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