1 // Copyright 2015 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 // SSE2 variant of alpha filters
11 //
12 // Author: Skal (pascal.massimino@gmail.com)
13
14 #include "./dsp.h"
15
16 #if defined(WEBP_USE_SSE2)
17
18 #include <assert.h>
19 #include <emmintrin.h>
20 #include <stdlib.h>
21 #include <string.h>
22
23 //------------------------------------------------------------------------------
24 // Helpful macro.
25
26 # define SANITY_CHECK(in, out) \
27 assert(in != NULL); \
28 assert(out != NULL); \
29 assert(width > 0); \
30 assert(height > 0); \
31 assert(stride >= width); \
32 assert(row >= 0 && num_rows > 0 && row + num_rows <= height); \
33 (void)height; // Silence unused warning.
34
PredictLineTop(const uint8_t * src,const uint8_t * pred,uint8_t * dst,int length)35 static void PredictLineTop(const uint8_t* src, const uint8_t* pred,
36 uint8_t* dst, int length) {
37 int i;
38 const int max_pos = length & ~31;
39 assert(length >= 0);
40 for (i = 0; i < max_pos; i += 32) {
41 const __m128i A0 = _mm_loadu_si128((const __m128i*)&src[i + 0]);
42 const __m128i A1 = _mm_loadu_si128((const __m128i*)&src[i + 16]);
43 const __m128i B0 = _mm_loadu_si128((const __m128i*)&pred[i + 0]);
44 const __m128i B1 = _mm_loadu_si128((const __m128i*)&pred[i + 16]);
45 const __m128i C0 = _mm_sub_epi8(A0, B0);
46 const __m128i C1 = _mm_sub_epi8(A1, B1);
47 _mm_storeu_si128((__m128i*)&dst[i + 0], C0);
48 _mm_storeu_si128((__m128i*)&dst[i + 16], C1);
49 }
50 for (; i < length; ++i) dst[i] = src[i] - pred[i];
51 }
52
53 // Special case for left-based prediction (when preds==dst-1 or preds==src-1).
PredictLineLeft(const uint8_t * src,uint8_t * dst,int length)54 static void PredictLineLeft(const uint8_t* src, uint8_t* dst, int length) {
55 int i;
56 const int max_pos = length & ~31;
57 assert(length >= 0);
58 for (i = 0; i < max_pos; i += 32) {
59 const __m128i A0 = _mm_loadu_si128((const __m128i*)(src + i + 0 ));
60 const __m128i B0 = _mm_loadu_si128((const __m128i*)(src + i + 0 - 1));
61 const __m128i A1 = _mm_loadu_si128((const __m128i*)(src + i + 16 ));
62 const __m128i B1 = _mm_loadu_si128((const __m128i*)(src + i + 16 - 1));
63 const __m128i C0 = _mm_sub_epi8(A0, B0);
64 const __m128i C1 = _mm_sub_epi8(A1, B1);
65 _mm_storeu_si128((__m128i*)(dst + i + 0), C0);
66 _mm_storeu_si128((__m128i*)(dst + i + 16), C1);
67 }
68 for (; i < length; ++i) dst[i] = src[i] - src[i - 1];
69 }
70
71 //------------------------------------------------------------------------------
72 // Horizontal filter.
73
DoHorizontalFilter(const uint8_t * in,int width,int height,int stride,int row,int num_rows,uint8_t * out)74 static WEBP_INLINE void DoHorizontalFilter(const uint8_t* in,
75 int width, int height, int stride,
76 int row, int num_rows,
77 uint8_t* out) {
78 const size_t start_offset = row * stride;
79 const int last_row = row + num_rows;
80 SANITY_CHECK(in, out);
81 in += start_offset;
82 out += start_offset;
83
84 if (row == 0) {
85 // Leftmost pixel is the same as input for topmost scanline.
86 out[0] = in[0];
87 PredictLineLeft(in + 1, out + 1, width - 1);
88 row = 1;
89 in += stride;
90 out += stride;
91 }
92
93 // Filter line-by-line.
94 while (row < last_row) {
95 // Leftmost pixel is predicted from above.
96 out[0] = in[0] - in[-stride];
97 PredictLineLeft(in + 1, out + 1, width - 1);
98 ++row;
99 in += stride;
100 out += stride;
101 }
102 }
103
104 //------------------------------------------------------------------------------
105 // Vertical filter.
106
DoVerticalFilter(const uint8_t * in,int width,int height,int stride,int row,int num_rows,uint8_t * out)107 static WEBP_INLINE void DoVerticalFilter(const uint8_t* in,
108 int width, int height, int stride,
109 int row, int num_rows, uint8_t* out) {
110 const size_t start_offset = row * stride;
111 const int last_row = row + num_rows;
112 SANITY_CHECK(in, out);
113 in += start_offset;
114 out += start_offset;
115
116 if (row == 0) {
117 // Very first top-left pixel is copied.
118 out[0] = in[0];
119 // Rest of top scan-line is left-predicted.
120 PredictLineLeft(in + 1, out + 1, width - 1);
121 row = 1;
122 in += stride;
123 out += stride;
124 }
125
126 // Filter line-by-line.
127 while (row < last_row) {
128 PredictLineTop(in, in - stride, out, width);
129 ++row;
130 in += stride;
131 out += stride;
132 }
133 }
134
135 //------------------------------------------------------------------------------
136 // Gradient filter.
137
GradientPredictorC(uint8_t a,uint8_t b,uint8_t c)138 static WEBP_INLINE int GradientPredictorC(uint8_t a, uint8_t b, uint8_t c) {
139 const int g = a + b - c;
140 return ((g & ~0xff) == 0) ? g : (g < 0) ? 0 : 255; // clip to 8bit
141 }
142
GradientPredictDirect(const uint8_t * const row,const uint8_t * const top,uint8_t * const out,int length)143 static void GradientPredictDirect(const uint8_t* const row,
144 const uint8_t* const top,
145 uint8_t* const out, int length) {
146 const int max_pos = length & ~7;
147 int i;
148 const __m128i zero = _mm_setzero_si128();
149 for (i = 0; i < max_pos; i += 8) {
150 const __m128i A0 = _mm_loadl_epi64((const __m128i*)&row[i - 1]);
151 const __m128i B0 = _mm_loadl_epi64((const __m128i*)&top[i]);
152 const __m128i C0 = _mm_loadl_epi64((const __m128i*)&top[i - 1]);
153 const __m128i D = _mm_loadl_epi64((const __m128i*)&row[i]);
154 const __m128i A1 = _mm_unpacklo_epi8(A0, zero);
155 const __m128i B1 = _mm_unpacklo_epi8(B0, zero);
156 const __m128i C1 = _mm_unpacklo_epi8(C0, zero);
157 const __m128i E = _mm_add_epi16(A1, B1);
158 const __m128i F = _mm_sub_epi16(E, C1);
159 const __m128i G = _mm_packus_epi16(F, zero);
160 const __m128i H = _mm_sub_epi8(D, G);
161 _mm_storel_epi64((__m128i*)(out + i), H);
162 }
163 for (; i < length; ++i) {
164 out[i] = row[i] - GradientPredictorC(row[i - 1], top[i], top[i - 1]);
165 }
166 }
167
DoGradientFilter(const uint8_t * in,int width,int height,int stride,int row,int num_rows,uint8_t * out)168 static WEBP_INLINE void DoGradientFilter(const uint8_t* in,
169 int width, int height, int stride,
170 int row, int num_rows,
171 uint8_t* out) {
172 const size_t start_offset = row * stride;
173 const int last_row = row + num_rows;
174 SANITY_CHECK(in, out);
175 in += start_offset;
176 out += start_offset;
177
178 // left prediction for top scan-line
179 if (row == 0) {
180 out[0] = in[0];
181 PredictLineLeft(in + 1, out + 1, width - 1);
182 row = 1;
183 in += stride;
184 out += stride;
185 }
186
187 // Filter line-by-line.
188 while (row < last_row) {
189 out[0] = in[0] - in[-stride];
190 GradientPredictDirect(in + 1, in + 1 - stride, out + 1, width - 1);
191 ++row;
192 in += stride;
193 out += stride;
194 }
195 }
196
197 #undef SANITY_CHECK
198
199 //------------------------------------------------------------------------------
200
HorizontalFilter(const uint8_t * data,int width,int height,int stride,uint8_t * filtered_data)201 static void HorizontalFilter(const uint8_t* data, int width, int height,
202 int stride, uint8_t* filtered_data) {
203 DoHorizontalFilter(data, width, height, stride, 0, height, filtered_data);
204 }
205
VerticalFilter(const uint8_t * data,int width,int height,int stride,uint8_t * filtered_data)206 static void VerticalFilter(const uint8_t* data, int width, int height,
207 int stride, uint8_t* filtered_data) {
208 DoVerticalFilter(data, width, height, stride, 0, height, filtered_data);
209 }
210
GradientFilter(const uint8_t * data,int width,int height,int stride,uint8_t * filtered_data)211 static void GradientFilter(const uint8_t* data, int width, int height,
212 int stride, uint8_t* filtered_data) {
213 DoGradientFilter(data, width, height, stride, 0, height, filtered_data);
214 }
215
216 //------------------------------------------------------------------------------
217 // Inverse transforms
218
HorizontalUnfilter(const uint8_t * prev,const uint8_t * in,uint8_t * out,int width)219 static void HorizontalUnfilter(const uint8_t* prev, const uint8_t* in,
220 uint8_t* out, int width) {
221 int i;
222 __m128i last;
223 out[0] = in[0] + (prev == NULL ? 0 : prev[0]);
224 if (width <= 1) return;
225 last = _mm_set_epi32(0, 0, 0, out[0]);
226 for (i = 1; i + 8 <= width; i += 8) {
227 const __m128i A0 = _mm_loadl_epi64((const __m128i*)(in + i));
228 const __m128i A1 = _mm_add_epi8(A0, last);
229 const __m128i A2 = _mm_slli_si128(A1, 1);
230 const __m128i A3 = _mm_add_epi8(A1, A2);
231 const __m128i A4 = _mm_slli_si128(A3, 2);
232 const __m128i A5 = _mm_add_epi8(A3, A4);
233 const __m128i A6 = _mm_slli_si128(A5, 4);
234 const __m128i A7 = _mm_add_epi8(A5, A6);
235 _mm_storel_epi64((__m128i*)(out + i), A7);
236 last = _mm_srli_epi64(A7, 56);
237 }
238 for (; i < width; ++i) out[i] = in[i] + out[i - 1];
239 }
240
VerticalUnfilter(const uint8_t * prev,const uint8_t * in,uint8_t * out,int width)241 static void VerticalUnfilter(const uint8_t* prev, const uint8_t* in,
242 uint8_t* out, int width) {
243 if (prev == NULL) {
244 HorizontalUnfilter(NULL, in, out, width);
245 } else {
246 int i;
247 const int max_pos = width & ~31;
248 assert(width >= 0);
249 for (i = 0; i < max_pos; i += 32) {
250 const __m128i A0 = _mm_loadu_si128((const __m128i*)&in[i + 0]);
251 const __m128i A1 = _mm_loadu_si128((const __m128i*)&in[i + 16]);
252 const __m128i B0 = _mm_loadu_si128((const __m128i*)&prev[i + 0]);
253 const __m128i B1 = _mm_loadu_si128((const __m128i*)&prev[i + 16]);
254 const __m128i C0 = _mm_add_epi8(A0, B0);
255 const __m128i C1 = _mm_add_epi8(A1, B1);
256 _mm_storeu_si128((__m128i*)&out[i + 0], C0);
257 _mm_storeu_si128((__m128i*)&out[i + 16], C1);
258 }
259 for (; i < width; ++i) out[i] = in[i] + prev[i];
260 }
261 }
262
GradientPredictInverse(const uint8_t * const in,const uint8_t * const top,uint8_t * const row,int length)263 static void GradientPredictInverse(const uint8_t* const in,
264 const uint8_t* const top,
265 uint8_t* const row, int length) {
266 if (length > 0) {
267 int i;
268 const int max_pos = length & ~7;
269 const __m128i zero = _mm_setzero_si128();
270 __m128i A = _mm_set_epi32(0, 0, 0, row[-1]); // left sample
271 for (i = 0; i < max_pos; i += 8) {
272 const __m128i tmp0 = _mm_loadl_epi64((const __m128i*)&top[i]);
273 const __m128i tmp1 = _mm_loadl_epi64((const __m128i*)&top[i - 1]);
274 const __m128i B = _mm_unpacklo_epi8(tmp0, zero);
275 const __m128i C = _mm_unpacklo_epi8(tmp1, zero);
276 const __m128i D = _mm_loadl_epi64((const __m128i*)&in[i]); // base input
277 const __m128i E = _mm_sub_epi16(B, C); // unclipped gradient basis B - C
278 __m128i out = zero; // accumulator for output
279 __m128i mask_hi = _mm_set_epi32(0, 0, 0, 0xff);
280 int k = 8;
281 while (1) {
282 const __m128i tmp3 = _mm_add_epi16(A, E); // delta = A + B - C
283 const __m128i tmp4 = _mm_packus_epi16(tmp3, zero); // saturate delta
284 const __m128i tmp5 = _mm_add_epi8(tmp4, D); // add to in[]
285 A = _mm_and_si128(tmp5, mask_hi); // 1-complement clip
286 out = _mm_or_si128(out, A); // accumulate output
287 if (--k == 0) break;
288 A = _mm_slli_si128(A, 1); // rotate left sample
289 mask_hi = _mm_slli_si128(mask_hi, 1); // rotate mask
290 A = _mm_unpacklo_epi8(A, zero); // convert 8b->16b
291 }
292 A = _mm_srli_si128(A, 7); // prepare left sample for next iteration
293 _mm_storel_epi64((__m128i*)&row[i], out);
294 }
295 for (; i < length; ++i) {
296 row[i] = in[i] + GradientPredictorC(row[i - 1], top[i], top[i - 1]);
297 }
298 }
299 }
300
GradientUnfilter(const uint8_t * prev,const uint8_t * in,uint8_t * out,int width)301 static void GradientUnfilter(const uint8_t* prev, const uint8_t* in,
302 uint8_t* out, int width) {
303 if (prev == NULL) {
304 HorizontalUnfilter(NULL, in, out, width);
305 } else {
306 out[0] = in[0] + prev[0]; // predict from above
307 GradientPredictInverse(in + 1, prev + 1, out + 1, width - 1);
308 }
309 }
310
311 //------------------------------------------------------------------------------
312 // Entry point
313
314 extern void VP8FiltersInitSSE2(void);
315
VP8FiltersInitSSE2(void)316 WEBP_TSAN_IGNORE_FUNCTION void VP8FiltersInitSSE2(void) {
317 WebPUnfilters[WEBP_FILTER_HORIZONTAL] = HorizontalUnfilter;
318 WebPUnfilters[WEBP_FILTER_VERTICAL] = VerticalUnfilter;
319 WebPUnfilters[WEBP_FILTER_GRADIENT] = GradientUnfilter;
320
321 WebPFilters[WEBP_FILTER_HORIZONTAL] = HorizontalFilter;
322 WebPFilters[WEBP_FILTER_VERTICAL] = VerticalFilter;
323 WebPFilters[WEBP_FILTER_GRADIENT] = GradientFilter;
324 }
325
326 #else // !WEBP_USE_SSE2
327
328 WEBP_DSP_INIT_STUB(VP8FiltersInitSSE2)
329
330 #endif // WEBP_USE_SSE2
331