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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 #ifndef VP9_ENCODER_VP9_RATECTRL_H_
12 #define VP9_ENCODER_VP9_RATECTRL_H_
13 
14 #include "vpx/vpx_codec.h"
15 #include "vpx/vpx_integer.h"
16 
17 #include "vp9/common/vp9_blockd.h"
18 #include "vp9/encoder/vp9_lookahead.h"
19 
20 #ifdef __cplusplus
21 extern "C" {
22 #endif
23 
24 // Used to control aggressive VBR mode.
25 // #define AGGRESSIVE_VBR 1
26 
27 // Bits Per MB at different Q (Multiplied by 512)
28 #define BPER_MB_NORMBITS 9
29 
30 #define MIN_GF_INTERVAL 4
31 #define MAX_GF_INTERVAL 16
32 #define FIXED_GF_INTERVAL 8  // Used in some testing modes only
33 #define ONEHALFONLY_RESIZE 0
34 
35 typedef enum {
36   INTER_NORMAL = 0,
37   INTER_HIGH = 1,
38   GF_ARF_LOW = 2,
39   GF_ARF_STD = 3,
40   KF_STD = 4,
41   RATE_FACTOR_LEVELS = 5
42 } RATE_FACTOR_LEVEL;
43 
44 // Internal frame scaling level.
45 typedef enum {
46   UNSCALED = 0,     // Frame is unscaled.
47   SCALE_STEP1 = 1,  // First-level down-scaling.
48   FRAME_SCALE_STEPS
49 } FRAME_SCALE_LEVEL;
50 
51 typedef enum {
52   NO_RESIZE = 0,
53   DOWN_THREEFOUR = 1,  // From orig to 3/4.
54   DOWN_ONEHALF = 2,    // From orig or 3/4 to 1/2.
55   UP_THREEFOUR = -1,   // From 1/2 to 3/4.
56   UP_ORIG = -2,        // From 1/2 or 3/4 to orig.
57 } RESIZE_ACTION;
58 
59 typedef enum { ORIG = 0, THREE_QUARTER = 1, ONE_HALF = 2 } RESIZE_STATE;
60 
61 // Frame dimensions multiplier wrt the native frame size, in 1/16ths,
62 // specified for the scale-up case.
63 // e.g. 24 => 16/24 = 2/3 of native size. The restriction to 1/16th is
64 // intended to match the capabilities of the normative scaling filters,
65 // giving precedence to the up-scaling accuracy.
66 static const int frame_scale_factor[FRAME_SCALE_STEPS] = { 16, 24 };
67 
68 // Multiplier of the target rate to be used as threshold for triggering scaling.
69 static const double rate_thresh_mult[FRAME_SCALE_STEPS] = { 1.0, 2.0 };
70 
71 // Scale dependent Rate Correction Factor multipliers. Compensates for the
72 // greater number of bits per pixel generated in down-scaled frames.
73 static const double rcf_mult[FRAME_SCALE_STEPS] = { 1.0, 2.0 };
74 
75 typedef struct {
76   // Rate targetting variables
77   int base_frame_target;  // A baseline frame target before adjustment
78                           // for previous under or over shoot.
79   int this_frame_target;  // Actual frame target after rc adjustment.
80   int projected_frame_size;
81   int sb64_target_rate;
82   int last_q[FRAME_TYPES];  // Separate values for Intra/Inter
83   int last_boosted_qindex;  // Last boosted GF/KF/ARF q
84   int last_kf_qindex;       // Q index of the last key frame coded.
85 
86   int gfu_boost;
87   int last_boost;
88   int kf_boost;
89 
90   double rate_correction_factors[RATE_FACTOR_LEVELS];
91 
92   int frames_since_golden;
93   int frames_till_gf_update_due;
94   int min_gf_interval;
95   int max_gf_interval;
96   int static_scene_max_gf_interval;
97   int baseline_gf_interval;
98   int constrained_gf_group;
99   int frames_to_key;
100   int frames_since_key;
101   int this_key_frame_forced;
102   int next_key_frame_forced;
103   int source_alt_ref_pending;
104   int source_alt_ref_active;
105   int is_src_frame_alt_ref;
106 
107   int avg_frame_bandwidth;  // Average frame size target for clip
108   int min_frame_bandwidth;  // Minimum allocation used for any frame
109   int max_frame_bandwidth;  // Maximum burst rate allowed for a frame.
110 
111   int ni_av_qi;
112   int ni_tot_qi;
113   int ni_frames;
114   int avg_frame_qindex[FRAME_TYPES];
115   double tot_q;
116   double avg_q;
117 
118   int64_t buffer_level;
119   int64_t bits_off_target;
120   int64_t vbr_bits_off_target;
121   int64_t vbr_bits_off_target_fast;
122 
123   int decimation_factor;
124   int decimation_count;
125 
126   int rolling_target_bits;
127   int rolling_actual_bits;
128 
129   int long_rolling_target_bits;
130   int long_rolling_actual_bits;
131 
132   int rate_error_estimate;
133 
134   int64_t total_actual_bits;
135   int64_t total_target_bits;
136   int64_t total_target_vs_actual;
137 
138   int worst_quality;
139   int best_quality;
140 
141   int64_t starting_buffer_level;
142   int64_t optimal_buffer_level;
143   int64_t maximum_buffer_size;
144 
145   // rate control history for last frame(1) and the frame before(2).
146   // -1: undershot
147   //  1: overshoot
148   //  0: not initialized.
149   int rc_1_frame;
150   int rc_2_frame;
151   int q_1_frame;
152   int q_2_frame;
153 
154   // Auto frame-scaling variables.
155   FRAME_SCALE_LEVEL frame_size_selector;
156   FRAME_SCALE_LEVEL next_frame_size_selector;
157   int frame_width[FRAME_SCALE_STEPS];
158   int frame_height[FRAME_SCALE_STEPS];
159   int rf_level_maxq[RATE_FACTOR_LEVELS];
160 
161   int fac_active_worst_inter;
162   int fac_active_worst_gf;
163   uint64_t avg_source_sad[MAX_LAG_BUFFERS];
164   uint64_t prev_avg_source_sad_lag;
165   int high_source_sad_lagindex;
166   int alt_ref_gf_group;
167   int high_source_sad;
168   int count_last_scene_change;
169   int avg_frame_low_motion;
170   int af_ratio_onepass_vbr;
171   int force_qpmin;
172 } RATE_CONTROL;
173 
174 struct VP9_COMP;
175 struct VP9EncoderConfig;
176 
177 void vp9_rc_init(const struct VP9EncoderConfig *oxcf, int pass,
178                  RATE_CONTROL *rc);
179 
180 int vp9_estimate_bits_at_q(FRAME_TYPE frame_kind, int q, int mbs,
181                            double correction_factor, vpx_bit_depth_t bit_depth);
182 
183 double vp9_convert_qindex_to_q(int qindex, vpx_bit_depth_t bit_depth);
184 
185 int vp9_convert_q_to_qindex(double q_val, vpx_bit_depth_t bit_depth);
186 
187 void vp9_rc_init_minq_luts(void);
188 
189 int vp9_rc_get_default_min_gf_interval(int width, int height, double framerate);
190 // Note vp9_rc_get_default_max_gf_interval() requires the min_gf_interval to
191 // be passed in to ensure that the max_gf_interval returned is at least as bis
192 // as that.
193 int vp9_rc_get_default_max_gf_interval(double framerate, int min_frame_rate);
194 
195 // Generally at the high level, the following flow is expected
196 // to be enforced for rate control:
197 // First call per frame, one of:
198 //   vp9_rc_get_one_pass_vbr_params()
199 //   vp9_rc_get_one_pass_cbr_params()
200 //   vp9_rc_get_svc_params()
201 //   vp9_rc_get_first_pass_params()
202 //   vp9_rc_get_second_pass_params()
203 // depending on the usage to set the rate control encode parameters desired.
204 //
205 // Then, call encode_frame_to_data_rate() to perform the
206 // actual encode. This function will in turn call encode_frame()
207 // one or more times, followed by one of:
208 //   vp9_rc_postencode_update()
209 //   vp9_rc_postencode_update_drop_frame()
210 //
211 // The majority of rate control parameters are only expected
212 // to be set in the vp9_rc_get_..._params() functions and
213 // updated during the vp9_rc_postencode_update...() functions.
214 // The only exceptions are vp9_rc_drop_frame() and
215 // vp9_rc_update_rate_correction_factors() functions.
216 
217 // Functions to set parameters for encoding before the actual
218 // encode_frame_to_data_rate() function.
219 void vp9_rc_get_one_pass_vbr_params(struct VP9_COMP *cpi);
220 void vp9_rc_get_one_pass_cbr_params(struct VP9_COMP *cpi);
221 void vp9_rc_get_svc_params(struct VP9_COMP *cpi);
222 
223 // Post encode update of the rate control parameters based
224 // on bytes used
225 void vp9_rc_postencode_update(struct VP9_COMP *cpi, uint64_t bytes_used);
226 // Post encode update of the rate control parameters for dropped frames
227 void vp9_rc_postencode_update_drop_frame(struct VP9_COMP *cpi);
228 
229 // Updates rate correction factors
230 // Changes only the rate correction factors in the rate control structure.
231 void vp9_rc_update_rate_correction_factors(struct VP9_COMP *cpi);
232 
233 // Decide if we should drop this frame: For 1-pass CBR.
234 // Changes only the decimation count in the rate control structure
235 int vp9_rc_drop_frame(struct VP9_COMP *cpi);
236 
237 // Computes frame size bounds.
238 void vp9_rc_compute_frame_size_bounds(const struct VP9_COMP *cpi,
239                                       int this_frame_target,
240                                       int *frame_under_shoot_limit,
241                                       int *frame_over_shoot_limit);
242 
243 // Picks q and q bounds given the target for bits
244 int vp9_rc_pick_q_and_bounds(const struct VP9_COMP *cpi, int *bottom_index,
245                              int *top_index);
246 
247 // Estimates q to achieve a target bits per frame
248 int vp9_rc_regulate_q(const struct VP9_COMP *cpi, int target_bits_per_frame,
249                       int active_best_quality, int active_worst_quality);
250 
251 // Estimates bits per mb for a given qindex and correction factor.
252 int vp9_rc_bits_per_mb(FRAME_TYPE frame_type, int qindex,
253                        double correction_factor, vpx_bit_depth_t bit_depth);
254 
255 // Clamping utilities for bitrate targets for iframes and pframes.
256 int vp9_rc_clamp_iframe_target_size(const struct VP9_COMP *const cpi,
257                                     int target);
258 int vp9_rc_clamp_pframe_target_size(const struct VP9_COMP *const cpi,
259                                     int target);
260 // Utility to set frame_target into the RATE_CONTROL structure
261 // This function is called only from the vp9_rc_get_..._params() functions.
262 void vp9_rc_set_frame_target(struct VP9_COMP *cpi, int target);
263 
264 // Computes a q delta (in "q index" terms) to get from a starting q value
265 // to a target q value
266 int vp9_compute_qdelta(const RATE_CONTROL *rc, double qstart, double qtarget,
267                        vpx_bit_depth_t bit_depth);
268 
269 // Computes a q delta (in "q index" terms) to get from a starting q value
270 // to a value that should equate to the given rate ratio.
271 int vp9_compute_qdelta_by_rate(const RATE_CONTROL *rc, FRAME_TYPE frame_type,
272                                int qindex, double rate_target_ratio,
273                                vpx_bit_depth_t bit_depth);
274 
275 int vp9_frame_type_qdelta(const struct VP9_COMP *cpi, int rf_level, int q);
276 
277 void vp9_rc_update_framerate(struct VP9_COMP *cpi);
278 
279 void vp9_rc_set_gf_interval_range(const struct VP9_COMP *const cpi,
280                                   RATE_CONTROL *const rc);
281 
282 void vp9_set_target_rate(struct VP9_COMP *cpi);
283 
284 int vp9_resize_one_pass_cbr(struct VP9_COMP *cpi);
285 
286 void vp9_scene_detection_onepass(struct VP9_COMP *cpi);
287 
288 int vp9_encodedframe_overshoot(struct VP9_COMP *cpi, int frame_size, int *q);
289 
290 #ifdef __cplusplus
291 }  // extern "C"
292 #endif
293 
294 #endif  // VP9_ENCODER_VP9_RATECTRL_H_
295