diff -r 000000000000 -r 6474c204b198 media/libvpx/vp9/encoder/vp9_ratectrl.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/media/libvpx/vp9/encoder/vp9_ratectrl.c Wed Dec 31 06:09:35 2014 +0100 @@ -0,0 +1,476 @@ +/* + * Copyright (c) 2010 The WebM project authors. All Rights Reserved. + * + * Use of this source code is governed by a BSD-style license + * that can be found in the LICENSE file in the root of the source + * tree. An additional intellectual property rights grant can be found + * in the file PATENTS. All contributing project authors may + * be found in the AUTHORS file in the root of the source tree. + */ + + +#include +#include +#include +#include +#include +#include + +#include "vp9/common/vp9_alloccommon.h" +#include "vp9/common/vp9_common.h" +#include "vp9/encoder/vp9_ratectrl.h" +#include "vp9/common/vp9_entropymode.h" +#include "vpx_mem/vpx_mem.h" +#include "vp9/common/vp9_systemdependent.h" +#include "vp9/encoder/vp9_encodemv.h" +#include "vp9/common/vp9_quant_common.h" +#include "vp9/common/vp9_seg_common.h" + +#define MIN_BPB_FACTOR 0.005 +#define MAX_BPB_FACTOR 50 + +// Bits Per MB at different Q (Multiplied by 512) +#define BPER_MB_NORMBITS 9 + +static const unsigned int prior_key_frame_weight[KEY_FRAME_CONTEXT] = + { 1, 2, 3, 4, 5 }; + +// These functions use formulaic calculations to make playing with the +// quantizer tables easier. If necessary they can be replaced by lookup +// tables if and when things settle down in the experimental bitstream +double vp9_convert_qindex_to_q(int qindex) { + // Convert the index to a real Q value (scaled down to match old Q values) + return vp9_ac_quant(qindex, 0) / 4.0; +} + +int vp9_gfboost_qadjust(int qindex) { + const double q = vp9_convert_qindex_to_q(qindex); + return (int)((0.00000828 * q * q * q) + + (-0.0055 * q * q) + + (1.32 * q) + 79.3); +} + +static int kfboost_qadjust(int qindex) { + const double q = vp9_convert_qindex_to_q(qindex); + return (int)((0.00000973 * q * q * q) + + (-0.00613 * q * q) + + (1.316 * q) + 121.2); +} + +int vp9_bits_per_mb(FRAME_TYPE frame_type, int qindex, + double correction_factor) { + const double q = vp9_convert_qindex_to_q(qindex); + int enumerator = frame_type == KEY_FRAME ? 3300000 : 2250000; + + // q based adjustment to baseline enumerator + enumerator += (int)(enumerator * q) >> 12; + return (int)(0.5 + (enumerator * correction_factor / q)); +} + +void vp9_save_coding_context(VP9_COMP *cpi) { + CODING_CONTEXT *const cc = &cpi->coding_context; + VP9_COMMON *cm = &cpi->common; + + // Stores a snapshot of key state variables which can subsequently be + // restored with a call to vp9_restore_coding_context. These functions are + // intended for use in a re-code loop in vp9_compress_frame where the + // quantizer value is adjusted between loop iterations. + vp9_copy(cc->nmvjointcost, cpi->mb.nmvjointcost); + vp9_copy(cc->nmvcosts, cpi->mb.nmvcosts); + vp9_copy(cc->nmvcosts_hp, cpi->mb.nmvcosts_hp); + + vp9_copy(cc->segment_pred_probs, cm->seg.pred_probs); + + vpx_memcpy(cpi->coding_context.last_frame_seg_map_copy, + cm->last_frame_seg_map, (cm->mi_rows * cm->mi_cols)); + + vp9_copy(cc->last_ref_lf_deltas, cm->lf.last_ref_deltas); + vp9_copy(cc->last_mode_lf_deltas, cm->lf.last_mode_deltas); + + cc->fc = cm->fc; +} + +void vp9_restore_coding_context(VP9_COMP *cpi) { + CODING_CONTEXT *const cc = &cpi->coding_context; + VP9_COMMON *cm = &cpi->common; + + // Restore key state variables to the snapshot state stored in the + // previous call to vp9_save_coding_context. + vp9_copy(cpi->mb.nmvjointcost, cc->nmvjointcost); + vp9_copy(cpi->mb.nmvcosts, cc->nmvcosts); + vp9_copy(cpi->mb.nmvcosts_hp, cc->nmvcosts_hp); + + vp9_copy(cm->seg.pred_probs, cc->segment_pred_probs); + + vpx_memcpy(cm->last_frame_seg_map, + cpi->coding_context.last_frame_seg_map_copy, + (cm->mi_rows * cm->mi_cols)); + + vp9_copy(cm->lf.last_ref_deltas, cc->last_ref_lf_deltas); + vp9_copy(cm->lf.last_mode_deltas, cc->last_mode_lf_deltas); + + cm->fc = cc->fc; +} + +void vp9_setup_key_frame(VP9_COMP *cpi) { + VP9_COMMON *cm = &cpi->common; + + vp9_setup_past_independence(cm); + + // interval before next GF + cpi->frames_till_gf_update_due = cpi->baseline_gf_interval; + /* All buffers are implicitly updated on key frames. */ + cpi->refresh_golden_frame = 1; + cpi->refresh_alt_ref_frame = 1; +} + +void vp9_setup_inter_frame(VP9_COMP *cpi) { + VP9_COMMON *cm = &cpi->common; + if (cm->error_resilient_mode || cm->intra_only) + vp9_setup_past_independence(cm); + + assert(cm->frame_context_idx < NUM_FRAME_CONTEXTS); + cm->fc = cm->frame_contexts[cm->frame_context_idx]; +} + +static int estimate_bits_at_q(int frame_kind, int q, int mbs, + double correction_factor) { + const int bpm = (int)(vp9_bits_per_mb(frame_kind, q, correction_factor)); + + // Attempt to retain reasonable accuracy without overflow. The cutoff is + // chosen such that the maximum product of Bpm and MBs fits 31 bits. The + // largest Bpm takes 20 bits. + return (mbs > (1 << 11)) ? (bpm >> BPER_MB_NORMBITS) * mbs + : (bpm * mbs) >> BPER_MB_NORMBITS; +} + + +static void calc_iframe_target_size(VP9_COMP *cpi) { + // boost defaults to half second + int target; + + // Clear down mmx registers to allow floating point in what follows + vp9_clear_system_state(); // __asm emms; + + // New Two pass RC + target = cpi->per_frame_bandwidth; + + if (cpi->oxcf.rc_max_intra_bitrate_pct) { + int max_rate = cpi->per_frame_bandwidth + * cpi->oxcf.rc_max_intra_bitrate_pct / 100; + + if (target > max_rate) + target = max_rate; + } + + cpi->this_frame_target = target; +} + + +// Do the best we can to define the parameters for the next GF based +// on what information we have available. +// +// In this experimental code only two pass is supported +// so we just use the interval determined in the two pass code. +static void calc_gf_params(VP9_COMP *cpi) { + // Set the gf interval + cpi->frames_till_gf_update_due = cpi->baseline_gf_interval; +} + + +static void calc_pframe_target_size(VP9_COMP *cpi) { + const int min_frame_target = MAX(cpi->min_frame_bandwidth, + cpi->av_per_frame_bandwidth >> 5); + if (cpi->refresh_alt_ref_frame) { + // Special alt reference frame case + // Per frame bit target for the alt ref frame + cpi->per_frame_bandwidth = cpi->twopass.gf_bits; + cpi->this_frame_target = cpi->per_frame_bandwidth; + } else { + // Normal frames (gf,and inter) + cpi->this_frame_target = cpi->per_frame_bandwidth; + } + + // Check that the total sum of adjustments is not above the maximum allowed. + // That is, having allowed for the KF and GF penalties, we have not pushed + // the current inter-frame target too low. If the adjustment we apply here is + // not capable of recovering all the extra bits we have spent in the KF or GF, + // then the remainder will have to be recovered over a longer time span via + // other buffer / rate control mechanisms. + if (cpi->this_frame_target < min_frame_target) + cpi->this_frame_target = min_frame_target; + + if (!cpi->refresh_alt_ref_frame) + // Note the baseline target data rate for this inter frame. + cpi->inter_frame_target = cpi->this_frame_target; + + // Adjust target frame size for Golden Frames: + if (cpi->frames_till_gf_update_due == 0) { + const int q = (cpi->oxcf.fixed_q < 0) ? cpi->last_q[INTER_FRAME] + : cpi->oxcf.fixed_q; + + cpi->refresh_golden_frame = 1; + + calc_gf_params(cpi); + + // If we are using alternate ref instead of gf then do not apply the boost + // It will instead be applied to the altref update + // Jims modified boost + if (!cpi->source_alt_ref_active) { + if (cpi->oxcf.fixed_q < 0) { + // The spend on the GF is defined in the two pass code + // for two pass encodes + cpi->this_frame_target = cpi->per_frame_bandwidth; + } else { + cpi->this_frame_target = + (estimate_bits_at_q(1, q, cpi->common.MBs, 1.0) + * cpi->last_boost) / 100; + } + } else { + // If there is an active ARF at this location use the minimum + // bits on this frame even if it is a constructed arf. + // The active maximum quantizer insures that an appropriate + // number of bits will be spent if needed for constructed ARFs. + cpi->this_frame_target = 0; + } + } +} + + +void vp9_update_rate_correction_factors(VP9_COMP *cpi, int damp_var) { + const int q = cpi->common.base_qindex; + int correction_factor = 100; + double rate_correction_factor; + double adjustment_limit; + + int projected_size_based_on_q = 0; + + // Clear down mmx registers to allow floating point in what follows + vp9_clear_system_state(); // __asm emms; + + if (cpi->common.frame_type == KEY_FRAME) { + rate_correction_factor = cpi->key_frame_rate_correction_factor; + } else { + if (cpi->refresh_alt_ref_frame || cpi->refresh_golden_frame) + rate_correction_factor = cpi->gf_rate_correction_factor; + else + rate_correction_factor = cpi->rate_correction_factor; + } + + // Work out how big we would have expected the frame to be at this Q given + // the current correction factor. + // Stay in double to avoid int overflow when values are large + projected_size_based_on_q = estimate_bits_at_q(cpi->common.frame_type, q, + cpi->common.MBs, + rate_correction_factor); + + // Work out a size correction factor. + if (projected_size_based_on_q > 0) + correction_factor = + (100 * cpi->projected_frame_size) / projected_size_based_on_q; + + // More heavily damped adjustment used if we have been oscillating either side + // of target. + switch (damp_var) { + case 0: + adjustment_limit = 0.75; + break; + case 1: + adjustment_limit = 0.375; + break; + case 2: + default: + adjustment_limit = 0.25; + break; + } + + // if ( (correction_factor > 102) && (Q < cpi->active_worst_quality) ) + if (correction_factor > 102) { + // We are not already at the worst allowable quality + correction_factor = + (int)(100 + ((correction_factor - 100) * adjustment_limit)); + rate_correction_factor = + ((rate_correction_factor * correction_factor) / 100); + + // Keep rate_correction_factor within limits + if (rate_correction_factor > MAX_BPB_FACTOR) + rate_correction_factor = MAX_BPB_FACTOR; + } else if (correction_factor < 99) { + // We are not already at the best allowable quality + correction_factor = + (int)(100 - ((100 - correction_factor) * adjustment_limit)); + rate_correction_factor = + ((rate_correction_factor * correction_factor) / 100); + + // Keep rate_correction_factor within limits + if (rate_correction_factor < MIN_BPB_FACTOR) + rate_correction_factor = MIN_BPB_FACTOR; + } + + if (cpi->common.frame_type == KEY_FRAME) { + cpi->key_frame_rate_correction_factor = rate_correction_factor; + } else { + if (cpi->refresh_alt_ref_frame || cpi->refresh_golden_frame) + cpi->gf_rate_correction_factor = rate_correction_factor; + else + cpi->rate_correction_factor = rate_correction_factor; + } +} + + +int vp9_regulate_q(VP9_COMP *cpi, int target_bits_per_frame) { + int q = cpi->active_worst_quality; + + int i; + int last_error = INT_MAX; + int target_bits_per_mb; + int bits_per_mb_at_this_q; + double correction_factor; + + // Select the appropriate correction factor based upon type of frame. + if (cpi->common.frame_type == KEY_FRAME) { + correction_factor = cpi->key_frame_rate_correction_factor; + } else { + if (cpi->refresh_alt_ref_frame || cpi->refresh_golden_frame) + correction_factor = cpi->gf_rate_correction_factor; + else + correction_factor = cpi->rate_correction_factor; + } + + // Calculate required scaling factor based on target frame size and size of + // frame produced using previous Q. + if (target_bits_per_frame >= (INT_MAX >> BPER_MB_NORMBITS)) + target_bits_per_mb = + (target_bits_per_frame / cpi->common.MBs) + << BPER_MB_NORMBITS; // Case where we would overflow int + else + target_bits_per_mb = + (target_bits_per_frame << BPER_MB_NORMBITS) / cpi->common.MBs; + + i = cpi->active_best_quality; + + do { + bits_per_mb_at_this_q = (int)vp9_bits_per_mb(cpi->common.frame_type, i, + correction_factor); + + if (bits_per_mb_at_this_q <= target_bits_per_mb) { + if ((target_bits_per_mb - bits_per_mb_at_this_q) <= last_error) + q = i; + else + q = i - 1; + + break; + } else { + last_error = bits_per_mb_at_this_q - target_bits_per_mb; + } + } while (++i <= cpi->active_worst_quality); + + return q; +} + + +static int estimate_keyframe_frequency(VP9_COMP *cpi) { + int i; + + // Average key frame frequency + int av_key_frame_frequency = 0; + + /* First key frame at start of sequence is a special case. We have no + * frequency data. + */ + if (cpi->key_frame_count == 1) { + /* Assume a default of 1 kf every 2 seconds, or the max kf interval, + * whichever is smaller. + */ + int key_freq = cpi->oxcf.key_freq > 0 ? cpi->oxcf.key_freq : 1; + av_key_frame_frequency = (int)cpi->output_framerate * 2; + + if (cpi->oxcf.auto_key && av_key_frame_frequency > key_freq) + av_key_frame_frequency = cpi->oxcf.key_freq; + + cpi->prior_key_frame_distance[KEY_FRAME_CONTEXT - 1] + = av_key_frame_frequency; + } else { + unsigned int total_weight = 0; + int last_kf_interval = + (cpi->frames_since_key > 0) ? cpi->frames_since_key : 1; + + /* reset keyframe context and calculate weighted average of last + * KEY_FRAME_CONTEXT keyframes + */ + for (i = 0; i < KEY_FRAME_CONTEXT; i++) { + if (i < KEY_FRAME_CONTEXT - 1) + cpi->prior_key_frame_distance[i] + = cpi->prior_key_frame_distance[i + 1]; + else + cpi->prior_key_frame_distance[i] = last_kf_interval; + + av_key_frame_frequency += prior_key_frame_weight[i] + * cpi->prior_key_frame_distance[i]; + total_weight += prior_key_frame_weight[i]; + } + + av_key_frame_frequency /= total_weight; + } + return av_key_frame_frequency; +} + + +void vp9_adjust_key_frame_context(VP9_COMP *cpi) { + // Clear down mmx registers to allow floating point in what follows + vp9_clear_system_state(); + + cpi->frames_since_key = 0; + cpi->key_frame_count++; +} + + +void vp9_compute_frame_size_bounds(VP9_COMP *cpi, int *frame_under_shoot_limit, + int *frame_over_shoot_limit) { + // Set-up bounds on acceptable frame size: + if (cpi->oxcf.fixed_q >= 0) { + // Fixed Q scenario: frame size never outranges target (there is no target!) + *frame_under_shoot_limit = 0; + *frame_over_shoot_limit = INT_MAX; + } else { + if (cpi->common.frame_type == KEY_FRAME) { + *frame_over_shoot_limit = cpi->this_frame_target * 9 / 8; + *frame_under_shoot_limit = cpi->this_frame_target * 7 / 8; + } else { + if (cpi->refresh_alt_ref_frame || cpi->refresh_golden_frame) { + *frame_over_shoot_limit = cpi->this_frame_target * 9 / 8; + *frame_under_shoot_limit = cpi->this_frame_target * 7 / 8; + } else { + // Stron overshoot limit for constrained quality + if (cpi->oxcf.end_usage == USAGE_CONSTRAINED_QUALITY) { + *frame_over_shoot_limit = cpi->this_frame_target * 11 / 8; + *frame_under_shoot_limit = cpi->this_frame_target * 2 / 8; + } else { + *frame_over_shoot_limit = cpi->this_frame_target * 11 / 8; + *frame_under_shoot_limit = cpi->this_frame_target * 5 / 8; + } + } + } + + // For very small rate targets where the fractional adjustment + // (eg * 7/8) may be tiny make sure there is at least a minimum + // range. + *frame_over_shoot_limit += 200; + *frame_under_shoot_limit -= 200; + if (*frame_under_shoot_limit < 0) + *frame_under_shoot_limit = 0; + } +} + + +// return of 0 means drop frame +int vp9_pick_frame_size(VP9_COMP *cpi) { + VP9_COMMON *cm = &cpi->common; + + if (cm->frame_type == KEY_FRAME) + calc_iframe_target_size(cpi); + else + calc_pframe_target_size(cpi); + + return 1; +}