| 1 | const HISTORY_SIZE: usize = 512; |
| 2 | |
| 3 | fn val2sign(val: i32) -> i32 { |
| 4 | if val > 0 { |
| 5 | -1 |
| 6 | } else if val < 0 { |
| 7 | 1 |
| 8 | } else { |
| 9 | 0 |
| 10 | } |
| 11 | } |
| 12 | |
| 13 | pub struct OldFilt { |
| 14 | version: u16, |
| 15 | compression: u16, |
| 16 | } |
| 17 | |
| 18 | pub struct NewFilt { |
| 19 | version: u16, |
| 20 | filters: [NFilterContext; 3], |
| 21 | lfilt: LastFilterContext, |
| 22 | rfilt: LastFilterContext, |
| 23 | } |
| 24 | |
| 25 | #[allow(clippy::large_enum_variant)] |
| 26 | pub enum FilterMode { |
| 27 | Old(OldFilt), |
| 28 | New(NewFilt), |
| 29 | None, |
| 30 | } |
| 31 | |
| 32 | impl FilterMode { |
| 33 | pub fn new(version: u16, compression: u16) -> Self { |
| 34 | if version < 3930 { |
| 35 | FilterMode::Old(OldFilt::new(version, compression)) |
| 36 | } else { |
| 37 | FilterMode::New(NewFilt::new(version, compression)) |
| 38 | } |
| 39 | } |
| 40 | pub fn filter_mono(&mut self, l: &mut [i32]) { |
| 41 | match *self { |
| 42 | FilterMode::Old(ref mut ofilt) => ofilt.filter(l), |
| 43 | FilterMode::New(ref mut nfilt) => nfilt.filter_mono(l), |
| 44 | FilterMode::None => unreachable!(), |
| 45 | }; |
| 46 | } |
| 47 | pub fn filter_stereo(&mut self, l: &mut [i32], r: &mut [i32]) { |
| 48 | match *self { |
| 49 | FilterMode::Old(ref mut ofilt) => { |
| 50 | ofilt.filter(l); |
| 51 | ofilt.filter(r); |
| 52 | for (l, r) in l.iter_mut().zip(r.iter_mut()) { |
| 53 | let new_l = *l - *r / 2; |
| 54 | let new_r = *r + new_l; |
| 55 | *l = new_l; |
| 56 | *r = new_r; |
| 57 | } |
| 58 | }, |
| 59 | FilterMode::New(ref mut nfilt) => { |
| 60 | nfilt.filter_stereo(l, r); |
| 61 | for (l, r) in l.iter_mut().zip(r.iter_mut()) { |
| 62 | let new_l = *r - *l / 2; |
| 63 | let new_r = *l + new_l; |
| 64 | *l = new_l; |
| 65 | *r = new_r; |
| 66 | } |
| 67 | }, |
| 68 | FilterMode::None => unreachable!(), |
| 69 | }; |
| 70 | } |
| 71 | } |
| 72 | |
| 73 | const NEW_FILTER_PARAMS: [[(u8, u8); 3]; 5] = [ |
| 74 | [ (0, 0), ( 0, 0), ( 0, 0) ], |
| 75 | [ (1, 11), ( 0, 0), ( 0, 0) ], |
| 76 | [ (4, 11), ( 0, 0), ( 0, 0) ], |
| 77 | [ (2, 10), (16, 13), ( 0, 0) ], |
| 78 | [ (1, 11), (16, 13), (80, 15) ], |
| 79 | ]; |
| 80 | |
| 81 | #[derive(Clone,Default)] |
| 82 | struct NFilterContext { |
| 83 | buf: Vec<i32>, |
| 84 | coeffs: Vec<i32>, |
| 85 | order: usize, |
| 86 | bits: u8, |
| 87 | avg: i32, |
| 88 | new: bool, |
| 89 | } |
| 90 | |
| 91 | fn adapt_loop(filt: &mut [i32], coeffs: &[i32], adapt: &[i32], val: i32) -> i32 { |
| 92 | let mut sum = 0i32; |
| 93 | for (coef, (res, adapt)) in filt.iter_mut().zip(coeffs.iter().zip(adapt.iter())) { |
| 94 | sum += *coef * *res; |
| 95 | if val < 0 { |
| 96 | *coef += *adapt; |
| 97 | } else if val > 0 { |
| 98 | *coef -= *adapt; |
| 99 | } |
| 100 | *coef = *coef << 16 >> 16; |
| 101 | } |
| 102 | sum |
| 103 | } |
| 104 | |
| 105 | impl NFilterContext { |
| 106 | fn new(ord16: u8, bits: u8, new: bool) -> Self { |
| 107 | let order = ord16 as usize * 16; |
| 108 | Self { |
| 109 | buf: if order > 0 { vec![0; order * 2 + HISTORY_SIZE] } else { Vec::new() }, |
| 110 | coeffs: vec![0; order], |
| 111 | order, |
| 112 | bits, |
| 113 | avg: 0, |
| 114 | new, |
| 115 | } |
| 116 | } |
| 117 | fn reset(&mut self) { |
| 118 | for el in self.buf[..self.order * 2].iter_mut() { *el = 0; } |
| 119 | for el in self.coeffs.iter_mut() { *el = 0; } |
| 120 | self.avg = 0; |
| 121 | } |
| 122 | fn apply(&mut self, dst: &mut [i32]) { |
| 123 | if self.order == 0 { return; } |
| 124 | let mut adapt_pos = self.order; |
| 125 | let mut delay_pos = self.order * 2; |
| 126 | for el in dst.iter_mut() { |
| 127 | let sum = adapt_loop(&mut self.coeffs, |
| 128 | &self.buf[delay_pos - self.order..], |
| 129 | &self.buf[adapt_pos - self.order..], *el); |
| 130 | let pred = (sum + (1 << (self.bits - 1))) >> self.bits; |
| 131 | let val = *el + pred; |
| 132 | *el = val; |
| 133 | self.buf[delay_pos] = val.min(32767).max(-32768); |
| 134 | if self.new { |
| 135 | let aval = val.abs(); |
| 136 | let sign = val2sign(val); |
| 137 | self.buf[adapt_pos] = if aval == 0 { |
| 138 | 0 |
| 139 | } else if aval <= self.avg * 4 / 3 { |
| 140 | sign * 8 |
| 141 | } else if aval <= self.avg * 3 { |
| 142 | sign * 16 |
| 143 | } else { |
| 144 | sign * 32 |
| 145 | }; |
| 146 | self.avg += (aval - self.avg) / 16; |
| 147 | self.buf[adapt_pos - 1] >>= 1; |
| 148 | self.buf[adapt_pos - 2] >>= 1; |
| 149 | self.buf[adapt_pos - 8] >>= 1; |
| 150 | } else { |
| 151 | self.buf[adapt_pos] = 4 * val2sign(val); |
| 152 | self.buf[adapt_pos - 4] >>= 1; |
| 153 | self.buf[adapt_pos - 8] >>= 1; |
| 154 | } |
| 155 | delay_pos += 1; |
| 156 | adapt_pos += 1; |
| 157 | if delay_pos == HISTORY_SIZE + self.order * 2 { |
| 158 | delay_pos = self.order * 2; |
| 159 | adapt_pos = self.order; |
| 160 | for i in 0..self.order * 2 { |
| 161 | self.buf[i] = self.buf[HISTORY_SIZE + i]; |
| 162 | } |
| 163 | } |
| 164 | } |
| 165 | } |
| 166 | } |
| 167 | |
| 168 | #[derive(Clone,Copy,Default)] |
| 169 | struct LastFilterContext { |
| 170 | last_a: i32, |
| 171 | filter_a: i32, |
| 172 | filter_b: i32, |
| 173 | coeffs_a: [i32; 4], |
| 174 | coeffs_b: [i32; 5], |
| 175 | delay_a: [i32; 4], |
| 176 | adapt_a: [i32; 4], |
| 177 | delay_b: [i32; 5], |
| 178 | adapt_b: [i32; 5], |
| 179 | } |
| 180 | |
| 181 | impl LastFilterContext { |
| 182 | fn init(&mut self) { |
| 183 | const COEFFS_A_NEW: [i32; 4] = [360, 317, -109, 98]; |
| 184 | |
| 185 | self.filter_a = 0; |
| 186 | self.filter_b = 0; |
| 187 | self.coeffs_a = COEFFS_A_NEW; |
| 188 | self.coeffs_b = [0; 5]; |
| 189 | self.last_a = 0; |
| 190 | self.delay_a = [0; 4]; |
| 191 | self.adapt_a = [0; 4]; |
| 192 | self.delay_b = [0; 5]; |
| 193 | self.adapt_b = [0; 5]; |
| 194 | } |
| 195 | fn predict_a(&mut self) -> i32 { |
| 196 | for i in (0..3).rev() { |
| 197 | self.delay_a[i + 1] = self.delay_a[i]; |
| 198 | self.adapt_a[i + 1] = self.adapt_a[i]; |
| 199 | } |
| 200 | self.delay_a[0] = self.last_a; |
| 201 | self.delay_a[1] = self.last_a - self.delay_a[1]; |
| 202 | self.adapt_a[0] = val2sign(self.delay_a[0]); |
| 203 | self.adapt_a[1] = val2sign(self.delay_a[1]); |
| 204 | |
| 205 | self.delay_a[0] * self.coeffs_a[0] + |
| 206 | self.delay_a[1] * self.coeffs_a[1] + |
| 207 | self.delay_a[2] * self.coeffs_a[2] + |
| 208 | self.delay_a[3] * self.coeffs_a[3] |
| 209 | } |
| 210 | fn predict_b(&mut self, other_a: i32) -> i32 { |
| 211 | for i in (0..4).rev() { |
| 212 | self.delay_b[i + 1] = self.delay_b[i]; |
| 213 | self.adapt_b[i + 1] = self.adapt_b[i]; |
| 214 | } |
| 215 | self.delay_b[0] = other_a - ((self.filter_b * 31) >> 5); |
| 216 | self.delay_b[1] = self.delay_b[0] - self.delay_b[1]; |
| 217 | self.adapt_b[0] = val2sign(self.delay_b[0]); |
| 218 | self.adapt_b[1] = val2sign(self.delay_b[1]); |
| 219 | |
| 220 | self.filter_b = other_a; |
| 221 | |
| 222 | (self.delay_b[0] * self.coeffs_b[0] + |
| 223 | self.delay_b[1] * self.coeffs_b[1] + |
| 224 | self.delay_b[2] * self.coeffs_b[2] + |
| 225 | self.delay_b[3] * self.coeffs_b[3] + |
| 226 | self.delay_b[4] * self.coeffs_b[4]) >> 1 |
| 227 | } |
| 228 | fn update_a(&mut self, pred: i32, diff: i32) -> i32 { |
| 229 | self.last_a = diff + (pred >> 10); |
| 230 | let sign = val2sign(diff); |
| 231 | for i in 0..4 { |
| 232 | self.coeffs_a[i] += self.adapt_a[i] * sign; |
| 233 | } |
| 234 | self.filter_a = self.last_a + ((self.filter_a * 31) >> 5); |
| 235 | |
| 236 | self.filter_a |
| 237 | } |
| 238 | fn update_b(&mut self, diff: i32) { |
| 239 | let sign = val2sign(diff); |
| 240 | for i in 0..5 { |
| 241 | self.coeffs_b[i] += self.adapt_b[i] * sign; |
| 242 | } |
| 243 | } |
| 244 | fn predict_3930(&mut self, diff: i32) -> i32 { |
| 245 | for i in (0..3).rev() { |
| 246 | self.delay_a[i + 1] = self.delay_a[i]; |
| 247 | } |
| 248 | self.delay_a[0] = self.last_a; |
| 249 | let d0 = self.delay_a[0]; |
| 250 | let d1 = self.delay_a[0] - self.delay_a[1]; |
| 251 | let d2 = self.delay_a[1] - self.delay_a[2]; |
| 252 | let d3 = self.delay_a[2] - self.delay_a[3]; |
| 253 | |
| 254 | let pred = (self.coeffs_a[0] * d0 + |
| 255 | self.coeffs_a[1] * d1 + |
| 256 | self.coeffs_a[2] * d2 + |
| 257 | self.coeffs_a[3] * d3) >> 9; |
| 258 | self.last_a = diff + pred; |
| 259 | self.filter_a = self.last_a + ((self.filter_a * 31) >> 5); |
| 260 | |
| 261 | let sign = val2sign(diff); |
| 262 | self.coeffs_a[0] += if d0 < 0 { sign } else { -sign }; |
| 263 | self.coeffs_a[1] += if d1 < 0 { sign } else { -sign }; |
| 264 | self.coeffs_a[2] += if d2 < 0 { sign } else { -sign }; |
| 265 | self.coeffs_a[3] += if d3 < 0 { sign } else { -sign }; |
| 266 | |
| 267 | self.filter_a |
| 268 | } |
| 269 | } |
| 270 | |
| 271 | impl NewFilt { |
| 272 | fn new(version: u16, compression: u16) -> Self { |
| 273 | let cidx = (compression / 1000) as usize - 1; |
| 274 | let mut obj = Self { |
| 275 | version, |
| 276 | filters: [NFilterContext::default(), NFilterContext::default(), NFilterContext::default()], |
| 277 | lfilt: LastFilterContext::default(), |
| 278 | rfilt: LastFilterContext::default(), |
| 279 | }; |
| 280 | obj.version = version; |
| 281 | let new = version >= 3980; |
| 282 | for i in 0..3 { |
| 283 | let (ord16, bits) = NEW_FILTER_PARAMS[cidx][i]; |
| 284 | obj.filters[i] = NFilterContext::new(ord16, bits, new); |
| 285 | } |
| 286 | obj |
| 287 | } |
| 288 | fn filter_mono(&mut self, dst: &mut [i32]) { |
| 289 | for filt in self.filters.iter_mut() { |
| 290 | filt.reset(); |
| 291 | filt.apply(dst); |
| 292 | } |
| 293 | self.lfilt.init(); |
| 294 | if self.version >= 3950 { |
| 295 | for el in dst.iter_mut() { |
| 296 | let pred = self.lfilt.predict_a(); |
| 297 | *el = self.lfilt.update_a(pred, *el); |
| 298 | } |
| 299 | } else { |
| 300 | for el in dst.iter_mut() { |
| 301 | *el = self.lfilt.predict_3930(*el); |
| 302 | } |
| 303 | } |
| 304 | } |
| 305 | fn filter_stereo(&mut self, l: &mut [i32], r: &mut [i32]) { |
| 306 | for filt in self.filters.iter_mut() { |
| 307 | filt.reset(); |
| 308 | filt.apply(l); |
| 309 | filt.reset(); |
| 310 | filt.apply(r); |
| 311 | } |
| 312 | self.lfilt.init(); |
| 313 | self.rfilt.init(); |
| 314 | if self.version >= 3950 { |
| 315 | for (l, r) in l.iter_mut().zip(r.iter_mut()) { |
| 316 | let mut pred = self.lfilt.predict_a(); |
| 317 | pred += self.lfilt.predict_b(self.rfilt.filter_a); |
| 318 | let new_l = self.lfilt.update_a(pred, *l); |
| 319 | self.lfilt.update_b(*l); |
| 320 | *l = new_l; |
| 321 | |
| 322 | let mut pred = self.rfilt.predict_a(); |
| 323 | pred += self.rfilt.predict_b(self.lfilt.filter_a); |
| 324 | let new_r = self.rfilt.update_a(pred, *r); |
| 325 | self.rfilt.update_b(*r); |
| 326 | *r = new_r; |
| 327 | } |
| 328 | } else { |
| 329 | for (l, r) in l.iter_mut().zip(r.iter_mut()) { |
| 330 | let new_l = self.lfilt.predict_3930(*r); |
| 331 | let new_r = self.rfilt.predict_3930(*l); |
| 332 | *l = new_l; |
| 333 | *r = new_r; |
| 334 | } |
| 335 | } |
| 336 | } |
| 337 | } |
| 338 | |
| 339 | impl OldFilt { |
| 340 | fn new(version: u16, compression: u16) -> Self { |
| 341 | Self { |
| 342 | version, compression |
| 343 | } |
| 344 | } |
| 345 | fn filter(&mut self, dst: &mut [i32]) { |
| 346 | match self.compression { |
| 347 | 1000 => { |
| 348 | Self::filter_fast(dst); |
| 349 | }, |
| 350 | 2000 => { |
| 351 | Self::filter_normal(dst, 4, 10); |
| 352 | }, |
| 353 | 3000 => { |
| 354 | Self::filter_high(dst, 16, 9); |
| 355 | Self::filter_normal(dst, 16, 10); |
| 356 | }, |
| 357 | 4000 => { |
| 358 | if self.version < 3830 { |
| 359 | Self::filter_high(dst, 128, 11); |
| 360 | Self::filter_normal(dst, 128, 10); |
| 361 | } else { |
| 362 | Self::filter_extra_high(dst); |
| 363 | Self::filter_high(dst, 256, 12); |
| 364 | Self::filter_normal(dst, 256, 11); |
| 365 | } |
| 366 | }, |
| 367 | _ => unreachable!(), |
| 368 | }; |
| 369 | } |
| 370 | fn filter_fast(dst: &mut [i32]) { |
| 371 | const COEFF_A_FAST: i32 = 375; |
| 372 | |
| 373 | if dst.len() <= 3 { |
| 374 | return; |
| 375 | } |
| 376 | let mut delay = [dst[1], dst[0]]; |
| 377 | let mut last = dst[2]; |
| 378 | let mut filter = dst[2]; |
| 379 | let mut weight = COEFF_A_FAST; |
| 380 | for el in dst[3..].iter_mut() { |
| 381 | delay[1] = delay[0]; |
| 382 | delay[0] = last; |
| 383 | let pred = delay[0] * 2 - delay[1]; |
| 384 | last = *el + ((pred * weight) >> 9); |
| 385 | if (*el ^ pred) > 0 { |
| 386 | weight += 1; |
| 387 | } else { |
| 388 | weight -= 1; |
| 389 | } |
| 390 | filter += last; |
| 391 | *el = filter; |
| 392 | } |
| 393 | } |
| 394 | fn filter_normal(dst: &mut [i32], start: usize, shift: u8) { |
| 395 | const COEFFS_A_NORMAL: [i32; 3] = [64, 115, 64]; |
| 396 | const COEFFS_B_NORMAL: [i32; 2] = [740, 0]; |
| 397 | |
| 398 | let mut last = 0; |
| 399 | let mut coeffs_a = COEFFS_A_NORMAL; |
| 400 | let mut coeffs_b = COEFFS_B_NORMAL; |
| 401 | let mut filter_a = 0; |
| 402 | let mut filter_b = 0; |
| 403 | let mut delay_a = [0; 3]; |
| 404 | let mut delay_b = [0; 2]; |
| 405 | |
| 406 | for (i, el) in dst.iter_mut().enumerate() { |
| 407 | delay_a[2] = delay_a[1]; delay_a[1] = delay_a[0]; delay_a[0] = last; |
| 408 | delay_b[1] = delay_b[0]; delay_b[0] = filter_b; |
| 409 | if i < start { |
| 410 | let val = *el + filter_a; |
| 411 | last = *el; |
| 412 | filter_b = *el; |
| 413 | filter_a = val; |
| 414 | *el = val; |
| 415 | continue; |
| 416 | } |
| 417 | let a0 = delay_a[0] + (delay_a[2] - delay_a[1]) * 8; |
| 418 | let a1 = (delay_a[0] - delay_a[1]) * 2; |
| 419 | let a2 = delay_a[0]; |
| 420 | let b0 = delay_b[0] * 2 - delay_b[1]; |
| 421 | let b1 = delay_b[0]; |
| 422 | |
| 423 | let pred_a = a0 * coeffs_a[0] + a1 * coeffs_a[1] + a2 * coeffs_a[2]; |
| 424 | let pred_b = b0 * coeffs_b[0] - b1 * coeffs_b[1]; |
| 425 | |
| 426 | let sign = val2sign(*el); |
| 427 | coeffs_a[0] += (((a0 >> 30) & 2) - 1) * sign; |
| 428 | coeffs_a[1] += (((a1 >> 28) & 8) - 4) * sign; |
| 429 | coeffs_a[2] += (((a2 >> 28) & 8) - 4) * sign; |
| 430 | last = *el + (pred_a >> 11); |
| 431 | |
| 432 | let sign = val2sign(last); |
| 433 | coeffs_b[0] += (((b0 >> 29) & 4) - 2) * sign; |
| 434 | coeffs_b[1] -= (((b1 >> 30) & 2) - 1) * sign; |
| 435 | |
| 436 | filter_b = last + (pred_b >> shift); |
| 437 | filter_a = filter_b + ((filter_a * 31) >> 5); |
| 438 | |
| 439 | *el = filter_a; |
| 440 | } |
| 441 | } |
| 442 | fn filter_high(dst: &mut [i32], order: usize, shift: u8) { |
| 443 | let mut coeffs = [0i32; 256]; |
| 444 | let mut delay = [0i32; 256]; |
| 445 | if dst.len() <= order { |
| 446 | return; |
| 447 | } |
| 448 | delay[..order].copy_from_slice(&dst[..order]); |
| 449 | for el in dst[order..].iter_mut() { |
| 450 | let sign = val2sign(*el); |
| 451 | let mut sum = 0; |
| 452 | for i in 0..order { |
| 453 | sum += delay[i] * coeffs[i]; |
| 454 | coeffs[i] -= (((delay[i] >> 30) & 2) - 1) * sign; |
| 455 | } |
| 456 | *el -= sum >> shift; |
| 457 | for i in 0..order-1 { |
| 458 | delay[i] = delay[i + 1]; |
| 459 | } |
| 460 | delay[order - 1] = *el; |
| 461 | } |
| 462 | } |
| 463 | fn filter_extra_high(dst: &mut [i32]) { |
| 464 | let mut coeffs = [0i32; 8]; |
| 465 | let mut delay = [0i32; 8]; |
| 466 | for el in dst[256..].iter_mut() { |
| 467 | let sign = val2sign(*el); |
| 468 | let mut sum = 0; |
| 469 | for i in 0..8 { |
| 470 | sum += delay[i] * coeffs[i]; |
| 471 | coeffs[i] -= (((delay[i] >> 30) & 2) - 1) * sign; |
| 472 | } |
| 473 | for i in (0..7).rev() { |
| 474 | delay[i + 1] = delay[i]; |
| 475 | } |
| 476 | delay[0] = *el; |
| 477 | *el -= sum >> 9; |
| 478 | } |
| 479 | } |
| 480 | } |