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 #ifndef AOM_AV1_ENCODER_RATECTRL_H_
13 #define AOM_AV1_ENCODER_RATECTRL_H_
14 
15 #include "aom/aom_codec.h"
16 #include "aom/aom_integer.h"
17 
18 #include "aom_ports/mem.h"
19 
20 #include "av1/common/av1_common_int.h"
21 #include "av1/common/blockd.h"
22 
23 #ifdef __cplusplus
24 extern "C" {
25 #endif
26 
27 // Bits Per MB at different Q (Multiplied by 512)
28 #define BPER_MB_NORMBITS 9
29 
30 // Use this macro to turn on/off use of alt-refs in one-pass mode.
31 #define USE_ALTREF_FOR_ONE_PASS 1
32 
33 // Threshold used to define if a KF group is static (e.g. a slide show).
34 // Essentially, this means that no frame in the group has more than 1% of MBs
35 // that are not marked as coded with 0,0 motion in the first pass.
36 #define STATIC_KF_GROUP_THRESH 99
37 #define STATIC_KF_GROUP_FLOAT_THRESH 0.99
38 
39 // The maximum duration of a GF group that is static (e.g. a slide show).
40 #define MAX_STATIC_GF_GROUP_LENGTH 250
41 
42 // Minimum and maximum height for the new pyramid structure.
43 // (Old structure supports height = 1, but does NOT support height = 4).
44 #define MIN_PYRAMID_LVL 0
45 #define MAX_PYRAMID_LVL 4
46 
47 #define MIN_GF_INTERVAL 4
48 #define MAX_GF_INTERVAL 32
49 #define FIXED_GF_INTERVAL 8  // Used in some testing modes only
50 #define MAX_GF_LENGTH_LAP 16
51 
52 #define MAX_NUM_GF_INTERVALS 15
53 
54 #define MAX_ARF_LAYERS 6
55 // #define STRICT_RC
56 
57 typedef struct {
58   int resize_width;
59   int resize_height;
60   uint8_t superres_denom;
61 } size_params_type;
62 
63 enum {
64   INTER_NORMAL,
65   GF_ARF_LOW,
66   GF_ARF_STD,
67   KF_STD,
68   RATE_FACTOR_LEVELS
69 } UENUM1BYTE(RATE_FACTOR_LEVEL);
70 
71 enum {
72   KF_UPDATE,
73   LF_UPDATE,
74   GF_UPDATE,
75   ARF_UPDATE,
76   OVERLAY_UPDATE,
77   INTNL_OVERLAY_UPDATE,  // Internal Overlay Frame
78   INTNL_ARF_UPDATE,      // Internal Altref Frame
79   FRAME_UPDATE_TYPES
80 } UENUM1BYTE(FRAME_UPDATE_TYPE);
81 
82 typedef struct {
83   // Rate targetting variables
84   int base_frame_target;  // A baseline frame target before adjustment
85                           // for previous under or over shoot.
86   int this_frame_target;  // Actual frame target after rc adjustment.
87 
88   // gop bit budget
89   int64_t gf_group_bits;
90 
91   int projected_frame_size;
92   int sb64_target_rate;
93   int last_q[FRAME_TYPES];  // Separate values for Intra/Inter
94   int last_boosted_qindex;  // Last boosted GF/KF/ARF q
95   int last_kf_qindex;       // Q index of the last key frame coded.
96 
97   int gfu_boost;
98   int kf_boost;
99 
100   double rate_correction_factors[RATE_FACTOR_LEVELS];
101 
102   int frames_since_golden;
103   int frames_till_gf_update_due;
104 
105   // number of determined gf group length left
106   int intervals_till_gf_calculate_due;
107   // stores gf group length intervals
108   int gf_intervals[MAX_NUM_GF_INTERVALS];
109   // the current index in gf_intervals
110   int cur_gf_index;
111 
112   int min_gf_interval;
113   int max_gf_interval;
114   int static_scene_max_gf_interval;
115   int baseline_gf_interval;
116   int constrained_gf_group;
117   int frames_to_key;
118   int frames_since_key;
119   int this_key_frame_forced;
120   int next_key_frame_forced;
121   int source_alt_ref_pending;
122   int source_alt_ref_active;
123   int is_src_frame_alt_ref;
124   int sframe_due;
125 
126   int avg_frame_bandwidth;  // Average frame size target for clip
127   int min_frame_bandwidth;  // Minimum allocation used for any frame
128   int max_frame_bandwidth;  // Maximum burst rate allowed for a frame.
129   int prev_avg_frame_bandwidth;
130 
131   int ni_av_qi;
132   int ni_tot_qi;
133   int ni_frames;
134   int avg_frame_qindex[FRAME_TYPES];
135   double tot_q;
136   double avg_q;
137 
138   int64_t buffer_level;
139   int64_t bits_off_target;
140   int64_t vbr_bits_off_target;
141   int64_t vbr_bits_off_target_fast;
142 
143   int decimation_factor;
144   int decimation_count;
145 
146   int rolling_target_bits;
147   int rolling_actual_bits;
148 
149   int long_rolling_target_bits;
150   int long_rolling_actual_bits;
151 
152   int rate_error_estimate;
153 
154   int64_t total_actual_bits;
155   int64_t total_target_bits;
156   int64_t total_target_vs_actual;
157 
158   int worst_quality;
159   int best_quality;
160 
161   int64_t starting_buffer_level;
162   int64_t optimal_buffer_level;
163   int64_t maximum_buffer_size;
164 
165   // rate control history for last frame(1) and the frame before(2).
166   // -1: undershot
167   //  1: overshoot
168   //  0: not initialized.
169   int rc_1_frame;
170   int rc_2_frame;
171   int q_1_frame;
172   int q_2_frame;
173 
174   float_t arf_boost_factor;
175   // Q index used for ALT frame
176   int arf_q;
177   int active_worst_quality;
178   int active_best_quality[MAX_ARF_LAYERS + 1];
179   int base_layer_qp;
180 
181   // Total number of stats used only for kf_boost calculation.
182   int num_stats_used_for_kf_boost;
183   // Total number of stats used only for gfu_boost calculation.
184   int num_stats_used_for_gfu_boost;
185   // Total number of stats required by gfu_boost calculation.
186   int num_stats_required_for_gfu_boost;
187   int next_is_fwd_key;
188   int enable_scenecut_detection;
189 } RATE_CONTROL;
190 
191 struct AV1_COMP;
192 struct AV1EncoderConfig;
193 
194 void av1_rc_init(const struct AV1EncoderConfig *oxcf, int pass,
195                  RATE_CONTROL *rc);
196 
197 int av1_estimate_bits_at_q(FRAME_TYPE frame_kind, int q, int mbs,
198                            double correction_factor, aom_bit_depth_t bit_depth);
199 
200 double av1_convert_qindex_to_q(int qindex, aom_bit_depth_t bit_depth);
201 
202 void av1_rc_init_minq_luts(void);
203 
204 int av1_rc_get_default_min_gf_interval(int width, int height, double framerate);
205 // Note av1_rc_get_default_max_gf_interval() requires the min_gf_interval to
206 // be passed in to ensure that the max_gf_interval returned is at least as bis
207 // as that.
208 int av1_rc_get_default_max_gf_interval(double framerate, int min_gf_interval);
209 
210 // Generally at the high level, the following flow is expected
211 // to be enforced for rate control:
212 // First call per frame, one of:
213 //   av1_rc_get_first_pass_params()
214 //   av1_rc_get_second_pass_params()
215 // depending on the usage to set the rate control encode parameters desired.
216 //
217 // Then, call encode_frame_to_data_rate() to perform the
218 // actual encode. This function will in turn call encode_frame()
219 // one or more times, followed by one of:
220 //   av1_rc_postencode_update()
221 //   av1_rc_postencode_update_drop_frame()
222 //
223 // The majority of rate control parameters are only expected
224 // to be set in the av1_rc_get_..._params() functions and
225 // updated during the av1_rc_postencode_update...() functions.
226 // The only exceptions are av1_rc_drop_frame() and
227 // av1_rc_update_rate_correction_factors() functions.
228 
229 // Functions to set parameters for encoding before the actual
230 // encode_frame_to_data_rate() function.
231 struct EncodeFrameParams;
232 
233 // Post encode update of the rate control parameters based
234 // on bytes used
235 void av1_rc_postencode_update(struct AV1_COMP *cpi, uint64_t bytes_used);
236 // Post encode update of the rate control parameters for dropped frames
237 void av1_rc_postencode_update_drop_frame(struct AV1_COMP *cpi);
238 
239 // Updates rate correction factors
240 // Changes only the rate correction factors in the rate control structure.
241 void av1_rc_update_rate_correction_factors(struct AV1_COMP *cpi, int width,
242                                            int height);
243 
244 // Decide if we should drop this frame: For 1-pass CBR.
245 // Changes only the decimation count in the rate control structure
246 int av1_rc_drop_frame(struct AV1_COMP *cpi);
247 
248 // Computes frame size bounds.
249 void av1_rc_compute_frame_size_bounds(const struct AV1_COMP *cpi,
250                                       int this_frame_target,
251                                       int *frame_under_shoot_limit,
252                                       int *frame_over_shoot_limit);
253 
254 // Picks q and q bounds given the target for bits
255 int av1_rc_pick_q_and_bounds(const struct AV1_COMP *cpi, RATE_CONTROL *rc,
256                              int width, int height, int gf_index,
257                              int *bottom_index, int *top_index);
258 
259 // Estimates q to achieve a target bits per frame
260 int av1_rc_regulate_q(const struct AV1_COMP *cpi, int target_bits_per_frame,
261                       int active_best_quality, int active_worst_quality,
262                       int width, int height);
263 
264 // Estimates bits per mb for a given qindex and correction factor.
265 int av1_rc_bits_per_mb(FRAME_TYPE frame_type, int qindex,
266                        double correction_factor, aom_bit_depth_t bit_depth);
267 
268 // Clamping utilities for bitrate targets for iframes and pframes.
269 int av1_rc_clamp_iframe_target_size(const struct AV1_COMP *const cpi,
270                                     int target);
271 int av1_rc_clamp_pframe_target_size(const struct AV1_COMP *const cpi,
272                                     int target, uint8_t frame_update_type);
273 
274 // Find q_index corresponding to desired_q, within [best_qindex, worst_qindex].
275 // To be precise, 'q_index' is the smallest integer, for which the corresponding
276 // q >= desired_q.
277 // If no such q index is found, returns 'worst_qindex'.
278 int av1_find_qindex(double desired_q, aom_bit_depth_t bit_depth,
279                     int best_qindex, int worst_qindex);
280 
281 // Computes a q delta (in "q index" terms) to get from a starting q value
282 // to a target q value
283 int av1_compute_qdelta(const RATE_CONTROL *rc, double qstart, double qtarget,
284                        aom_bit_depth_t bit_depth);
285 
286 // Computes a q delta (in "q index" terms) to get from a starting q value
287 // to a value that should equate to the given rate ratio.
288 int av1_compute_qdelta_by_rate(const RATE_CONTROL *rc, FRAME_TYPE frame_type,
289                                int qindex, double rate_target_ratio,
290                                aom_bit_depth_t bit_depth);
291 
292 int av1_frame_type_qdelta(const struct AV1_COMP *cpi, int q);
293 
294 void av1_rc_update_framerate(struct AV1_COMP *cpi, int width, int height);
295 
296 void av1_rc_set_gf_interval_range(const struct AV1_COMP *const cpi,
297                                   RATE_CONTROL *const rc);
298 
299 void av1_set_target_rate(struct AV1_COMP *cpi, int width, int height);
300 
301 int av1_resize_one_pass_cbr(struct AV1_COMP *cpi);
302 
303 void av1_rc_set_frame_target(struct AV1_COMP *cpi, int target, int width,
304                              int height);
305 
306 int av1_calc_pframe_target_size_one_pass_vbr(
307     const struct AV1_COMP *const cpi, FRAME_UPDATE_TYPE frame_update_type);
308 
309 int av1_calc_iframe_target_size_one_pass_vbr(const struct AV1_COMP *const cpi);
310 
311 int av1_calc_pframe_target_size_one_pass_cbr(
312     const struct AV1_COMP *cpi, FRAME_UPDATE_TYPE frame_update_type);
313 
314 int av1_calc_iframe_target_size_one_pass_cbr(const struct AV1_COMP *cpi);
315 
316 void av1_get_one_pass_rt_params(struct AV1_COMP *cpi,
317                                 struct EncodeFrameParams *const frame_params,
318                                 unsigned int frame_flags);
319 
320 #ifdef __cplusplus
321 }  // extern "C"
322 #endif
323 
324 #endif  // AOM_AV1_ENCODER_RATECTRL_H_
325