michael@0: /*
michael@0:  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
michael@0:  *
michael@0:  *  Use of this source code is governed by a BSD-style license
michael@0:  *  that can be found in the LICENSE file in the root of the source
michael@0:  *  tree. An additional intellectual property rights grant can be found
michael@0:  *  in the file PATENTS.  All contributing project authors may
michael@0:  *  be found in the AUTHORS file in the root of the source tree.
michael@0:  */
michael@0: 
michael@0: 
michael@0: #include <stdlib.h>
michael@0: #include <stdio.h>
michael@0: #include <string.h>
michael@0: #include <limits.h>
michael@0: #include <assert.h>
michael@0: #include <math.h>
michael@0: 
michael@0: #include "vp9/common/vp9_alloccommon.h"
michael@0: #include "vp9/common/vp9_common.h"
michael@0: #include "vp9/encoder/vp9_ratectrl.h"
michael@0: #include "vp9/common/vp9_entropymode.h"
michael@0: #include "vpx_mem/vpx_mem.h"
michael@0: #include "vp9/common/vp9_systemdependent.h"
michael@0: #include "vp9/encoder/vp9_encodemv.h"
michael@0: #include "vp9/common/vp9_quant_common.h"
michael@0: #include "vp9/common/vp9_seg_common.h"
michael@0: 
michael@0: #define MIN_BPB_FACTOR 0.005
michael@0: #define MAX_BPB_FACTOR 50
michael@0: 
michael@0: // Bits Per MB at different Q (Multiplied by 512)
michael@0: #define BPER_MB_NORMBITS    9
michael@0: 
michael@0: static const unsigned int prior_key_frame_weight[KEY_FRAME_CONTEXT] =
michael@0:     { 1, 2, 3, 4, 5 };
michael@0: 
michael@0: // These functions use formulaic calculations to make playing with the
michael@0: // quantizer tables easier. If necessary they can be replaced by lookup
michael@0: // tables if and when things settle down in the experimental bitstream
michael@0: double vp9_convert_qindex_to_q(int qindex) {
michael@0:   // Convert the index to a real Q value (scaled down to match old Q values)
michael@0:   return vp9_ac_quant(qindex, 0) / 4.0;
michael@0: }
michael@0: 
michael@0: int vp9_gfboost_qadjust(int qindex) {
michael@0:   const double q = vp9_convert_qindex_to_q(qindex);
michael@0:   return (int)((0.00000828 * q * q * q) +
michael@0:                (-0.0055 * q * q) +
michael@0:                (1.32 * q) + 79.3);
michael@0: }
michael@0: 
michael@0: static int kfboost_qadjust(int qindex) {
michael@0:   const double q = vp9_convert_qindex_to_q(qindex);
michael@0:   return (int)((0.00000973 * q * q * q) +
michael@0:                (-0.00613 * q * q) +
michael@0:                (1.316 * q) + 121.2);
michael@0: }
michael@0: 
michael@0: int vp9_bits_per_mb(FRAME_TYPE frame_type, int qindex,
michael@0:                     double correction_factor) {
michael@0:   const double q = vp9_convert_qindex_to_q(qindex);
michael@0:   int enumerator = frame_type == KEY_FRAME ? 3300000 : 2250000;
michael@0: 
michael@0:   // q based adjustment to baseline enumerator
michael@0:   enumerator += (int)(enumerator * q) >> 12;
michael@0:   return (int)(0.5 + (enumerator * correction_factor / q));
michael@0: }
michael@0: 
michael@0: void vp9_save_coding_context(VP9_COMP *cpi) {
michael@0:   CODING_CONTEXT *const cc = &cpi->coding_context;
michael@0:   VP9_COMMON *cm = &cpi->common;
michael@0: 
michael@0:   // Stores a snapshot of key state variables which can subsequently be
michael@0:   // restored with a call to vp9_restore_coding_context. These functions are
michael@0:   // intended for use in a re-code loop in vp9_compress_frame where the
michael@0:   // quantizer value is adjusted between loop iterations.
michael@0:   vp9_copy(cc->nmvjointcost,  cpi->mb.nmvjointcost);
michael@0:   vp9_copy(cc->nmvcosts,  cpi->mb.nmvcosts);
michael@0:   vp9_copy(cc->nmvcosts_hp,  cpi->mb.nmvcosts_hp);
michael@0: 
michael@0:   vp9_copy(cc->segment_pred_probs, cm->seg.pred_probs);
michael@0: 
michael@0:   vpx_memcpy(cpi->coding_context.last_frame_seg_map_copy,
michael@0:              cm->last_frame_seg_map, (cm->mi_rows * cm->mi_cols));
michael@0: 
michael@0:   vp9_copy(cc->last_ref_lf_deltas, cm->lf.last_ref_deltas);
michael@0:   vp9_copy(cc->last_mode_lf_deltas, cm->lf.last_mode_deltas);
michael@0: 
michael@0:   cc->fc = cm->fc;
michael@0: }
michael@0: 
michael@0: void vp9_restore_coding_context(VP9_COMP *cpi) {
michael@0:   CODING_CONTEXT *const cc = &cpi->coding_context;
michael@0:   VP9_COMMON *cm = &cpi->common;
michael@0: 
michael@0:   // Restore key state variables to the snapshot state stored in the
michael@0:   // previous call to vp9_save_coding_context.
michael@0:   vp9_copy(cpi->mb.nmvjointcost, cc->nmvjointcost);
michael@0:   vp9_copy(cpi->mb.nmvcosts, cc->nmvcosts);
michael@0:   vp9_copy(cpi->mb.nmvcosts_hp, cc->nmvcosts_hp);
michael@0: 
michael@0:   vp9_copy(cm->seg.pred_probs, cc->segment_pred_probs);
michael@0: 
michael@0:   vpx_memcpy(cm->last_frame_seg_map,
michael@0:              cpi->coding_context.last_frame_seg_map_copy,
michael@0:              (cm->mi_rows * cm->mi_cols));
michael@0: 
michael@0:   vp9_copy(cm->lf.last_ref_deltas, cc->last_ref_lf_deltas);
michael@0:   vp9_copy(cm->lf.last_mode_deltas, cc->last_mode_lf_deltas);
michael@0: 
michael@0:   cm->fc = cc->fc;
michael@0: }
michael@0: 
michael@0: void vp9_setup_key_frame(VP9_COMP *cpi) {
michael@0:   VP9_COMMON *cm = &cpi->common;
michael@0: 
michael@0:   vp9_setup_past_independence(cm);
michael@0: 
michael@0:   // interval before next GF
michael@0:   cpi->frames_till_gf_update_due = cpi->baseline_gf_interval;
michael@0:   /* All buffers are implicitly updated on key frames. */
michael@0:   cpi->refresh_golden_frame = 1;
michael@0:   cpi->refresh_alt_ref_frame = 1;
michael@0: }
michael@0: 
michael@0: void vp9_setup_inter_frame(VP9_COMP *cpi) {
michael@0:   VP9_COMMON *cm = &cpi->common;
michael@0:   if (cm->error_resilient_mode || cm->intra_only)
michael@0:     vp9_setup_past_independence(cm);
michael@0: 
michael@0:   assert(cm->frame_context_idx < NUM_FRAME_CONTEXTS);
michael@0:   cm->fc = cm->frame_contexts[cm->frame_context_idx];
michael@0: }
michael@0: 
michael@0: static int estimate_bits_at_q(int frame_kind, int q, int mbs,
michael@0:                               double correction_factor) {
michael@0:   const int bpm = (int)(vp9_bits_per_mb(frame_kind, q, correction_factor));
michael@0: 
michael@0:   // Attempt to retain reasonable accuracy without overflow. The cutoff is
michael@0:   // chosen such that the maximum product of Bpm and MBs fits 31 bits. The
michael@0:   // largest Bpm takes 20 bits.
michael@0:   return (mbs > (1 << 11)) ? (bpm >> BPER_MB_NORMBITS) * mbs
michael@0:                            : (bpm * mbs) >> BPER_MB_NORMBITS;
michael@0: }
michael@0: 
michael@0: 
michael@0: static void calc_iframe_target_size(VP9_COMP *cpi) {
michael@0:   // boost defaults to half second
michael@0:   int target;
michael@0: 
michael@0:   // Clear down mmx registers to allow floating point in what follows
michael@0:   vp9_clear_system_state();  // __asm emms;
michael@0: 
michael@0:   // New Two pass RC
michael@0:   target = cpi->per_frame_bandwidth;
michael@0: 
michael@0:   if (cpi->oxcf.rc_max_intra_bitrate_pct) {
michael@0:     int max_rate = cpi->per_frame_bandwidth
michael@0:                  * cpi->oxcf.rc_max_intra_bitrate_pct / 100;
michael@0: 
michael@0:     if (target > max_rate)
michael@0:       target = max_rate;
michael@0:   }
michael@0: 
michael@0:   cpi->this_frame_target = target;
michael@0: }
michael@0: 
michael@0: 
michael@0: //  Do the best we can to define the parameters for the next GF based
michael@0: //  on what information we have available.
michael@0: //
michael@0: //  In this experimental code only two pass is supported
michael@0: //  so we just use the interval determined in the two pass code.
michael@0: static void calc_gf_params(VP9_COMP *cpi) {
michael@0:   // Set the gf interval
michael@0:   cpi->frames_till_gf_update_due = cpi->baseline_gf_interval;
michael@0: }
michael@0: 
michael@0: 
michael@0: static void calc_pframe_target_size(VP9_COMP *cpi) {
michael@0:   const int min_frame_target = MAX(cpi->min_frame_bandwidth,
michael@0:                                    cpi->av_per_frame_bandwidth >> 5);
michael@0:   if (cpi->refresh_alt_ref_frame) {
michael@0:     // Special alt reference frame case
michael@0:     // Per frame bit target for the alt ref frame
michael@0:     cpi->per_frame_bandwidth = cpi->twopass.gf_bits;
michael@0:     cpi->this_frame_target = cpi->per_frame_bandwidth;
michael@0:   } else {
michael@0:     // Normal frames (gf,and inter)
michael@0:     cpi->this_frame_target = cpi->per_frame_bandwidth;
michael@0:   }
michael@0: 
michael@0:   // Check that the total sum of adjustments is not above the maximum allowed.
michael@0:   // That is, having allowed for the KF and GF penalties, we have not pushed
michael@0:   // the current inter-frame target too low. If the adjustment we apply here is
michael@0:   // not capable of recovering all the extra bits we have spent in the KF or GF,
michael@0:   // then the remainder will have to be recovered over a longer time span via
michael@0:   // other buffer / rate control mechanisms.
michael@0:   if (cpi->this_frame_target < min_frame_target)
michael@0:     cpi->this_frame_target = min_frame_target;
michael@0: 
michael@0:   if (!cpi->refresh_alt_ref_frame)
michael@0:     // Note the baseline target data rate for this inter frame.
michael@0:     cpi->inter_frame_target = cpi->this_frame_target;
michael@0: 
michael@0:   // Adjust target frame size for Golden Frames:
michael@0:   if (cpi->frames_till_gf_update_due == 0) {
michael@0:     const int q = (cpi->oxcf.fixed_q < 0) ? cpi->last_q[INTER_FRAME]
michael@0:                                           : cpi->oxcf.fixed_q;
michael@0: 
michael@0:     cpi->refresh_golden_frame = 1;
michael@0: 
michael@0:     calc_gf_params(cpi);
michael@0: 
michael@0:     // If we are using alternate ref instead of gf then do not apply the boost
michael@0:     // It will instead be applied to the altref update
michael@0:     // Jims modified boost
michael@0:     if (!cpi->source_alt_ref_active) {
michael@0:       if (cpi->oxcf.fixed_q < 0) {
michael@0:         // The spend on the GF is defined in the two pass code
michael@0:         // for two pass encodes
michael@0:         cpi->this_frame_target = cpi->per_frame_bandwidth;
michael@0:       } else {
michael@0:         cpi->this_frame_target =
michael@0:           (estimate_bits_at_q(1, q, cpi->common.MBs, 1.0)
michael@0:            * cpi->last_boost) / 100;
michael@0:       }
michael@0:     } else {
michael@0:       // If there is an active ARF at this location use the minimum
michael@0:       // bits on this frame even if it is a constructed arf.
michael@0:       // The active maximum quantizer insures that an appropriate
michael@0:       // number of bits will be spent if needed for constructed ARFs.
michael@0:       cpi->this_frame_target = 0;
michael@0:     }
michael@0:   }
michael@0: }
michael@0: 
michael@0: 
michael@0: void vp9_update_rate_correction_factors(VP9_COMP *cpi, int damp_var) {
michael@0:   const int q = cpi->common.base_qindex;
michael@0:   int correction_factor = 100;
michael@0:   double rate_correction_factor;
michael@0:   double adjustment_limit;
michael@0: 
michael@0:   int projected_size_based_on_q = 0;
michael@0: 
michael@0:   // Clear down mmx registers to allow floating point in what follows
michael@0:   vp9_clear_system_state();  // __asm emms;
michael@0: 
michael@0:   if (cpi->common.frame_type == KEY_FRAME) {
michael@0:     rate_correction_factor = cpi->key_frame_rate_correction_factor;
michael@0:   } else {
michael@0:     if (cpi->refresh_alt_ref_frame || cpi->refresh_golden_frame)
michael@0:       rate_correction_factor = cpi->gf_rate_correction_factor;
michael@0:     else
michael@0:       rate_correction_factor = cpi->rate_correction_factor;
michael@0:   }
michael@0: 
michael@0:   // Work out how big we would have expected the frame to be at this Q given
michael@0:   // the current correction factor.
michael@0:   // Stay in double to avoid int overflow when values are large
michael@0:   projected_size_based_on_q = estimate_bits_at_q(cpi->common.frame_type, q,
michael@0:                                                  cpi->common.MBs,
michael@0:                                                  rate_correction_factor);
michael@0: 
michael@0:   // Work out a size correction factor.
michael@0:   if (projected_size_based_on_q > 0)
michael@0:     correction_factor =
michael@0:         (100 * cpi->projected_frame_size) / projected_size_based_on_q;
michael@0: 
michael@0:   // More heavily damped adjustment used if we have been oscillating either side
michael@0:   // of target.
michael@0:   switch (damp_var) {
michael@0:     case 0:
michael@0:       adjustment_limit = 0.75;
michael@0:       break;
michael@0:     case 1:
michael@0:       adjustment_limit = 0.375;
michael@0:       break;
michael@0:     case 2:
michael@0:     default:
michael@0:       adjustment_limit = 0.25;
michael@0:       break;
michael@0:   }
michael@0: 
michael@0:   // if ( (correction_factor > 102) && (Q < cpi->active_worst_quality) )
michael@0:   if (correction_factor > 102) {
michael@0:     // We are not already at the worst allowable quality
michael@0:     correction_factor =
michael@0:         (int)(100 + ((correction_factor - 100) * adjustment_limit));
michael@0:     rate_correction_factor =
michael@0:         ((rate_correction_factor * correction_factor) / 100);
michael@0: 
michael@0:     // Keep rate_correction_factor within limits
michael@0:     if (rate_correction_factor > MAX_BPB_FACTOR)
michael@0:       rate_correction_factor = MAX_BPB_FACTOR;
michael@0:   } else if (correction_factor < 99) {
michael@0:     // We are not already at the best allowable quality
michael@0:     correction_factor =
michael@0:         (int)(100 - ((100 - correction_factor) * adjustment_limit));
michael@0:     rate_correction_factor =
michael@0:         ((rate_correction_factor * correction_factor) / 100);
michael@0: 
michael@0:     // Keep rate_correction_factor within limits
michael@0:     if (rate_correction_factor < MIN_BPB_FACTOR)
michael@0:       rate_correction_factor = MIN_BPB_FACTOR;
michael@0:   }
michael@0: 
michael@0:   if (cpi->common.frame_type == KEY_FRAME) {
michael@0:     cpi->key_frame_rate_correction_factor = rate_correction_factor;
michael@0:   } else {
michael@0:     if (cpi->refresh_alt_ref_frame || cpi->refresh_golden_frame)
michael@0:       cpi->gf_rate_correction_factor = rate_correction_factor;
michael@0:     else
michael@0:       cpi->rate_correction_factor = rate_correction_factor;
michael@0:   }
michael@0: }
michael@0: 
michael@0: 
michael@0: int vp9_regulate_q(VP9_COMP *cpi, int target_bits_per_frame) {
michael@0:   int q = cpi->active_worst_quality;
michael@0: 
michael@0:   int i;
michael@0:   int last_error = INT_MAX;
michael@0:   int target_bits_per_mb;
michael@0:   int bits_per_mb_at_this_q;
michael@0:   double correction_factor;
michael@0: 
michael@0:   // Select the appropriate correction factor based upon type of frame.
michael@0:   if (cpi->common.frame_type == KEY_FRAME) {
michael@0:     correction_factor = cpi->key_frame_rate_correction_factor;
michael@0:   } else {
michael@0:     if (cpi->refresh_alt_ref_frame || cpi->refresh_golden_frame)
michael@0:       correction_factor = cpi->gf_rate_correction_factor;
michael@0:     else
michael@0:       correction_factor = cpi->rate_correction_factor;
michael@0:   }
michael@0: 
michael@0:   // Calculate required scaling factor based on target frame size and size of
michael@0:   // frame produced using previous Q.
michael@0:   if (target_bits_per_frame >= (INT_MAX >> BPER_MB_NORMBITS))
michael@0:     target_bits_per_mb =
michael@0:         (target_bits_per_frame / cpi->common.MBs)
michael@0:         << BPER_MB_NORMBITS;  // Case where we would overflow int
michael@0:   else
michael@0:     target_bits_per_mb =
michael@0:         (target_bits_per_frame << BPER_MB_NORMBITS) / cpi->common.MBs;
michael@0: 
michael@0:   i = cpi->active_best_quality;
michael@0: 
michael@0:   do {
michael@0:     bits_per_mb_at_this_q = (int)vp9_bits_per_mb(cpi->common.frame_type, i,
michael@0:                                                  correction_factor);
michael@0: 
michael@0:     if (bits_per_mb_at_this_q <= target_bits_per_mb) {
michael@0:       if ((target_bits_per_mb - bits_per_mb_at_this_q) <= last_error)
michael@0:         q = i;
michael@0:       else
michael@0:         q = i - 1;
michael@0: 
michael@0:       break;
michael@0:     } else {
michael@0:       last_error = bits_per_mb_at_this_q - target_bits_per_mb;
michael@0:     }
michael@0:   } while (++i <= cpi->active_worst_quality);
michael@0: 
michael@0:   return q;
michael@0: }
michael@0: 
michael@0: 
michael@0: static int estimate_keyframe_frequency(VP9_COMP *cpi) {
michael@0:   int i;
michael@0: 
michael@0:   // Average key frame frequency
michael@0:   int av_key_frame_frequency = 0;
michael@0: 
michael@0:   /* First key frame at start of sequence is a special case. We have no
michael@0:    * frequency data.
michael@0:    */
michael@0:   if (cpi->key_frame_count == 1) {
michael@0:     /* Assume a default of 1 kf every 2 seconds, or the max kf interval,
michael@0:      * whichever is smaller.
michael@0:      */
michael@0:     int key_freq = cpi->oxcf.key_freq > 0 ? cpi->oxcf.key_freq : 1;
michael@0:     av_key_frame_frequency = (int)cpi->output_framerate * 2;
michael@0: 
michael@0:     if (cpi->oxcf.auto_key && av_key_frame_frequency > key_freq)
michael@0:       av_key_frame_frequency = cpi->oxcf.key_freq;
michael@0: 
michael@0:     cpi->prior_key_frame_distance[KEY_FRAME_CONTEXT - 1]
michael@0:       = av_key_frame_frequency;
michael@0:   } else {
michael@0:     unsigned int total_weight = 0;
michael@0:     int last_kf_interval =
michael@0:       (cpi->frames_since_key > 0) ? cpi->frames_since_key : 1;
michael@0: 
michael@0:     /* reset keyframe context and calculate weighted average of last
michael@0:      * KEY_FRAME_CONTEXT keyframes
michael@0:      */
michael@0:     for (i = 0; i < KEY_FRAME_CONTEXT; i++) {
michael@0:       if (i < KEY_FRAME_CONTEXT - 1)
michael@0:         cpi->prior_key_frame_distance[i]
michael@0:           = cpi->prior_key_frame_distance[i + 1];
michael@0:       else
michael@0:         cpi->prior_key_frame_distance[i] = last_kf_interval;
michael@0: 
michael@0:       av_key_frame_frequency += prior_key_frame_weight[i]
michael@0:                                 * cpi->prior_key_frame_distance[i];
michael@0:       total_weight += prior_key_frame_weight[i];
michael@0:     }
michael@0: 
michael@0:     av_key_frame_frequency /= total_weight;
michael@0:   }
michael@0:   return av_key_frame_frequency;
michael@0: }
michael@0: 
michael@0: 
michael@0: void vp9_adjust_key_frame_context(VP9_COMP *cpi) {
michael@0:   // Clear down mmx registers to allow floating point in what follows
michael@0:   vp9_clear_system_state();
michael@0: 
michael@0:   cpi->frames_since_key = 0;
michael@0:   cpi->key_frame_count++;
michael@0: }
michael@0: 
michael@0: 
michael@0: void vp9_compute_frame_size_bounds(VP9_COMP *cpi, int *frame_under_shoot_limit,
michael@0:                                    int *frame_over_shoot_limit) {
michael@0:   // Set-up bounds on acceptable frame size:
michael@0:   if (cpi->oxcf.fixed_q >= 0) {
michael@0:     // Fixed Q scenario: frame size never outranges target (there is no target!)
michael@0:     *frame_under_shoot_limit = 0;
michael@0:     *frame_over_shoot_limit  = INT_MAX;
michael@0:   } else {
michael@0:     if (cpi->common.frame_type == KEY_FRAME) {
michael@0:       *frame_over_shoot_limit  = cpi->this_frame_target * 9 / 8;
michael@0:       *frame_under_shoot_limit = cpi->this_frame_target * 7 / 8;
michael@0:     } else {
michael@0:       if (cpi->refresh_alt_ref_frame || cpi->refresh_golden_frame) {
michael@0:         *frame_over_shoot_limit  = cpi->this_frame_target * 9 / 8;
michael@0:         *frame_under_shoot_limit = cpi->this_frame_target * 7 / 8;
michael@0:       } else {
michael@0:         // Stron overshoot limit for constrained quality
michael@0:         if (cpi->oxcf.end_usage == USAGE_CONSTRAINED_QUALITY) {
michael@0:           *frame_over_shoot_limit  = cpi->this_frame_target * 11 / 8;
michael@0:           *frame_under_shoot_limit = cpi->this_frame_target * 2 / 8;
michael@0:         } else {
michael@0:           *frame_over_shoot_limit  = cpi->this_frame_target * 11 / 8;
michael@0:           *frame_under_shoot_limit = cpi->this_frame_target * 5 / 8;
michael@0:         }
michael@0:       }
michael@0:     }
michael@0: 
michael@0:     // For very small rate targets where the fractional adjustment
michael@0:     // (eg * 7/8) may be tiny make sure there is at least a minimum
michael@0:     // range.
michael@0:     *frame_over_shoot_limit += 200;
michael@0:     *frame_under_shoot_limit -= 200;
michael@0:     if (*frame_under_shoot_limit < 0)
michael@0:       *frame_under_shoot_limit = 0;
michael@0:   }
michael@0: }
michael@0: 
michael@0: 
michael@0: // return of 0 means drop frame
michael@0: int vp9_pick_frame_size(VP9_COMP *cpi) {
michael@0:   VP9_COMMON *cm = &cpi->common;
michael@0: 
michael@0:   if (cm->frame_type == KEY_FRAME)
michael@0:     calc_iframe_target_size(cpi);
michael@0:   else
michael@0:     calc_pframe_target_size(cpi);
michael@0: 
michael@0:   return 1;
michael@0: }