3); |
| 858 | if (bit_offset > get_bits_left(&s->gb)) { |
| 859 | av_log(avctx, AV_LOG_ERROR, |
| 860 | "Invalid last frame bit offset %d > buf size %d (%d)\n", |
| 861 | bit_offset, get_bits_left(&s->gb), buf_size); |
| 862 | goto fail; |
| 863 | } |
| 864 | |
| 865 | if (s->last_superframe_len > 0) { |
| 866 | /* add bit_offset bits to last frame */ |
| 867 | if ((s->last_superframe_len + ((bit_offset + 7) >> 3)) > |
| 868 | MAX_CODED_SUPERFRAME_SIZE) |
| 869 | goto fail; |
| 870 | q = s->last_superframe + s->last_superframe_len; |
| 871 | len = bit_offset; |
| 872 | while (len > 7) { |
| 873 | *q++ = (get_bits) (&s->gb, 8); |
| 874 | len -= 8; |
| 875 | } |
| 876 | if (len > 0) |
| 877 | *q++ = (get_bits) (&s->gb, len) << (8 - len); |
| 878 | memset(q, 0, FF_INPUT_BUFFER_PADDING_SIZE); |
| 879 | |
| 880 | /* XXX: bit_offset bits into last frame */ |
| 881 | init_get_bits(&s->gb, s->last_superframe, |
| 882 | s->last_superframe_len * 8 + bit_offset); |
| 883 | /* skip unused bits */ |
| 884 | if (s->last_bitoffset > 0) |
| 885 | skip_bits(&s->gb, s->last_bitoffset); |
| 886 | /* this frame is stored in the last superframe and in the |
| 887 | * current one */ |
| 888 | if (wma_decode_frame(s, samples, samples_offset) < 0) |
| 889 | goto fail; |
| 890 | samples_offset += s->frame_len; |
| 891 | nb_frames--; |
| 892 | } |
| 893 | |
| 894 | /* read each frame starting from bit_offset */ |
| 895 | pos = bit_offset + 4 + 4 + s->byte_offset_bits + 3; |
| 896 | if (pos >= MAX_CODED_SUPERFRAME_SIZE * 8 || pos > buf_size * 8) |
| 897 | return AVERROR_INVALIDDATA; |
| 898 | init_get_bits(&s->gb, buf + (pos >> 3), (buf_size - (pos >> 3)) * 8); |
| 899 | len = pos & 7; |
| 900 | if (len > 0) |
| 901 | skip_bits(&s->gb, len); |
| 902 | |
| 903 | s->reset_block_lengths = 1; |
| 904 | for (i = 0; i < nb_frames; i++) { |
| 905 | if (wma_decode_frame(s, samples, samples_offset) < 0) |
| 906 | goto fail; |
| 907 | samples_offset += s->frame_len; |
| 908 | } |
| 909 | |
| 910 | /* we copy the end of the frame in the last frame buffer */ |
| 911 | pos = get_bits_count(&s->gb) + |
| 912 | ((bit_offset + 4 + 4 + s->byte_offset_bits + 3) & ~7); |
| 913 | s->last_bitoffset = pos & 7; |
| 914 | pos >>= 3; |
| 915 | len = buf_size - pos; |
| 916 | if (len > MAX_CODED_SUPERFRAME_SIZE || len < 0) { |
| 917 | av_log(s->avctx, AV_LOG_ERROR, "len %d invalid\n", len); |
| 918 | goto fail; |
| 919 | } |
| 920 | s->last_superframe_len = len; |
| 921 | memcpy(s->last_superframe, buf + pos, len); |
| 922 | } else { |
| 923 | /* single frame decode */ |
| 924 | if (wma_decode_frame(s, samples, samples_offset) < 0) |
| 925 | goto fail; |
| 926 | samples_offset += s->frame_len; |
| 927 | } |
| 928 | |
| 929 | av_dlog(s->avctx, "%d %d %d %d outbytes:%"PTRDIFF_SPECIFIER" eaten:%d\n", |
| 930 | s->frame_len_bits, s->block_len_bits, s->frame_len, s->block_len, |
| 931 | (int8_t *) samples - (int8_t *) data, avctx->block_align); |
| 932 | |
| 933 | *got_frame_ptr = 1; |
| 934 | |
| 935 | return buf_size; |
| 936 | |
| 937 | fail: |
| 938 | /* when error, we reset the bit reservoir */ |
| 939 | s->last_superframe_len = 0; |
| 940 | return -1; |
| 941 | } |
| 942 | |
| 943 | static av_cold void flush(AVCodecContext *avctx) |
| 944 | { |
| 945 | WMACodecContext *s = avctx->priv_data; |
| 946 | |
| 947 | s->last_bitoffset = |
| 948 | s->last_superframe_len = 0; |
| 949 | } |
| 950 | |
| 951 | #if CONFIG_WMAV1_DECODER |
| 952 | AVCodec ff_wmav1_decoder = { |
| 953 | .name = "wmav1", |
| 954 | .long_name = NULL_IF_CONFIG_SMALL("Windows Media Audio 1"), |
| 955 | .type = AVMEDIA_TYPE_AUDIO, |
| 956 | .id = AV_CODEC_ID_WMAV1, |
| 957 | .priv_data_size = sizeof(WMACodecContext), |
| 958 | .init = wma_decode_init, |
| 959 | .close = ff_wma_end, |
| 960 | .decode = wma_decode_superframe, |
| 961 | .flush = flush, |
| 962 | .capabilities = CODEC_CAP_DR1, |
| 963 | .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP, |
| 964 | AV_SAMPLE_FMT_NONE }, |
| 965 | }; |
| 966 | #endif |
| 967 | #if CONFIG_WMAV2_DECODER |
| 968 | AVCodec ff_wmav2_decoder = { |
| 969 | .name = "wmav2", |
| 970 | .long_name = NULL_IF_CONFIG_SMALL("Windows Media Audio 2"), |
| 971 | .type = AVMEDIA_TYPE_AUDIO, |
| 972 | .id = AV_CODEC_ID_WMAV2, |
| 973 | .priv_data_size = sizeof(WMACodecContext), |
| 974 | .init = wma_decode_init, |
| 975 | .close = ff_wma_end, |
| 976 | .decode = wma_decode_superframe, |
| 977 | .flush = flush, |
| 978 | .capabilities = CODEC_CAP_DR1, |
| 979 | .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP, |
| 980 | AV_SAMPLE_FMT_NONE }, |
| 981 | }; |
| 982 | #endif |