tor-browser

ratectrl.h (23367B)

---

/*
* Copyright (c) 2016, Alliance for Open Media. All rights reserved.
*
* This source code is subject to the terms of the BSD 2 Clause License and
* the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
* was not distributed with this source code in the LICENSE file, you can
* obtain it at www.aomedia.org/license/software. If the Alliance for Open
* Media Patent License 1.0 was not distributed with this source code in the
* PATENTS file, you can obtain it at www.aomedia.org/license/patent.
*/

#ifndef AOM_AV1_ENCODER_RATECTRL_H_
#define AOM_AV1_ENCODER_RATECTRL_H_

#include "aom/aom_codec.h"
#include "aom/aom_integer.h"

#include "aom_ports/mem.h"

#include "av1/common/av1_common_int.h"
#include "av1/common/blockd.h"

#ifdef __cplusplus
extern "C" {
#endif

/*!\cond */

// Bits Per MB at different Q (Multiplied by 512)
#define BPER_MB_NORMBITS 9

// Use this macro to turn on/off use of alt-refs in one-pass mode.
#define USE_ALTREF_FOR_ONE_PASS 1

// Threshold used to define if a KF group is static (e.g. a slide show).
// Essentially, this means that no frame in the group has more than 1% of MBs
// that are not marked as coded with 0,0 motion in the first pass.
#define STATIC_KF_GROUP_THRESH 99
#define STATIC_KF_GROUP_FLOAT_THRESH 0.99

// The maximum duration of a GF group that is static (e.g. a slide show).
#define MAX_STATIC_GF_GROUP_LENGTH 250

#define MIN_GF_INTERVAL 4
#define MAX_GF_INTERVAL 32
#define FIXED_GF_INTERVAL 16
#define MAX_GF_LENGTH_LAP 16

#define FIXED_GF_INTERVAL_RT 80
#define MAX_GF_INTERVAL_RT 160

#define MAX_NUM_GF_INTERVALS 15

#define MAX_ARF_LAYERS 6
// #define STRICT_RC

#define DEFAULT_KF_BOOST_RT 2300
#define DEFAULT_GF_BOOST_RT 2000

// A passive rate control strategy for screen content type in real-time mode.
// When it is turned on, the compression performance is improved by
// 7.8% (overall_psnr), 5.0% (VMAF) on average. Some clips see gains
// over 20% on metric.
// The downside is that it does not guarantee frame size.
// Since RT mode has a tight restriction on buffer overflow control, we
// turn it off by default.
#define RT_PASSIVE_STRATEGY 0
#define MAX_Q_HISTORY 1000

typedef struct {
 int resize_width;
 int resize_height;
 uint8_t superres_denom;
} size_params_type;

enum {
 INTER_NORMAL,
 GF_ARF_LOW,
 GF_ARF_STD,
 KF_STD,
 RATE_FACTOR_LEVELS
} UENUM1BYTE(RATE_FACTOR_LEVEL);

enum {
 KF_UPDATE,
 LF_UPDATE,
 GF_UPDATE,
 ARF_UPDATE,
 OVERLAY_UPDATE,
 INTNL_OVERLAY_UPDATE,  // Internal Overlay Frame
 INTNL_ARF_UPDATE,      // Internal Altref Frame
 FRAME_UPDATE_TYPES
} UENUM1BYTE(FRAME_UPDATE_TYPE);

enum {
 REFBUF_RESET,   // Clear reference frame buffer
 REFBUF_UPDATE,  // Refresh reference frame buffer
 REFBUF_STATES
} UENUM1BYTE(REFBUF_STATE);

typedef enum {
 NO_RESIZE = 0,
 DOWN_THREEFOUR = 1,  // From orig to 3/4.
 DOWN_ONEHALF = 2,    // From orig or 3/4 to 1/2.
 UP_THREEFOUR = -1,   // From 1/2 to 3/4.
 UP_ORIG = -2,        // From 1/2 or 3/4 to orig.
} RESIZE_ACTION;

typedef enum { ORIG = 0, THREE_QUARTER = 1, ONE_HALF = 2 } RESIZE_STATE;

#define MAX_FIRSTPASS_ANALYSIS_FRAMES 150
typedef enum region_types {
 STABLE_REGION = 0,
 HIGH_VAR_REGION = 1,
 SCENECUT_REGION = 2,
 BLENDING_REGION = 3,
} REGION_TYPES;

typedef struct regions {
 int start;
 int last;
 double avg_noise_var;
 double avg_cor_coeff;
 double avg_sr_fr_ratio;
 double avg_intra_err;
 double avg_coded_err;
 REGION_TYPES type;
} REGIONS;

/*!\endcond */
/*!
* \brief  Rate Control parameters and status
*/
typedef struct {
 // Rate targetting variables

 /*!
  * Baseline target rate for frame before adjustment for previous under or
  * over shoot.
  */
 int base_frame_target;
 /*!
  * Target rate for frame after adjustment for previous under or over shoot.
  */
 int this_frame_target;  // Actual frame target after rc adjustment.

 /*!
  * Projected size for current frame
  */
 int projected_frame_size;

 /*!
  * Bit size of transform coefficient for current frame.
  */
 int coefficient_size;

 /*!
  * Super block rate target used with some adaptive quantization strategies.
  */
 int sb64_target_rate;

 /*!
  * Number of frames since the last ARF / GF.
  */
 int frames_since_golden;

 /*!
  * Number of frames till the next ARF / GF is due.
  */
 int frames_till_gf_update_due;

 /*!
  * Number of determined gf groups left
  */
 int intervals_till_gf_calculate_due;

 /*!\cond */
 int min_gf_interval;
 int max_gf_interval;
 int static_scene_max_gf_interval;
 /*!\endcond */
 /*!
  * Frames before the next key frame
  */
 int frames_to_key;
 /*!\cond */
 int frames_since_key;
 int frames_to_fwd_kf;
 int is_src_frame_alt_ref;
 int sframe_due;

 int high_source_sad;
 int high_motion_content_screen_rtc;
 uint64_t avg_source_sad;
 uint64_t prev_avg_source_sad;
 uint64_t frame_source_sad;
 uint64_t frame_spatial_variance;
 int static_since_last_scene_change;
 int last_encoded_size_keyframe;
 int last_target_size_keyframe;
 int frames_since_scene_change;
 int perc_spatial_flat_blocks;
 int num_col_blscroll_last_tl0;
 int num_row_blscroll_last_tl0;

 int avg_frame_bandwidth;  // Average frame size target for clip
 int min_frame_bandwidth;  // Minimum allocation used for any frame
 int max_frame_bandwidth;  // Maximum burst rate allowed for a frame.
 int prev_avg_frame_bandwidth;

 int ni_av_qi;
 int ni_tot_qi;

 int decimation_factor;
 int decimation_count;
 int prev_frame_is_dropped;
 int drop_count_consec;
 int max_consec_drop;
 int force_max_q;
 int postencode_drop;

 /*!
  * Frame number for encoded frames (non-dropped).
  * Use for setting the rtc reference structure.
  */
 unsigned int frame_number_encoded;

 /*!\endcond */
 /*!
  * User specified maximum Q allowed for current frame
  */
 int worst_quality;
 /*!
  * User specified minimum Q allowed for current frame
  */
 int best_quality;

 /*!\cond */

 // rate control history for last frame(1) and the frame before(2).
 // -1: overshoot
 //  1: undershoot
 //  0: not initialized.
 int rc_1_frame;
 int rc_2_frame;
 int q_1_frame;
 int q_2_frame;

 /*!\endcond */
 /*!
  * Proposed maximum allowed Q for current frame
  */
 int active_worst_quality;

 /*!\cond */
 // Track amount of low motion in scene
 int avg_frame_low_motion;
 int cnt_zeromv;

 // signals if number of blocks with motion is high
 int percent_blocks_with_motion;

 // signals percentage of 16x16 blocks that are inactive, via active_maps
 int percent_blocks_inactive;

 // Maximum value of source sad across all blocks of frame.
 uint64_t max_block_source_sad;

 // For dynamic resize, 1 pass cbr.
 RESIZE_STATE resize_state;
 int resize_avg_qp;
 int resize_buffer_underflow;
 int resize_count;

 // Flag to disable content related qp adjustment.
 int rtc_external_ratectrl;

 // Stores fast_extra_bits of the current frame.
 int frame_level_fast_extra_bits;

 double frame_level_rate_correction_factors[RATE_FACTOR_LEVELS];

 int frame_num_last_gf_refresh;

 int prev_coded_width;
 int prev_coded_height;

 // The ratio used for inter frames in bit estimation.
 // TODO(yunqing): if golden frame is treated differently (e.g. gf_cbr_boost_
 // pct > THR), consider to add bit_est_ratio_g for golden frames.
 int bit_est_ratio;

 // Whether to use a fixed qp for the frame, bypassing internal rate control.
 // This flag will reset to 0 after every frame.
 int use_external_qp_one_pass;
 /*!\endcond */
} RATE_CONTROL;

/*!
* \brief  Primary Rate Control parameters and status
*/
typedef struct {
 // Sub-gop level Rate targetting variables

 /*!
  * Target bit budget for the current GF / ARF group of frame.
  */
 int64_t gf_group_bits;

 /*!
  * Boost factor used to calculate the extra bits allocated to the key frame
  */
 int kf_boost;

 /*!
  * Boost factor used to calculate the extra bits allocated to ARFs and GFs
  */
 int gfu_boost;

 /*!
  * Stores the determined gf group lengths for a set of gf groups
  */
 int gf_intervals[MAX_NUM_GF_INTERVALS];

 /*!
  * The current group's index into gf_intervals[]
  */
 int cur_gf_index;

 /*!\cond */
 int num_regions;

 REGIONS regions[MAX_FIRSTPASS_ANALYSIS_FRAMES];
 int regions_offset;  // offset of regions from the last keyframe
 int frames_till_regions_update;

 int baseline_gf_interval;

 int constrained_gf_group;

 int this_key_frame_forced;

 int next_key_frame_forced;
 /*!\endcond */

 /*!
  * Initial buffuer level in ms for CBR / low delay encoding
  */
 int64_t starting_buffer_level;

 /*!
  * Optimum / target buffuer level in ms for CBR / low delay encoding
  */
 int64_t optimal_buffer_level;

 /*!
  * Maximum target buffuer level in ms for CBR / low delay encoding
  */
 int64_t maximum_buffer_size;

 /*!
  * Q index used for ALT frame
  */
 int arf_q;

 /*!\cond */
 float_t arf_boost_factor;

 int base_layer_qp;

 // Total number of stats used only for kf_boost calculation.
 int num_stats_used_for_kf_boost;

 // Total number of stats used only for gfu_boost calculation.
 int num_stats_used_for_gfu_boost;

 // Total number of stats required by gfu_boost calculation.
 int num_stats_required_for_gfu_boost;

 int enable_scenecut_detection;

 int use_arf_in_this_kf_group;

 int ni_frames;

 double tot_q;
 /*!\endcond */

 /*!
  * Q used for last boosted (non leaf) frame
  */
 int last_kf_qindex;

 /*!
  * Average of q index of previous encoded frames in a sequence.
  */
 int avg_frame_qindex[FRAME_TYPES];

#if CONFIG_FPMT_TEST
 /*!
  * Temporary variable used in simulating the delayed update of
  * active_best_quality.
  */
 int temp_active_best_quality[MAX_ARF_LAYERS + 1];

 /*!
  * Temporary variable used in simulating the delayed update of
  * last_boosted_qindex.
  */
 int temp_last_boosted_qindex;

 /*!
  * Temporary variable used in simulating the delayed update of
  * avg_q.
  */
 double temp_avg_q;

 /*!
  * Temporary variable used in simulating the delayed update of
  * last_q.
  */
 int temp_last_q[FRAME_TYPES];

 /*!
  * Temporary variable used in simulating the delayed update of
  * projected_frame_size.
  */
 int temp_projected_frame_size;

 /*!
  * Temporary variable used in simulating the delayed update of
  * total_actual_bits.
  */
 int64_t temp_total_actual_bits;

 /*!
  * Temporary variable used in simulating the delayed update of
  * buffer_level.
  */
 int64_t temp_buffer_level;

 /*!
  * Temporary variable used in simulating the delayed update of
  * vbr_bits_off_target.
  */
 int64_t temp_vbr_bits_off_target;

 /*!
  * Temporary variable used in simulating the delayed update of
  * vbr_bits_off_target_fast.
  */
 int64_t temp_vbr_bits_off_target_fast;

 /*!
  * Temporary variable used in simulating the delayed update of
  * rate_correction_factors.
  */
 double temp_rate_correction_factors[RATE_FACTOR_LEVELS];

 /*!
  * Temporary variable used in simulating the delayed update of
  * rate_error_estimate.
  */
 int temp_rate_error_estimate;

 /*!
  * Temporary variable used in simulating the delayed update of
  * rolling_arf_group_target_bits.
  */
 int temp_rolling_arf_group_target_bits;

 /*!
  * Temporary variable used in simulating the delayed update of
  * rolling_arf_group_actual_bits;.
  */
 int temp_rolling_arf_group_actual_bits;

 /*!
  * Temporary variable used in simulating the delayed update of
  * bits_left;.
  */
 int64_t temp_bits_left;

 /*!
  * Temporary variable used in simulating the delayed update of
  * extend_minq.
  */
 int temp_extend_minq;

 /*!
  * Temporary variable used in simulating the delayed update of
  * extend_maxq.
  */
 int temp_extend_maxq;

#endif
 /*!
  * Proposed minimum allowed Q different layers in a coding pyramid
  */
 int active_best_quality[MAX_ARF_LAYERS + 1];

 /*!
  * Q used for last boosted (non leaf) frame (GF/KF/ARF)
  */
 int last_boosted_qindex;

 /*!
  * Average Q value of previous inter frames
  */
 double avg_q;

 /*!
  * Q used on last encoded frame of the given type.
  */
 int last_q[FRAME_TYPES];

 /*!
  * Correction factors used to adjust the q estimate for a given target rate
  * in the encode loop.
  */
 double rate_correction_factors[RATE_FACTOR_LEVELS];

 /*!
  * Current total consumed bits.
  */
 int64_t total_actual_bits;

 /*!
  * Current total target bits.
  */
 int64_t total_target_bits;

 /*!
  * Current buffer level.
  */
 int64_t buffer_level;

 /*!
  * PCT rc error.
  */
 int rate_error_estimate;

 /*!
  * Error bits available from previously encoded frames.
  */
 int64_t vbr_bits_off_target;

 /*!
  * Error bits available from previously encoded frames undershoot.
  */
 int64_t vbr_bits_off_target_fast;

 /*!
  * Total bits deviated from the average frame target, from previously
  * encoded frames.
  */
 int64_t bits_off_target;

 /*!
  * Rolling monitor target bits updated based on current frame target size.
  */
 int rolling_target_bits;

 /*!
  * Rolling monitor actual bits updated based on current frame final projected
  * size.
  */
 int rolling_actual_bits;

 /*!
  * The history of qindex for each frame.
  * Only used when RT_PASSIVE_STRATEGY = 1.
  */
 int q_history[MAX_Q_HISTORY];
} PRIMARY_RATE_CONTROL;

/*!\cond */

struct AV1_COMP;
struct AV1EncoderConfig;
struct GF_GROUP;

void av1_primary_rc_init(const struct AV1EncoderConfig *oxcf,
                        PRIMARY_RATE_CONTROL *p_rc);

void av1_rc_init(const struct AV1EncoderConfig *oxcf, RATE_CONTROL *rc);

int av1_estimate_bits_at_q(const struct AV1_COMP *cpi, int q,
                          double correction_factor);

double av1_convert_qindex_to_q(int qindex, aom_bit_depth_t bit_depth);

// Converts a Q value to a qindex.
int av1_convert_q_to_qindex(double q, aom_bit_depth_t bit_depth);

void av1_rc_init_minq_luts(void);

int av1_rc_get_default_min_gf_interval(int width, int height, double framerate);

// Generally at the high level, the following flow is expected
// to be enforced for rate control:
// First call per frame, one of:
//   av1_get_one_pass_rt_params()
//   av1_get_second_pass_params()
// depending on the usage to set the rate control encode parameters desired.
//
// Then, call encode_frame_to_data_rate() to perform the
// actual encode. This function will in turn call encode_frame()
// one or more times, followed by:
//   av1_rc_postencode_update_drop_frame()
//
// The majority of rate control parameters are only expected
// to be set in the av1_get_..._params() functions and
// updated during the av1_rc_postencode_update...() functions.
// The only exceptions are av1_rc_drop_frame() and
// av1_rc_update_rate_correction_factors() functions.

// Functions to set parameters for encoding before the actual
// encode_frame_to_data_rate() function.
struct EncodeFrameInput;

// Post encode update of the rate control parameters based
// on bytes used
void av1_rc_postencode_update(struct AV1_COMP *cpi, uint64_t bytes_used);
// Post encode update of the rate control parameters for dropped frames
void av1_rc_postencode_update_drop_frame(struct AV1_COMP *cpi);

/*!\endcond */
/*!\brief Updates the rate correction factor linking Q to output bits
*
* This function updates the Q rate correction factor after an encode
* cycle depending on whether we overshot or undershot the target rate.
*
* \ingroup rate_control
* \param[in]   cpi                   Top level encoder instance structure
* \param[in]   is_encode_stage       Indicates if recode loop or post-encode
* \param[in]   width                 Frame width
* \param[in]   height                Frame height
*
* \remark Updates the relevant rate correction factor in cpi->rc
*/
void av1_rc_update_rate_correction_factors(struct AV1_COMP *cpi,
                                          int is_encode_stage, int width,
                                          int height);
/*!\cond */

// Decide if we should drop this frame: For 1-pass CBR.
// Changes only the decimation count in the rate control structure
int av1_rc_drop_frame(struct AV1_COMP *cpi);

// Computes frame size bounds.
void av1_rc_compute_frame_size_bounds(const struct AV1_COMP *cpi,
                                     int this_frame_target,
                                     int *frame_under_shoot_limit,
                                     int *frame_over_shoot_limit);

/*!\endcond */

/*!\brief Picks q and q bounds given the rate control parameters in \c cpi->rc.
*
* \ingroup rate_control
* \param[in]       cpi          Top level encoder structure
* \param[in]       width        Coded frame width
* \param[in]       height       Coded frame height
* \param[in]       gf_index     Index of this frame in the golden frame group
* \param[out]      bottom_index Bottom bound for q index (best quality)
* \param[out]      top_index    Top bound for q index (worst quality)
* \return Returns selected q index to be used for encoding this frame.
* Also, updates \c rc->arf_q.
*/
int av1_rc_pick_q_and_bounds(struct AV1_COMP *cpi, int width, int height,
                            int gf_index, int *bottom_index, int *top_index);

/*!\brief Estimates q to achieve a target bits per frame
*
* \ingroup rate_control
* \param[in]   cpi                   Top level encoder instance structure
* \param[in]   target_bits_per_frame Frame rate target
* \param[in]   active_worst_quality  Max Q allowed
* \param[in]   active_best_quality   Min Q allowed
* \param[in]   width                 Frame width
* \param[in]   height                Frame height
*
* \return Returns a q index value
*/
int av1_rc_regulate_q(const struct AV1_COMP *cpi, int target_bits_per_frame,
                     int active_best_quality, int active_worst_quality,
                     int width, int height);

/*!\cond */
// Estimates bits per mb for a given qindex and correction factor.
int av1_rc_bits_per_mb(const struct AV1_COMP *cpi, FRAME_TYPE frame_type,
                      int qindex, double correction_factor,
                      int accurate_estimate);

// Find q_index corresponding to desired_q, within [best_qindex, worst_qindex].
// To be precise, 'q_index' is the smallest integer, for which the corresponding
// q >= desired_q.
// If no such q index is found, returns 'worst_qindex'.
int av1_find_qindex(double desired_q, aom_bit_depth_t bit_depth,
                   int best_qindex, int worst_qindex);

// Computes a q delta (in "q index" terms) to get from a starting q value
// to a target q value
int av1_compute_qdelta(const RATE_CONTROL *rc, double qstart, double qtarget,
                      aom_bit_depth_t bit_depth);

// Computes a q delta (in "q index" terms) to get from a starting q value
// to a value that should equate to the given rate ratio.
int av1_compute_qdelta_by_rate(const struct AV1_COMP *cpi,
                              FRAME_TYPE frame_type, int qindex,
                              double rate_target_ratio);

void av1_rc_update_framerate(struct AV1_COMP *cpi, int width, int height);

void av1_set_target_rate(struct AV1_COMP *cpi, int width, int height);

int av1_resize_one_pass_cbr(struct AV1_COMP *cpi);

void av1_rc_set_frame_target(struct AV1_COMP *cpi, int target, int width,
                            int height);

void av1_adjust_gf_refresh_qp_one_pass_rt(struct AV1_COMP *cpi);

void av1_set_rtc_reference_structure_one_layer(struct AV1_COMP *cpi,
                                              int gf_update);

/*!\endcond */
/*!\brief Calculates how many bits to use for a P frame in one pass vbr
*
* \ingroup rate_control
* \callgraph
* \callergraph
*
* \param[in]       cpi                 Top level encoder structure
* \param[in]       frame_update_type   Type of frame
*
* \return	Returns the target number of bits for this frame.
*/
int av1_calc_pframe_target_size_one_pass_vbr(
   const struct AV1_COMP *const cpi, FRAME_UPDATE_TYPE frame_update_type);

/*!\brief Calculates how many bits to use for an i frame in one pass vbr
*
* \ingroup rate_control
* \callgraph
* \callergraph
*
* \param[in]       cpi  Top level encoder structure
*
* \return	Returns the target number of bits for this frame.
*/
int av1_calc_iframe_target_size_one_pass_vbr(const struct AV1_COMP *const cpi);

/*!\brief Calculates how many bits to use for a P frame in one pass cbr
*
* \ingroup rate_control
* \callgraph
* \callergraph
*
* \param[in]       cpi                 Top level encoder structure
* \param[in]       frame_update_type   Type of frame
*
* \return  Returns the target number of bits for this frame.
*/
int av1_calc_pframe_target_size_one_pass_cbr(
   const struct AV1_COMP *cpi, FRAME_UPDATE_TYPE frame_update_type);

/*!\brief Calculates how many bits to use for an i frame in one pass cbr
*
* \ingroup rate_control
* \callgraph
* \callergraph
*
* \param[in]       cpi  Top level encoder structure
*
* \return  Returns the target number of bits for this frame.
*/
int av1_calc_iframe_target_size_one_pass_cbr(const struct AV1_COMP *cpi);

/*!\brief Setup the rate control parameters for 1 pass real-time mode.
*
* - Sets the frame type and target frame size.
* - Sets the GF update.
* - Checks for scene change.
* - Sets the reference prediction structure for 1 layers (non-SVC).
* - Resets and updates are done for SVC.
*
* \ingroup rate_control
* \param[in]       cpi          Top level encoder structure
* \param[in]       frame_type   Encoder frame type
* \param[in]       frame_input  Current and last input source frames
* \param[in]       frame_flags  Encoder frame flags
*
* \remark Nothing is returned. Instead the settings computed in this
* function are set in: \c frame_params, \c cpi->common, \c cpi->rc,
* \c cpi->svc.
*/
void av1_get_one_pass_rt_params(struct AV1_COMP *cpi,
                               FRAME_TYPE *const frame_type,
                               const struct EncodeFrameInput *frame_input,
                               unsigned int frame_flags);

/*!\brief Increase q on expected encoder overshoot, for CBR mode.
*
*  Handles the case when encoder is expected to create a large frame:
*  - q is increased to value closer to \c cpi->rc.worst_quality
*  - avg_frame_qindex is reset
*  - buffer levels are reset
*  - rate correction factor is adjusted
*
* \ingroup rate_control
* \param[in]       cpi          Top level encoder structure
* \param[in]        q           Current q index
*
* \return q is returned, and updates are done to \c cpi->rc.
*/
int av1_encodedframe_overshoot_cbr(struct AV1_COMP *cpi, int *q);

/*!\brief Check if frame should be dropped, for RTC mode.
*
* \ingroup rate_control
* \param[in]       cpi          Top level encoder structure
* \param[in,out]       size         Size of encoded frame
*
* \return 1 if frame is to be dropped, 0 otherwise (no drop).
* Set cpi->rc.force_max_q if frame is to be dropped, and updates are
* made to rate control parameters. *size is set to 0 when this
* function returns 1 (frame is dropped).
*/
int av1_postencode_drop_cbr(struct AV1_COMP *cpi, size_t *size);

#ifdef __cplusplus
}  // extern "C"
#endif

#endif  // AOM_AV1_ENCODER_RATECTRL_H_