xref: /aosp_15_r20/external/libvpx/vp8/encoder/picklpf.c (revision fb1b10ab9aebc7c7068eedab379b749d7e3900be)
1 /*
2  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #include "./vpx_dsp_rtcd.h"
12 #include "./vpx_scale_rtcd.h"
13 #include "vp8/common/onyxc_int.h"
14 #include "onyx_int.h"
15 #include "vp8/encoder/picklpf.h"
16 #include "vp8/encoder/quantize.h"
17 #include "vpx_mem/vpx_mem.h"
18 #include "vpx_scale/vpx_scale.h"
19 #include "vp8/common/alloccommon.h"
20 #include "vp8/common/loopfilter.h"
21 #if VPX_ARCH_ARM
22 #include "vpx_ports/arm.h"
23 #endif
24 
25 extern int vp8_calc_ss_err(YV12_BUFFER_CONFIG *source,
26                            YV12_BUFFER_CONFIG *dest);
27 
yv12_copy_partial_frame(YV12_BUFFER_CONFIG * src_ybc,YV12_BUFFER_CONFIG * dst_ybc)28 static void yv12_copy_partial_frame(YV12_BUFFER_CONFIG *src_ybc,
29                                     YV12_BUFFER_CONFIG *dst_ybc) {
30   unsigned char *src_y, *dst_y;
31   int yheight;
32   int ystride;
33   int yoffset;
34   int linestocopy;
35 
36   yheight = src_ybc->y_height;
37   ystride = src_ybc->y_stride;
38 
39   /* number of MB rows to use in partial filtering */
40   linestocopy = (yheight >> 4) / PARTIAL_FRAME_FRACTION;
41   linestocopy = linestocopy ? linestocopy << 4 : 16; /* 16 lines per MB */
42 
43   /* Copy extra 4 so that full filter context is available if filtering done
44    * on the copied partial frame and not original. Partial filter does mb
45    * filtering for top row also, which can modify3 pixels above.
46    */
47   linestocopy += 4;
48   /* partial image starts at ~middle of frame (macroblock border)*/
49   yoffset = ystride * (((yheight >> 5) * 16) - 4);
50   src_y = src_ybc->y_buffer + yoffset;
51   dst_y = dst_ybc->y_buffer + yoffset;
52 
53   // The border will be used in vp8_loop_filter_partial_frame so it needs to be
54   // extended to avoid a valgrind warning.
55   const unsigned char *const top_row = src_ybc->y_buffer;
56   for (int i = yoffset; i < 0; i += ystride, --linestocopy) {
57     memcpy(dst_y, top_row, ystride);
58     dst_y += ystride;
59     src_y += ystride;
60   }
61   memcpy(dst_y, src_y, ystride * linestocopy);
62 }
63 
calc_partial_ssl_err(YV12_BUFFER_CONFIG * source,YV12_BUFFER_CONFIG * dest)64 static int calc_partial_ssl_err(YV12_BUFFER_CONFIG *source,
65                                 YV12_BUFFER_CONFIG *dest) {
66   int i, j;
67   int Total = 0;
68   int srcoffset, dstoffset;
69   unsigned char *src = source->y_buffer;
70   unsigned char *dst = dest->y_buffer;
71 
72   int linestocopy;
73 
74   /* number of MB rows to use in partial filtering */
75   linestocopy = (source->y_height >> 4) / PARTIAL_FRAME_FRACTION;
76   linestocopy = linestocopy ? linestocopy << 4 : 16; /* 16 lines per MB */
77 
78   /* partial image starts at ~middle of frame (macroblock border)*/
79   srcoffset = source->y_stride * ((dest->y_height >> 5) * 16);
80   dstoffset = dest->y_stride * ((dest->y_height >> 5) * 16);
81 
82   src += srcoffset;
83   dst += dstoffset;
84 
85   /* Loop through the Y plane raw and reconstruction data summing
86    * (square differences)
87    */
88   for (i = 0; i < linestocopy; i += 16) {
89     for (j = 0; j < source->y_width; j += 16) {
90       unsigned int sse;
91       Total += vpx_mse16x16(src + j, source->y_stride, dst + j, dest->y_stride,
92                             &sse);
93     }
94 
95     src += 16 * source->y_stride;
96     dst += 16 * dest->y_stride;
97   }
98 
99   return Total;
100 }
101 
102 /* Enforce a minimum filter level based upon baseline Q */
get_min_filter_level(VP8_COMP * cpi,int base_qindex)103 static int get_min_filter_level(VP8_COMP *cpi, int base_qindex) {
104   int min_filter_level;
105 
106   if (cpi->source_alt_ref_active && cpi->common.refresh_golden_frame &&
107       !cpi->common.refresh_alt_ref_frame) {
108     min_filter_level = 0;
109   } else {
110     if (base_qindex <= 6) {
111       min_filter_level = 0;
112     } else if (base_qindex <= 16) {
113       min_filter_level = 1;
114     } else {
115       min_filter_level = (base_qindex / 8);
116     }
117   }
118 
119   return min_filter_level;
120 }
121 
122 /* Enforce a maximum filter level based upon baseline Q */
get_max_filter_level(VP8_COMP * cpi,int base_qindex)123 static int get_max_filter_level(VP8_COMP *cpi, int base_qindex) {
124   /* PGW August 2006: Highest filter values almost always a bad idea */
125 
126   /* jbb chg: 20100118 - not so any more with this overquant stuff allow
127    * high values with lots of intra coming in.
128    */
129   int max_filter_level = MAX_LOOP_FILTER;
130   (void)base_qindex;
131 
132   if (cpi->twopass.section_intra_rating > 8) {
133     max_filter_level = MAX_LOOP_FILTER * 3 / 4;
134   }
135 
136   return max_filter_level;
137 }
138 
vp8cx_pick_filter_level_fast(YV12_BUFFER_CONFIG * sd,VP8_COMP * cpi)139 void vp8cx_pick_filter_level_fast(YV12_BUFFER_CONFIG *sd, VP8_COMP *cpi) {
140   VP8_COMMON *cm = &cpi->common;
141 
142   int best_err = 0;
143   int filt_err = 0;
144   int min_filter_level = get_min_filter_level(cpi, cm->base_qindex);
145   int max_filter_level = get_max_filter_level(cpi, cm->base_qindex);
146   int filt_val;
147   int best_filt_val;
148   YV12_BUFFER_CONFIG *saved_frame = cm->frame_to_show;
149 
150   /* Replace unfiltered frame buffer with a new one */
151   cm->frame_to_show = &cpi->pick_lf_lvl_frame;
152 
153   if (cm->frame_type == KEY_FRAME) {
154     cm->sharpness_level = 0;
155   } else {
156     cm->sharpness_level = cpi->oxcf.Sharpness;
157   }
158 
159   if (cm->sharpness_level != cm->last_sharpness_level) {
160     vp8_loop_filter_update_sharpness(&cm->lf_info, cm->sharpness_level);
161     cm->last_sharpness_level = cm->sharpness_level;
162   }
163 
164   /* Start the search at the previous frame filter level unless it is
165    * now out of range.
166    */
167   if (cm->filter_level < min_filter_level) {
168     cm->filter_level = min_filter_level;
169   } else if (cm->filter_level > max_filter_level) {
170     cm->filter_level = max_filter_level;
171   }
172 
173   filt_val = cm->filter_level;
174   best_filt_val = filt_val;
175 
176   /* Get the err using the previous frame's filter value. */
177 
178   /* Copy the unfiltered / processed recon buffer to the new buffer */
179   yv12_copy_partial_frame(saved_frame, cm->frame_to_show);
180   vp8_loop_filter_partial_frame(cm, &cpi->mb.e_mbd, filt_val);
181 
182   best_err = calc_partial_ssl_err(sd, cm->frame_to_show);
183 
184   filt_val -= 1 + (filt_val > 10);
185 
186   /* Search lower filter levels */
187   while (filt_val >= min_filter_level) {
188     /* Apply the loop filter */
189     yv12_copy_partial_frame(saved_frame, cm->frame_to_show);
190     vp8_loop_filter_partial_frame(cm, &cpi->mb.e_mbd, filt_val);
191 
192     /* Get the err for filtered frame */
193     filt_err = calc_partial_ssl_err(sd, cm->frame_to_show);
194 
195     /* Update the best case record or exit loop. */
196     if (filt_err < best_err) {
197       best_err = filt_err;
198       best_filt_val = filt_val;
199     } else {
200       break;
201     }
202 
203     /* Adjust filter level */
204     filt_val -= 1 + (filt_val > 10);
205   }
206 
207   /* Search up (note that we have already done filt_val = cm->filter_level) */
208   filt_val = cm->filter_level + 1 + (filt_val > 10);
209 
210   if (best_filt_val == cm->filter_level) {
211     /* Resist raising filter level for very small gains */
212     best_err -= (best_err >> 10);
213 
214     while (filt_val < max_filter_level) {
215       /* Apply the loop filter */
216       yv12_copy_partial_frame(saved_frame, cm->frame_to_show);
217 
218       vp8_loop_filter_partial_frame(cm, &cpi->mb.e_mbd, filt_val);
219 
220       /* Get the err for filtered frame */
221       filt_err = calc_partial_ssl_err(sd, cm->frame_to_show);
222 
223       /* Update the best case record or exit loop. */
224       if (filt_err < best_err) {
225         /* Do not raise filter level if improvement is < 1 part
226          * in 4096
227          */
228         best_err = filt_err - (filt_err >> 10);
229 
230         best_filt_val = filt_val;
231       } else {
232         break;
233       }
234 
235       /* Adjust filter level */
236       filt_val += 1 + (filt_val > 10);
237     }
238   }
239 
240   cm->filter_level = best_filt_val;
241 
242   if (cm->filter_level < min_filter_level) cm->filter_level = min_filter_level;
243 
244   if (cm->filter_level > max_filter_level) cm->filter_level = max_filter_level;
245 
246   /* restore unfiltered frame pointer */
247   cm->frame_to_show = saved_frame;
248 }
249 
250 /* Stub function for now Alt LF not used */
vp8cx_set_alt_lf_level(VP8_COMP * cpi,int filt_val)251 void vp8cx_set_alt_lf_level(VP8_COMP *cpi, int filt_val) {
252   MACROBLOCKD *mbd = &cpi->mb.e_mbd;
253   (void)filt_val;
254 
255   mbd->segment_feature_data[MB_LVL_ALT_LF][0] =
256       cpi->segment_feature_data[MB_LVL_ALT_LF][0];
257   mbd->segment_feature_data[MB_LVL_ALT_LF][1] =
258       cpi->segment_feature_data[MB_LVL_ALT_LF][1];
259   mbd->segment_feature_data[MB_LVL_ALT_LF][2] =
260       cpi->segment_feature_data[MB_LVL_ALT_LF][2];
261   mbd->segment_feature_data[MB_LVL_ALT_LF][3] =
262       cpi->segment_feature_data[MB_LVL_ALT_LF][3];
263 }
264 
vp8cx_pick_filter_level(YV12_BUFFER_CONFIG * sd,VP8_COMP * cpi)265 void vp8cx_pick_filter_level(YV12_BUFFER_CONFIG *sd, VP8_COMP *cpi) {
266   VP8_COMMON *cm = &cpi->common;
267 
268   int best_err = 0;
269   int filt_err = 0;
270   int min_filter_level = get_min_filter_level(cpi, cm->base_qindex);
271   int max_filter_level = get_max_filter_level(cpi, cm->base_qindex);
272 
273   int filter_step;
274   int filt_high = 0;
275   int filt_mid;
276   int filt_low = 0;
277   int filt_best;
278   int filt_direction = 0;
279 
280   /* Bias against raising loop filter and in favor of lowering it */
281   int Bias = 0;
282 
283   int ss_err[MAX_LOOP_FILTER + 1];
284 
285   YV12_BUFFER_CONFIG *saved_frame = cm->frame_to_show;
286 
287   memset(ss_err, 0, sizeof(ss_err));
288 
289   /* Replace unfiltered frame buffer with a new one */
290   cm->frame_to_show = &cpi->pick_lf_lvl_frame;
291 
292   if (cm->frame_type == KEY_FRAME) {
293     cm->sharpness_level = 0;
294   } else {
295     cm->sharpness_level = cpi->oxcf.Sharpness;
296   }
297 
298   /* Start the search at the previous frame filter level unless it is
299    * now out of range.
300    */
301   filt_mid = cm->filter_level;
302 
303   if (filt_mid < min_filter_level) {
304     filt_mid = min_filter_level;
305   } else if (filt_mid > max_filter_level) {
306     filt_mid = max_filter_level;
307   }
308 
309   /* Define the initial step size */
310   filter_step = (filt_mid < 16) ? 4 : filt_mid / 4;
311 
312   /* Get baseline error score */
313 
314   /* Copy the unfiltered / processed recon buffer to the new buffer */
315   vpx_yv12_copy_y(saved_frame, cm->frame_to_show);
316 
317   vp8cx_set_alt_lf_level(cpi, filt_mid);
318   vp8_loop_filter_frame_yonly(cm, &cpi->mb.e_mbd, filt_mid);
319 
320   best_err = vp8_calc_ss_err(sd, cm->frame_to_show);
321 
322   ss_err[filt_mid] = best_err;
323 
324   filt_best = filt_mid;
325 
326   while (filter_step > 0) {
327     Bias = (best_err >> (15 - (filt_mid / 8))) * filter_step;
328 
329     if (cpi->twopass.section_intra_rating < 20) {
330       Bias = Bias * cpi->twopass.section_intra_rating / 20;
331     }
332 
333     filt_high = ((filt_mid + filter_step) > max_filter_level)
334                     ? max_filter_level
335                     : (filt_mid + filter_step);
336     filt_low = ((filt_mid - filter_step) < min_filter_level)
337                    ? min_filter_level
338                    : (filt_mid - filter_step);
339 
340     if ((filt_direction <= 0) && (filt_low != filt_mid)) {
341       if (ss_err[filt_low] == 0) {
342         /* Get Low filter error score */
343         vpx_yv12_copy_y(saved_frame, cm->frame_to_show);
344         vp8cx_set_alt_lf_level(cpi, filt_low);
345         vp8_loop_filter_frame_yonly(cm, &cpi->mb.e_mbd, filt_low);
346 
347         filt_err = vp8_calc_ss_err(sd, cm->frame_to_show);
348         ss_err[filt_low] = filt_err;
349       } else {
350         filt_err = ss_err[filt_low];
351       }
352 
353       /* If value is close to the best so far then bias towards a
354        * lower loop filter value.
355        */
356       if ((filt_err - Bias) < best_err) {
357         /* Was it actually better than the previous best? */
358         if (filt_err < best_err) best_err = filt_err;
359 
360         filt_best = filt_low;
361       }
362     }
363 
364     /* Now look at filt_high */
365     if ((filt_direction >= 0) && (filt_high != filt_mid)) {
366       if (ss_err[filt_high] == 0) {
367         vpx_yv12_copy_y(saved_frame, cm->frame_to_show);
368         vp8cx_set_alt_lf_level(cpi, filt_high);
369         vp8_loop_filter_frame_yonly(cm, &cpi->mb.e_mbd, filt_high);
370 
371         filt_err = vp8_calc_ss_err(sd, cm->frame_to_show);
372         ss_err[filt_high] = filt_err;
373       } else {
374         filt_err = ss_err[filt_high];
375       }
376 
377       /* Was it better than the previous best? */
378       if (filt_err < (best_err - Bias)) {
379         best_err = filt_err;
380         filt_best = filt_high;
381       }
382     }
383 
384     /* Half the step distance if the best filter value was the same
385      * as last time
386      */
387     if (filt_best == filt_mid) {
388       filter_step = filter_step / 2;
389       filt_direction = 0;
390     } else {
391       filt_direction = (filt_best < filt_mid) ? -1 : 1;
392       filt_mid = filt_best;
393     }
394   }
395 
396   cm->filter_level = filt_best;
397 
398   /* restore unfiltered frame pointer */
399   cm->frame_to_show = saved_frame;
400 }
401