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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, default plain-C implementations.
11 //
12 // Author: Skal (pascal.massimino@gmail.com)
13 
14 #include "./dsp.h"
15 #include "../dec/vp8i.h"
16 
17 //------------------------------------------------------------------------------
18 
clip_8b(int v)19 static WEBP_INLINE uint8_t clip_8b(int v) {
20   return (!(v & ~0xff)) ? v : (v < 0) ? 0 : 255;
21 }
22 
23 //------------------------------------------------------------------------------
24 // Transforms (Paragraph 14.4)
25 
26 #define STORE(x, y, v) \
27   dst[x + y * BPS] = clip_8b(dst[x + y * BPS] + ((v) >> 3))
28 
29 #define STORE2(y, dc, d, c) do {    \
30   const int DC = (dc);              \
31   STORE(0, y, DC + (d));            \
32   STORE(1, y, DC + (c));            \
33   STORE(2, y, DC - (c));            \
34   STORE(3, y, DC - (d));            \
35 } while (0)
36 
37 #define MUL1(a) ((((a) * 20091) >> 16) + (a))
38 #define MUL2(a) (((a) * 35468) >> 16)
39 
TransformOne(const int16_t * in,uint8_t * dst)40 static void TransformOne(const int16_t* in, uint8_t* dst) {
41   int C[4 * 4], *tmp;
42   int i;
43   tmp = C;
44   for (i = 0; i < 4; ++i) {    // vertical pass
45     const int a = in[0] + in[8];    // [-4096, 4094]
46     const int b = in[0] - in[8];    // [-4095, 4095]
47     const int c = MUL2(in[4]) - MUL1(in[12]);   // [-3783, 3783]
48     const int d = MUL1(in[4]) + MUL2(in[12]);   // [-3785, 3781]
49     tmp[0] = a + d;   // [-7881, 7875]
50     tmp[1] = b + c;   // [-7878, 7878]
51     tmp[2] = b - c;   // [-7878, 7878]
52     tmp[3] = a - d;   // [-7877, 7879]
53     tmp += 4;
54     in++;
55   }
56   // Each pass is expanding the dynamic range by ~3.85 (upper bound).
57   // The exact value is (2. + (20091 + 35468) / 65536).
58   // After the second pass, maximum interval is [-3794, 3794], assuming
59   // an input in [-2048, 2047] interval. We then need to add a dst value
60   // in the [0, 255] range.
61   // In the worst case scenario, the input to clip_8b() can be as large as
62   // [-60713, 60968].
63   tmp = C;
64   for (i = 0; i < 4; ++i) {    // horizontal pass
65     const int dc = tmp[0] + 4;
66     const int a =  dc +  tmp[8];
67     const int b =  dc -  tmp[8];
68     const int c = MUL2(tmp[4]) - MUL1(tmp[12]);
69     const int d = MUL1(tmp[4]) + MUL2(tmp[12]);
70     STORE(0, 0, a + d);
71     STORE(1, 0, b + c);
72     STORE(2, 0, b - c);
73     STORE(3, 0, a - d);
74     tmp++;
75     dst += BPS;
76   }
77 }
78 
79 // Simplified transform when only in[0], in[1] and in[4] are non-zero
TransformAC3(const int16_t * in,uint8_t * dst)80 static void TransformAC3(const int16_t* in, uint8_t* dst) {
81   const int a = in[0] + 4;
82   const int c4 = MUL2(in[4]);
83   const int d4 = MUL1(in[4]);
84   const int c1 = MUL2(in[1]);
85   const int d1 = MUL1(in[1]);
86   STORE2(0, a + d4, d1, c1);
87   STORE2(1, a + c4, d1, c1);
88   STORE2(2, a - c4, d1, c1);
89   STORE2(3, a - d4, d1, c1);
90 }
91 #undef MUL1
92 #undef MUL2
93 #undef STORE2
94 
TransformTwo(const int16_t * in,uint8_t * dst,int do_two)95 static void TransformTwo(const int16_t* in, uint8_t* dst, int do_two) {
96   TransformOne(in, dst);
97   if (do_two) {
98     TransformOne(in + 16, dst + 4);
99   }
100 }
101 
TransformUV(const int16_t * in,uint8_t * dst)102 static void TransformUV(const int16_t* in, uint8_t* dst) {
103   VP8Transform(in + 0 * 16, dst, 1);
104   VP8Transform(in + 2 * 16, dst + 4 * BPS, 1);
105 }
106 
TransformDC(const int16_t * in,uint8_t * dst)107 static void TransformDC(const int16_t* in, uint8_t* dst) {
108   const int DC = in[0] + 4;
109   int i, j;
110   for (j = 0; j < 4; ++j) {
111     for (i = 0; i < 4; ++i) {
112       STORE(i, j, DC);
113     }
114   }
115 }
116 
TransformDCUV(const int16_t * in,uint8_t * dst)117 static void TransformDCUV(const int16_t* in, uint8_t* dst) {
118   if (in[0 * 16]) VP8TransformDC(in + 0 * 16, dst);
119   if (in[1 * 16]) VP8TransformDC(in + 1 * 16, dst + 4);
120   if (in[2 * 16]) VP8TransformDC(in + 2 * 16, dst + 4 * BPS);
121   if (in[3 * 16]) VP8TransformDC(in + 3 * 16, dst + 4 * BPS + 4);
122 }
123 
124 #undef STORE
125 
126 //------------------------------------------------------------------------------
127 // Paragraph 14.3
128 
TransformWHT(const int16_t * in,int16_t * out)129 static void TransformWHT(const int16_t* in, int16_t* out) {
130   int tmp[16];
131   int i;
132   for (i = 0; i < 4; ++i) {
133     const int a0 = in[0 + i] + in[12 + i];
134     const int a1 = in[4 + i] + in[ 8 + i];
135     const int a2 = in[4 + i] - in[ 8 + i];
136     const int a3 = in[0 + i] - in[12 + i];
137     tmp[0  + i] = a0 + a1;
138     tmp[8  + i] = a0 - a1;
139     tmp[4  + i] = a3 + a2;
140     tmp[12 + i] = a3 - a2;
141   }
142   for (i = 0; i < 4; ++i) {
143     const int dc = tmp[0 + i * 4] + 3;    // w/ rounder
144     const int a0 = dc             + tmp[3 + i * 4];
145     const int a1 = tmp[1 + i * 4] + tmp[2 + i * 4];
146     const int a2 = tmp[1 + i * 4] - tmp[2 + i * 4];
147     const int a3 = dc             - tmp[3 + i * 4];
148     out[ 0] = (a0 + a1) >> 3;
149     out[16] = (a3 + a2) >> 3;
150     out[32] = (a0 - a1) >> 3;
151     out[48] = (a3 - a2) >> 3;
152     out += 64;
153   }
154 }
155 
156 void (*VP8TransformWHT)(const int16_t* in, int16_t* out);
157 
158 //------------------------------------------------------------------------------
159 // Intra predictions
160 
161 #define DST(x, y) dst[(x) + (y) * BPS]
162 
TrueMotion(uint8_t * dst,int size)163 static WEBP_INLINE void TrueMotion(uint8_t* dst, int size) {
164   const uint8_t* top = dst - BPS;
165   const uint8_t* const clip0 = VP8kclip1 - top[-1];
166   int y;
167   for (y = 0; y < size; ++y) {
168     const uint8_t* const clip = clip0 + dst[-1];
169     int x;
170     for (x = 0; x < size; ++x) {
171       dst[x] = clip[top[x]];
172     }
173     dst += BPS;
174   }
175 }
TM4(uint8_t * dst)176 static void TM4(uint8_t* dst)   { TrueMotion(dst, 4); }
TM8uv(uint8_t * dst)177 static void TM8uv(uint8_t* dst) { TrueMotion(dst, 8); }
TM16(uint8_t * dst)178 static void TM16(uint8_t* dst)  { TrueMotion(dst, 16); }
179 
180 //------------------------------------------------------------------------------
181 // 16x16
182 
VE16(uint8_t * dst)183 static void VE16(uint8_t* dst) {     // vertical
184   int j;
185   for (j = 0; j < 16; ++j) {
186     memcpy(dst + j * BPS, dst - BPS, 16);
187   }
188 }
189 
HE16(uint8_t * dst)190 static void HE16(uint8_t* dst) {     // horizontal
191   int j;
192   for (j = 16; j > 0; --j) {
193     memset(dst, dst[-1], 16);
194     dst += BPS;
195   }
196 }
197 
Put16(int v,uint8_t * dst)198 static WEBP_INLINE void Put16(int v, uint8_t* dst) {
199   int j;
200   for (j = 0; j < 16; ++j) {
201     memset(dst + j * BPS, v, 16);
202   }
203 }
204 
DC16(uint8_t * dst)205 static void DC16(uint8_t* dst) {    // DC
206   int DC = 16;
207   int j;
208   for (j = 0; j < 16; ++j) {
209     DC += dst[-1 + j * BPS] + dst[j - BPS];
210   }
211   Put16(DC >> 5, dst);
212 }
213 
DC16NoTop(uint8_t * dst)214 static void DC16NoTop(uint8_t* dst) {   // DC with top samples not available
215   int DC = 8;
216   int j;
217   for (j = 0; j < 16; ++j) {
218     DC += dst[-1 + j * BPS];
219   }
220   Put16(DC >> 4, dst);
221 }
222 
DC16NoLeft(uint8_t * dst)223 static void DC16NoLeft(uint8_t* dst) {  // DC with left samples not available
224   int DC = 8;
225   int i;
226   for (i = 0; i < 16; ++i) {
227     DC += dst[i - BPS];
228   }
229   Put16(DC >> 4, dst);
230 }
231 
DC16NoTopLeft(uint8_t * dst)232 static void DC16NoTopLeft(uint8_t* dst) {  // DC with no top and left samples
233   Put16(0x80, dst);
234 }
235 
236 VP8PredFunc VP8PredLuma16[NUM_B_DC_MODES];
237 
238 //------------------------------------------------------------------------------
239 // 4x4
240 
241 #define AVG3(a, b, c) (((a) + 2 * (b) + (c) + 2) >> 2)
242 #define AVG2(a, b) (((a) + (b) + 1) >> 1)
243 
VE4(uint8_t * dst)244 static void VE4(uint8_t* dst) {    // vertical
245   const uint8_t* top = dst - BPS;
246   const uint8_t vals[4] = {
247     AVG3(top[-1], top[0], top[1]),
248     AVG3(top[ 0], top[1], top[2]),
249     AVG3(top[ 1], top[2], top[3]),
250     AVG3(top[ 2], top[3], top[4])
251   };
252   int i;
253   for (i = 0; i < 4; ++i) {
254     memcpy(dst + i * BPS, vals, sizeof(vals));
255   }
256 }
257 
HE4(uint8_t * dst)258 static void HE4(uint8_t* dst) {    // horizontal
259   const int A = dst[-1 - BPS];
260   const int B = dst[-1];
261   const int C = dst[-1 + BPS];
262   const int D = dst[-1 + 2 * BPS];
263   const int E = dst[-1 + 3 * BPS];
264   WebPUint32ToMem(dst + 0 * BPS, 0x01010101U * AVG3(A, B, C));
265   WebPUint32ToMem(dst + 1 * BPS, 0x01010101U * AVG3(B, C, D));
266   WebPUint32ToMem(dst + 2 * BPS, 0x01010101U * AVG3(C, D, E));
267   WebPUint32ToMem(dst + 3 * BPS, 0x01010101U * AVG3(D, E, E));
268 }
269 
DC4(uint8_t * dst)270 static void DC4(uint8_t* dst) {   // DC
271   uint32_t dc = 4;
272   int i;
273   for (i = 0; i < 4; ++i) dc += dst[i - BPS] + dst[-1 + i * BPS];
274   dc >>= 3;
275   for (i = 0; i < 4; ++i) memset(dst + i * BPS, dc, 4);
276 }
277 
RD4(uint8_t * dst)278 static void RD4(uint8_t* dst) {   // Down-right
279   const int I = dst[-1 + 0 * BPS];
280   const int J = dst[-1 + 1 * BPS];
281   const int K = dst[-1 + 2 * BPS];
282   const int L = dst[-1 + 3 * BPS];
283   const int X = dst[-1 - BPS];
284   const int A = dst[0 - BPS];
285   const int B = dst[1 - BPS];
286   const int C = dst[2 - BPS];
287   const int D = dst[3 - BPS];
288   DST(0, 3)                                     = AVG3(J, K, L);
289   DST(1, 3) = DST(0, 2)                         = AVG3(I, J, K);
290   DST(2, 3) = DST(1, 2) = DST(0, 1)             = AVG3(X, I, J);
291   DST(3, 3) = DST(2, 2) = DST(1, 1) = DST(0, 0) = AVG3(A, X, I);
292               DST(3, 2) = DST(2, 1) = DST(1, 0) = AVG3(B, A, X);
293                           DST(3, 1) = DST(2, 0) = AVG3(C, B, A);
294                                       DST(3, 0) = AVG3(D, C, B);
295 }
296 
LD4(uint8_t * dst)297 static void LD4(uint8_t* dst) {   // Down-Left
298   const int A = dst[0 - BPS];
299   const int B = dst[1 - BPS];
300   const int C = dst[2 - BPS];
301   const int D = dst[3 - BPS];
302   const int E = dst[4 - BPS];
303   const int F = dst[5 - BPS];
304   const int G = dst[6 - BPS];
305   const int H = dst[7 - BPS];
306   DST(0, 0)                                     = AVG3(A, B, C);
307   DST(1, 0) = DST(0, 1)                         = AVG3(B, C, D);
308   DST(2, 0) = DST(1, 1) = DST(0, 2)             = AVG3(C, D, E);
309   DST(3, 0) = DST(2, 1) = DST(1, 2) = DST(0, 3) = AVG3(D, E, F);
310               DST(3, 1) = DST(2, 2) = DST(1, 3) = AVG3(E, F, G);
311                           DST(3, 2) = DST(2, 3) = AVG3(F, G, H);
312                                       DST(3, 3) = AVG3(G, H, H);
313 }
314 
VR4(uint8_t * dst)315 static void VR4(uint8_t* dst) {   // Vertical-Right
316   const int I = dst[-1 + 0 * BPS];
317   const int J = dst[-1 + 1 * BPS];
318   const int K = dst[-1 + 2 * BPS];
319   const int X = dst[-1 - BPS];
320   const int A = dst[0 - BPS];
321   const int B = dst[1 - BPS];
322   const int C = dst[2 - BPS];
323   const int D = dst[3 - BPS];
324   DST(0, 0) = DST(1, 2) = AVG2(X, A);
325   DST(1, 0) = DST(2, 2) = AVG2(A, B);
326   DST(2, 0) = DST(3, 2) = AVG2(B, C);
327   DST(3, 0)             = AVG2(C, D);
328 
329   DST(0, 3) =             AVG3(K, J, I);
330   DST(0, 2) =             AVG3(J, I, X);
331   DST(0, 1) = DST(1, 3) = AVG3(I, X, A);
332   DST(1, 1) = DST(2, 3) = AVG3(X, A, B);
333   DST(2, 1) = DST(3, 3) = AVG3(A, B, C);
334   DST(3, 1) =             AVG3(B, C, D);
335 }
336 
VL4(uint8_t * dst)337 static void VL4(uint8_t* dst) {   // Vertical-Left
338   const int A = dst[0 - BPS];
339   const int B = dst[1 - BPS];
340   const int C = dst[2 - BPS];
341   const int D = dst[3 - BPS];
342   const int E = dst[4 - BPS];
343   const int F = dst[5 - BPS];
344   const int G = dst[6 - BPS];
345   const int H = dst[7 - BPS];
346   DST(0, 0) =             AVG2(A, B);
347   DST(1, 0) = DST(0, 2) = AVG2(B, C);
348   DST(2, 0) = DST(1, 2) = AVG2(C, D);
349   DST(3, 0) = DST(2, 2) = AVG2(D, E);
350 
351   DST(0, 1) =             AVG3(A, B, C);
352   DST(1, 1) = DST(0, 3) = AVG3(B, C, D);
353   DST(2, 1) = DST(1, 3) = AVG3(C, D, E);
354   DST(3, 1) = DST(2, 3) = AVG3(D, E, F);
355               DST(3, 2) = AVG3(E, F, G);
356               DST(3, 3) = AVG3(F, G, H);
357 }
358 
HU4(uint8_t * dst)359 static void HU4(uint8_t* dst) {   // Horizontal-Up
360   const int I = dst[-1 + 0 * BPS];
361   const int J = dst[-1 + 1 * BPS];
362   const int K = dst[-1 + 2 * BPS];
363   const int L = dst[-1 + 3 * BPS];
364   DST(0, 0) =             AVG2(I, J);
365   DST(2, 0) = DST(0, 1) = AVG2(J, K);
366   DST(2, 1) = DST(0, 2) = AVG2(K, L);
367   DST(1, 0) =             AVG3(I, J, K);
368   DST(3, 0) = DST(1, 1) = AVG3(J, K, L);
369   DST(3, 1) = DST(1, 2) = AVG3(K, L, L);
370   DST(3, 2) = DST(2, 2) =
371     DST(0, 3) = DST(1, 3) = DST(2, 3) = DST(3, 3) = L;
372 }
373 
HD4(uint8_t * dst)374 static void HD4(uint8_t* dst) {  // Horizontal-Down
375   const int I = dst[-1 + 0 * BPS];
376   const int J = dst[-1 + 1 * BPS];
377   const int K = dst[-1 + 2 * BPS];
378   const int L = dst[-1 + 3 * BPS];
379   const int X = dst[-1 - BPS];
380   const int A = dst[0 - BPS];
381   const int B = dst[1 - BPS];
382   const int C = dst[2 - BPS];
383 
384   DST(0, 0) = DST(2, 1) = AVG2(I, X);
385   DST(0, 1) = DST(2, 2) = AVG2(J, I);
386   DST(0, 2) = DST(2, 3) = AVG2(K, J);
387   DST(0, 3)             = AVG2(L, K);
388 
389   DST(3, 0)             = AVG3(A, B, C);
390   DST(2, 0)             = AVG3(X, A, B);
391   DST(1, 0) = DST(3, 1) = AVG3(I, X, A);
392   DST(1, 1) = DST(3, 2) = AVG3(J, I, X);
393   DST(1, 2) = DST(3, 3) = AVG3(K, J, I);
394   DST(1, 3)             = AVG3(L, K, J);
395 }
396 
397 #undef DST
398 #undef AVG3
399 #undef AVG2
400 
401 VP8PredFunc VP8PredLuma4[NUM_BMODES];
402 
403 //------------------------------------------------------------------------------
404 // Chroma
405 
VE8uv(uint8_t * dst)406 static void VE8uv(uint8_t* dst) {    // vertical
407   int j;
408   for (j = 0; j < 8; ++j) {
409     memcpy(dst + j * BPS, dst - BPS, 8);
410   }
411 }
412 
HE8uv(uint8_t * dst)413 static void HE8uv(uint8_t* dst) {    // horizontal
414   int j;
415   for (j = 0; j < 8; ++j) {
416     memset(dst, dst[-1], 8);
417     dst += BPS;
418   }
419 }
420 
421 // helper for chroma-DC predictions
Put8x8uv(uint8_t value,uint8_t * dst)422 static WEBP_INLINE void Put8x8uv(uint8_t value, uint8_t* dst) {
423   int j;
424   for (j = 0; j < 8; ++j) {
425     memset(dst + j * BPS, value, 8);
426   }
427 }
428 
DC8uv(uint8_t * dst)429 static void DC8uv(uint8_t* dst) {     // DC
430   int dc0 = 8;
431   int i;
432   for (i = 0; i < 8; ++i) {
433     dc0 += dst[i - BPS] + dst[-1 + i * BPS];
434   }
435   Put8x8uv(dc0 >> 4, dst);
436 }
437 
DC8uvNoLeft(uint8_t * dst)438 static void DC8uvNoLeft(uint8_t* dst) {   // DC with no left samples
439   int dc0 = 4;
440   int i;
441   for (i = 0; i < 8; ++i) {
442     dc0 += dst[i - BPS];
443   }
444   Put8x8uv(dc0 >> 3, dst);
445 }
446 
DC8uvNoTop(uint8_t * dst)447 static void DC8uvNoTop(uint8_t* dst) {  // DC with no top samples
448   int dc0 = 4;
449   int i;
450   for (i = 0; i < 8; ++i) {
451     dc0 += dst[-1 + i * BPS];
452   }
453   Put8x8uv(dc0 >> 3, dst);
454 }
455 
DC8uvNoTopLeft(uint8_t * dst)456 static void DC8uvNoTopLeft(uint8_t* dst) {    // DC with nothing
457   Put8x8uv(0x80, dst);
458 }
459 
460 VP8PredFunc VP8PredChroma8[NUM_B_DC_MODES];
461 
462 //------------------------------------------------------------------------------
463 // Edge filtering functions
464 
465 // 4 pixels in, 2 pixels out
do_filter2(uint8_t * p,int step)466 static WEBP_INLINE void do_filter2(uint8_t* p, int step) {
467   const int p1 = p[-2*step], p0 = p[-step], q0 = p[0], q1 = p[step];
468   const int a = 3 * (q0 - p0) + VP8ksclip1[p1 - q1];  // in [-893,892]
469   const int a1 = VP8ksclip2[(a + 4) >> 3];            // in [-16,15]
470   const int a2 = VP8ksclip2[(a + 3) >> 3];
471   p[-step] = VP8kclip1[p0 + a2];
472   p[    0] = VP8kclip1[q0 - a1];
473 }
474 
475 // 4 pixels in, 4 pixels out
do_filter4(uint8_t * p,int step)476 static WEBP_INLINE void do_filter4(uint8_t* p, int step) {
477   const int p1 = p[-2*step], p0 = p[-step], q0 = p[0], q1 = p[step];
478   const int a = 3 * (q0 - p0);
479   const int a1 = VP8ksclip2[(a + 4) >> 3];
480   const int a2 = VP8ksclip2[(a + 3) >> 3];
481   const int a3 = (a1 + 1) >> 1;
482   p[-2*step] = VP8kclip1[p1 + a3];
483   p[-  step] = VP8kclip1[p0 + a2];
484   p[      0] = VP8kclip1[q0 - a1];
485   p[   step] = VP8kclip1[q1 - a3];
486 }
487 
488 // 6 pixels in, 6 pixels out
do_filter6(uint8_t * p,int step)489 static WEBP_INLINE void do_filter6(uint8_t* p, int step) {
490   const int p2 = p[-3*step], p1 = p[-2*step], p0 = p[-step];
491   const int q0 = p[0], q1 = p[step], q2 = p[2*step];
492   const int a = VP8ksclip1[3 * (q0 - p0) + VP8ksclip1[p1 - q1]];
493   // a is in [-128,127], a1 in [-27,27], a2 in [-18,18] and a3 in [-9,9]
494   const int a1 = (27 * a + 63) >> 7;  // eq. to ((3 * a + 7) * 9) >> 7
495   const int a2 = (18 * a + 63) >> 7;  // eq. to ((2 * a + 7) * 9) >> 7
496   const int a3 = (9  * a + 63) >> 7;  // eq. to ((1 * a + 7) * 9) >> 7
497   p[-3*step] = VP8kclip1[p2 + a3];
498   p[-2*step] = VP8kclip1[p1 + a2];
499   p[-  step] = VP8kclip1[p0 + a1];
500   p[      0] = VP8kclip1[q0 - a1];
501   p[   step] = VP8kclip1[q1 - a2];
502   p[ 2*step] = VP8kclip1[q2 - a3];
503 }
504 
hev(const uint8_t * p,int step,int thresh)505 static WEBP_INLINE int hev(const uint8_t* p, int step, int thresh) {
506   const int p1 = p[-2*step], p0 = p[-step], q0 = p[0], q1 = p[step];
507   return (VP8kabs0[p1 - p0] > thresh) || (VP8kabs0[q1 - q0] > thresh);
508 }
509 
needs_filter(const uint8_t * p,int step,int t)510 static WEBP_INLINE int needs_filter(const uint8_t* p, int step, int t) {
511   const int p1 = p[-2 * step], p0 = p[-step], q0 = p[0], q1 = p[step];
512   return ((4 * VP8kabs0[p0 - q0] + VP8kabs0[p1 - q1]) <= t);
513 }
514 
needs_filter2(const uint8_t * p,int step,int t,int it)515 static WEBP_INLINE int needs_filter2(const uint8_t* p,
516                                      int step, int t, int it) {
517   const int p3 = p[-4 * step], p2 = p[-3 * step], p1 = p[-2 * step];
518   const int p0 = p[-step], q0 = p[0];
519   const int q1 = p[step], q2 = p[2 * step], q3 = p[3 * step];
520   if ((4 * VP8kabs0[p0 - q0] + VP8kabs0[p1 - q1]) > t) return 0;
521   return VP8kabs0[p3 - p2] <= it && VP8kabs0[p2 - p1] <= it &&
522          VP8kabs0[p1 - p0] <= it && VP8kabs0[q3 - q2] <= it &&
523          VP8kabs0[q2 - q1] <= it && VP8kabs0[q1 - q0] <= it;
524 }
525 
526 //------------------------------------------------------------------------------
527 // Simple In-loop filtering (Paragraph 15.2)
528 
SimpleVFilter16(uint8_t * p,int stride,int thresh)529 static void SimpleVFilter16(uint8_t* p, int stride, int thresh) {
530   int i;
531   const int thresh2 = 2 * thresh + 1;
532   for (i = 0; i < 16; ++i) {
533     if (needs_filter(p + i, stride, thresh2)) {
534       do_filter2(p + i, stride);
535     }
536   }
537 }
538 
SimpleHFilter16(uint8_t * p,int stride,int thresh)539 static void SimpleHFilter16(uint8_t* p, int stride, int thresh) {
540   int i;
541   const int thresh2 = 2 * thresh + 1;
542   for (i = 0; i < 16; ++i) {
543     if (needs_filter(p + i * stride, 1, thresh2)) {
544       do_filter2(p + i * stride, 1);
545     }
546   }
547 }
548 
SimpleVFilter16i(uint8_t * p,int stride,int thresh)549 static void SimpleVFilter16i(uint8_t* p, int stride, int thresh) {
550   int k;
551   for (k = 3; k > 0; --k) {
552     p += 4 * stride;
553     SimpleVFilter16(p, stride, thresh);
554   }
555 }
556 
SimpleHFilter16i(uint8_t * p,int stride,int thresh)557 static void SimpleHFilter16i(uint8_t* p, int stride, int thresh) {
558   int k;
559   for (k = 3; k > 0; --k) {
560     p += 4;
561     SimpleHFilter16(p, stride, thresh);
562   }
563 }
564 
565 //------------------------------------------------------------------------------
566 // Complex In-loop filtering (Paragraph 15.3)
567 
FilterLoop26(uint8_t * p,int hstride,int vstride,int size,int thresh,int ithresh,int hev_thresh)568 static WEBP_INLINE void FilterLoop26(uint8_t* p,
569                                      int hstride, int vstride, int size,
570                                      int thresh, int ithresh, int hev_thresh) {
571   const int thresh2 = 2 * thresh + 1;
572   while (size-- > 0) {
573     if (needs_filter2(p, hstride, thresh2, ithresh)) {
574       if (hev(p, hstride, hev_thresh)) {
575         do_filter2(p, hstride);
576       } else {
577         do_filter6(p, hstride);
578       }
579     }
580     p += vstride;
581   }
582 }
583 
FilterLoop24(uint8_t * p,int hstride,int vstride,int size,int thresh,int ithresh,int hev_thresh)584 static WEBP_INLINE void FilterLoop24(uint8_t* p,
585                                      int hstride, int vstride, int size,
586                                      int thresh, int ithresh, int hev_thresh) {
587   const int thresh2 = 2 * thresh + 1;
588   while (size-- > 0) {
589     if (needs_filter2(p, hstride, thresh2, ithresh)) {
590       if (hev(p, hstride, hev_thresh)) {
591         do_filter2(p, hstride);
592       } else {
593         do_filter4(p, hstride);
594       }
595     }
596     p += vstride;
597   }
598 }
599 
600 // on macroblock edges
VFilter16(uint8_t * p,int stride,int thresh,int ithresh,int hev_thresh)601 static void VFilter16(uint8_t* p, int stride,
602                       int thresh, int ithresh, int hev_thresh) {
603   FilterLoop26(p, stride, 1, 16, thresh, ithresh, hev_thresh);
604 }
605 
HFilter16(uint8_t * p,int stride,int thresh,int ithresh,int hev_thresh)606 static void HFilter16(uint8_t* p, int stride,
607                       int thresh, int ithresh, int hev_thresh) {
608   FilterLoop26(p, 1, stride, 16, thresh, ithresh, hev_thresh);
609 }
610 
611 // on three inner edges
VFilter16i(uint8_t * p,int stride,int thresh,int ithresh,int hev_thresh)612 static void VFilter16i(uint8_t* p, int stride,
613                        int thresh, int ithresh, int hev_thresh) {
614   int k;
615   for (k = 3; k > 0; --k) {
616     p += 4 * stride;
617     FilterLoop24(p, stride, 1, 16, thresh, ithresh, hev_thresh);
618   }
619 }
620 
HFilter16i(uint8_t * p,int stride,int thresh,int ithresh,int hev_thresh)621 static void HFilter16i(uint8_t* p, int stride,
622                        int thresh, int ithresh, int hev_thresh) {
623   int k;
624   for (k = 3; k > 0; --k) {
625     p += 4;
626     FilterLoop24(p, 1, stride, 16, thresh, ithresh, hev_thresh);
627   }
628 }
629 
630 // 8-pixels wide variant, for chroma filtering
VFilter8(uint8_t * u,uint8_t * v,int stride,int thresh,int ithresh,int hev_thresh)631 static void VFilter8(uint8_t* u, uint8_t* v, int stride,
632                      int thresh, int ithresh, int hev_thresh) {
633   FilterLoop26(u, stride, 1, 8, thresh, ithresh, hev_thresh);
634   FilterLoop26(v, stride, 1, 8, thresh, ithresh, hev_thresh);
635 }
636 
HFilter8(uint8_t * u,uint8_t * v,int stride,int thresh,int ithresh,int hev_thresh)637 static void HFilter8(uint8_t* u, uint8_t* v, int stride,
638                      int thresh, int ithresh, int hev_thresh) {
639   FilterLoop26(u, 1, stride, 8, thresh, ithresh, hev_thresh);
640   FilterLoop26(v, 1, stride, 8, thresh, ithresh, hev_thresh);
641 }
642 
VFilter8i(uint8_t * u,uint8_t * v,int stride,int thresh,int ithresh,int hev_thresh)643 static void VFilter8i(uint8_t* u, uint8_t* v, int stride,
644                       int thresh, int ithresh, int hev_thresh) {
645   FilterLoop24(u + 4 * stride, stride, 1, 8, thresh, ithresh, hev_thresh);
646   FilterLoop24(v + 4 * stride, stride, 1, 8, thresh, ithresh, hev_thresh);
647 }
648 
HFilter8i(uint8_t * u,uint8_t * v,int stride,int thresh,int ithresh,int hev_thresh)649 static void HFilter8i(uint8_t* u, uint8_t* v, int stride,
650                       int thresh, int ithresh, int hev_thresh) {
651   FilterLoop24(u + 4, 1, stride, 8, thresh, ithresh, hev_thresh);
652   FilterLoop24(v + 4, 1, stride, 8, thresh, ithresh, hev_thresh);
653 }
654 
655 //------------------------------------------------------------------------------
656 
657 VP8DecIdct2 VP8Transform;
658 VP8DecIdct VP8TransformAC3;
659 VP8DecIdct VP8TransformUV;
660 VP8DecIdct VP8TransformDC;
661 VP8DecIdct VP8TransformDCUV;
662 
663 VP8LumaFilterFunc VP8VFilter16;
664 VP8LumaFilterFunc VP8HFilter16;
665 VP8ChromaFilterFunc VP8VFilter8;
666 VP8ChromaFilterFunc VP8HFilter8;
667 VP8LumaFilterFunc VP8VFilter16i;
668 VP8LumaFilterFunc VP8HFilter16i;
669 VP8ChromaFilterFunc VP8VFilter8i;
670 VP8ChromaFilterFunc VP8HFilter8i;
671 VP8SimpleFilterFunc VP8SimpleVFilter16;
672 VP8SimpleFilterFunc VP8SimpleHFilter16;
673 VP8SimpleFilterFunc VP8SimpleVFilter16i;
674 VP8SimpleFilterFunc VP8SimpleHFilter16i;
675 
676 extern void VP8DspInitSSE2(void);
677 extern void VP8DspInitSSE41(void);
678 extern void VP8DspInitNEON(void);
679 extern void VP8DspInitMIPS32(void);
680 extern void VP8DspInitMIPSdspR2(void);
681 
682 static volatile VP8CPUInfo dec_last_cpuinfo_used =
683     (VP8CPUInfo)&dec_last_cpuinfo_used;
684 
VP8DspInit(void)685 WEBP_TSAN_IGNORE_FUNCTION void VP8DspInit(void) {
686   if (dec_last_cpuinfo_used == VP8GetCPUInfo) return;
687 
688   VP8InitClipTables();
689 
690   VP8TransformWHT = TransformWHT;
691   VP8Transform = TransformTwo;
692   VP8TransformUV = TransformUV;
693   VP8TransformDC = TransformDC;
694   VP8TransformDCUV = TransformDCUV;
695   VP8TransformAC3 = TransformAC3;
696 
697   VP8VFilter16 = VFilter16;
698   VP8HFilter16 = HFilter16;
699   VP8VFilter8 = VFilter8;
700   VP8HFilter8 = HFilter8;
701   VP8VFilter16i = VFilter16i;
702   VP8HFilter16i = HFilter16i;
703   VP8VFilter8i = VFilter8i;
704   VP8HFilter8i = HFilter8i;
705   VP8SimpleVFilter16 = SimpleVFilter16;
706   VP8SimpleHFilter16 = SimpleHFilter16;
707   VP8SimpleVFilter16i = SimpleVFilter16i;
708   VP8SimpleHFilter16i = SimpleHFilter16i;
709 
710   VP8PredLuma4[0] = DC4;
711   VP8PredLuma4[1] = TM4;
712   VP8PredLuma4[2] = VE4;
713   VP8PredLuma4[3] = HE4;
714   VP8PredLuma4[4] = RD4;
715   VP8PredLuma4[5] = VR4;
716   VP8PredLuma4[6] = LD4;
717   VP8PredLuma4[7] = VL4;
718   VP8PredLuma4[8] = HD4;
719   VP8PredLuma4[9] = HU4;
720 
721   VP8PredLuma16[0] = DC16;
722   VP8PredLuma16[1] = TM16;
723   VP8PredLuma16[2] = VE16;
724   VP8PredLuma16[3] = HE16;
725   VP8PredLuma16[4] = DC16NoTop;
726   VP8PredLuma16[5] = DC16NoLeft;
727   VP8PredLuma16[6] = DC16NoTopLeft;
728 
729   VP8PredChroma8[0] = DC8uv;
730   VP8PredChroma8[1] = TM8uv;
731   VP8PredChroma8[2] = VE8uv;
732   VP8PredChroma8[3] = HE8uv;
733   VP8PredChroma8[4] = DC8uvNoTop;
734   VP8PredChroma8[5] = DC8uvNoLeft;
735   VP8PredChroma8[6] = DC8uvNoTopLeft;
736 
737   // If defined, use CPUInfo() to overwrite some pointers with faster versions.
738   if (VP8GetCPUInfo != NULL) {
739 #if defined(WEBP_USE_SSE2)
740     if (VP8GetCPUInfo(kSSE2)) {
741       VP8DspInitSSE2();
742 #if defined(WEBP_USE_SSE41)
743       if (VP8GetCPUInfo(kSSE4_1)) {
744         VP8DspInitSSE41();
745       }
746 #endif
747     }
748 #endif
749 #if defined(WEBP_USE_NEON)
750     if (VP8GetCPUInfo(kNEON)) {
751       VP8DspInitNEON();
752     }
753 #endif
754 #if defined(WEBP_USE_MIPS32)
755     if (VP8GetCPUInfo(kMIPS32)) {
756       VP8DspInitMIPS32();
757     }
758 #endif
759 #if defined(WEBP_USE_MIPS_DSP_R2)
760     if (VP8GetCPUInfo(kMIPSdspR2)) {
761       VP8DspInitMIPSdspR2();
762     }
763 #endif
764   }
765   dec_last_cpuinfo_used = VP8GetCPUInfo;
766 }
767