dec.c revision 8b720228d581a84fd173b6dcb2fa295b59db489a
1// Copyright 2010 Google Inc. All Rights Reserved.
2//
3// Use of this source code is governed by a BSD-style license
4// that can be found in the COPYING file in the root of the source
5// tree. An additional intellectual property rights grant can be found
6// in the file PATENTS. All contributing project authors may
7// be found in the AUTHORS file in the root of the source tree.
8// -----------------------------------------------------------------------------
9//
10// Speed-critical decoding functions.
11//
12// Author: Skal (pascal.massimino@gmail.com)
13
14#include "./dsp.h"
15#include "../dec/vp8i.h"
16
17//------------------------------------------------------------------------------
18// run-time tables (~4k)
19
20static uint8_t abs0[255 + 255 + 1];     // abs(i)
21static uint8_t abs1[255 + 255 + 1];     // abs(i)>>1
22static int8_t sclip1[1020 + 1020 + 1];  // clips [-1020, 1020] to [-128, 127]
23static int8_t sclip2[112 + 112 + 1];    // clips [-112, 112] to [-16, 15]
24static uint8_t clip1[255 + 510 + 1];    // clips [-255,510] to [0,255]
25
26// We declare this variable 'volatile' to prevent instruction reordering
27// and make sure it's set to true _last_ (so as to be thread-safe)
28static volatile int tables_ok = 0;
29
30static void DspInitTables(void) {
31  if (!tables_ok) {
32    int i;
33    for (i = -255; i <= 255; ++i) {
34      abs0[255 + i] = (i < 0) ? -i : i;
35      abs1[255 + i] = abs0[255 + i] >> 1;
36    }
37    for (i = -1020; i <= 1020; ++i) {
38      sclip1[1020 + i] = (i < -128) ? -128 : (i > 127) ? 127 : i;
39    }
40    for (i = -112; i <= 112; ++i) {
41      sclip2[112 + i] = (i < -16) ? -16 : (i > 15) ? 15 : i;
42    }
43    for (i = -255; i <= 255 + 255; ++i) {
44      clip1[255 + i] = (i < 0) ? 0 : (i > 255) ? 255 : i;
45    }
46    tables_ok = 1;
47  }
48}
49
50static WEBP_INLINE uint8_t clip_8b(int v) {
51  return (!(v & ~0xff)) ? v : (v < 0) ? 0 : 255;
52}
53
54//------------------------------------------------------------------------------
55// Transforms (Paragraph 14.4)
56
57#define STORE(x, y, v) \
58  dst[x + y * BPS] = clip_8b(dst[x + y * BPS] + ((v) >> 3))
59
60#define STORE2(y, dc, d, c) do {    \
61  const int DC = (dc);              \
62  STORE(0, y, DC + (d));            \
63  STORE(1, y, DC + (c));            \
64  STORE(2, y, DC - (c));            \
65  STORE(3, y, DC - (d));            \
66} while (0)
67
68static const int kC1 = 20091 + (1 << 16);
69static const int kC2 = 35468;
70#define MUL(a, b) (((a) * (b)) >> 16)
71
72static void TransformOne(const int16_t* in, uint8_t* dst) {
73  int C[4 * 4], *tmp;
74  int i;
75  tmp = C;
76  for (i = 0; i < 4; ++i) {    // vertical pass
77    const int a = in[0] + in[8];    // [-4096, 4094]
78    const int b = in[0] - in[8];    // [-4095, 4095]
79    const int c = MUL(in[4], kC2) - MUL(in[12], kC1);   // [-3783, 3783]
80    const int d = MUL(in[4], kC1) + MUL(in[12], kC2);   // [-3785, 3781]
81    tmp[0] = a + d;   // [-7881, 7875]
82    tmp[1] = b + c;   // [-7878, 7878]
83    tmp[2] = b - c;   // [-7878, 7878]
84    tmp[3] = a - d;   // [-7877, 7879]
85    tmp += 4;
86    in++;
87  }
88  // Each pass is expanding the dynamic range by ~3.85 (upper bound).
89  // The exact value is (2. + (kC1 + kC2) / 65536).
90  // After the second pass, maximum interval is [-3794, 3794], assuming
91  // an input in [-2048, 2047] interval. We then need to add a dst value
92  // in the [0, 255] range.
93  // In the worst case scenario, the input to clip_8b() can be as large as
94  // [-60713, 60968].
95  tmp = C;
96  for (i = 0; i < 4; ++i) {    // horizontal pass
97    const int dc = tmp[0] + 4;
98    const int a =  dc +  tmp[8];
99    const int b =  dc -  tmp[8];
100    const int c = MUL(tmp[4], kC2) - MUL(tmp[12], kC1);
101    const int d = MUL(tmp[4], kC1) + MUL(tmp[12], kC2);
102    STORE(0, 0, a + d);
103    STORE(1, 0, b + c);
104    STORE(2, 0, b - c);
105    STORE(3, 0, a - d);
106    tmp++;
107    dst += BPS;
108  }
109}
110
111// Simplified transform when only in[0], in[1] and in[4] are non-zero
112static void TransformAC3(const int16_t* in, uint8_t* dst) {
113  const int a = in[0] + 4;
114  const int c4 = MUL(in[4], kC2);
115  const int d4 = MUL(in[4], kC1);
116  const int c1 = MUL(in[1], kC2);
117  const int d1 = MUL(in[1], kC1);
118  STORE2(0, a + d4, d1, c1);
119  STORE2(1, a + c4, d1, c1);
120  STORE2(2, a - c4, d1, c1);
121  STORE2(3, a - d4, d1, c1);
122}
123#undef MUL
124#undef STORE2
125
126static void TransformTwo(const int16_t* in, uint8_t* dst, int do_two) {
127  TransformOne(in, dst);
128  if (do_two) {
129    TransformOne(in + 16, dst + 4);
130  }
131}
132
133static void TransformUV(const int16_t* in, uint8_t* dst) {
134  VP8Transform(in + 0 * 16, dst, 1);
135  VP8Transform(in + 2 * 16, dst + 4 * BPS, 1);
136}
137
138static void TransformDC(const int16_t *in, uint8_t* dst) {
139  const int DC = in[0] + 4;
140  int i, j;
141  for (j = 0; j < 4; ++j) {
142    for (i = 0; i < 4; ++i) {
143      STORE(i, j, DC);
144    }
145  }
146}
147
148static void TransformDCUV(const int16_t* in, uint8_t* dst) {
149  if (in[0 * 16]) TransformDC(in + 0 * 16, dst);
150  if (in[1 * 16]) TransformDC(in + 1 * 16, dst + 4);
151  if (in[2 * 16]) TransformDC(in + 2 * 16, dst + 4 * BPS);
152  if (in[3 * 16]) TransformDC(in + 3 * 16, dst + 4 * BPS + 4);
153}
154
155#undef STORE
156
157//------------------------------------------------------------------------------
158// Paragraph 14.3
159
160static void TransformWHT(const int16_t* in, int16_t* out) {
161  int tmp[16];
162  int i;
163  for (i = 0; i < 4; ++i) {
164    const int a0 = in[0 + i] + in[12 + i];
165    const int a1 = in[4 + i] + in[ 8 + i];
166    const int a2 = in[4 + i] - in[ 8 + i];
167    const int a3 = in[0 + i] - in[12 + i];
168    tmp[0  + i] = a0 + a1;
169    tmp[8  + i] = a0 - a1;
170    tmp[4  + i] = a3 + a2;
171    tmp[12 + i] = a3 - a2;
172  }
173  for (i = 0; i < 4; ++i) {
174    const int dc = tmp[0 + i * 4] + 3;    // w/ rounder
175    const int a0 = dc             + tmp[3 + i * 4];
176    const int a1 = tmp[1 + i * 4] + tmp[2 + i * 4];
177    const int a2 = tmp[1 + i * 4] - tmp[2 + i * 4];
178    const int a3 = dc             - tmp[3 + i * 4];
179    out[ 0] = (a0 + a1) >> 3;
180    out[16] = (a3 + a2) >> 3;
181    out[32] = (a0 - a1) >> 3;
182    out[48] = (a3 - a2) >> 3;
183    out += 64;
184  }
185}
186
187void (*VP8TransformWHT)(const int16_t* in, int16_t* out) = TransformWHT;
188
189//------------------------------------------------------------------------------
190// Intra predictions
191
192#define DST(x, y) dst[(x) + (y) * BPS]
193
194static WEBP_INLINE void TrueMotion(uint8_t *dst, int size) {
195  const uint8_t* top = dst - BPS;
196  const uint8_t* const clip0 = clip1 + 255 - top[-1];
197  int y;
198  for (y = 0; y < size; ++y) {
199    const uint8_t* const clip = clip0 + dst[-1];
200    int x;
201    for (x = 0; x < size; ++x) {
202      dst[x] = clip[top[x]];
203    }
204    dst += BPS;
205  }
206}
207static void TM4(uint8_t *dst)   { TrueMotion(dst, 4); }
208static void TM8uv(uint8_t *dst) { TrueMotion(dst, 8); }
209static void TM16(uint8_t *dst)  { TrueMotion(dst, 16); }
210
211//------------------------------------------------------------------------------
212// 16x16
213
214static void VE16(uint8_t *dst) {     // vertical
215  int j;
216  for (j = 0; j < 16; ++j) {
217    memcpy(dst + j * BPS, dst - BPS, 16);
218  }
219}
220
221static void HE16(uint8_t *dst) {     // horizontal
222  int j;
223  for (j = 16; j > 0; --j) {
224    memset(dst, dst[-1], 16);
225    dst += BPS;
226  }
227}
228
229static WEBP_INLINE void Put16(int v, uint8_t* dst) {
230  int j;
231  for (j = 0; j < 16; ++j) {
232    memset(dst + j * BPS, v, 16);
233  }
234}
235
236static void DC16(uint8_t *dst) {    // DC
237  int DC = 16;
238  int j;
239  for (j = 0; j < 16; ++j) {
240    DC += dst[-1 + j * BPS] + dst[j - BPS];
241  }
242  Put16(DC >> 5, dst);
243}
244
245static void DC16NoTop(uint8_t *dst) {   // DC with top samples not available
246  int DC = 8;
247  int j;
248  for (j = 0; j < 16; ++j) {
249    DC += dst[-1 + j * BPS];
250  }
251  Put16(DC >> 4, dst);
252}
253
254static void DC16NoLeft(uint8_t *dst) {  // DC with left samples not available
255  int DC = 8;
256  int i;
257  for (i = 0; i < 16; ++i) {
258    DC += dst[i - BPS];
259  }
260  Put16(DC >> 4, dst);
261}
262
263static void DC16NoTopLeft(uint8_t *dst) {  // DC with no top and left samples
264  Put16(0x80, dst);
265}
266
267//------------------------------------------------------------------------------
268// 4x4
269
270#define AVG3(a, b, c) (((a) + 2 * (b) + (c) + 2) >> 2)
271#define AVG2(a, b) (((a) + (b) + 1) >> 1)
272
273static void VE4(uint8_t *dst) {    // vertical
274  const uint8_t* top = dst - BPS;
275  const uint8_t vals[4] = {
276    AVG3(top[-1], top[0], top[1]),
277    AVG3(top[ 0], top[1], top[2]),
278    AVG3(top[ 1], top[2], top[3]),
279    AVG3(top[ 2], top[3], top[4])
280  };
281  int i;
282  for (i = 0; i < 4; ++i) {
283    memcpy(dst + i * BPS, vals, sizeof(vals));
284  }
285}
286
287static void HE4(uint8_t *dst) {    // horizontal
288  const int A = dst[-1 - BPS];
289  const int B = dst[-1];
290  const int C = dst[-1 + BPS];
291  const int D = dst[-1 + 2 * BPS];
292  const int E = dst[-1 + 3 * BPS];
293  *(uint32_t*)(dst + 0 * BPS) = 0x01010101U * AVG3(A, B, C);
294  *(uint32_t*)(dst + 1 * BPS) = 0x01010101U * AVG3(B, C, D);
295  *(uint32_t*)(dst + 2 * BPS) = 0x01010101U * AVG3(C, D, E);
296  *(uint32_t*)(dst + 3 * BPS) = 0x01010101U * AVG3(D, E, E);
297}
298
299static void DC4(uint8_t *dst) {   // DC
300  uint32_t dc = 4;
301  int i;
302  for (i = 0; i < 4; ++i) dc += dst[i - BPS] + dst[-1 + i * BPS];
303  dc >>= 3;
304  for (i = 0; i < 4; ++i) memset(dst + i * BPS, dc, 4);
305}
306
307static void RD4(uint8_t *dst) {   // Down-right
308  const int I = dst[-1 + 0 * BPS];
309  const int J = dst[-1 + 1 * BPS];
310  const int K = dst[-1 + 2 * BPS];
311  const int L = dst[-1 + 3 * BPS];
312  const int X = dst[-1 - BPS];
313  const int A = dst[0 - BPS];
314  const int B = dst[1 - BPS];
315  const int C = dst[2 - BPS];
316  const int D = dst[3 - BPS];
317  DST(0, 3)                                     = AVG3(J, K, L);
318  DST(0, 2) = DST(1, 3)                         = AVG3(I, J, K);
319  DST(0, 1) = DST(1, 2) = DST(2, 3)             = AVG3(X, I, J);
320  DST(0, 0) = DST(1, 1) = DST(2, 2) = DST(3, 3) = AVG3(A, X, I);
321  DST(1, 0) = DST(2, 1) = DST(3, 2)             = AVG3(B, A, X);
322  DST(2, 0) = DST(3, 1)                         = AVG3(C, B, A);
323  DST(3, 0)                                     = AVG3(D, C, B);
324}
325
326static void LD4(uint8_t *dst) {   // Down-Left
327  const int A = dst[0 - BPS];
328  const int B = dst[1 - BPS];
329  const int C = dst[2 - BPS];
330  const int D = dst[3 - BPS];
331  const int E = dst[4 - BPS];
332  const int F = dst[5 - BPS];
333  const int G = dst[6 - BPS];
334  const int H = dst[7 - BPS];
335  DST(0, 0)                                     = AVG3(A, B, C);
336  DST(1, 0) = DST(0, 1)                         = AVG3(B, C, D);
337  DST(2, 0) = DST(1, 1) = DST(0, 2)             = AVG3(C, D, E);
338  DST(3, 0) = DST(2, 1) = DST(1, 2) = DST(0, 3) = AVG3(D, E, F);
339  DST(3, 1) = DST(2, 2) = DST(1, 3)             = AVG3(E, F, G);
340  DST(3, 2) = DST(2, 3)                         = AVG3(F, G, H);
341  DST(3, 3)                                     = AVG3(G, H, H);
342}
343
344static void VR4(uint8_t *dst) {   // Vertical-Right
345  const int I = dst[-1 + 0 * BPS];
346  const int J = dst[-1 + 1 * BPS];
347  const int K = dst[-1 + 2 * BPS];
348  const int X = dst[-1 - BPS];
349  const int A = dst[0 - BPS];
350  const int B = dst[1 - BPS];
351  const int C = dst[2 - BPS];
352  const int D = dst[3 - BPS];
353  DST(0, 0) = DST(1, 2) = AVG2(X, A);
354  DST(1, 0) = DST(2, 2) = AVG2(A, B);
355  DST(2, 0) = DST(3, 2) = AVG2(B, C);
356  DST(3, 0)             = AVG2(C, D);
357
358  DST(0, 3) =             AVG3(K, J, I);
359  DST(0, 2) =             AVG3(J, I, X);
360  DST(0, 1) = DST(1, 3) = AVG3(I, X, A);
361  DST(1, 1) = DST(2, 3) = AVG3(X, A, B);
362  DST(2, 1) = DST(3, 3) = AVG3(A, B, C);
363  DST(3, 1) =             AVG3(B, C, D);
364}
365
366static void VL4(uint8_t *dst) {   // Vertical-Left
367  const int A = dst[0 - BPS];
368  const int B = dst[1 - BPS];
369  const int C = dst[2 - BPS];
370  const int D = dst[3 - BPS];
371  const int E = dst[4 - BPS];
372  const int F = dst[5 - BPS];
373  const int G = dst[6 - BPS];
374  const int H = dst[7 - BPS];
375  DST(0, 0) =             AVG2(A, B);
376  DST(1, 0) = DST(0, 2) = AVG2(B, C);
377  DST(2, 0) = DST(1, 2) = AVG2(C, D);
378  DST(3, 0) = DST(2, 2) = AVG2(D, E);
379
380  DST(0, 1) =             AVG3(A, B, C);
381  DST(1, 1) = DST(0, 3) = AVG3(B, C, D);
382  DST(2, 1) = DST(1, 3) = AVG3(C, D, E);
383  DST(3, 1) = DST(2, 3) = AVG3(D, E, F);
384              DST(3, 2) = AVG3(E, F, G);
385              DST(3, 3) = AVG3(F, G, H);
386}
387
388static void HU4(uint8_t *dst) {   // Horizontal-Up
389  const int I = dst[-1 + 0 * BPS];
390  const int J = dst[-1 + 1 * BPS];
391  const int K = dst[-1 + 2 * BPS];
392  const int L = dst[-1 + 3 * BPS];
393  DST(0, 0) =             AVG2(I, J);
394  DST(2, 0) = DST(0, 1) = AVG2(J, K);
395  DST(2, 1) = DST(0, 2) = AVG2(K, L);
396  DST(1, 0) =             AVG3(I, J, K);
397  DST(3, 0) = DST(1, 1) = AVG3(J, K, L);
398  DST(3, 1) = DST(1, 2) = AVG3(K, L, L);
399  DST(3, 2) = DST(2, 2) =
400    DST(0, 3) = DST(1, 3) = DST(2, 3) = DST(3, 3) = L;
401}
402
403static void HD4(uint8_t *dst) {  // Horizontal-Down
404  const int I = dst[-1 + 0 * BPS];
405  const int J = dst[-1 + 1 * BPS];
406  const int K = dst[-1 + 2 * BPS];
407  const int L = dst[-1 + 3 * BPS];
408  const int X = dst[-1 - BPS];
409  const int A = dst[0 - BPS];
410  const int B = dst[1 - BPS];
411  const int C = dst[2 - BPS];
412
413  DST(0, 0) = DST(2, 1) = AVG2(I, X);
414  DST(0, 1) = DST(2, 2) = AVG2(J, I);
415  DST(0, 2) = DST(2, 3) = AVG2(K, J);
416  DST(0, 3)             = AVG2(L, K);
417
418  DST(3, 0)             = AVG3(A, B, C);
419  DST(2, 0)             = AVG3(X, A, B);
420  DST(1, 0) = DST(3, 1) = AVG3(I, X, A);
421  DST(1, 1) = DST(3, 2) = AVG3(J, I, X);
422  DST(1, 2) = DST(3, 3) = AVG3(K, J, I);
423  DST(1, 3)             = AVG3(L, K, J);
424}
425
426#undef DST
427#undef AVG3
428#undef AVG2
429
430//------------------------------------------------------------------------------
431// Chroma
432
433static void VE8uv(uint8_t *dst) {    // vertical
434  int j;
435  for (j = 0; j < 8; ++j) {
436    memcpy(dst + j * BPS, dst - BPS, 8);
437  }
438}
439
440static void HE8uv(uint8_t *dst) {    // horizontal
441  int j;
442  for (j = 0; j < 8; ++j) {
443    memset(dst, dst[-1], 8);
444    dst += BPS;
445  }
446}
447
448// helper for chroma-DC predictions
449static WEBP_INLINE void Put8x8uv(uint8_t value, uint8_t* dst) {
450  int j;
451#ifndef WEBP_REFERENCE_IMPLEMENTATION
452  const uint64_t v = (uint64_t)value * 0x0101010101010101ULL;
453  for (j = 0; j < 8; ++j) {
454    *(uint64_t*)(dst + j * BPS) = v;
455  }
456#else
457  for (j = 0; j < 8; ++j) memset(dst + j * BPS, value, 8);
458#endif
459}
460
461static void DC8uv(uint8_t *dst) {     // DC
462  int dc0 = 8;
463  int i;
464  for (i = 0; i < 8; ++i) {
465    dc0 += dst[i - BPS] + dst[-1 + i * BPS];
466  }
467  Put8x8uv(dc0 >> 4, dst);
468}
469
470static void DC8uvNoLeft(uint8_t *dst) {   // DC with no left samples
471  int dc0 = 4;
472  int i;
473  for (i = 0; i < 8; ++i) {
474    dc0 += dst[i - BPS];
475  }
476  Put8x8uv(dc0 >> 3, dst);
477}
478
479static void DC8uvNoTop(uint8_t *dst) {  // DC with no top samples
480  int dc0 = 4;
481  int i;
482  for (i = 0; i < 8; ++i) {
483    dc0 += dst[-1 + i * BPS];
484  }
485  Put8x8uv(dc0 >> 3, dst);
486}
487
488static void DC8uvNoTopLeft(uint8_t *dst) {    // DC with nothing
489  Put8x8uv(0x80, dst);
490}
491
492//------------------------------------------------------------------------------
493// default C implementations
494
495const VP8PredFunc VP8PredLuma4[NUM_BMODES] = {
496  DC4, TM4, VE4, HE4, RD4, VR4, LD4, VL4, HD4, HU4
497};
498
499const VP8PredFunc VP8PredLuma16[NUM_B_DC_MODES] = {
500  DC16, TM16, VE16, HE16,
501  DC16NoTop, DC16NoLeft, DC16NoTopLeft
502};
503
504const VP8PredFunc VP8PredChroma8[NUM_B_DC_MODES] = {
505  DC8uv, TM8uv, VE8uv, HE8uv,
506  DC8uvNoTop, DC8uvNoLeft, DC8uvNoTopLeft
507};
508
509//------------------------------------------------------------------------------
510// Edge filtering functions
511
512// 4 pixels in, 2 pixels out
513static WEBP_INLINE void do_filter2(uint8_t* p, int step) {
514  const int p1 = p[-2*step], p0 = p[-step], q0 = p[0], q1 = p[step];
515  const int a = 3 * (q0 - p0) + sclip1[1020 + p1 - q1];
516  const int a1 = sclip2[112 + ((a + 4) >> 3)];
517  const int a2 = sclip2[112 + ((a + 3) >> 3)];
518  p[-step] = clip1[255 + p0 + a2];
519  p[    0] = clip1[255 + q0 - a1];
520}
521
522// 4 pixels in, 4 pixels out
523static WEBP_INLINE void do_filter4(uint8_t* p, int step) {
524  const int p1 = p[-2*step], p0 = p[-step], q0 = p[0], q1 = p[step];
525  const int a = 3 * (q0 - p0);
526  const int a1 = sclip2[112 + ((a + 4) >> 3)];
527  const int a2 = sclip2[112 + ((a + 3) >> 3)];
528  const int a3 = (a1 + 1) >> 1;
529  p[-2*step] = clip1[255 + p1 + a3];
530  p[-  step] = clip1[255 + p0 + a2];
531  p[      0] = clip1[255 + q0 - a1];
532  p[   step] = clip1[255 + q1 - a3];
533}
534
535// 6 pixels in, 6 pixels out
536static WEBP_INLINE void do_filter6(uint8_t* p, int step) {
537  const int p2 = p[-3*step], p1 = p[-2*step], p0 = p[-step];
538  const int q0 = p[0], q1 = p[step], q2 = p[2*step];
539  const int a = sclip1[1020 + 3 * (q0 - p0) + sclip1[1020 + p1 - q1]];
540  const int a1 = (27 * a + 63) >> 7;  // eq. to ((3 * a + 7) * 9) >> 7
541  const int a2 = (18 * a + 63) >> 7;  // eq. to ((2 * a + 7) * 9) >> 7
542  const int a3 = (9  * a + 63) >> 7;  // eq. to ((1 * a + 7) * 9) >> 7
543  p[-3*step] = clip1[255 + p2 + a3];
544  p[-2*step] = clip1[255 + p1 + a2];
545  p[-  step] = clip1[255 + p0 + a1];
546  p[      0] = clip1[255 + q0 - a1];
547  p[   step] = clip1[255 + q1 - a2];
548  p[ 2*step] = clip1[255 + q2 - a3];
549}
550
551static WEBP_INLINE int hev(const uint8_t* p, int step, int thresh) {
552  const int p1 = p[-2*step], p0 = p[-step], q0 = p[0], q1 = p[step];
553  return (abs0[255 + p1 - p0] > thresh) || (abs0[255 + q1 - q0] > thresh);
554}
555
556static WEBP_INLINE int needs_filter(const uint8_t* p, int step, int thresh) {
557  const int p1 = p[-2*step], p0 = p[-step], q0 = p[0], q1 = p[step];
558  return (2 * abs0[255 + p0 - q0] + abs1[255 + p1 - q1]) <= thresh;
559}
560
561static WEBP_INLINE int needs_filter2(const uint8_t* p,
562                                     int step, int t, int it) {
563  const int p3 = p[-4*step], p2 = p[-3*step], p1 = p[-2*step], p0 = p[-step];
564  const int q0 = p[0], q1 = p[step], q2 = p[2*step], q3 = p[3*step];
565  if ((2 * abs0[255 + p0 - q0] + abs1[255 + p1 - q1]) > t)
566    return 0;
567  return abs0[255 + p3 - p2] <= it && abs0[255 + p2 - p1] <= it &&
568         abs0[255 + p1 - p0] <= it && abs0[255 + q3 - q2] <= it &&
569         abs0[255 + q2 - q1] <= it && abs0[255 + q1 - q0] <= it;
570}
571
572//------------------------------------------------------------------------------
573// Simple In-loop filtering (Paragraph 15.2)
574
575static void SimpleVFilter16(uint8_t* p, int stride, int thresh) {
576  int i;
577  for (i = 0; i < 16; ++i) {
578    if (needs_filter(p + i, stride, thresh)) {
579      do_filter2(p + i, stride);
580    }
581  }
582}
583
584static void SimpleHFilter16(uint8_t* p, int stride, int thresh) {
585  int i;
586  for (i = 0; i < 16; ++i) {
587    if (needs_filter(p + i * stride, 1, thresh)) {
588      do_filter2(p + i * stride, 1);
589    }
590  }
591}
592
593static void SimpleVFilter16i(uint8_t* p, int stride, int thresh) {
594  int k;
595  for (k = 3; k > 0; --k) {
596    p += 4 * stride;
597    SimpleVFilter16(p, stride, thresh);
598  }
599}
600
601static void SimpleHFilter16i(uint8_t* p, int stride, int thresh) {
602  int k;
603  for (k = 3; k > 0; --k) {
604    p += 4;
605    SimpleHFilter16(p, stride, thresh);
606  }
607}
608
609//------------------------------------------------------------------------------
610// Complex In-loop filtering (Paragraph 15.3)
611
612static WEBP_INLINE void FilterLoop26(uint8_t* p,
613                                     int hstride, int vstride, int size,
614                                     int thresh, int ithresh, int hev_thresh) {
615  while (size-- > 0) {
616    if (needs_filter2(p, hstride, thresh, ithresh)) {
617      if (hev(p, hstride, hev_thresh)) {
618        do_filter2(p, hstride);
619      } else {
620        do_filter6(p, hstride);
621      }
622    }
623    p += vstride;
624  }
625}
626
627static WEBP_INLINE void FilterLoop24(uint8_t* p,
628                                     int hstride, int vstride, int size,
629                                     int thresh, int ithresh, int hev_thresh) {
630  while (size-- > 0) {
631    if (needs_filter2(p, hstride, thresh, ithresh)) {
632      if (hev(p, hstride, hev_thresh)) {
633        do_filter2(p, hstride);
634      } else {
635        do_filter4(p, hstride);
636      }
637    }
638    p += vstride;
639  }
640}
641
642// on macroblock edges
643static void VFilter16(uint8_t* p, int stride,
644                      int thresh, int ithresh, int hev_thresh) {
645  FilterLoop26(p, stride, 1, 16, thresh, ithresh, hev_thresh);
646}
647
648static void HFilter16(uint8_t* p, int stride,
649                      int thresh, int ithresh, int hev_thresh) {
650  FilterLoop26(p, 1, stride, 16, thresh, ithresh, hev_thresh);
651}
652
653// on three inner edges
654static void VFilter16i(uint8_t* p, int stride,
655                       int thresh, int ithresh, int hev_thresh) {
656  int k;
657  for (k = 3; k > 0; --k) {
658    p += 4 * stride;
659    FilterLoop24(p, stride, 1, 16, thresh, ithresh, hev_thresh);
660  }
661}
662
663static void HFilter16i(uint8_t* p, int stride,
664                       int thresh, int ithresh, int hev_thresh) {
665  int k;
666  for (k = 3; k > 0; --k) {
667    p += 4;
668    FilterLoop24(p, 1, stride, 16, thresh, ithresh, hev_thresh);
669  }
670}
671
672// 8-pixels wide variant, for chroma filtering
673static void VFilter8(uint8_t* u, uint8_t* v, int stride,
674                     int thresh, int ithresh, int hev_thresh) {
675  FilterLoop26(u, stride, 1, 8, thresh, ithresh, hev_thresh);
676  FilterLoop26(v, stride, 1, 8, thresh, ithresh, hev_thresh);
677}
678
679static void HFilter8(uint8_t* u, uint8_t* v, int stride,
680                     int thresh, int ithresh, int hev_thresh) {
681  FilterLoop26(u, 1, stride, 8, thresh, ithresh, hev_thresh);
682  FilterLoop26(v, 1, stride, 8, thresh, ithresh, hev_thresh);
683}
684
685static void VFilter8i(uint8_t* u, uint8_t* v, int stride,
686                      int thresh, int ithresh, int hev_thresh) {
687  FilterLoop24(u + 4 * stride, stride, 1, 8, thresh, ithresh, hev_thresh);
688  FilterLoop24(v + 4 * stride, stride, 1, 8, thresh, ithresh, hev_thresh);
689}
690
691static void HFilter8i(uint8_t* u, uint8_t* v, int stride,
692                      int thresh, int ithresh, int hev_thresh) {
693  FilterLoop24(u + 4, 1, stride, 8, thresh, ithresh, hev_thresh);
694  FilterLoop24(v + 4, 1, stride, 8, thresh, ithresh, hev_thresh);
695}
696
697//------------------------------------------------------------------------------
698
699VP8DecIdct2 VP8Transform;
700VP8DecIdct VP8TransformAC3;
701VP8DecIdct VP8TransformUV;
702VP8DecIdct VP8TransformDC;
703VP8DecIdct VP8TransformDCUV;
704
705VP8LumaFilterFunc VP8VFilter16;
706VP8LumaFilterFunc VP8HFilter16;
707VP8ChromaFilterFunc VP8VFilter8;
708VP8ChromaFilterFunc VP8HFilter8;
709VP8LumaFilterFunc VP8VFilter16i;
710VP8LumaFilterFunc VP8HFilter16i;
711VP8ChromaFilterFunc VP8VFilter8i;
712VP8ChromaFilterFunc VP8HFilter8i;
713VP8SimpleFilterFunc VP8SimpleVFilter16;
714VP8SimpleFilterFunc VP8SimpleHFilter16;
715VP8SimpleFilterFunc VP8SimpleVFilter16i;
716VP8SimpleFilterFunc VP8SimpleHFilter16i;
717
718extern void VP8DspInitSSE2(void);
719extern void VP8DspInitNEON(void);
720
721void VP8DspInit(void) {
722  DspInitTables();
723
724  VP8Transform = TransformTwo;
725  VP8TransformUV = TransformUV;
726  VP8TransformDC = TransformDC;
727  VP8TransformDCUV = TransformDCUV;
728  VP8TransformAC3 = TransformAC3;
729
730  VP8VFilter16 = VFilter16;
731  VP8HFilter16 = HFilter16;
732  VP8VFilter8 = VFilter8;
733  VP8HFilter8 = HFilter8;
734  VP8VFilter16i = VFilter16i;
735  VP8HFilter16i = HFilter16i;
736  VP8VFilter8i = VFilter8i;
737  VP8HFilter8i = HFilter8i;
738  VP8SimpleVFilter16 = SimpleVFilter16;
739  VP8SimpleHFilter16 = SimpleHFilter16;
740  VP8SimpleVFilter16i = SimpleVFilter16i;
741  VP8SimpleHFilter16i = SimpleHFilter16i;
742
743  // If defined, use CPUInfo() to overwrite some pointers with faster versions.
744  if (VP8GetCPUInfo) {
745#if defined(WEBP_USE_SSE2)
746    if (VP8GetCPUInfo(kSSE2)) {
747      VP8DspInitSSE2();
748    }
749#elif defined(WEBP_USE_NEON)
750    if (VP8GetCPUInfo(kNEON)) {
751      VP8DspInitNEON();
752    }
753#endif
754  }
755}
756
757