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
12#ifndef VP8_ENCODER_ONYX_INT_H_
13#define VP8_ENCODER_ONYX_INT_H_
14
15#include <stdio.h>
16#include "vpx_config.h"
17#include "vp8/common/onyx.h"
18#include "treewriter.h"
19#include "tokenize.h"
20#include "vp8/common/onyxc_int.h"
21#include "vp8/common/variance.h"
22#include "encodemb.h"
23#include "quantize.h"
24#include "vp8/common/entropy.h"
25#include "vp8/common/threading.h"
26#include "vpx_ports/mem.h"
27#include "vpx/internal/vpx_codec_internal.h"
28#include "vpx/vp8.h"
29#include "mcomp.h"
30#include "vp8/common/findnearmv.h"
31#include "lookahead.h"
32#if CONFIG_TEMPORAL_DENOISING
33#include "vp8/encoder/denoising.h"
34#endif
35
36#ifdef __cplusplus
37extern "C" {
38#endif
39
40#define MIN_GF_INTERVAL             4
41#define DEFAULT_GF_INTERVAL         7
42
43#define KEY_FRAME_CONTEXT 5
44
45#define MAX_LAG_BUFFERS (CONFIG_REALTIME_ONLY? 1 : 25)
46
47#define AF_THRESH   25
48#define AF_THRESH2  100
49#define ARF_DECAY_THRESH 12
50
51
52#define MIN_THRESHMULT  32
53#define MAX_THRESHMULT  512
54
55#define GF_ZEROMV_ZBIN_BOOST 12
56#define LF_ZEROMV_ZBIN_BOOST 6
57#define MV_ZBIN_BOOST        4
58#define ZBIN_OQ_MAX 192
59
60#if !(CONFIG_REALTIME_ONLY)
61#define VP8_TEMPORAL_ALT_REF 1
62#endif
63
64typedef struct
65{
66    int kf_indicated;
67    unsigned int frames_since_key;
68    unsigned int frames_since_golden;
69    int filter_level;
70    int frames_till_gf_update_due;
71    int recent_ref_frame_usage[MAX_REF_FRAMES];
72
73    MV_CONTEXT mvc[2];
74    int mvcosts[2][MVvals+1];
75
76#ifdef MODE_STATS
77    int y_modes[5];
78    int uv_modes[4];
79    int b_modes[10];
80    int inter_y_modes[10];
81    int inter_uv_modes[4];
82    int inter_b_modes[10];
83#endif
84
85    vp8_prob ymode_prob[4], uv_mode_prob[3];   /* interframe intra mode probs */
86    vp8_prob kf_ymode_prob[4], kf_uv_mode_prob[3];   /* keyframe "" */
87
88    int ymode_count[5], uv_mode_count[4];  /* intra MB type cts this frame */
89
90    int count_mb_ref_frame_usage[MAX_REF_FRAMES];
91
92    int this_frame_percent_intra;
93    int last_frame_percent_intra;
94
95
96} CODING_CONTEXT;
97
98typedef struct
99{
100    double frame;
101    double intra_error;
102    double coded_error;
103    double ssim_weighted_pred_err;
104    double pcnt_inter;
105    double pcnt_motion;
106    double pcnt_second_ref;
107    double pcnt_neutral;
108    double MVr;
109    double mvr_abs;
110    double MVc;
111    double mvc_abs;
112    double MVrv;
113    double MVcv;
114    double mv_in_out_count;
115    double new_mv_count;
116    double duration;
117    double count;
118}
119FIRSTPASS_STATS;
120
121typedef struct
122{
123    int frames_so_far;
124    double frame_intra_error;
125    double frame_coded_error;
126    double frame_pcnt_inter;
127    double frame_pcnt_motion;
128    double frame_mvr;
129    double frame_mvr_abs;
130    double frame_mvc;
131    double frame_mvc_abs;
132
133} ONEPASS_FRAMESTATS;
134
135
136typedef enum
137{
138    THR_ZERO1          = 0,
139    THR_DC             = 1,
140
141    THR_NEAREST1       = 2,
142    THR_NEAR1          = 3,
143
144    THR_ZERO2          = 4,
145    THR_NEAREST2       = 5,
146
147    THR_ZERO3          = 6,
148    THR_NEAREST3       = 7,
149
150    THR_NEAR2          = 8,
151    THR_NEAR3          = 9,
152
153    THR_V_PRED         = 10,
154    THR_H_PRED         = 11,
155    THR_TM             = 12,
156
157    THR_NEW1           = 13,
158    THR_NEW2           = 14,
159    THR_NEW3           = 15,
160
161    THR_SPLIT1         = 16,
162    THR_SPLIT2         = 17,
163    THR_SPLIT3         = 18,
164
165    THR_B_PRED         = 19
166}
167THR_MODES;
168
169typedef enum
170{
171    DIAMOND = 0,
172    NSTEP = 1,
173    HEX = 2
174} SEARCH_METHODS;
175
176typedef struct
177{
178    int RD;
179    SEARCH_METHODS search_method;
180    int improved_quant;
181    int improved_dct;
182    int auto_filter;
183    int recode_loop;
184    int iterative_sub_pixel;
185    int half_pixel_search;
186    int quarter_pixel_search;
187    int thresh_mult[MAX_MODES];
188    int max_step_search_steps;
189    int first_step;
190    int optimize_coefficients;
191
192    int use_fastquant_for_pick;
193    int no_skip_block4x4_search;
194    int improved_mv_pred;
195
196} SPEED_FEATURES;
197
198typedef struct
199{
200    MACROBLOCK  mb;
201    int segment_counts[MAX_MB_SEGMENTS];
202    int totalrate;
203} MB_ROW_COMP;
204
205typedef struct
206{
207    TOKENEXTRA *start;
208    TOKENEXTRA *stop;
209} TOKENLIST;
210
211typedef struct
212{
213    int ithread;
214    void *ptr1;
215    void *ptr2;
216} ENCODETHREAD_DATA;
217typedef struct
218{
219    int ithread;
220    void *ptr1;
221} LPFTHREAD_DATA;
222
223enum
224{
225    BLOCK_16X8,
226    BLOCK_8X16,
227    BLOCK_8X8,
228    BLOCK_4X4,
229    BLOCK_16X16,
230    BLOCK_MAX_SEGMENTS
231};
232
233typedef struct
234{
235    /* Layer configuration */
236    double framerate;
237    int target_bandwidth;
238
239    /* Layer specific coding parameters */
240    int64_t starting_buffer_level;
241    int64_t optimal_buffer_level;
242    int64_t maximum_buffer_size;
243    int64_t starting_buffer_level_in_ms;
244    int64_t optimal_buffer_level_in_ms;
245    int64_t maximum_buffer_size_in_ms;
246
247    int avg_frame_size_for_layer;
248
249    int64_t buffer_level;
250    int64_t bits_off_target;
251
252    int64_t total_actual_bits;
253    int total_target_vs_actual;
254
255    int worst_quality;
256    int active_worst_quality;
257    int best_quality;
258    int active_best_quality;
259
260    int ni_av_qi;
261    int ni_tot_qi;
262    int ni_frames;
263    int avg_frame_qindex;
264
265    double rate_correction_factor;
266    double key_frame_rate_correction_factor;
267    double gf_rate_correction_factor;
268
269    int zbin_over_quant;
270
271    int inter_frame_target;
272    int64_t total_byte_count;
273
274    int filter_level;
275
276    int last_frame_percent_intra;
277
278    int count_mb_ref_frame_usage[MAX_REF_FRAMES];
279
280} LAYER_CONTEXT;
281
282typedef struct VP8_COMP
283{
284
285    DECLARE_ALIGNED(16, short, Y1quant[QINDEX_RANGE][16]);
286    DECLARE_ALIGNED(16, short, Y1quant_shift[QINDEX_RANGE][16]);
287    DECLARE_ALIGNED(16, short, Y1zbin[QINDEX_RANGE][16]);
288    DECLARE_ALIGNED(16, short, Y1round[QINDEX_RANGE][16]);
289
290    DECLARE_ALIGNED(16, short, Y2quant[QINDEX_RANGE][16]);
291    DECLARE_ALIGNED(16, short, Y2quant_shift[QINDEX_RANGE][16]);
292    DECLARE_ALIGNED(16, short, Y2zbin[QINDEX_RANGE][16]);
293    DECLARE_ALIGNED(16, short, Y2round[QINDEX_RANGE][16]);
294
295    DECLARE_ALIGNED(16, short, UVquant[QINDEX_RANGE][16]);
296    DECLARE_ALIGNED(16, short, UVquant_shift[QINDEX_RANGE][16]);
297    DECLARE_ALIGNED(16, short, UVzbin[QINDEX_RANGE][16]);
298    DECLARE_ALIGNED(16, short, UVround[QINDEX_RANGE][16]);
299
300    DECLARE_ALIGNED(16, short, zrun_zbin_boost_y1[QINDEX_RANGE][16]);
301    DECLARE_ALIGNED(16, short, zrun_zbin_boost_y2[QINDEX_RANGE][16]);
302    DECLARE_ALIGNED(16, short, zrun_zbin_boost_uv[QINDEX_RANGE][16]);
303    DECLARE_ALIGNED(16, short, Y1quant_fast[QINDEX_RANGE][16]);
304    DECLARE_ALIGNED(16, short, Y2quant_fast[QINDEX_RANGE][16]);
305    DECLARE_ALIGNED(16, short, UVquant_fast[QINDEX_RANGE][16]);
306
307
308    MACROBLOCK mb;
309    VP8_COMMON common;
310    vp8_writer bc[9]; /* one boolcoder for each partition */
311
312    VP8_CONFIG oxcf;
313
314    struct lookahead_ctx    *lookahead;
315    struct lookahead_entry  *source;
316    struct lookahead_entry  *alt_ref_source;
317    struct lookahead_entry  *last_source;
318
319    YV12_BUFFER_CONFIG *Source;
320    YV12_BUFFER_CONFIG *un_scaled_source;
321    YV12_BUFFER_CONFIG scaled_source;
322    YV12_BUFFER_CONFIG *last_frame_unscaled_source;
323
324    unsigned int frames_till_alt_ref_frame;
325    /* frame in src_buffers has been identified to be encoded as an alt ref */
326    int source_alt_ref_pending;
327    /* an alt ref frame has been encoded and is usable */
328    int source_alt_ref_active;
329    /* source of frame to encode is an exact copy of an alt ref frame */
330    int is_src_frame_alt_ref;
331
332    /* golden frame same as last frame ( short circuit gold searches) */
333    int gold_is_last;
334    /* Alt reference frame same as last ( short circuit altref search) */
335    int alt_is_last;
336    /* don't do both alt and gold search ( just do gold). */
337    int gold_is_alt;
338
339    YV12_BUFFER_CONFIG pick_lf_lvl_frame;
340
341    TOKENEXTRA *tok;
342    unsigned int tok_count;
343
344
345    unsigned int frames_since_key;
346    unsigned int key_frame_frequency;
347    unsigned int this_key_frame_forced;
348    unsigned int next_key_frame_forced;
349
350    /* Ambient reconstruction err target for force key frames */
351    int ambient_err;
352
353    unsigned int mode_check_freq[MAX_MODES];
354
355    int rd_baseline_thresh[MAX_MODES];
356
357    int RDMULT;
358    int RDDIV ;
359
360    CODING_CONTEXT coding_context;
361
362    /* Rate targetting variables */
363    int64_t last_prediction_error;
364    int64_t last_intra_error;
365
366    int this_frame_target;
367    int projected_frame_size;
368    int last_q[2];                   /* Separate values for Intra/Inter */
369
370    double rate_correction_factor;
371    double key_frame_rate_correction_factor;
372    double gf_rate_correction_factor;
373
374    unsigned int frames_since_golden;
375    /* Count down till next GF */
376    int frames_till_gf_update_due;
377
378    /* GF interval chosen when we coded the last GF */
379    int current_gf_interval;
380
381    /* Total bits overspent becasue of GF boost (cumulative) */
382    int gf_overspend_bits;
383
384    /* Used in the few frames following a GF to recover the extra bits
385     * spent in that GF
386     */
387    int non_gf_bitrate_adjustment;
388
389    /* Extra bits spent on key frames that need to be recovered */
390    int kf_overspend_bits;
391
392    /* Current number of bit s to try and recover on each inter frame. */
393    int kf_bitrate_adjustment;
394    int max_gf_interval;
395    int baseline_gf_interval;
396    int active_arnr_frames;
397
398    int64_t key_frame_count;
399    int prior_key_frame_distance[KEY_FRAME_CONTEXT];
400    /* Current section per frame bandwidth target */
401    int per_frame_bandwidth;
402    /* Average frame size target for clip */
403    int av_per_frame_bandwidth;
404    /* Minimum allocation that should be used for any frame */
405    int min_frame_bandwidth;
406    int inter_frame_target;
407    double output_framerate;
408    int64_t last_time_stamp_seen;
409    int64_t last_end_time_stamp_seen;
410    int64_t first_time_stamp_ever;
411
412    int ni_av_qi;
413    int ni_tot_qi;
414    int ni_frames;
415    int avg_frame_qindex;
416
417    int64_t total_byte_count;
418
419    int buffered_mode;
420
421    double framerate;
422    double ref_framerate;
423    int64_t buffer_level;
424    int64_t bits_off_target;
425
426    int rolling_target_bits;
427    int rolling_actual_bits;
428
429    int long_rolling_target_bits;
430    int long_rolling_actual_bits;
431
432    int64_t total_actual_bits;
433    int total_target_vs_actual; /* debug stats */
434
435    int worst_quality;
436    int active_worst_quality;
437    int best_quality;
438    int active_best_quality;
439
440    int cq_target_quality;
441
442    int drop_frames_allowed; /* Are we permitted to drop frames? */
443    int drop_frame;          /* Drop this frame? */
444
445    vp8_prob frame_coef_probs [BLOCK_TYPES] [COEF_BANDS] [PREV_COEF_CONTEXTS] [ENTROPY_NODES];
446    char update_probs [BLOCK_TYPES] [COEF_BANDS] [PREV_COEF_CONTEXTS] [ENTROPY_NODES];
447
448    unsigned int frame_branch_ct [BLOCK_TYPES] [COEF_BANDS] [PREV_COEF_CONTEXTS] [ENTROPY_NODES][2];
449
450    int gfu_boost;
451    int kf_boost;
452    int last_boost;
453
454    int target_bandwidth;
455    struct vpx_codec_pkt_list  *output_pkt_list;
456
457#if 0
458    /* Experimental code for lagged and one pass */
459    ONEPASS_FRAMESTATS one_pass_frame_stats[MAX_LAG_BUFFERS];
460    int one_pass_frame_index;
461#endif
462
463    int decimation_factor;
464    int decimation_count;
465
466    /* for real time encoding */
467    int avg_encode_time;     /* microsecond */
468    int avg_pick_mode_time;  /* microsecond */
469    int Speed;
470    int compressor_speed;
471
472    int auto_gold;
473    int auto_adjust_gold_quantizer;
474    int auto_worst_q;
475    int cpu_used;
476    int pass;
477
478
479    int prob_intra_coded;
480    int prob_last_coded;
481    int prob_gf_coded;
482    int prob_skip_false;
483    int last_skip_false_probs[3];
484    int last_skip_probs_q[3];
485    int recent_ref_frame_usage[MAX_REF_FRAMES];
486
487    int this_frame_percent_intra;
488    int last_frame_percent_intra;
489
490    int ref_frame_flags;
491
492    SPEED_FEATURES sf;
493
494    /* Count ZEROMV on all reference frames. */
495    int zeromv_count;
496    int lf_zeromv_pct;
497
498    unsigned char *segmentation_map;
499    signed char segment_feature_data[MB_LVL_MAX][MAX_MB_SEGMENTS];
500    int  segment_encode_breakout[MAX_MB_SEGMENTS];
501
502    unsigned char *active_map;
503    unsigned int active_map_enabled;
504
505    /* Video conferencing cyclic refresh mode flags. This is a mode
506     * designed to clean up the background over time in live encoding
507     * scenarious. It uses segmentation.
508     */
509    int cyclic_refresh_mode_enabled;
510    int cyclic_refresh_mode_max_mbs_perframe;
511    int cyclic_refresh_mode_index;
512    int cyclic_refresh_q;
513    signed char *cyclic_refresh_map;
514    // Count on how many (consecutive) times a macroblock uses ZER0MV_LAST.
515    unsigned char *consec_zero_last;
516
517    // Frame counter for the temporal pattern. Counter is rest when the temporal
518    // layers are changed dynamically (run-time change).
519    unsigned int temporal_pattern_counter;
520
521#if CONFIG_MULTITHREAD
522    /* multithread data */
523    int * mt_current_mb_col;
524    int mt_sync_range;
525    int b_multi_threaded;
526    int encoding_thread_count;
527    int b_lpf_running;
528
529    pthread_t *h_encoding_thread;
530    pthread_t h_filter_thread;
531
532    MB_ROW_COMP *mb_row_ei;
533    ENCODETHREAD_DATA *en_thread_data;
534    LPFTHREAD_DATA lpf_thread_data;
535
536    /* events */
537    sem_t *h_event_start_encoding;
538    sem_t h_event_end_encoding;
539    sem_t h_event_start_lpf;
540    sem_t h_event_end_lpf;
541#endif
542
543    TOKENLIST *tplist;
544    unsigned int partition_sz[MAX_PARTITIONS];
545    unsigned char *partition_d[MAX_PARTITIONS];
546    unsigned char *partition_d_end[MAX_PARTITIONS];
547
548
549    fractional_mv_step_fp *find_fractional_mv_step;
550    vp8_full_search_fn_t full_search_sad;
551    vp8_refining_search_fn_t refining_search_sad;
552    vp8_diamond_search_fn_t diamond_search_sad;
553    vp8_variance_fn_ptr_t fn_ptr[BLOCK_MAX_SEGMENTS];
554    uint64_t time_receive_data;
555    uint64_t time_compress_data;
556    uint64_t time_pick_lpf;
557    uint64_t time_encode_mb_row;
558
559    int base_skip_false_prob[128];
560
561    FRAME_CONTEXT lfc_n; /* last frame entropy */
562    FRAME_CONTEXT lfc_a; /* last alt ref entropy */
563    FRAME_CONTEXT lfc_g; /* last gold ref entropy */
564
565
566    struct twopass_rc
567    {
568        unsigned int section_intra_rating;
569        double section_max_qfactor;
570        unsigned int next_iiratio;
571        unsigned int this_iiratio;
572        FIRSTPASS_STATS total_stats;
573        FIRSTPASS_STATS this_frame_stats;
574        FIRSTPASS_STATS *stats_in, *stats_in_end, *stats_in_start;
575        FIRSTPASS_STATS total_left_stats;
576        int first_pass_done;
577        int64_t bits_left;
578        int64_t clip_bits_total;
579        double avg_iiratio;
580        double modified_error_total;
581        double modified_error_used;
582        double modified_error_left;
583        double kf_intra_err_min;
584        double gf_intra_err_min;
585        int frames_to_key;
586        int maxq_max_limit;
587        int maxq_min_limit;
588        int gf_decay_rate;
589        int static_scene_max_gf_interval;
590        int kf_bits;
591        /* Remaining error from uncoded frames in a gf group. */
592        int gf_group_error_left;
593        /* Projected total bits available for a key frame group of frames */
594        int64_t kf_group_bits;
595        /* Error score of frames still to be coded in kf group */
596        int64_t kf_group_error_left;
597        /* Projected Bits available for a group including 1 GF or ARF */
598        int64_t gf_group_bits;
599        /* Bits for the golden frame or ARF */
600        int gf_bits;
601        int alt_extra_bits;
602        double est_max_qcorrection_factor;
603    } twopass;
604
605#if VP8_TEMPORAL_ALT_REF
606    YV12_BUFFER_CONFIG alt_ref_buffer;
607    YV12_BUFFER_CONFIG *frames[MAX_LAG_BUFFERS];
608    int fixed_divide[512];
609#endif
610
611#if CONFIG_INTERNAL_STATS
612    int    count;
613    double total_y;
614    double total_u;
615    double total_v;
616    double total ;
617    double total_sq_error;
618    double totalp_y;
619    double totalp_u;
620    double totalp_v;
621    double totalp;
622    double total_sq_error2;
623    int    bytes;
624    double summed_quality;
625    double summed_weights;
626    unsigned int tot_recode_hits;
627
628
629    double total_ssimg_y;
630    double total_ssimg_u;
631    double total_ssimg_v;
632    double total_ssimg_all;
633
634    int b_calculate_ssimg;
635#endif
636    int b_calculate_psnr;
637
638    /* Per MB activity measurement */
639    unsigned int activity_avg;
640    unsigned int * mb_activity_map;
641
642    /* Record of which MBs still refer to last golden frame either
643     * directly or through 0,0
644     */
645    unsigned char *gf_active_flags;
646    int gf_active_count;
647
648    int output_partition;
649
650    /* Store last frame's MV info for next frame MV prediction */
651    int_mv *lfmv;
652    int *lf_ref_frame_sign_bias;
653    int *lf_ref_frame;
654
655    /* force next frame to intra when kf_auto says so */
656    int force_next_frame_intra;
657
658    int droppable;
659
660#if CONFIG_TEMPORAL_DENOISING
661    VP8_DENOISER denoiser;
662#endif
663
664    /* Coding layer state variables */
665    unsigned int current_layer;
666    LAYER_CONTEXT layer_context[VPX_TS_MAX_LAYERS];
667
668    int64_t frames_in_layer[VPX_TS_MAX_LAYERS];
669    int64_t bytes_in_layer[VPX_TS_MAX_LAYERS];
670    double sum_psnr[VPX_TS_MAX_LAYERS];
671    double sum_psnr_p[VPX_TS_MAX_LAYERS];
672    double total_error2[VPX_TS_MAX_LAYERS];
673    double total_error2_p[VPX_TS_MAX_LAYERS];
674    double sum_ssim[VPX_TS_MAX_LAYERS];
675    double sum_weights[VPX_TS_MAX_LAYERS];
676
677    double total_ssimg_y_in_layer[VPX_TS_MAX_LAYERS];
678    double total_ssimg_u_in_layer[VPX_TS_MAX_LAYERS];
679    double total_ssimg_v_in_layer[VPX_TS_MAX_LAYERS];
680    double total_ssimg_all_in_layer[VPX_TS_MAX_LAYERS];
681
682#if CONFIG_MULTI_RES_ENCODING
683    /* Number of MBs per row at lower-resolution level */
684    int    mr_low_res_mb_cols;
685    /* Indicate if lower-res mv info is available */
686    unsigned char  mr_low_res_mv_avail;
687#endif
688    /* The frame number of each reference frames */
689    unsigned int current_ref_frames[MAX_REF_FRAMES];
690    MV_REFERENCE_FRAME closest_reference_frame;
691
692    struct rd_costs_struct
693    {
694        int mvcosts[2][MVvals+1];
695        int mvsadcosts[2][MVfpvals+1];
696        int mbmode_cost[2][MB_MODE_COUNT];
697        int intra_uv_mode_cost[2][MB_MODE_COUNT];
698        int bmode_costs[10][10][10];
699        int inter_bmode_costs[B_MODE_COUNT];
700        int token_costs[BLOCK_TYPES][COEF_BANDS]
701        [PREV_COEF_CONTEXTS][MAX_ENTROPY_TOKENS];
702    } rd_costs;
703} VP8_COMP;
704
705void vp8_pack_bitstream(VP8_COMP *cpi, unsigned char *dest,
706                        unsigned char *dest_end, unsigned long *size);
707
708void vp8_tokenize_mb(VP8_COMP *, MACROBLOCK *, TOKENEXTRA **);
709
710void vp8_set_speed_features(VP8_COMP *cpi);
711
712#if CONFIG_DEBUG
713#define CHECK_MEM_ERROR(lval,expr) do {\
714        lval = (expr); \
715        if(!lval) \
716            vpx_internal_error(&cpi->common.error, VPX_CODEC_MEM_ERROR,\
717                               "Failed to allocate "#lval" at %s:%d", \
718                               __FILE__,__LINE__);\
719    } while(0)
720#else
721#define CHECK_MEM_ERROR(lval,expr) do {\
722        lval = (expr); \
723        if(!lval) \
724            vpx_internal_error(&cpi->common.error, VPX_CODEC_MEM_ERROR,\
725                               "Failed to allocate "#lval);\
726    } while(0)
727#endif
728#ifdef __cplusplus
729}  // extern "C"
730#endif
731
732#endif  // VP8_ENCODER_ONYX_INT_H_
733