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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 #define FRAME_OVERHEAD_BITS 200
36 
37 typedef enum {
38   INTER_NORMAL = 0,
39   INTER_HIGH = 1,
40   GF_ARF_LOW = 2,
41   GF_ARF_STD = 3,
42   KF_STD = 4,
43   RATE_FACTOR_LEVELS = 5
44 } RATE_FACTOR_LEVEL;
45 
46 // Internal frame scaling level.
47 typedef enum {
48   UNSCALED = 0,     // Frame is unscaled.
49   SCALE_STEP1 = 1,  // First-level down-scaling.
50   FRAME_SCALE_STEPS
51 } FRAME_SCALE_LEVEL;
52 
53 typedef enum {
54   NO_RESIZE = 0,
55   DOWN_THREEFOUR = 1,  // From orig to 3/4.
56   DOWN_ONEHALF = 2,    // From orig or 3/4 to 1/2.
57   UP_THREEFOUR = -1,   // From 1/2 to 3/4.
58   UP_ORIG = -2,        // From 1/2 or 3/4 to orig.
59 } RESIZE_ACTION;
60 
61 typedef enum { ORIG = 0, THREE_QUARTER = 1, ONE_HALF = 2 } RESIZE_STATE;
62 
63 // Frame dimensions multiplier wrt the native frame size, in 1/16ths,
64 // specified for the scale-up case.
65 // e.g. 24 => 16/24 = 2/3 of native size. The restriction to 1/16th is
66 // intended to match the capabilities of the normative scaling filters,
67 // giving precedence to the up-scaling accuracy.
68 static const int frame_scale_factor[FRAME_SCALE_STEPS] = { 16, 24 };
69 
70 // Multiplier of the target rate to be used as threshold for triggering scaling.
71 static const double rate_thresh_mult[FRAME_SCALE_STEPS] = { 1.0, 2.0 };
72 
73 // Scale dependent Rate Correction Factor multipliers. Compensates for the
74 // greater number of bits per pixel generated in down-scaled frames.
75 static const double rcf_mult[FRAME_SCALE_STEPS] = { 1.0, 2.0 };
76 
77 typedef struct {
78   // Rate targetting variables
79   int base_frame_target;  // A baseline frame target before adjustment
80                           // for previous under or over shoot.
81   int this_frame_target;  // Actual frame target after rc adjustment.
82   int projected_frame_size;
83   int sb64_target_rate;
84   int last_q[FRAME_TYPES];  // Separate values for Intra/Inter
85   int last_boosted_qindex;  // Last boosted GF/KF/ARF q
86   int last_kf_qindex;       // Q index of the last key frame coded.
87 
88   int gfu_boost;
89   int last_boost;
90   int kf_boost;
91 
92   double rate_correction_factors[RATE_FACTOR_LEVELS];
93 
94   int frames_since_golden;
95   int frames_till_gf_update_due;
96   int min_gf_interval;
97   int max_gf_interval;
98   int static_scene_max_gf_interval;
99   int baseline_gf_interval;
100   int constrained_gf_group;
101   int frames_to_key;
102   int frames_since_key;
103   int this_key_frame_forced;
104   int next_key_frame_forced;
105   int source_alt_ref_pending;
106   int source_alt_ref_active;
107   int is_src_frame_alt_ref;
108 
109   int avg_frame_bandwidth;  // Average frame size target for clip
110   int min_frame_bandwidth;  // Minimum allocation used for any frame
111   int max_frame_bandwidth;  // Maximum burst rate allowed for a frame.
112 
113   int ni_av_qi;
114   int ni_tot_qi;
115   int ni_frames;
116   int avg_frame_qindex[FRAME_TYPES];
117   double tot_q;
118   double avg_q;
119 
120   int64_t buffer_level;
121   int64_t bits_off_target;
122   int64_t vbr_bits_off_target;
123   int64_t vbr_bits_off_target_fast;
124 
125   int decimation_factor;
126   int decimation_count;
127 
128   int rolling_target_bits;
129   int rolling_actual_bits;
130 
131   int long_rolling_target_bits;
132   int long_rolling_actual_bits;
133 
134   int rate_error_estimate;
135 
136   int64_t total_actual_bits;
137   int64_t total_target_bits;
138   int64_t total_target_vs_actual;
139 
140   int worst_quality;
141   int best_quality;
142 
143   int64_t starting_buffer_level;
144   int64_t optimal_buffer_level;
145   int64_t maximum_buffer_size;
146 
147   // rate control history for last frame(1) and the frame before(2).
148   // -1: undershot
149   //  1: overshoot
150   //  0: not initialized.
151   int rc_1_frame;
152   int rc_2_frame;
153   int q_1_frame;
154   int q_2_frame;
155   // Keep track of the last target average frame bandwidth.
156   int last_avg_frame_bandwidth;
157 
158   // Auto frame-scaling variables.
159   FRAME_SCALE_LEVEL frame_size_selector;
160   FRAME_SCALE_LEVEL next_frame_size_selector;
161   int frame_width[FRAME_SCALE_STEPS];
162   int frame_height[FRAME_SCALE_STEPS];
163   int rf_level_maxq[RATE_FACTOR_LEVELS];
164 
165   int fac_active_worst_inter;
166   int fac_active_worst_gf;
167   uint64_t avg_source_sad[MAX_LAG_BUFFERS];
168   uint64_t prev_avg_source_sad_lag;
169   int high_source_sad_lagindex;
170   int alt_ref_gf_group;
171   int last_frame_is_src_altref;
172   int high_source_sad;
173   int count_last_scene_change;
174   int avg_frame_low_motion;
175   int af_ratio_onepass_vbr;
176   int force_qpmin;
177   int reset_high_source_sad;
178   double perc_arf_usage;
179 } RATE_CONTROL;
180 
181 struct VP9_COMP;
182 struct VP9EncoderConfig;
183 
184 void vp9_rc_init(const struct VP9EncoderConfig *oxcf, int pass,
185                  RATE_CONTROL *rc);
186 
187 int vp9_estimate_bits_at_q(FRAME_TYPE frame_kind, int q, int mbs,
188                            double correction_factor, vpx_bit_depth_t bit_depth);
189 
190 double vp9_convert_qindex_to_q(int qindex, vpx_bit_depth_t bit_depth);
191 
192 int vp9_convert_q_to_qindex(double q_val, vpx_bit_depth_t bit_depth);
193 
194 void vp9_rc_init_minq_luts(void);
195 
196 int vp9_rc_get_default_min_gf_interval(int width, int height, double framerate);
197 // Note vp9_rc_get_default_max_gf_interval() requires the min_gf_interval to
198 // be passed in to ensure that the max_gf_interval returned is at least as bis
199 // as that.
200 int vp9_rc_get_default_max_gf_interval(double framerate, int min_frame_rate);
201 
202 // Generally at the high level, the following flow is expected
203 // to be enforced for rate control:
204 // First call per frame, one of:
205 //   vp9_rc_get_one_pass_vbr_params()
206 //   vp9_rc_get_one_pass_cbr_params()
207 //   vp9_rc_get_svc_params()
208 //   vp9_rc_get_first_pass_params()
209 //   vp9_rc_get_second_pass_params()
210 // depending on the usage to set the rate control encode parameters desired.
211 //
212 // Then, call encode_frame_to_data_rate() to perform the
213 // actual encode. This function will in turn call encode_frame()
214 // one or more times, followed by one of:
215 //   vp9_rc_postencode_update()
216 //   vp9_rc_postencode_update_drop_frame()
217 //
218 // The majority of rate control parameters are only expected
219 // to be set in the vp9_rc_get_..._params() functions and
220 // updated during the vp9_rc_postencode_update...() functions.
221 // The only exceptions are vp9_rc_drop_frame() and
222 // vp9_rc_update_rate_correction_factors() functions.
223 
224 // Functions to set parameters for encoding before the actual
225 // encode_frame_to_data_rate() function.
226 void vp9_rc_get_one_pass_vbr_params(struct VP9_COMP *cpi);
227 void vp9_rc_get_one_pass_cbr_params(struct VP9_COMP *cpi);
228 void vp9_rc_get_svc_params(struct VP9_COMP *cpi);
229 
230 // Post encode update of the rate control parameters based
231 // on bytes used
232 void vp9_rc_postencode_update(struct VP9_COMP *cpi, uint64_t bytes_used);
233 // Post encode update of the rate control parameters for dropped frames
234 void vp9_rc_postencode_update_drop_frame(struct VP9_COMP *cpi);
235 
236 // Updates rate correction factors
237 // Changes only the rate correction factors in the rate control structure.
238 void vp9_rc_update_rate_correction_factors(struct VP9_COMP *cpi);
239 
240 // Decide if we should drop this frame: For 1-pass CBR.
241 // Changes only the decimation count in the rate control structure
242 int vp9_rc_drop_frame(struct VP9_COMP *cpi);
243 
244 // Computes frame size bounds.
245 void vp9_rc_compute_frame_size_bounds(const struct VP9_COMP *cpi,
246                                       int this_frame_target,
247                                       int *frame_under_shoot_limit,
248                                       int *frame_over_shoot_limit);
249 
250 // Picks q and q bounds given the target for bits
251 int vp9_rc_pick_q_and_bounds(const struct VP9_COMP *cpi, int *bottom_index,
252                              int *top_index);
253 
254 // Estimates q to achieve a target bits per frame
255 int vp9_rc_regulate_q(const struct VP9_COMP *cpi, int target_bits_per_frame,
256                       int active_best_quality, int active_worst_quality);
257 
258 // Estimates bits per mb for a given qindex and correction factor.
259 int vp9_rc_bits_per_mb(FRAME_TYPE frame_type, int qindex,
260                        double correction_factor, vpx_bit_depth_t bit_depth);
261 
262 // Clamping utilities for bitrate targets for iframes and pframes.
263 int vp9_rc_clamp_iframe_target_size(const struct VP9_COMP *const cpi,
264                                     int target);
265 int vp9_rc_clamp_pframe_target_size(const struct VP9_COMP *const cpi,
266                                     int target);
267 // Utility to set frame_target into the RATE_CONTROL structure
268 // This function is called only from the vp9_rc_get_..._params() functions.
269 void vp9_rc_set_frame_target(struct VP9_COMP *cpi, int target);
270 
271 // Computes a q delta (in "q index" terms) to get from a starting q value
272 // to a target q value
273 int vp9_compute_qdelta(const RATE_CONTROL *rc, double qstart, double qtarget,
274                        vpx_bit_depth_t bit_depth);
275 
276 // Computes a q delta (in "q index" terms) to get from a starting q value
277 // to a value that should equate to the given rate ratio.
278 int vp9_compute_qdelta_by_rate(const RATE_CONTROL *rc, FRAME_TYPE frame_type,
279                                int qindex, double rate_target_ratio,
280                                vpx_bit_depth_t bit_depth);
281 
282 int vp9_frame_type_qdelta(const struct VP9_COMP *cpi, int rf_level, int q);
283 
284 void vp9_rc_update_framerate(struct VP9_COMP *cpi);
285 
286 void vp9_rc_set_gf_interval_range(const struct VP9_COMP *const cpi,
287                                   RATE_CONTROL *const rc);
288 
289 void vp9_set_target_rate(struct VP9_COMP *cpi);
290 
291 int vp9_resize_one_pass_cbr(struct VP9_COMP *cpi);
292 
293 void vp9_scene_detection_onepass(struct VP9_COMP *cpi);
294 
295 int vp9_encodedframe_overshoot(struct VP9_COMP *cpi, int frame_size, int *q);
296 
297 #ifdef __cplusplus
298 }  // extern "C"
299 #endif
300 
301 #endif  // VP9_ENCODER_VP9_RATECTRL_H_
302