2 * Copyright (c) 2010 The WebM project authors. All Rights Reserved.
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.
19 #include "vp8/common/common.h"
21 #include "vp8/common/entropymode.h"
22 #include "vpx_mem/vpx_mem.h"
23 #include "vp8/common/systemdependent.h"
27 #define MIN_BPB_FACTOR 0.01
28 #define MAX_BPB_FACTOR 50
30 extern const MB_PREDICTION_MODE vp8_mode_order[MAX_MODES];
35 extern int y_modes[5];
36 extern int uv_modes[4];
37 extern int b_modes[10];
39 extern int inter_y_modes[10];
40 extern int inter_uv_modes[4];
41 extern int inter_b_modes[10];
44 /* Bits Per MB at different Q (Multiplied by 512) */
45 #define BPER_MB_NORMBITS 9
47 /* Work in progress recalibration of baseline rate tables based on
48 * the assumption that bits per mb is inversely proportional to the
51 const int vp8_bits_per_mb[2][QINDEX_RANGE] =
53 /* Intra case 450000/Qintra */
55 1125000,900000, 750000, 642857, 562500, 500000, 450000, 450000,
56 409090, 375000, 346153, 321428, 300000, 281250, 264705, 264705,
57 250000, 236842, 225000, 225000, 214285, 214285, 204545, 204545,
58 195652, 195652, 187500, 180000, 180000, 173076, 166666, 160714,
59 155172, 150000, 145161, 140625, 136363, 132352, 128571, 125000,
60 121621, 121621, 118421, 115384, 112500, 109756, 107142, 104651,
61 102272, 100000, 97826, 97826, 95744, 93750, 91836, 90000,
62 88235, 86538, 84905, 83333, 81818, 80357, 78947, 77586,
63 76271, 75000, 73770, 72580, 71428, 70312, 69230, 68181,
64 67164, 66176, 65217, 64285, 63380, 62500, 61643, 60810,
65 60000, 59210, 59210, 58441, 57692, 56962, 56250, 55555,
66 54878, 54216, 53571, 52941, 52325, 51724, 51136, 50561,
67 49450, 48387, 47368, 46875, 45918, 45000, 44554, 44117,
68 43269, 42452, 41666, 40909, 40178, 39473, 38793, 38135,
69 36885, 36290, 35714, 35156, 34615, 34090, 33582, 33088,
70 32608, 32142, 31468, 31034, 30405, 29801, 29220, 28662,
72 /* Inter case 285000/Qinter */
74 712500, 570000, 475000, 407142, 356250, 316666, 285000, 259090,
75 237500, 219230, 203571, 190000, 178125, 167647, 158333, 150000,
76 142500, 135714, 129545, 123913, 118750, 114000, 109615, 105555,
77 101785, 98275, 95000, 91935, 89062, 86363, 83823, 81428,
78 79166, 77027, 75000, 73076, 71250, 69512, 67857, 66279,
79 64772, 63333, 61956, 60638, 59375, 58163, 57000, 55882,
80 54807, 53773, 52777, 51818, 50892, 50000, 49137, 47500,
81 45967, 44531, 43181, 41911, 40714, 39583, 38513, 37500,
82 36538, 35625, 34756, 33928, 33139, 32386, 31666, 30978,
83 30319, 29687, 29081, 28500, 27941, 27403, 26886, 26388,
84 25909, 25446, 25000, 24568, 23949, 23360, 22800, 22265,
85 21755, 21268, 20802, 20357, 19930, 19520, 19127, 18750,
86 18387, 18037, 17701, 17378, 17065, 16764, 16473, 16101,
87 15745, 15405, 15079, 14766, 14467, 14179, 13902, 13636,
88 13380, 13133, 12895, 12666, 12445, 12179, 11924, 11632,
89 11445, 11220, 11003, 10795, 10594, 10401, 10215, 10035,
93 static const int kf_boost_qadjustment[QINDEX_RANGE] =
95 128, 129, 130, 131, 132, 133, 134, 135,
96 136, 137, 138, 139, 140, 141, 142, 143,
97 144, 145, 146, 147, 148, 149, 150, 151,
98 152, 153, 154, 155, 156, 157, 158, 159,
99 160, 161, 162, 163, 164, 165, 166, 167,
100 168, 169, 170, 171, 172, 173, 174, 175,
101 176, 177, 178, 179, 180, 181, 182, 183,
102 184, 185, 186, 187, 188, 189, 190, 191,
103 192, 193, 194, 195, 196, 197, 198, 199,
104 200, 200, 201, 201, 202, 203, 203, 203,
105 204, 204, 205, 205, 206, 206, 207, 207,
106 208, 208, 209, 209, 210, 210, 211, 211,
107 212, 212, 213, 213, 214, 214, 215, 215,
108 216, 216, 217, 217, 218, 218, 219, 219,
109 220, 220, 220, 220, 220, 220, 220, 220,
110 220, 220, 220, 220, 220, 220, 220, 220,
113 /* #define GFQ_ADJUSTMENT (Q+100) */
114 #define GFQ_ADJUSTMENT vp8_gf_boost_qadjustment[Q]
115 const int vp8_gf_boost_qadjustment[QINDEX_RANGE] =
117 80, 82, 84, 86, 88, 90, 92, 94,
118 96, 97, 98, 99, 100, 101, 102, 103,
119 104, 105, 106, 107, 108, 109, 110, 111,
120 112, 113, 114, 115, 116, 117, 118, 119,
121 120, 121, 122, 123, 124, 125, 126, 127,
122 128, 129, 130, 131, 132, 133, 134, 135,
123 136, 137, 138, 139, 140, 141, 142, 143,
124 144, 145, 146, 147, 148, 149, 150, 151,
125 152, 153, 154, 155, 156, 157, 158, 159,
126 160, 161, 162, 163, 164, 165, 166, 167,
127 168, 169, 170, 171, 172, 173, 174, 175,
128 176, 177, 178, 179, 180, 181, 182, 183,
129 184, 184, 185, 185, 186, 186, 187, 187,
130 188, 188, 189, 189, 190, 190, 191, 191,
131 192, 192, 193, 193, 194, 194, 194, 194,
132 195, 195, 196, 196, 197, 197, 198, 198
136 const int vp8_gf_boost_qadjustment[QINDEX_RANGE] =
138 100,101,102,103,104,105,105,106,
139 106,107,107,108,109,109,110,111,
140 112,113,114,115,116,117,118,119,
141 120,121,122,123,124,125,126,127,
142 128,129,130,131,132,133,134,135,
143 136,137,138,139,140,141,142,143,
144 144,145,146,147,148,149,150,151,
145 152,153,154,155,156,157,158,159,
146 160,161,162,163,164,165,166,167,
147 168,169,170,170,171,171,172,172,
148 173,173,173,174,174,174,175,175,
149 175,176,176,176,177,177,177,177,
150 178,178,179,179,180,180,181,181,
151 182,182,183,183,184,184,185,185,
152 186,186,187,187,188,188,189,189,
153 190,190,191,191,192,192,193,193,
157 static const int kf_gf_boost_qlimits[QINDEX_RANGE] =
159 150, 155, 160, 165, 170, 175, 180, 185,
160 190, 195, 200, 205, 210, 215, 220, 225,
161 230, 235, 240, 245, 250, 255, 260, 265,
162 270, 275, 280, 285, 290, 295, 300, 305,
163 310, 320, 330, 340, 350, 360, 370, 380,
164 390, 400, 410, 420, 430, 440, 450, 460,
165 470, 480, 490, 500, 510, 520, 530, 540,
166 550, 560, 570, 580, 590, 600, 600, 600,
167 600, 600, 600, 600, 600, 600, 600, 600,
168 600, 600, 600, 600, 600, 600, 600, 600,
169 600, 600, 600, 600, 600, 600, 600, 600,
170 600, 600, 600, 600, 600, 600, 600, 600,
171 600, 600, 600, 600, 600, 600, 600, 600,
172 600, 600, 600, 600, 600, 600, 600, 600,
173 600, 600, 600, 600, 600, 600, 600, 600,
174 600, 600, 600, 600, 600, 600, 600, 600,
177 /* % adjustment to target kf size based on seperation from previous frame */
178 static const int kf_boost_seperation_adjustment[16] =
180 30, 40, 50, 55, 60, 65, 70, 75,
181 80, 85, 90, 95, 100, 100, 100, 100,
185 static const int gf_adjust_table[101] =
188 115, 130, 145, 160, 175, 190, 200, 210, 220, 230,
189 240, 260, 270, 280, 290, 300, 310, 320, 330, 340,
190 350, 360, 370, 380, 390, 400, 400, 400, 400, 400,
191 400, 400, 400, 400, 400, 400, 400, 400, 400, 400,
192 400, 400, 400, 400, 400, 400, 400, 400, 400, 400,
193 400, 400, 400, 400, 400, 400, 400, 400, 400, 400,
194 400, 400, 400, 400, 400, 400, 400, 400, 400, 400,
195 400, 400, 400, 400, 400, 400, 400, 400, 400, 400,
196 400, 400, 400, 400, 400, 400, 400, 400, 400, 400,
197 400, 400, 400, 400, 400, 400, 400, 400, 400, 400,
200 static const int gf_intra_usage_adjustment[20] =
202 125, 120, 115, 110, 105, 100, 95, 85, 80, 75,
203 70, 65, 60, 55, 50, 50, 50, 50, 50, 50,
206 static const int gf_interval_table[101] =
209 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
210 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
211 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
212 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
213 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
214 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
215 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
216 10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
217 10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
218 11, 11, 11, 11, 11, 11, 11, 11, 11, 11,
221 static const unsigned int prior_key_frame_weight[KEY_FRAME_CONTEXT] = { 1, 2, 3, 4, 5 };
224 void vp8_save_coding_context(VP8_COMP *cpi)
226 CODING_CONTEXT *const cc = & cpi->coding_context;
228 /* Stores a snapshot of key state variables which can subsequently be
229 * restored with a call to vp8_restore_coding_context. These functions are
230 * intended for use in a re-code loop in vp8_compress_frame where the
231 * quantizer value is adjusted between loop iterations.
234 cc->frames_since_key = cpi->frames_since_key;
235 cc->filter_level = cpi->common.filter_level;
236 cc->frames_till_gf_update_due = cpi->frames_till_gf_update_due;
237 cc->frames_since_golden = cpi->common.frames_since_golden;
239 vp8_copy(cc->mvc, cpi->common.fc.mvc);
240 vp8_copy(cc->mvcosts, cpi->rd_costs.mvcosts);
242 vp8_copy(cc->ymode_prob, cpi->common.fc.ymode_prob);
243 vp8_copy(cc->uv_mode_prob, cpi->common.fc.uv_mode_prob);
245 vp8_copy(cc->ymode_count, cpi->ymode_count);
246 vp8_copy(cc->uv_mode_count, cpi->uv_mode_count);
251 vp8_copy(cc->y_modes, y_modes);
252 vp8_copy(cc->uv_modes, uv_modes);
253 vp8_copy(cc->b_modes, b_modes);
254 vp8_copy(cc->inter_y_modes, inter_y_modes);
255 vp8_copy(cc->inter_uv_modes, inter_uv_modes);
256 vp8_copy(cc->inter_b_modes, inter_b_modes);
259 cc->this_frame_percent_intra = cpi->this_frame_percent_intra;
263 void vp8_restore_coding_context(VP8_COMP *cpi)
265 CODING_CONTEXT *const cc = & cpi->coding_context;
267 /* Restore key state variables to the snapshot state stored in the
268 * previous call to vp8_save_coding_context.
271 cpi->frames_since_key = cc->frames_since_key;
272 cpi->common.filter_level = cc->filter_level;
273 cpi->frames_till_gf_update_due = cc->frames_till_gf_update_due;
274 cpi->common.frames_since_golden = cc->frames_since_golden;
276 vp8_copy(cpi->common.fc.mvc, cc->mvc);
278 vp8_copy(cpi->rd_costs.mvcosts, cc->mvcosts);
280 vp8_copy(cpi->common.fc.ymode_prob, cc->ymode_prob);
281 vp8_copy(cpi->common.fc.uv_mode_prob, cc->uv_mode_prob);
283 vp8_copy(cpi->ymode_count, cc->ymode_count);
284 vp8_copy(cpi->uv_mode_count, cc->uv_mode_count);
288 vp8_copy(y_modes, cc->y_modes);
289 vp8_copy(uv_modes, cc->uv_modes);
290 vp8_copy(b_modes, cc->b_modes);
291 vp8_copy(inter_y_modes, cc->inter_y_modes);
292 vp8_copy(inter_uv_modes, cc->inter_uv_modes);
293 vp8_copy(inter_b_modes, cc->inter_b_modes);
297 cpi->this_frame_percent_intra = cc->this_frame_percent_intra;
301 void vp8_setup_key_frame(VP8_COMP *cpi)
303 /* Setup for Key frame: */
305 vp8_default_coef_probs(& cpi->common);
307 vpx_memcpy(cpi->common.fc.mvc, vp8_default_mv_context, sizeof(vp8_default_mv_context));
309 int flag[2] = {1, 1};
310 vp8_build_component_cost_table(cpi->mb.mvcost, (const MV_CONTEXT *) cpi->common.fc.mvc, flag);
313 /* initialize pre_mvc to all zero. */
314 vpx_memset(cpi->common.fc.pre_mvc, 0, sizeof(cpi->common.fc.pre_mvc));
316 /* Make sure we initialize separate contexts for altref,gold, and normal.
317 * TODO shouldn't need 3 different copies of structure to do this!
319 vpx_memcpy(&cpi->lfc_a, &cpi->common.fc, sizeof(cpi->common.fc));
320 vpx_memcpy(&cpi->lfc_g, &cpi->common.fc, sizeof(cpi->common.fc));
321 vpx_memcpy(&cpi->lfc_n, &cpi->common.fc, sizeof(cpi->common.fc));
323 cpi->common.filter_level = cpi->common.base_qindex * 3 / 8 ;
325 /* Provisional interval before next GF */
327 cpi->frames_till_gf_update_due = cpi->baseline_gf_interval;
329 cpi->frames_till_gf_update_due = cpi->goldfreq;
331 cpi->common.refresh_golden_frame = 1;
332 cpi->common.refresh_alt_ref_frame = 1;
336 static int estimate_bits_at_q(int frame_kind, int Q, int MBs,
337 double correction_factor)
339 int Bpm = (int)(.5 + correction_factor * vp8_bits_per_mb[frame_kind][Q]);
341 /* Attempt to retain reasonable accuracy without overflow. The cutoff is
342 * chosen such that the maximum product of Bpm and MBs fits 31 bits. The
343 * largest Bpm takes 20 bits.
346 return (Bpm >> BPER_MB_NORMBITS) * MBs;
348 return (Bpm * MBs) >> BPER_MB_NORMBITS;
352 static void calc_iframe_target_size(VP8_COMP *cpi)
354 /* boost defaults to half second */
358 /* Clear down mmx registers to allow floating point in what follows */
359 vp8_clear_system_state();
361 if (cpi->oxcf.fixed_q >= 0)
363 int Q = cpi->oxcf.key_q;
365 target = estimate_bits_at_q(INTRA_FRAME, Q, cpi->common.MBs,
366 cpi->key_frame_rate_correction_factor);
368 else if (cpi->pass == 2)
370 /* New Two pass RC */
371 target = cpi->per_frame_bandwidth;
373 /* First Frame is a special case */
374 else if (cpi->common.current_video_frame == 0)
376 /* 1 Pass there is no information on which to base size so use
377 * bandwidth per second * fraction of the initial buffer
380 target = cpi->oxcf.starting_buffer_level / 2;
382 if(target > cpi->oxcf.target_bandwidth * 3 / 2)
383 target = cpi->oxcf.target_bandwidth * 3 / 2;
387 /* if this keyframe was forced, use a more recent Q estimate */
388 int Q = (cpi->common.frame_flags & FRAMEFLAGS_KEY)
389 ? cpi->avg_frame_qindex : cpi->ni_av_qi;
391 int initial_boost = 24; /* |2.5 * per_frame_bandwidth| */
392 /* Boost depends somewhat on frame rate: only used for 1 layer case. */
393 if (cpi->oxcf.number_of_layers == 1) {
394 kf_boost = MAX(initial_boost, (int)(2 * cpi->output_frame_rate - 16));
397 /* Initial factor: set target size to: |2.5 * per_frame_bandwidth|. */
398 kf_boost = initial_boost;
401 /* adjustment up based on q: this factor ranges from ~1.2 to 2.2. */
402 kf_boost = kf_boost * kf_boost_qadjustment[Q] / 100;
404 /* frame separation adjustment ( down) */
405 if (cpi->frames_since_key < cpi->output_frame_rate / 2)
406 kf_boost = (int)(kf_boost
407 * cpi->frames_since_key / (cpi->output_frame_rate / 2));
409 /* Minimal target size is |2* per_frame_bandwidth|. */
413 target = ((16 + kf_boost) * cpi->per_frame_bandwidth) >> 4;
417 if (cpi->oxcf.rc_max_intra_bitrate_pct)
419 unsigned int max_rate = cpi->per_frame_bandwidth
420 * cpi->oxcf.rc_max_intra_bitrate_pct / 100;
422 if (target > max_rate)
426 cpi->this_frame_target = target;
428 /* TODO: if we separate rate targeting from Q targetting, move this.
429 * Reset the active worst quality to the baseline value for key frames.
432 cpi->active_worst_quality = cpi->worst_quality;
438 f = fopen("kf_boost.stt", "a");
439 fprintf(f, " %8u %10d %10d %10d\n",
440 cpi->common.current_video_frame, cpi->gfu_boost, cpi->baseline_gf_interval, cpi->source_alt_ref_pending);
448 /* Do the best we can to define the parameters for the next GF based on what
449 * information we have available.
451 static void calc_gf_params(VP8_COMP *cpi)
453 int Q = (cpi->oxcf.fixed_q < 0) ? cpi->last_q[INTER_FRAME] : cpi->oxcf.fixed_q;
456 int gf_frame_useage = 0; /* Golden frame useage since last GF */
457 int tot_mbs = cpi->recent_ref_frame_usage[INTRA_FRAME] +
458 cpi->recent_ref_frame_usage[LAST_FRAME] +
459 cpi->recent_ref_frame_usage[GOLDEN_FRAME] +
460 cpi->recent_ref_frame_usage[ALTREF_FRAME];
462 int pct_gf_active = (100 * cpi->gf_active_count) / (cpi->common.mb_rows * cpi->common.mb_cols);
465 gf_frame_useage = (cpi->recent_ref_frame_usage[GOLDEN_FRAME] + cpi->recent_ref_frame_usage[ALTREF_FRAME]) * 100 / tot_mbs;
467 if (pct_gf_active > gf_frame_useage)
468 gf_frame_useage = pct_gf_active;
473 /* Single Pass lagged mode: TBD */
478 /* Single Pass compression: Has to use current and historical data */
482 /* Experimental code */
483 int index = cpi->one_pass_frame_index;
484 int frames_to_scan = (cpi->max_gf_interval <= MAX_LAG_BUFFERS) ? cpi->max_gf_interval : MAX_LAG_BUFFERS;
486 /* ************** Experimental code - incomplete */
488 double decay_val = 1.0;
489 double IIAccumulator = 0.0;
490 double last_iiaccumulator = 0.0;
493 cpi->one_pass_frame_index = cpi->common.current_video_frame%MAX_LAG_BUFFERS;
495 for ( i = 0; i < (frames_to_scan - 1); i++ )
498 index = MAX_LAG_BUFFERS;
501 if ( cpi->one_pass_frame_stats[index].frame_coded_error > 0.0 )
503 IIRatio = cpi->one_pass_frame_stats[index].frame_intra_error / cpi->one_pass_frame_stats[index].frame_coded_error;
505 if ( IIRatio > 30.0 )
511 IIAccumulator += IIRatio * decay_val;
513 decay_val = decay_val * cpi->one_pass_frame_stats[index].frame_pcnt_inter;
515 if ( (i > MIN_GF_INTERVAL) &&
516 ((IIAccumulator - last_iiaccumulator) < 2.0) )
520 last_iiaccumulator = IIAccumulator;
523 Boost = IIAccumulator*100.0/16.0;
524 cpi->baseline_gf_interval = i;
529 /*************************************************************/
532 /* Adjust boost based upon ambient Q */
533 Boost = GFQ_ADJUSTMENT;
535 /* Adjust based upon most recently measure intra useage */
536 Boost = Boost * gf_intra_usage_adjustment[(cpi->this_frame_percent_intra < 15) ? cpi->this_frame_percent_intra : 14] / 100;
538 /* Adjust gf boost based upon GF usage since last GF */
539 Boost = Boost * gf_adjust_table[gf_frame_useage] / 100;
543 /* golden frame boost without recode loop often goes awry. be
544 * safe by keeping numbers down.
546 if (!cpi->sf.recode_loop)
548 if (cpi->compressor_speed == 2)
552 /* Apply an upper limit based on Q for 1 pass encodes */
553 if (Boost > kf_gf_boost_qlimits[Q] && (cpi->pass == 0))
554 Boost = kf_gf_boost_qlimits[Q];
556 /* Apply lower limits to boost. */
557 else if (Boost < 110)
560 /* Note the boost used */
561 cpi->last_boost = Boost;
565 /* Estimate next interval
566 * This is updated once the real frame size/boost is known.
568 if (cpi->oxcf.fixed_q == -1)
570 if (cpi->pass == 2) /* 2 Pass */
572 cpi->frames_till_gf_update_due = cpi->baseline_gf_interval;
576 cpi->frames_till_gf_update_due = cpi->baseline_gf_interval;
578 if (cpi->last_boost > 750)
579 cpi->frames_till_gf_update_due++;
581 if (cpi->last_boost > 1000)
582 cpi->frames_till_gf_update_due++;
584 if (cpi->last_boost > 1250)
585 cpi->frames_till_gf_update_due++;
587 if (cpi->last_boost >= 1500)
588 cpi->frames_till_gf_update_due ++;
590 if (gf_interval_table[gf_frame_useage] > cpi->frames_till_gf_update_due)
591 cpi->frames_till_gf_update_due = gf_interval_table[gf_frame_useage];
593 if (cpi->frames_till_gf_update_due > cpi->max_gf_interval)
594 cpi->frames_till_gf_update_due = cpi->max_gf_interval;
598 cpi->frames_till_gf_update_due = cpi->baseline_gf_interval;
603 /* For now Alt ref is not allowed except in 2 pass modes. */
604 cpi->source_alt_ref_pending = 0;
606 /*if ( cpi->oxcf.fixed_q == -1)
608 if ( cpi->oxcf.play_alternate && (cpi->last_boost > (100 + (AF_THRESH*cpi->frames_till_gf_update_due)) ) )
609 cpi->source_alt_ref_pending = 1;
611 cpi->source_alt_ref_pending = 0;
617 static void calc_pframe_target_size(VP8_COMP *cpi)
619 int min_frame_target;
621 int old_per_frame_bandwidth = cpi->per_frame_bandwidth;
623 if ( cpi->current_layer > 0)
624 cpi->per_frame_bandwidth =
625 cpi->layer_context[cpi->current_layer].avg_frame_size_for_layer;
627 min_frame_target = 0;
631 min_frame_target = cpi->min_frame_bandwidth;
633 if (min_frame_target < (cpi->av_per_frame_bandwidth >> 5))
634 min_frame_target = cpi->av_per_frame_bandwidth >> 5;
636 else if (min_frame_target < cpi->per_frame_bandwidth / 4)
637 min_frame_target = cpi->per_frame_bandwidth / 4;
640 /* Special alt reference frame case */
641 if((cpi->common.refresh_alt_ref_frame) && (cpi->oxcf.number_of_layers == 1))
645 /* Per frame bit target for the alt ref frame */
646 cpi->per_frame_bandwidth = cpi->twopass.gf_bits;
647 cpi->this_frame_target = cpi->per_frame_bandwidth;
650 /* One Pass ??? TBD */
653 /* Normal frames (gf,and inter) */
659 cpi->this_frame_target = cpi->per_frame_bandwidth;
664 /* Make rate adjustment to recover bits spent in key frame
665 * Test to see if the key frame inter data rate correction
666 * should still be in force
668 if (cpi->kf_overspend_bits > 0)
670 Adjustment = (cpi->kf_bitrate_adjustment <= cpi->kf_overspend_bits) ? cpi->kf_bitrate_adjustment : cpi->kf_overspend_bits;
672 if (Adjustment > (cpi->per_frame_bandwidth - min_frame_target))
673 Adjustment = (cpi->per_frame_bandwidth - min_frame_target);
675 cpi->kf_overspend_bits -= Adjustment;
677 /* Calculate an inter frame bandwidth target for the next
678 * few frames designed to recover any extra bits spent on
681 cpi->this_frame_target = cpi->per_frame_bandwidth - Adjustment;
683 if (cpi->this_frame_target < min_frame_target)
684 cpi->this_frame_target = min_frame_target;
687 cpi->this_frame_target = cpi->per_frame_bandwidth;
689 /* If appropriate make an adjustment to recover bits spent on a
692 if ((cpi->gf_overspend_bits > 0) && (cpi->this_frame_target > min_frame_target))
694 int Adjustment = (cpi->non_gf_bitrate_adjustment <= cpi->gf_overspend_bits) ? cpi->non_gf_bitrate_adjustment : cpi->gf_overspend_bits;
696 if (Adjustment > (cpi->this_frame_target - min_frame_target))
697 Adjustment = (cpi->this_frame_target - min_frame_target);
699 cpi->gf_overspend_bits -= Adjustment;
700 cpi->this_frame_target -= Adjustment;
703 /* Apply small + and - boosts for non gf frames */
704 if ((cpi->last_boost > 150) && (cpi->frames_till_gf_update_due > 0) &&
705 (cpi->current_gf_interval >= (MIN_GF_INTERVAL << 1)))
707 /* % Adjustment limited to the range 1% to 10% */
708 Adjustment = (cpi->last_boost - 100) >> 5;
712 else if (Adjustment > 10)
715 /* Convert to bits */
716 Adjustment = (cpi->this_frame_target * Adjustment) / 100;
718 if (Adjustment > (cpi->this_frame_target - min_frame_target))
719 Adjustment = (cpi->this_frame_target - min_frame_target);
721 if (cpi->common.frames_since_golden == (cpi->current_gf_interval >> 1))
722 cpi->this_frame_target += ((cpi->current_gf_interval - 1) * Adjustment);
724 cpi->this_frame_target -= Adjustment;
729 /* Sanity check that the total sum of adjustments is not above the
730 * maximum allowed That is that having allowed for KF and GF penalties
731 * we have not pushed the current interframe target to low. If the
732 * adjustment we apply here is not capable of recovering all the extra
733 * bits we have spent in the KF or GF then the remainder will have to
734 * be recovered over a longer time span via other buffer / rate control
737 if (cpi->this_frame_target < min_frame_target)
738 cpi->this_frame_target = min_frame_target;
740 if (!cpi->common.refresh_alt_ref_frame)
741 /* Note the baseline target data rate for this inter frame. */
742 cpi->inter_frame_target = cpi->this_frame_target;
744 /* One Pass specific code */
747 /* Adapt target frame size with respect to any buffering constraints: */
748 if (cpi->buffered_mode)
750 int one_percent_bits = 1 + cpi->oxcf.optimal_buffer_level / 100;
752 if ((cpi->buffer_level < cpi->oxcf.optimal_buffer_level) ||
753 (cpi->bits_off_target < cpi->oxcf.optimal_buffer_level))
757 /* Decide whether or not we need to adjust the frame data
760 * If we are are below the optimal buffer fullness level
761 * and adherence to buffering constraints is important to
762 * the end usage then adjust the per frame target.
764 if ((cpi->oxcf.end_usage == USAGE_STREAM_FROM_SERVER) &&
765 (cpi->buffer_level < cpi->oxcf.optimal_buffer_level))
768 (cpi->oxcf.optimal_buffer_level - cpi->buffer_level) /
771 /* Are we overshooting the long term clip data rate... */
772 else if (cpi->bits_off_target < 0)
774 /* Adjust per frame data target downwards to compensate. */
775 percent_low = (int)(100 * -cpi->bits_off_target /
776 (cpi->total_byte_count * 8));
779 if (percent_low > cpi->oxcf.under_shoot_pct)
780 percent_low = cpi->oxcf.under_shoot_pct;
781 else if (percent_low < 0)
784 /* lower the target bandwidth for this frame. */
785 cpi->this_frame_target -=
786 (cpi->this_frame_target * percent_low) / 200;
788 /* Are we using allowing control of active_worst_allowed_q
789 * according to buffer level.
791 if (cpi->auto_worst_q && cpi->ni_frames > 150)
793 int critical_buffer_level;
795 /* For streaming applications the most important factor is
796 * cpi->buffer_level as this takes into account the
797 * specified short term buffering constraints. However,
798 * hitting the long term clip data rate target is also
801 if (cpi->oxcf.end_usage == USAGE_STREAM_FROM_SERVER)
803 /* Take the smaller of cpi->buffer_level and
804 * cpi->bits_off_target
806 critical_buffer_level =
807 (cpi->buffer_level < cpi->bits_off_target)
808 ? cpi->buffer_level : cpi->bits_off_target;
810 /* For local file playback short term buffering constraints
811 * are less of an issue
815 /* Consider only how we are doing for the clip as a
818 critical_buffer_level = cpi->bits_off_target;
821 /* Set the active worst quality based upon the selected
822 * buffer fullness number.
824 if (critical_buffer_level < cpi->oxcf.optimal_buffer_level)
826 if ( critical_buffer_level >
827 (cpi->oxcf.optimal_buffer_level >> 2) )
829 int64_t qadjustment_range =
830 cpi->worst_quality - cpi->ni_av_qi;
832 (critical_buffer_level -
833 (cpi->oxcf.optimal_buffer_level >> 2));
835 /* Step active worst quality down from
836 * cpi->ni_av_qi when (critical_buffer_level ==
837 * cpi->optimal_buffer_level) to
838 * cpi->worst_quality when
839 * (critical_buffer_level ==
840 * cpi->optimal_buffer_level >> 2)
842 cpi->active_worst_quality =
844 ((qadjustment_range * above_base) /
845 (cpi->oxcf.optimal_buffer_level*3>>2));
849 cpi->active_worst_quality = cpi->worst_quality;
854 cpi->active_worst_quality = cpi->ni_av_qi;
859 cpi->active_worst_quality = cpi->worst_quality;
864 int percent_high = 0;
866 if ((cpi->oxcf.end_usage == USAGE_STREAM_FROM_SERVER)
867 && (cpi->buffer_level > cpi->oxcf.optimal_buffer_level))
869 percent_high = (cpi->buffer_level
870 - cpi->oxcf.optimal_buffer_level)
873 else if (cpi->bits_off_target > cpi->oxcf.optimal_buffer_level)
875 percent_high = (int)((100 * cpi->bits_off_target)
876 / (cpi->total_byte_count * 8));
879 if (percent_high > cpi->oxcf.over_shoot_pct)
880 percent_high = cpi->oxcf.over_shoot_pct;
881 else if (percent_high < 0)
884 cpi->this_frame_target += (cpi->this_frame_target *
887 /* Are we allowing control of active_worst_allowed_q according
890 if (cpi->auto_worst_q && cpi->ni_frames > 150)
892 /* When using the relaxed buffer model stick to the
893 * user specified value
895 cpi->active_worst_quality = cpi->ni_av_qi;
899 cpi->active_worst_quality = cpi->worst_quality;
903 /* Set active_best_quality to prevent quality rising too high */
904 cpi->active_best_quality = cpi->best_quality;
906 /* Worst quality obviously must not be better than best quality */
907 if (cpi->active_worst_quality <= cpi->active_best_quality)
908 cpi->active_worst_quality = cpi->active_best_quality + 1;
910 if(cpi->active_worst_quality > 127)
911 cpi->active_worst_quality = 127;
913 /* Unbuffered mode (eg. video conferencing) */
916 /* Set the active worst quality */
917 cpi->active_worst_quality = cpi->worst_quality;
920 /* Special trap for constrained quality mode
921 * "active_worst_quality" may never drop below cq level
922 * for any frame type.
924 if ( cpi->oxcf.end_usage == USAGE_CONSTRAINED_QUALITY &&
925 cpi->active_worst_quality < cpi->cq_target_quality)
927 cpi->active_worst_quality = cpi->cq_target_quality;
931 /* Test to see if we have to drop a frame
932 * The auto-drop frame code is only used in buffered mode.
933 * In unbufferd mode (eg vide conferencing) the descision to
934 * code or drop a frame is made outside the codec in response to real
935 * world comms or buffer considerations.
937 if (cpi->drop_frames_allowed &&
938 (cpi->oxcf.end_usage == USAGE_STREAM_FROM_SERVER) &&
939 ((cpi->common.frame_type != KEY_FRAME)))
941 /* Check for a buffer underun-crisis in which case we have to drop
944 if ((cpi->buffer_level < 0))
947 FILE *f = fopen("dec.stt", "a");
948 fprintf(f, "%10d %10d %10d %10d ***** BUFFER EMPTY\n",
949 (int) cpi->common.current_video_frame,
950 cpi->decimation_factor, cpi->common.horiz_scale,
951 (cpi->buffer_level * 100) / cpi->oxcf.optimal_buffer_level);
956 /* Update the buffer level variable. */
957 cpi->bits_off_target += cpi->av_per_frame_bandwidth;
958 if (cpi->bits_off_target > cpi->oxcf.maximum_buffer_size)
959 cpi->bits_off_target = cpi->oxcf.maximum_buffer_size;
960 cpi->buffer_level = cpi->bits_off_target;
964 /* Adjust target frame size for Golden Frames: */
965 if (cpi->oxcf.error_resilient_mode == 0 &&
966 (cpi->frames_till_gf_update_due == 0) && !cpi->drop_frame)
968 int Q = (cpi->oxcf.fixed_q < 0) ? cpi->last_q[INTER_FRAME] : cpi->oxcf.fixed_q;
970 int gf_frame_useage = 0; /* Golden frame useage since last GF */
971 int tot_mbs = cpi->recent_ref_frame_usage[INTRA_FRAME] +
972 cpi->recent_ref_frame_usage[LAST_FRAME] +
973 cpi->recent_ref_frame_usage[GOLDEN_FRAME] +
974 cpi->recent_ref_frame_usage[ALTREF_FRAME];
976 int pct_gf_active = (100 * cpi->gf_active_count) / (cpi->common.mb_rows * cpi->common.mb_cols);
979 gf_frame_useage = (cpi->recent_ref_frame_usage[GOLDEN_FRAME] + cpi->recent_ref_frame_usage[ALTREF_FRAME]) * 100 / tot_mbs;
981 if (pct_gf_active > gf_frame_useage)
982 gf_frame_useage = pct_gf_active;
984 /* Is a fixed manual GF frequency being used */
987 /* For one pass throw a GF if recent frame intra useage is
988 * low or the GF useage is high
990 if ((cpi->pass == 0) && (cpi->this_frame_percent_intra < 15 || gf_frame_useage >= 5))
991 cpi->common.refresh_golden_frame = 1;
993 /* Two pass GF descision */
994 else if (cpi->pass == 2)
995 cpi->common.refresh_golden_frame = 1;
1005 f = fopen("gf_useaget.stt", "a");
1006 fprintf(f, " %8ld %10ld %10ld %10ld %10ld\n",
1007 cpi->common.current_video_frame, cpi->gfu_boost, GFQ_ADJUSTMENT, cpi->gfu_boost, gf_frame_useage);
1013 if (cpi->common.refresh_golden_frame == 1)
1021 f = fopen("GFexit.stt", "a");
1022 fprintf(f, "%8ld GF coded\n", cpi->common.current_video_frame);
1028 if (cpi->auto_adjust_gold_quantizer)
1030 calc_gf_params(cpi);
1033 /* If we are using alternate ref instead of gf then do not apply the
1034 * boost It will instead be applied to the altref update Jims
1037 if (!cpi->source_alt_ref_active)
1039 if (cpi->oxcf.fixed_q < 0)
1043 /* The spend on the GF is defined in the two pass
1044 * code for two pass encodes
1046 cpi->this_frame_target = cpi->per_frame_bandwidth;
1050 int Boost = cpi->last_boost;
1051 int frames_in_section = cpi->frames_till_gf_update_due + 1;
1052 int allocation_chunks = (frames_in_section * 100) + (Boost - 100);
1053 int bits_in_section = cpi->inter_frame_target * frames_in_section;
1055 /* Normalize Altboost and allocations chunck down to
1058 while (Boost > 1000)
1061 allocation_chunks /= 2;
1064 /* Avoid loss of precision but avoid overflow */
1065 if ((bits_in_section >> 7) > allocation_chunks)
1066 cpi->this_frame_target = Boost * (bits_in_section / allocation_chunks);
1068 cpi->this_frame_target = (Boost * bits_in_section) / allocation_chunks;
1072 cpi->this_frame_target =
1073 (estimate_bits_at_q(1, Q, cpi->common.MBs, 1.0)
1074 * cpi->last_boost) / 100;
1077 /* If there is an active ARF at this location use the minimum
1078 * bits on this frame even if it is a contructed arf.
1079 * The active maximum quantizer insures that an appropriate
1080 * number of bits will be spent if needed for contstructed ARFs.
1084 cpi->this_frame_target = 0;
1087 cpi->current_gf_interval = cpi->frames_till_gf_update_due;
1092 cpi->per_frame_bandwidth = old_per_frame_bandwidth;
1096 void vp8_update_rate_correction_factors(VP8_COMP *cpi, int damp_var)
1098 int Q = cpi->common.base_qindex;
1099 int correction_factor = 100;
1100 double rate_correction_factor;
1101 double adjustment_limit;
1103 int projected_size_based_on_q = 0;
1105 /* Clear down mmx registers to allow floating point in what follows */
1106 vp8_clear_system_state();
1108 if (cpi->common.frame_type == KEY_FRAME)
1110 rate_correction_factor = cpi->key_frame_rate_correction_factor;
1114 if (cpi->common.refresh_alt_ref_frame || cpi->common.refresh_golden_frame)
1115 rate_correction_factor = cpi->gf_rate_correction_factor;
1117 rate_correction_factor = cpi->rate_correction_factor;
1120 /* Work out how big we would have expected the frame to be at this Q
1121 * given the current correction factor. Stay in double to avoid int
1122 * overflow when values are large
1124 projected_size_based_on_q = (int)(((.5 + rate_correction_factor * vp8_bits_per_mb[cpi->common.frame_type][Q]) * cpi->common.MBs) / (1 << BPER_MB_NORMBITS));
1126 /* Make some allowance for cpi->zbin_over_quant */
1127 if (cpi->zbin_over_quant > 0)
1129 int Z = cpi->zbin_over_quant;
1130 double Factor = 0.99;
1131 double factor_adjustment = 0.01 / 256.0;
1136 projected_size_based_on_q =
1137 (int)(Factor * projected_size_based_on_q);
1138 Factor += factor_adjustment;
1140 if (Factor >= 0.999)
1145 /* Work out a size correction factor. */
1146 if (projected_size_based_on_q > 0)
1147 correction_factor = (100 * cpi->projected_frame_size) / projected_size_based_on_q;
1149 /* More heavily damped adjustment used if we have been oscillating
1150 * either side of target
1155 adjustment_limit = 0.75;
1158 adjustment_limit = 0.375;
1162 adjustment_limit = 0.25;
1166 if (correction_factor > 102)
1168 /* We are not already at the worst allowable quality */
1169 correction_factor = (int)(100.5 + ((correction_factor - 100) * adjustment_limit));
1170 rate_correction_factor = ((rate_correction_factor * correction_factor) / 100);
1172 /* Keep rate_correction_factor within limits */
1173 if (rate_correction_factor > MAX_BPB_FACTOR)
1174 rate_correction_factor = MAX_BPB_FACTOR;
1176 else if (correction_factor < 99)
1178 /* We are not already at the best allowable quality */
1179 correction_factor = (int)(100.5 - ((100 - correction_factor) * adjustment_limit));
1180 rate_correction_factor = ((rate_correction_factor * correction_factor) / 100);
1182 /* Keep rate_correction_factor within limits */
1183 if (rate_correction_factor < MIN_BPB_FACTOR)
1184 rate_correction_factor = MIN_BPB_FACTOR;
1187 if (cpi->common.frame_type == KEY_FRAME)
1188 cpi->key_frame_rate_correction_factor = rate_correction_factor;
1191 if (cpi->common.refresh_alt_ref_frame || cpi->common.refresh_golden_frame)
1192 cpi->gf_rate_correction_factor = rate_correction_factor;
1194 cpi->rate_correction_factor = rate_correction_factor;
1199 int vp8_regulate_q(VP8_COMP *cpi, int target_bits_per_frame)
1201 int Q = cpi->active_worst_quality;
1203 /* Reset Zbin OQ value */
1204 cpi->zbin_over_quant = 0;
1206 if (cpi->oxcf.fixed_q >= 0)
1208 Q = cpi->oxcf.fixed_q;
1210 if (cpi->common.frame_type == KEY_FRAME)
1212 Q = cpi->oxcf.key_q;
1214 else if (cpi->common.refresh_alt_ref_frame)
1216 Q = cpi->oxcf.alt_q;
1218 else if (cpi->common.refresh_golden_frame)
1220 Q = cpi->oxcf.gold_q;
1227 int last_error = INT_MAX;
1228 int target_bits_per_mb;
1229 int bits_per_mb_at_this_q;
1230 double correction_factor;
1232 /* Select the appropriate correction factor based upon type of frame. */
1233 if (cpi->common.frame_type == KEY_FRAME)
1234 correction_factor = cpi->key_frame_rate_correction_factor;
1237 if (cpi->common.refresh_alt_ref_frame || cpi->common.refresh_golden_frame)
1238 correction_factor = cpi->gf_rate_correction_factor;
1240 correction_factor = cpi->rate_correction_factor;
1243 /* Calculate required scaling factor based on target frame size and
1244 * size of frame produced using previous Q
1246 if (target_bits_per_frame >= (INT_MAX >> BPER_MB_NORMBITS))
1247 /* Case where we would overflow int */
1248 target_bits_per_mb = (target_bits_per_frame / cpi->common.MBs) << BPER_MB_NORMBITS;
1250 target_bits_per_mb = (target_bits_per_frame << BPER_MB_NORMBITS) / cpi->common.MBs;
1252 i = cpi->active_best_quality;
1256 bits_per_mb_at_this_q = (int)(.5 + correction_factor * vp8_bits_per_mb[cpi->common.frame_type][i]);
1258 if (bits_per_mb_at_this_q <= target_bits_per_mb)
1260 if ((target_bits_per_mb - bits_per_mb_at_this_q) <= last_error)
1268 last_error = bits_per_mb_at_this_q - target_bits_per_mb;
1270 while (++i <= cpi->active_worst_quality);
1273 /* If we are at MAXQ then enable Q over-run which seeks to claw
1274 * back additional bits through things like the RD multiplier
1275 * and zero bin size.
1281 double Factor = 0.99;
1282 double factor_adjustment = 0.01 / 256.0;
1284 if (cpi->common.frame_type == KEY_FRAME)
1286 else if (cpi->common.refresh_alt_ref_frame || (cpi->common.refresh_golden_frame && !cpi->source_alt_ref_active))
1289 zbin_oqmax = ZBIN_OQ_MAX;
1292 double Factor = (double)target_bits_per_mb/(double)bits_per_mb_at_this_q;
1295 Factor = Factor/1.2683;
1297 Oq = pow( Factor, (1.0/-0.165) );
1299 if ( Oq > zbin_oqmax )
1302 cpi->zbin_over_quant = (int)Oq;
1305 /* Each incrment in the zbin is assumed to have a fixed effect
1306 * on bitrate. This is not of course true. The effect will be
1307 * highly clip dependent and may well have sudden steps. The
1308 * idea here is to acheive higher effective quantizers than the
1309 * normal maximum by expanding the zero bin and hence
1310 * decreasing the number of low magnitude non zero coefficients.
1312 while (cpi->zbin_over_quant < zbin_oqmax)
1314 cpi->zbin_over_quant ++;
1316 if (cpi->zbin_over_quant > zbin_oqmax)
1317 cpi->zbin_over_quant = zbin_oqmax;
1319 /* Adjust bits_per_mb_at_this_q estimate */
1320 bits_per_mb_at_this_q = (int)(Factor * bits_per_mb_at_this_q);
1321 Factor += factor_adjustment;
1323 if (Factor >= 0.999)
1326 /* Break out if we get down to the target rate */
1327 if (bits_per_mb_at_this_q <= target_bits_per_mb)
1338 static int estimate_keyframe_frequency(VP8_COMP *cpi)
1342 /* Average key frame frequency */
1343 int av_key_frame_frequency = 0;
1345 /* First key frame at start of sequence is a special case. We have no
1348 if (cpi->key_frame_count == 1)
1350 /* Assume a default of 1 kf every 2 seconds, or the max kf interval,
1351 * whichever is smaller.
1353 int key_freq = cpi->oxcf.key_freq>0 ? cpi->oxcf.key_freq : 1;
1354 av_key_frame_frequency = (int)cpi->output_frame_rate * 2;
1356 if (cpi->oxcf.auto_key && av_key_frame_frequency > key_freq)
1357 av_key_frame_frequency = cpi->oxcf.key_freq;
1359 cpi->prior_key_frame_distance[KEY_FRAME_CONTEXT - 1]
1360 = av_key_frame_frequency;
1364 unsigned int total_weight = 0;
1365 int last_kf_interval =
1366 (cpi->frames_since_key > 0) ? cpi->frames_since_key : 1;
1368 /* reset keyframe context and calculate weighted average of last
1369 * KEY_FRAME_CONTEXT keyframes
1371 for (i = 0; i < KEY_FRAME_CONTEXT; i++)
1373 if (i < KEY_FRAME_CONTEXT - 1)
1374 cpi->prior_key_frame_distance[i]
1375 = cpi->prior_key_frame_distance[i+1];
1377 cpi->prior_key_frame_distance[i] = last_kf_interval;
1379 av_key_frame_frequency += prior_key_frame_weight[i]
1380 * cpi->prior_key_frame_distance[i];
1381 total_weight += prior_key_frame_weight[i];
1384 av_key_frame_frequency /= total_weight;
1387 return av_key_frame_frequency;
1391 void vp8_adjust_key_frame_context(VP8_COMP *cpi)
1393 /* Clear down mmx registers to allow floating point in what follows */
1394 vp8_clear_system_state();
1396 /* Do we have any key frame overspend to recover? */
1397 /* Two-pass overspend handled elsewhere. */
1398 if ((cpi->pass != 2)
1399 && (cpi->projected_frame_size > cpi->per_frame_bandwidth))
1403 /* Update the count of key frame overspend to be recovered in
1404 * subsequent frames. A portion of the KF overspend is treated as gf
1405 * overspend (and hence recovered more quickly) as the kf is also a
1406 * gf. Otherwise the few frames following each kf tend to get more
1407 * bits allocated than those following other gfs.
1409 overspend = (cpi->projected_frame_size - cpi->per_frame_bandwidth);
1411 if (cpi->oxcf.number_of_layers > 1)
1412 cpi->kf_overspend_bits += overspend;
1415 cpi->kf_overspend_bits += overspend * 7 / 8;
1416 cpi->gf_overspend_bits += overspend * 1 / 8;
1419 /* Work out how much to try and recover per frame. */
1420 cpi->kf_bitrate_adjustment = cpi->kf_overspend_bits
1421 / estimate_keyframe_frequency(cpi);
1424 cpi->frames_since_key = 0;
1425 cpi->key_frame_count++;
1429 void vp8_compute_frame_size_bounds(VP8_COMP *cpi, int *frame_under_shoot_limit, int *frame_over_shoot_limit)
1431 /* Set-up bounds on acceptable frame size: */
1432 if (cpi->oxcf.fixed_q >= 0)
1434 /* Fixed Q scenario: frame size never outranges target
1435 * (there is no target!)
1437 *frame_under_shoot_limit = 0;
1438 *frame_over_shoot_limit = INT_MAX;
1442 if (cpi->common.frame_type == KEY_FRAME)
1444 *frame_over_shoot_limit = cpi->this_frame_target * 9 / 8;
1445 *frame_under_shoot_limit = cpi->this_frame_target * 7 / 8;
1449 if (cpi->oxcf.number_of_layers > 1 ||
1450 cpi->common.refresh_alt_ref_frame ||
1451 cpi->common.refresh_golden_frame)
1453 *frame_over_shoot_limit = cpi->this_frame_target * 9 / 8;
1454 *frame_under_shoot_limit = cpi->this_frame_target * 7 / 8;
1458 /* For CBR take buffer fullness into account */
1459 if (cpi->oxcf.end_usage == USAGE_STREAM_FROM_SERVER)
1461 if (cpi->buffer_level >= ((cpi->oxcf.optimal_buffer_level + cpi->oxcf.maximum_buffer_size) >> 1))
1463 /* Buffer is too full so relax overshoot and tighten
1466 *frame_over_shoot_limit = cpi->this_frame_target * 12 / 8;
1467 *frame_under_shoot_limit = cpi->this_frame_target * 6 / 8;
1469 else if (cpi->buffer_level <= (cpi->oxcf.optimal_buffer_level >> 1))
1471 /* Buffer is too low so relax undershoot and tighten
1474 *frame_over_shoot_limit = cpi->this_frame_target * 10 / 8;
1475 *frame_under_shoot_limit = cpi->this_frame_target * 4 / 8;
1479 *frame_over_shoot_limit = cpi->this_frame_target * 11 / 8;
1480 *frame_under_shoot_limit = cpi->this_frame_target * 5 / 8;
1483 /* VBR and CQ mode */
1484 /* Note that tighter restrictions here can help quality
1485 * but hurt encode speed
1489 /* Stron overshoot limit for constrained quality */
1490 if (cpi->oxcf.end_usage == USAGE_CONSTRAINED_QUALITY)
1492 *frame_over_shoot_limit = cpi->this_frame_target * 11 / 8;
1493 *frame_under_shoot_limit = cpi->this_frame_target * 2 / 8;
1497 *frame_over_shoot_limit = cpi->this_frame_target * 11 / 8;
1498 *frame_under_shoot_limit = cpi->this_frame_target * 5 / 8;
1504 /* For very small rate targets where the fractional adjustment
1505 * (eg * 7/8) may be tiny make sure there is at least a minimum
1508 *frame_over_shoot_limit += 200;
1509 *frame_under_shoot_limit -= 200;
1510 if ( *frame_under_shoot_limit < 0 )
1511 *frame_under_shoot_limit = 0;
1517 /* return of 0 means drop frame */
1518 int vp8_pick_frame_size(VP8_COMP *cpi)
1520 VP8_COMMON *cm = &cpi->common;
1522 if (cm->frame_type == KEY_FRAME)
1523 calc_iframe_target_size(cpi);
1526 calc_pframe_target_size(cpi);
1528 /* Check if we're dropping the frame: */
1529 if (cpi->drop_frame)
1531 cpi->drop_frame = 0;