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1 /*
2  * Copyright (c) 2016, Alliance for Open Media. All rights reserved
3  *
4  * This source code is subject to the terms of the BSD 2 Clause License and
5  * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
6  * was not distributed with this source code in the LICENSE file, you can
7  * obtain it at www.aomedia.org/license/software. If the Alliance for Open
8  * Media Patent License 1.0 was not distributed with this source code in the
9  * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
10  */
11 
12 #include <assert.h>
13 #include <limits.h>
14 
15 #include "config/aom_scale_rtcd.h"
16 
17 #include "aom_dsp/aom_dsp_common.h"
18 #include "aom_dsp/psnr.h"
19 #include "aom_mem/aom_mem.h"
20 #include "aom_ports/mem.h"
21 
22 #include "av1/common/av1_loopfilter.h"
23 #include "av1/common/onyxc_int.h"
24 #include "av1/common/quant_common.h"
25 
26 #include "av1/encoder/av1_quantize.h"
27 #include "av1/encoder/encoder.h"
28 #include "av1/encoder/picklpf.h"
29 
yv12_copy_plane(const YV12_BUFFER_CONFIG * src_bc,YV12_BUFFER_CONFIG * dst_bc,int plane)30 static void yv12_copy_plane(const YV12_BUFFER_CONFIG *src_bc,
31                             YV12_BUFFER_CONFIG *dst_bc, int plane) {
32   switch (plane) {
33     case 0: aom_yv12_copy_y(src_bc, dst_bc); break;
34     case 1: aom_yv12_copy_u(src_bc, dst_bc); break;
35     case 2: aom_yv12_copy_v(src_bc, dst_bc); break;
36     default: assert(plane >= 0 && plane <= 2); break;
37   }
38 }
39 
av1_get_max_filter_level(const AV1_COMP * cpi)40 int av1_get_max_filter_level(const AV1_COMP *cpi) {
41   if (cpi->oxcf.pass == 2) {
42     return cpi->twopass.section_intra_rating > 8 ? MAX_LOOP_FILTER * 3 / 4
43                                                  : MAX_LOOP_FILTER;
44   } else {
45     return MAX_LOOP_FILTER;
46   }
47 }
48 
try_filter_frame(const YV12_BUFFER_CONFIG * sd,AV1_COMP * const cpi,int filt_level,int partial_frame,int plane,int dir)49 static int64_t try_filter_frame(const YV12_BUFFER_CONFIG *sd,
50                                 AV1_COMP *const cpi, int filt_level,
51                                 int partial_frame, int plane, int dir) {
52   AV1_COMMON *const cm = &cpi->common;
53   int64_t filt_err;
54 
55   assert(plane >= 0 && plane <= 2);
56   int filter_level[2] = { filt_level, filt_level };
57   if (plane == 0 && dir == 0) filter_level[1] = cm->lf.filter_level[1];
58   if (plane == 0 && dir == 1) filter_level[0] = cm->lf.filter_level[0];
59 
60   // set base filters for use of get_filter_level when in DELTA_Q_LF mode
61   switch (plane) {
62     case 0:
63       cm->lf.filter_level[0] = filter_level[0];
64       cm->lf.filter_level[1] = filter_level[1];
65       break;
66     case 1: cm->lf.filter_level_u = filter_level[0]; break;
67     case 2: cm->lf.filter_level_v = filter_level[0]; break;
68   }
69 
70   // TODO(any): please enable multi-thread and remove the flag when loop
71   // filter mask is compatible with multi-thread.
72   if (cpi->num_workers > 1)
73     av1_loop_filter_frame_mt(&cm->cur_frame->buf, cm, &cpi->td.mb.e_mbd, plane,
74                              plane + 1, partial_frame,
75 #if LOOP_FILTER_BITMASK
76                              0,
77 #endif
78                              cpi->workers, cpi->num_workers, &cpi->lf_row_sync);
79   else
80     av1_loop_filter_frame(&cm->cur_frame->buf, cm, &cpi->td.mb.e_mbd,
81 #if LOOP_FILTER_BITMASK
82                           0,
83 #endif
84                           plane, plane + 1, partial_frame);
85 
86   filt_err = aom_get_sse_plane(sd, &cm->cur_frame->buf, plane,
87                                cm->seq_params.use_highbitdepth);
88 
89   // Re-instate the unfiltered frame
90   yv12_copy_plane(&cpi->last_frame_uf, &cm->cur_frame->buf, plane);
91 
92   return filt_err;
93 }
94 
search_filter_level(const YV12_BUFFER_CONFIG * sd,AV1_COMP * cpi,int partial_frame,const int * last_frame_filter_level,double * best_cost_ret,int plane,int dir)95 static int search_filter_level(const YV12_BUFFER_CONFIG *sd, AV1_COMP *cpi,
96                                int partial_frame,
97                                const int *last_frame_filter_level,
98                                double *best_cost_ret, int plane, int dir) {
99   const AV1_COMMON *const cm = &cpi->common;
100   const int min_filter_level = 0;
101   const int max_filter_level = av1_get_max_filter_level(cpi);
102   int filt_direction = 0;
103   int64_t best_err;
104   int filt_best;
105   MACROBLOCK *x = &cpi->td.mb;
106 
107   // Start the search at the previous frame filter level unless it is now out of
108   // range.
109   int lvl;
110   switch (plane) {
111     case 0:
112       switch (dir) {
113         case 2:
114           lvl = (last_frame_filter_level[0] + last_frame_filter_level[1] + 1) >>
115                 1;
116           break;
117         case 0:
118         case 1: lvl = last_frame_filter_level[dir]; break;
119         default: assert(dir >= 0 && dir <= 2); return 0;
120       }
121       break;
122     case 1: lvl = last_frame_filter_level[2]; break;
123     case 2: lvl = last_frame_filter_level[3]; break;
124     default: assert(plane >= 0 && plane <= 2); return 0;
125   }
126   int filt_mid = clamp(lvl, min_filter_level, max_filter_level);
127   int filter_step = filt_mid < 16 ? 4 : filt_mid / 4;
128   // Sum squared error at each filter level
129   int64_t ss_err[MAX_LOOP_FILTER + 1];
130 
131   // Set each entry to -1
132   memset(ss_err, 0xFF, sizeof(ss_err));
133   yv12_copy_plane(&cm->cur_frame->buf, &cpi->last_frame_uf, plane);
134   best_err = try_filter_frame(sd, cpi, filt_mid, partial_frame, plane, dir);
135   filt_best = filt_mid;
136   ss_err[filt_mid] = best_err;
137 
138   while (filter_step > 0) {
139     const int filt_high = AOMMIN(filt_mid + filter_step, max_filter_level);
140     const int filt_low = AOMMAX(filt_mid - filter_step, min_filter_level);
141 
142     // Bias against raising loop filter in favor of lowering it.
143     int64_t bias = (best_err >> (15 - (filt_mid / 8))) * filter_step;
144 
145     if ((cpi->oxcf.pass == 2) && (cpi->twopass.section_intra_rating < 20))
146       bias = (bias * cpi->twopass.section_intra_rating) / 20;
147 
148     // yx, bias less for large block size
149     if (cm->tx_mode != ONLY_4X4) bias >>= 1;
150 
151     if (filt_direction <= 0 && filt_low != filt_mid) {
152       // Get Low filter error score
153       if (ss_err[filt_low] < 0) {
154         ss_err[filt_low] =
155             try_filter_frame(sd, cpi, filt_low, partial_frame, plane, dir);
156       }
157       // If value is close to the best so far then bias towards a lower loop
158       // filter value.
159       if (ss_err[filt_low] < (best_err + bias)) {
160         // Was it actually better than the previous best?
161         if (ss_err[filt_low] < best_err) {
162           best_err = ss_err[filt_low];
163         }
164         filt_best = filt_low;
165       }
166     }
167 
168     // Now look at filt_high
169     if (filt_direction >= 0 && filt_high != filt_mid) {
170       if (ss_err[filt_high] < 0) {
171         ss_err[filt_high] =
172             try_filter_frame(sd, cpi, filt_high, partial_frame, plane, dir);
173       }
174       // If value is significantly better than previous best, bias added against
175       // raising filter value
176       if (ss_err[filt_high] < (best_err - bias)) {
177         best_err = ss_err[filt_high];
178         filt_best = filt_high;
179       }
180     }
181 
182     // Half the step distance if the best filter value was the same as last time
183     if (filt_best == filt_mid) {
184       filter_step /= 2;
185       filt_direction = 0;
186     } else {
187       filt_direction = (filt_best < filt_mid) ? -1 : 1;
188       filt_mid = filt_best;
189     }
190   }
191 
192   // Update best error
193   best_err = ss_err[filt_best];
194 
195   if (best_cost_ret) *best_cost_ret = RDCOST_DBL(x->rdmult, 0, best_err);
196   return filt_best;
197 }
198 
av1_pick_filter_level(const YV12_BUFFER_CONFIG * sd,AV1_COMP * cpi,LPF_PICK_METHOD method)199 void av1_pick_filter_level(const YV12_BUFFER_CONFIG *sd, AV1_COMP *cpi,
200                            LPF_PICK_METHOD method) {
201   AV1_COMMON *const cm = &cpi->common;
202   const int num_planes = av1_num_planes(cm);
203   struct loopfilter *const lf = &cm->lf;
204   (void)sd;
205 
206   lf->sharpness_level = 0;
207   cpi->td.mb.rdmult = cpi->rd.RDMULT;
208 
209   if (method == LPF_PICK_MINIMAL_LPF) {
210     lf->filter_level[0] = 0;
211     lf->filter_level[1] = 0;
212   } else if (method >= LPF_PICK_FROM_Q) {
213     const int min_filter_level = 0;
214     const int max_filter_level = av1_get_max_filter_level(cpi);
215     const int q = av1_ac_quant_Q3(cm->base_qindex, 0, cm->seq_params.bit_depth);
216     // based on tests result for rtc test set
217     // 0.04590 boosted or 0.02295 non-booseted in 18-bit fixed point
218     const int strength_boost_q_treshold = 700;
219     const int inter_frame_multiplier =
220         q > strength_boost_q_treshold ? 12034 : 6017;
221     // These values were determined by linear fitting the result of the
222     // searched level for 8 bit depth:
223     // Keyframes: filt_guess = q * 0.06699 - 1.60817
224     // Other frames: filt_guess = q * inter_frame_multiplier + 2.48225
225     //
226     // And high bit depth separately:
227     // filt_guess = q * 0.316206 + 3.87252
228     int filt_guess;
229     switch (cm->seq_params.bit_depth) {
230       case AOM_BITS_8:
231         filt_guess =
232             (cm->current_frame.frame_type == KEY_FRAME)
233                 ? ROUND_POWER_OF_TWO(q * 17563 - 421574, 18)
234                 : ROUND_POWER_OF_TWO(q * inter_frame_multiplier + 650707, 18);
235         break;
236       case AOM_BITS_10:
237         filt_guess = ROUND_POWER_OF_TWO(q * 20723 + 4060632, 20);
238         break;
239       case AOM_BITS_12:
240         filt_guess = ROUND_POWER_OF_TWO(q * 20723 + 16242526, 22);
241         break;
242       default:
243         assert(0 &&
244                "bit_depth should be AOM_BITS_8, AOM_BITS_10 "
245                "or AOM_BITS_12");
246         return;
247     }
248     if (cm->seq_params.bit_depth != AOM_BITS_8 &&
249         cm->current_frame.frame_type == KEY_FRAME)
250       filt_guess -= 4;
251     // TODO(chengchen): retrain the model for Y, U, V filter levels
252     lf->filter_level[0] = clamp(filt_guess, min_filter_level, max_filter_level);
253     lf->filter_level[1] = clamp(filt_guess, min_filter_level, max_filter_level);
254     lf->filter_level_u = clamp(filt_guess, min_filter_level, max_filter_level);
255     lf->filter_level_v = clamp(filt_guess, min_filter_level, max_filter_level);
256   } else {
257     const int last_frame_filter_level[4] = { lf->filter_level[0],
258                                              lf->filter_level[1],
259                                              lf->filter_level_u,
260                                              lf->filter_level_v };
261 
262     lf->filter_level[0] = lf->filter_level[1] =
263         search_filter_level(sd, cpi, method == LPF_PICK_FROM_SUBIMAGE,
264                             last_frame_filter_level, NULL, 0, 2);
265     lf->filter_level[0] =
266         search_filter_level(sd, cpi, method == LPF_PICK_FROM_SUBIMAGE,
267                             last_frame_filter_level, NULL, 0, 0);
268     lf->filter_level[1] =
269         search_filter_level(sd, cpi, method == LPF_PICK_FROM_SUBIMAGE,
270                             last_frame_filter_level, NULL, 0, 1);
271 
272     if (num_planes > 1) {
273       lf->filter_level_u =
274           search_filter_level(sd, cpi, method == LPF_PICK_FROM_SUBIMAGE,
275                               last_frame_filter_level, NULL, 1, 0);
276       lf->filter_level_v =
277           search_filter_level(sd, cpi, method == LPF_PICK_FROM_SUBIMAGE,
278                               last_frame_filter_level, NULL, 2, 0);
279     }
280   }
281 }
282