diff options
Diffstat (limited to 'media/libvpx/vp9/encoder/vp9_aq_cyclicrefresh.c')
| -rw-r--r-- | media/libvpx/vp9/encoder/vp9_aq_cyclicrefresh.c | 519 |
1 files changed, 519 insertions, 0 deletions
diff --git a/media/libvpx/vp9/encoder/vp9_aq_cyclicrefresh.c b/media/libvpx/vp9/encoder/vp9_aq_cyclicrefresh.c new file mode 100644 index 000000000..4b1c95957 --- /dev/null +++ b/media/libvpx/vp9/encoder/vp9_aq_cyclicrefresh.c @@ -0,0 +1,519 @@ +/* + * Copyright (c) 2014 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 <limits.h> +#include <math.h> + +#include "vp9/encoder/vp9_aq_cyclicrefresh.h" + +#include "vp9/common/vp9_seg_common.h" + +#include "vp9/encoder/vp9_ratectrl.h" +#include "vp9/encoder/vp9_segmentation.h" + +struct CYCLIC_REFRESH { + // Percentage of blocks per frame that are targeted as candidates + // for cyclic refresh. + int percent_refresh; + // Maximum q-delta as percentage of base q. + int max_qdelta_perc; + // Superblock starting index for cycling through the frame. + int sb_index; + // Controls how long block will need to wait to be refreshed again, in + // excess of the cycle time, i.e., in the case of all zero motion, block + // will be refreshed every (100/percent_refresh + time_for_refresh) frames. + int time_for_refresh; + // Target number of (8x8) blocks that are set for delta-q. + int target_num_seg_blocks; + // Actual number of (8x8) blocks that were applied delta-q. + int actual_num_seg1_blocks; + int actual_num_seg2_blocks; + // RD mult. parameters for segment 1. + int rdmult; + // Cyclic refresh map. + signed char *map; + // Thresholds applied to the projected rate/distortion of the coding block, + // when deciding whether block should be refreshed. + int64_t thresh_rate_sb; + int64_t thresh_dist_sb; + // Threshold applied to the motion vector (in units of 1/8 pel) of the + // coding block, when deciding whether block should be refreshed. + int16_t motion_thresh; + // Rate target ratio to set q delta. + double rate_ratio_qdelta; + double low_content_avg; + int qindex_delta_seg1; + int qindex_delta_seg2; +}; + +CYCLIC_REFRESH *vp9_cyclic_refresh_alloc(int mi_rows, int mi_cols) { + CYCLIC_REFRESH *const cr = vpx_calloc(1, sizeof(*cr)); + if (cr == NULL) + return NULL; + + cr->map = vpx_calloc(mi_rows * mi_cols, sizeof(*cr->map)); + if (cr->map == NULL) { + vpx_free(cr); + return NULL; + } + + return cr; +} + +void vp9_cyclic_refresh_free(CYCLIC_REFRESH *cr) { + vpx_free(cr->map); + vpx_free(cr); +} + +// Check if we should turn off cyclic refresh based on bitrate condition. +static int apply_cyclic_refresh_bitrate(const VP9_COMMON *cm, + const RATE_CONTROL *rc) { + // Turn off cyclic refresh if bits available per frame is not sufficiently + // larger than bit cost of segmentation. Segment map bit cost should scale + // with number of seg blocks, so compare available bits to number of blocks. + // Average bits available per frame = avg_frame_bandwidth + // Number of (8x8) blocks in frame = mi_rows * mi_cols; + const float factor = 0.25; + const int number_blocks = cm->mi_rows * cm->mi_cols; + // The condition below corresponds to turning off at target bitrates: + // (at 30fps), ~12kbps for CIF, 36kbps for VGA, 100kps for HD/720p. + // Also turn off at very small frame sizes, to avoid too large fraction of + // superblocks to be refreshed per frame. Threshold below is less than QCIF. + if (rc->avg_frame_bandwidth < factor * number_blocks || + number_blocks / 64 < 5) + return 0; + else + return 1; +} + +// Check if this coding block, of size bsize, should be considered for refresh +// (lower-qp coding). Decision can be based on various factors, such as +// size of the coding block (i.e., below min_block size rejected), coding +// mode, and rate/distortion. +static int candidate_refresh_aq(const CYCLIC_REFRESH *cr, + const MB_MODE_INFO *mbmi, + int64_t rate, + int64_t dist, + int bsize) { + MV mv = mbmi->mv[0].as_mv; + // Reject the block for lower-qp coding if projected distortion + // is above the threshold, and any of the following is true: + // 1) mode uses large mv + // 2) mode is an intra-mode + // Otherwise accept for refresh. + if (dist > cr->thresh_dist_sb && + (mv.row > cr->motion_thresh || mv.row < -cr->motion_thresh || + mv.col > cr->motion_thresh || mv.col < -cr->motion_thresh || + !is_inter_block(mbmi))) + return CR_SEGMENT_ID_BASE; + else if (bsize >= BLOCK_16X16 && + rate < cr->thresh_rate_sb && + is_inter_block(mbmi) && + mbmi->mv[0].as_int == 0) + // More aggressive delta-q for bigger blocks with zero motion. + return CR_SEGMENT_ID_BOOST2; + else + return CR_SEGMENT_ID_BOOST1; +} + +// Compute delta-q for the segment. +static int compute_deltaq(const VP9_COMP *cpi, int q, double rate_factor) { + const CYCLIC_REFRESH *const cr = cpi->cyclic_refresh; + const RATE_CONTROL *const rc = &cpi->rc; + int deltaq = vp9_compute_qdelta_by_rate(rc, cpi->common.frame_type, + q, rate_factor, + cpi->common.bit_depth); + if ((-deltaq) > cr->max_qdelta_perc * q / 100) { + deltaq = -cr->max_qdelta_perc * q / 100; + } + return deltaq; +} + +// For the just encoded frame, estimate the bits, incorporating the delta-q +// from non-base segment. For now ignore effect of multiple segments +// (with different delta-q). Note this function is called in the postencode +// (called from rc_update_rate_correction_factors()). +int vp9_cyclic_refresh_estimate_bits_at_q(const VP9_COMP *cpi, + double correction_factor) { + const VP9_COMMON *const cm = &cpi->common; + const CYCLIC_REFRESH *const cr = cpi->cyclic_refresh; + int estimated_bits; + int mbs = cm->MBs; + int num8x8bl = mbs << 2; + // Weight for non-base segments: use actual number of blocks refreshed in + // previous/just encoded frame. Note number of blocks here is in 8x8 units. + double weight_segment1 = (double)cr->actual_num_seg1_blocks / num8x8bl; + double weight_segment2 = (double)cr->actual_num_seg2_blocks / num8x8bl; + // Take segment weighted average for estimated bits. + estimated_bits = (int)((1.0 - weight_segment1 - weight_segment2) * + vp9_estimate_bits_at_q(cm->frame_type, cm->base_qindex, mbs, + correction_factor, cm->bit_depth) + + weight_segment1 * + vp9_estimate_bits_at_q(cm->frame_type, + cm->base_qindex + cr->qindex_delta_seg1, mbs, + correction_factor, cm->bit_depth) + + weight_segment2 * + vp9_estimate_bits_at_q(cm->frame_type, + cm->base_qindex + cr->qindex_delta_seg2, mbs, + correction_factor, cm->bit_depth)); + return estimated_bits; +} + +// Prior to encoding the frame, estimate the bits per mb, for a given q = i and +// a corresponding delta-q (for segment 1). This function is called in the +// rc_regulate_q() to set the base qp index. +// Note: the segment map is set to either 0/CR_SEGMENT_ID_BASE (no refresh) or +// to 1/CR_SEGMENT_ID_BOOST1 (refresh) for each superblock, prior to encoding. +int vp9_cyclic_refresh_rc_bits_per_mb(const VP9_COMP *cpi, int i, + double correction_factor) { + const VP9_COMMON *const cm = &cpi->common; + CYCLIC_REFRESH *const cr = cpi->cyclic_refresh; + int bits_per_mb; + int num8x8bl = cm->MBs << 2; + // Weight for segment prior to encoding: take the average of the target + // number for the frame to be encoded and the actual from the previous frame. + double weight_segment = (double)((cr->target_num_seg_blocks + + cr->actual_num_seg1_blocks + cr->actual_num_seg2_blocks) >> 1) / + num8x8bl; + // Compute delta-q corresponding to qindex i. + int deltaq = compute_deltaq(cpi, i, cr->rate_ratio_qdelta); + // Take segment weighted average for bits per mb. + bits_per_mb = (int)((1.0 - weight_segment) * + vp9_rc_bits_per_mb(cm->frame_type, i, correction_factor, cm->bit_depth) + + weight_segment * + vp9_rc_bits_per_mb(cm->frame_type, i + deltaq, correction_factor, + cm->bit_depth)); + return bits_per_mb; +} + +// Prior to coding a given prediction block, of size bsize at (mi_row, mi_col), +// check if we should reset the segment_id, and update the cyclic_refresh map +// and segmentation map. +void vp9_cyclic_refresh_update_segment(VP9_COMP *const cpi, + MB_MODE_INFO *const mbmi, + int mi_row, int mi_col, + BLOCK_SIZE bsize, + int64_t rate, + int64_t dist, + int skip) { + const VP9_COMMON *const cm = &cpi->common; + CYCLIC_REFRESH *const cr = cpi->cyclic_refresh; + const int bw = num_8x8_blocks_wide_lookup[bsize]; + const int bh = num_8x8_blocks_high_lookup[bsize]; + const int xmis = MIN(cm->mi_cols - mi_col, bw); + const int ymis = MIN(cm->mi_rows - mi_row, bh); + const int block_index = mi_row * cm->mi_cols + mi_col; + const int refresh_this_block = candidate_refresh_aq(cr, mbmi, rate, dist, + bsize); + // Default is to not update the refresh map. + int new_map_value = cr->map[block_index]; + int x = 0; int y = 0; + + // If this block is labeled for refresh, check if we should reset the + // segment_id. + if (cyclic_refresh_segment_id_boosted(mbmi->segment_id)) { + mbmi->segment_id = refresh_this_block; + // Reset segment_id if will be skipped. + if (skip) + mbmi->segment_id = CR_SEGMENT_ID_BASE; + } + + // Update the cyclic refresh map, to be used for setting segmentation map + // for the next frame. If the block will be refreshed this frame, mark it + // as clean. The magnitude of the -ve influences how long before we consider + // it for refresh again. + if (cyclic_refresh_segment_id_boosted(mbmi->segment_id)) { + new_map_value = -cr->time_for_refresh; + } else if (refresh_this_block) { + // Else if it is accepted as candidate for refresh, and has not already + // been refreshed (marked as 1) then mark it as a candidate for cleanup + // for future time (marked as 0), otherwise don't update it. + if (cr->map[block_index] == 1) + new_map_value = 0; + } else { + // Leave it marked as block that is not candidate for refresh. + new_map_value = 1; + } + + // Update entries in the cyclic refresh map with new_map_value, and + // copy mbmi->segment_id into global segmentation map. + for (y = 0; y < ymis; y++) + for (x = 0; x < xmis; x++) { + cr->map[block_index + y * cm->mi_cols + x] = new_map_value; + cpi->segmentation_map[block_index + y * cm->mi_cols + x] = + mbmi->segment_id; + } +} + +// Update the actual number of blocks that were applied the segment delta q. +void vp9_cyclic_refresh_postencode(VP9_COMP *const cpi) { + VP9_COMMON *const cm = &cpi->common; + CYCLIC_REFRESH *const cr = cpi->cyclic_refresh; + unsigned char *const seg_map = cpi->segmentation_map; + int mi_row, mi_col; + cr->actual_num_seg1_blocks = 0; + cr->actual_num_seg2_blocks = 0; + for (mi_row = 0; mi_row < cm->mi_rows; mi_row++) + for (mi_col = 0; mi_col < cm->mi_cols; mi_col++) { + if (cyclic_refresh_segment_id( + seg_map[mi_row * cm->mi_cols + mi_col]) == CR_SEGMENT_ID_BOOST1) + cr->actual_num_seg1_blocks++; + else if (cyclic_refresh_segment_id( + seg_map[mi_row * cm->mi_cols + mi_col]) == CR_SEGMENT_ID_BOOST2) + cr->actual_num_seg2_blocks++; + } +} + +// Set golden frame update interval, for non-svc 1 pass CBR mode. +void vp9_cyclic_refresh_set_golden_update(VP9_COMP *const cpi) { + RATE_CONTROL *const rc = &cpi->rc; + CYCLIC_REFRESH *const cr = cpi->cyclic_refresh; + // Set minimum gf_interval for GF update to a multiple (== 2) of refresh + // period. Depending on past encoding stats, GF flag may be reset and update + // may not occur until next baseline_gf_interval. + if (cr->percent_refresh > 0) + rc->baseline_gf_interval = 4 * (100 / cr->percent_refresh); + else + rc->baseline_gf_interval = 40; +} + +// Update some encoding stats (from the just encoded frame). If this frame's +// background has high motion, refresh the golden frame. Otherwise, if the +// golden reference is to be updated check if we should NOT update the golden +// ref. +void vp9_cyclic_refresh_check_golden_update(VP9_COMP *const cpi) { + VP9_COMMON *const cm = &cpi->common; + CYCLIC_REFRESH *const cr = cpi->cyclic_refresh; + int mi_row, mi_col; + double fraction_low = 0.0; + int low_content_frame = 0; + + MODE_INFO **mi = cm->mi_grid_visible; + RATE_CONTROL *const rc = &cpi->rc; + const int rows = cm->mi_rows, cols = cm->mi_cols; + int cnt1 = 0, cnt2 = 0; + int force_gf_refresh = 0; + + for (mi_row = 0; mi_row < rows; mi_row++) { + for (mi_col = 0; mi_col < cols; mi_col++) { + int16_t abs_mvr = mi[0]->mbmi.mv[0].as_mv.row >= 0 ? + mi[0]->mbmi.mv[0].as_mv.row : -1 * mi[0]->mbmi.mv[0].as_mv.row; + int16_t abs_mvc = mi[0]->mbmi.mv[0].as_mv.col >= 0 ? + mi[0]->mbmi.mv[0].as_mv.col : -1 * mi[0]->mbmi.mv[0].as_mv.col; + + // Calculate the motion of the background. + if (abs_mvr <= 16 && abs_mvc <= 16) { + cnt1++; + if (abs_mvr == 0 && abs_mvc == 0) + cnt2++; + } + mi++; + + // Accumulate low_content_frame. + if (cr->map[mi_row * cols + mi_col] < 1) + low_content_frame++; + } + mi += 8; + } + + // For video conference clips, if the background has high motion in current + // frame because of the camera movement, set this frame as the golden frame. + // Use 70% and 5% as the thresholds for golden frame refreshing. + if (cnt1 * 10 > (70 * rows * cols) && cnt2 * 20 < cnt1) { + vp9_cyclic_refresh_set_golden_update(cpi); + rc->frames_till_gf_update_due = rc->baseline_gf_interval; + + if (rc->frames_till_gf_update_due > rc->frames_to_key) + rc->frames_till_gf_update_due = rc->frames_to_key; + cpi->refresh_golden_frame = 1; + force_gf_refresh = 1; + } + + fraction_low = + (double)low_content_frame / (rows * cols); + // Update average. + cr->low_content_avg = (fraction_low + 3 * cr->low_content_avg) / 4; + if (!force_gf_refresh && cpi->refresh_golden_frame == 1) { + // Don't update golden reference if the amount of low_content for the + // current encoded frame is small, or if the recursive average of the + // low_content over the update interval window falls below threshold. + if (fraction_low < 0.8 || cr->low_content_avg < 0.7) + cpi->refresh_golden_frame = 0; + // Reset for next internal. + cr->low_content_avg = fraction_low; + } +} + +// Update the segmentation map, and related quantities: cyclic refresh map, +// refresh sb_index, and target number of blocks to be refreshed. +// The map is set to either 0/CR_SEGMENT_ID_BASE (no refresh) or to +// 1/CR_SEGMENT_ID_BOOST1 (refresh) for each superblock. +// Blocks labeled as BOOST1 may later get set to BOOST2 (during the +// encoding of the superblock). +static void cyclic_refresh_update_map(VP9_COMP *const cpi) { + VP9_COMMON *const cm = &cpi->common; + CYCLIC_REFRESH *const cr = cpi->cyclic_refresh; + unsigned char *const seg_map = cpi->segmentation_map; + int i, block_count, bl_index, sb_rows, sb_cols, sbs_in_frame; + int xmis, ymis, x, y; + memset(seg_map, CR_SEGMENT_ID_BASE, cm->mi_rows * cm->mi_cols); + sb_cols = (cm->mi_cols + MI_BLOCK_SIZE - 1) / MI_BLOCK_SIZE; + sb_rows = (cm->mi_rows + MI_BLOCK_SIZE - 1) / MI_BLOCK_SIZE; + sbs_in_frame = sb_cols * sb_rows; + // Number of target blocks to get the q delta (segment 1). + block_count = cr->percent_refresh * cm->mi_rows * cm->mi_cols / 100; + // Set the segmentation map: cycle through the superblocks, starting at + // cr->mb_index, and stopping when either block_count blocks have been found + // to be refreshed, or we have passed through whole frame. + assert(cr->sb_index < sbs_in_frame); + i = cr->sb_index; + cr->target_num_seg_blocks = 0; + do { + int sum_map = 0; + // Get the mi_row/mi_col corresponding to superblock index i. + int sb_row_index = (i / sb_cols); + int sb_col_index = i - sb_row_index * sb_cols; + int mi_row = sb_row_index * MI_BLOCK_SIZE; + int mi_col = sb_col_index * MI_BLOCK_SIZE; + assert(mi_row >= 0 && mi_row < cm->mi_rows); + assert(mi_col >= 0 && mi_col < cm->mi_cols); + bl_index = mi_row * cm->mi_cols + mi_col; + // Loop through all 8x8 blocks in superblock and update map. + xmis = MIN(cm->mi_cols - mi_col, + num_8x8_blocks_wide_lookup[BLOCK_64X64]); + ymis = MIN(cm->mi_rows - mi_row, + num_8x8_blocks_high_lookup[BLOCK_64X64]); + for (y = 0; y < ymis; y++) { + for (x = 0; x < xmis; x++) { + const int bl_index2 = bl_index + y * cm->mi_cols + x; + // If the block is as a candidate for clean up then mark it + // for possible boost/refresh (segment 1). The segment id may get + // reset to 0 later if block gets coded anything other than ZEROMV. + if (cr->map[bl_index2] == 0) { + sum_map++; + } else if (cr->map[bl_index2] < 0) { + cr->map[bl_index2]++; + } + } + } + // Enforce constant segment over superblock. + // If segment is at least half of superblock, set to 1. + if (sum_map >= xmis * ymis / 2) { + for (y = 0; y < ymis; y++) + for (x = 0; x < xmis; x++) { + seg_map[bl_index + y * cm->mi_cols + x] = CR_SEGMENT_ID_BOOST1; + } + cr->target_num_seg_blocks += xmis * ymis; + } + i++; + if (i == sbs_in_frame) { + i = 0; + } + } while (cr->target_num_seg_blocks < block_count && i != cr->sb_index); + cr->sb_index = i; +} + +// Set/update global/frame level cyclic refresh parameters. +void vp9_cyclic_refresh_update_parameters(VP9_COMP *const cpi) { + const RATE_CONTROL *const rc = &cpi->rc; + CYCLIC_REFRESH *const cr = cpi->cyclic_refresh; + cr->percent_refresh = 10; + // Use larger delta-qp (increase rate_ratio_qdelta) for first few (~4) + // periods of the refresh cycle, after a key frame. This corresponds to ~40 + // frames with cr->percent_refresh = 10. + if (rc->frames_since_key < 40) + cr->rate_ratio_qdelta = 3.0; + else + cr->rate_ratio_qdelta = 2.0; +} + +// Setup cyclic background refresh: set delta q and segmentation map. +void vp9_cyclic_refresh_setup(VP9_COMP *const cpi) { + VP9_COMMON *const cm = &cpi->common; + const RATE_CONTROL *const rc = &cpi->rc; + CYCLIC_REFRESH *const cr = cpi->cyclic_refresh; + struct segmentation *const seg = &cm->seg; + const int apply_cyclic_refresh = apply_cyclic_refresh_bitrate(cm, rc); + if (cm->current_video_frame == 0) + cr->low_content_avg = 0.0; + // Don't apply refresh on key frame or enhancement layer frames. + if (!apply_cyclic_refresh || + (cm->frame_type == KEY_FRAME) || + (cpi->svc.temporal_layer_id > 0) || + (cpi->svc.spatial_layer_id > 0)) { + // Set segmentation map to 0 and disable. + unsigned char *const seg_map = cpi->segmentation_map; + memset(seg_map, 0, cm->mi_rows * cm->mi_cols); + vp9_disable_segmentation(&cm->seg); + if (cm->frame_type == KEY_FRAME) + cr->sb_index = 0; + return; + } else { + int qindex_delta = 0; + int qindex2; + const double q = vp9_convert_qindex_to_q(cm->base_qindex, cm->bit_depth); + vp9_clear_system_state(); + cr->max_qdelta_perc = 50; + cr->time_for_refresh = 0; + // Set rate threshold to some multiple (set to 2 for now) of the target + // rate (target is given by sb64_target_rate and scaled by 256). + cr->thresh_rate_sb = ((int64_t)(rc->sb64_target_rate) << 8) << 2; + // Distortion threshold, quadratic in Q, scale factor to be adjusted. + // q will not exceed 457, so (q * q) is within 32bit; see: + // vp9_convert_qindex_to_q(), vp9_ac_quant(), ac_qlookup*[]. + cr->thresh_dist_sb = ((int64_t)(q * q)) << 2; + cr->motion_thresh = 32; + // Set up segmentation. + // Clear down the segment map. + vp9_enable_segmentation(&cm->seg); + vp9_clearall_segfeatures(seg); + // Select delta coding method. + seg->abs_delta = SEGMENT_DELTADATA; + + // Note: setting temporal_update has no effect, as the seg-map coding method + // (temporal or spatial) is determined in vp9_choose_segmap_coding_method(), + // based on the coding cost of each method. For error_resilient mode on the + // last_frame_seg_map is set to 0, so if temporal coding is used, it is + // relative to 0 previous map. + // seg->temporal_update = 0; + + // Segment BASE "Q" feature is disabled so it defaults to the baseline Q. + vp9_disable_segfeature(seg, CR_SEGMENT_ID_BASE, SEG_LVL_ALT_Q); + // Use segment BOOST1 for in-frame Q adjustment. + vp9_enable_segfeature(seg, CR_SEGMENT_ID_BOOST1, SEG_LVL_ALT_Q); + // Use segment BOOST2 for more aggressive in-frame Q adjustment. + vp9_enable_segfeature(seg, CR_SEGMENT_ID_BOOST2, SEG_LVL_ALT_Q); + + // Set the q delta for segment BOOST1. + qindex_delta = compute_deltaq(cpi, cm->base_qindex, cr->rate_ratio_qdelta); + cr->qindex_delta_seg1 = qindex_delta; + + // Compute rd-mult for segment BOOST1. + qindex2 = clamp(cm->base_qindex + cm->y_dc_delta_q + qindex_delta, 0, MAXQ); + + cr->rdmult = vp9_compute_rd_mult(cpi, qindex2); + + vp9_set_segdata(seg, CR_SEGMENT_ID_BOOST1, SEG_LVL_ALT_Q, qindex_delta); + + // Set a more aggressive (higher) q delta for segment BOOST2. + qindex_delta = compute_deltaq(cpi, cm->base_qindex, + MIN(CR_MAX_RATE_TARGET_RATIO, + CR_BOOST2_FAC * cr->rate_ratio_qdelta)); + cr->qindex_delta_seg2 = qindex_delta; + vp9_set_segdata(seg, CR_SEGMENT_ID_BOOST2, SEG_LVL_ALT_Q, qindex_delta); + + // Update the segmentation and refresh map. + cyclic_refresh_update_map(cpi); + } +} + +int vp9_cyclic_refresh_get_rdmult(const CYCLIC_REFRESH *cr) { + return cr->rdmult; +} |