From: Marco Paniconi Date: Thu, 3 Apr 2014 01:37:04 +0000 (-0700) Subject: Cyclic refresh: factor segment delta-q into rate control. X-Git-Tag: v1.4.0~450^2 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=83fd18977fcde783d2e44b248c2dea4a8eb04955;p=libvpx Cyclic refresh: factor segment delta-q into rate control. Incorporate segment delta-q into estimated bits. This generally improves the rate control under cyclic refresh (aq=3) mode. Change-Id: I1dc60fb230e7d08357fae18909d8ed27bf58e037 --- diff --git a/vp9/encoder/vp9_aq_cyclicrefresh.c b/vp9/encoder/vp9_aq_cyclicrefresh.c index 3806cf888..bc68b3756 100644 --- a/vp9/encoder/vp9_aq_cyclicrefresh.c +++ b/vp9/encoder/vp9_aq_cyclicrefresh.c @@ -19,21 +19,23 @@ #include "vp9/encoder/vp9_segmentation.h" struct CYCLIC_REFRESH { - // Percentage of super-blocks per frame that are targeted as candidates + // Percentage of blocks per frame that are targeted as candidates // for cyclic refresh. - int max_sbs_perframe; + int percent_refresh; // Maximum q-delta as percentage of base q. int max_qdelta_perc; // Block size below which we don't apply cyclic refresh. BLOCK_SIZE min_block_size; // Superblock starting index for cycling through the frame. int sb_index; - // Controls how long a block will need to wait to be refreshed again. + // 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 (segment 1). + int target_num_seg_blocks; // Actual number of (8x8) blocks that were applied delta-q (segment 1). - int num_seg_blocks; - // Actual encoding bits for segment 1. - int actual_seg_bits; + int actual_num_seg_blocks; // RD mult. parameters for segment 1. int rdmult; // Cyclic refresh map. @@ -41,6 +43,8 @@ struct CYCLIC_REFRESH { // Thresholds applied to projected rate/distortion of the superblock. int64_t thresh_rate_sb; int64_t thresh_dist_sb; + // Rate target ratio to set q delta. + double rate_ratio_qdelta; }; CYCLIC_REFRESH *vp9_cyclic_refresh_alloc(int mi_rows, int mi_cols) { @@ -117,6 +121,73 @@ static int candidate_refresh_aq(const CYCLIC_REFRESH *cr, } } +// Compute delta-q for the segment. +static int compute_deltaq(const VP9_COMP *cpi, int q) { + 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, cr->rate_ratio_qdelta, + 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 segment 1. 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 segment 1: use actual number of blocks refreshed in + // previous/just encoded frame. Note number of blocks here is in 8x8 units. + double weight_segment = (double)cr->actual_num_seg_blocks / num8x8bl; + // Compute delta-q that was used in the just encoded frame. + int deltaq = compute_deltaq(cpi, cm->base_qindex); + // Take segment weighted average for estimated bits. + estimated_bits = (int)((1.0 - weight_segment) * + vp9_estimate_bits_at_q(cm->frame_type, cm->base_qindex, mbs, + correction_factor, cm->bit_depth) + + weight_segment * + vp9_estimate_bits_at_q(cm->frame_type, cm->base_qindex + deltaq, 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. +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 1 prior to encoding: take the target number for the + // frame to be encoded. Number of blocks here is in 8x8 units. + // Note that this is called in rc_regulate_q, which is called before the + // cyclic_refresh_setup (which sets cr->target_num_seg_blocks). So a mismatch + // may occur between the cr->target_num_seg_blocks value here and the + // cr->target_num_seg_block set for encoding the frame. For the current use + // case of fixed cr->percent_refresh and cr->time_for_refresh = 0, mismatch + // does not occur/is very small. + double weight_segment = (double)cr->target_num_seg_blocks / num8x8bl; + // Compute delta-q corresponding to qindex i. + int deltaq = compute_deltaq(cpi, i); + // 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. @@ -167,10 +238,85 @@ void vp9_cyclic_refresh_update_segment(VP9_COMP *const cpi, cpi->segmentation_map[block_index + y * cm->mi_cols + x] = mbmi->segment_id; } - // Keep track of actual number (in units of 8x8) of blocks in segment 1 used - // for encoding this frame. - if (mbmi->segment_id) - cr->num_seg_blocks += xmis * ymis; +} + +// Update the actual number of blocks that were applied the segment delta q. +void vp9_cyclic_refresh_update_actual_count(struct 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_seg_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 (seg_map[mi_row * cm->mi_cols + mi_col] == 1) + cr->actual_num_seg_blocks++; + } +} + +// Update the segmentation map, and related quantities: cyclic refresh map, +// refresh sb_index, and target number of blocks to be refreshed. +void vp9_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; + vpx_memset(seg_map, 0, 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] = 1; + } + 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; } // Setup cyclic background refresh: set delta q and segmentation map. @@ -179,7 +325,6 @@ void vp9_cyclic_refresh_setup(VP9_COMP *const cpi) { const RATE_CONTROL *const rc = &cpi->rc; CYCLIC_REFRESH *const cr = cpi->cyclic_refresh; struct segmentation *const seg = &cm->seg; - unsigned char *const seg_map = cpi->segmentation_map; const int apply_cyclic_refresh = apply_cyclic_refresh_bitrate(cm, rc); // Don't apply refresh on key frame or enhancement layer frames. if (!apply_cyclic_refresh || @@ -187,6 +332,7 @@ void vp9_cyclic_refresh_setup(VP9_COMP *const cpi) { (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; vpx_memset(seg_map, 0, cm->mi_rows * cm->mi_cols); vp9_disable_segmentation(&cm->seg); if (cm->frame_type == KEY_FRAME) @@ -194,18 +340,15 @@ void vp9_cyclic_refresh_setup(VP9_COMP *const cpi) { return; } else { int qindex_delta = 0; - int i, block_count, bl_index, sb_rows, sb_cols, sbs_in_frame; - int xmis, ymis, x, y, qindex2; - - // Rate target ratio to set q delta. - const float rate_ratio_qdelta = 2.0; + int qindex2; const double q = vp9_convert_qindex_to_q(cm->base_qindex, cm->bit_depth); vp9_clear_system_state(); // Some of these parameters may be set via codec-control function later. - cr->max_sbs_perframe = 10; + cr->percent_refresh = 10; + cr->rate_ratio_qdelta = 2.0; cr->max_qdelta_perc = 50; cr->min_block_size = BLOCK_8X8; - cr->time_for_refresh = 1; + cr->time_for_refresh = 0; // Set rate threshold to some fraction of target (and scaled by 256). cr->thresh_rate_sb = (rc->sb64_target_rate * 256) >> 2; // Distortion threshold, quadratic in Q, scale factor to be adjusted. @@ -217,10 +360,8 @@ void vp9_cyclic_refresh_setup(VP9_COMP *const cpi) { cr->thresh_dist_sb = 16 * (int)(q * q); } - cr->num_seg_blocks = 0; // Set up segmentation. // Clear down the segment map. - vpx_memset(seg_map, 0, cm->mi_rows * cm->mi_cols); vp9_enable_segmentation(&cm->seg); vp9_clearall_segfeatures(seg); // Select delta coding method. @@ -239,14 +380,7 @@ void vp9_cyclic_refresh_setup(VP9_COMP *const cpi) { vp9_enable_segfeature(seg, 1, SEG_LVL_ALT_Q); // Set the q delta for segment 1. - qindex_delta = vp9_compute_qdelta_by_rate(rc, cm->frame_type, - cm->base_qindex, - rate_ratio_qdelta, - cm->bit_depth); - // TODO(marpan): Incorporate the actual-vs-target rate over/undershoot from - // previous encoded frame. - if (-qindex_delta > cr->max_qdelta_perc * cm->base_qindex / 100) - qindex_delta = -cr->max_qdelta_perc * cm->base_qindex / 100; + qindex_delta = compute_deltaq(cpi, cm->base_qindex); // Compute rd-mult for segment 1. qindex2 = clamp(cm->base_qindex + cm->y_dc_delta_q + qindex_delta, 0, MAXQ); @@ -254,61 +388,8 @@ void vp9_cyclic_refresh_setup(VP9_COMP *const cpi) { vp9_set_segdata(seg, 1, SEG_LVL_ALT_Q, qindex_delta); - 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 superblocks to get the q delta (segment 1). - block_count = cr->max_sbs_perframe * sbs_in_frame / 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; - 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) { - seg_map[bl_index2] = 1; - sum_map++; - } else if (cr->map[bl_index2] < 0) { - cr->map[bl_index2]++; - } - } - } - // Enforce constant segment over superblock. - // If segment is partial over superblock, reset to either all 1 or 0. - if (sum_map > 0 && sum_map < xmis * ymis) { - const int new_value = (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] = new_value; - } - i++; - if (i == sbs_in_frame) { - i = 0; - } - if (sum_map >= xmis * ymis /2) - block_count--; - } while (block_count && i != cr->sb_index); - cr->sb_index = i; + // Update the segmentation and refresh map. + vp9_cyclic_refresh_update_map(cpi); } } diff --git a/vp9/encoder/vp9_aq_cyclicrefresh.h b/vp9/encoder/vp9_aq_cyclicrefresh.h index fbc057b6f..3fc677646 100644 --- a/vp9/encoder/vp9_aq_cyclicrefresh.h +++ b/vp9/encoder/vp9_aq_cyclicrefresh.h @@ -27,6 +27,16 @@ CYCLIC_REFRESH *vp9_cyclic_refresh_alloc(int mi_rows, int mi_cols); void vp9_cyclic_refresh_free(CYCLIC_REFRESH *cr); +// Estimate the bits, incorporating the delta-q from segment 1, after encoding +// the frame. +int vp9_cyclic_refresh_estimate_bits_at_q(const struct VP9_COMP *cpi, + double correction_factor); + +// Estimate the bits per mb, for a given q = i and a corresponding delta-q +// (for segment 1), prior to encoding the frame. +int vp9_cyclic_refresh_rc_bits_per_mb(const struct VP9_COMP *cpi, int i, + double correction_factor); + // 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. @@ -36,6 +46,13 @@ void vp9_cyclic_refresh_update_segment(struct VP9_COMP *const cpi, BLOCK_SIZE bsize, int use_rd, int64_t rate_sb); +// Update the segmentation map, and related quantities: cyclic refresh map, +// refresh sb_index, and target number of blocks to be refreshed. +void vp9_cyclic_refresh_update__map(struct VP9_COMP *const cpi); + +// Update the actual number of blocks that were applied the segment delta q. +void vp9_cyclic_refresh_update_actual_count(struct VP9_COMP *const cpi); + // Setup cyclic background refresh: set delta q and segmentation map. void vp9_cyclic_refresh_setup(struct VP9_COMP *const cpi); diff --git a/vp9/encoder/vp9_ratectrl.c b/vp9/encoder/vp9_ratectrl.c index 97ededc5d..e96c9046d 100644 --- a/vp9/encoder/vp9_ratectrl.c +++ b/vp9/encoder/vp9_ratectrl.c @@ -18,6 +18,7 @@ #include "vpx_mem/vpx_mem.h" #include "vp9/common/vp9_alloccommon.h" +#include "vp9/encoder/vp9_aq_cyclicrefresh.h" #include "vp9/common/vp9_common.h" #include "vp9/common/vp9_entropymode.h" #include "vp9/common/vp9_quant_common.h" @@ -185,9 +186,9 @@ int vp9_rc_bits_per_mb(FRAME_TYPE frame_type, int qindex, return (int)(enumerator * correction_factor / q); } -static int estimate_bits_at_q(FRAME_TYPE frame_type, int q, int mbs, - double correction_factor, - vpx_bit_depth_t bit_depth) { +int vp9_estimate_bits_at_q(FRAME_TYPE frame_type, int q, int mbs, + double correction_factor, + vpx_bit_depth_t bit_depth) { const int bpm = (int)(vp9_rc_bits_per_mb(frame_type, q, correction_factor, bit_depth)); return MAX(FRAME_OVERHEAD_BITS, @@ -232,7 +233,6 @@ int vp9_rc_clamp_iframe_target_size(const VP9_COMP *const cpi, int target) { return target; } - // Update the buffer level for higher layers, given the encoded current layer. static void update_layer_buffer_level(SVC *svc, int encoded_frame_size) { int temporal_layer = 0; @@ -414,10 +414,16 @@ void vp9_rc_update_rate_correction_factors(VP9_COMP *cpi, int damp_var) { // 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(cm->frame_type, - cm->base_qindex, cm->MBs, - rate_correction_factor, - cm->bit_depth); + if (cpi->oxcf.aq_mode == CYCLIC_REFRESH_AQ && cpi->common.seg.enabled) { + projected_size_based_on_q = + vp9_cyclic_refresh_estimate_bits_at_q(cpi, rate_correction_factor); + } else { + projected_size_based_on_q = vp9_estimate_bits_at_q(cpi->common.frame_type, + cm->base_qindex, + cm->MBs, + rate_correction_factor, + cm->bit_depth); + } // Work out a size correction factor. if (projected_size_based_on_q > FRAME_OVERHEAD_BITS) correction_factor = (100 * cpi->rc.projected_frame_size) / @@ -477,7 +483,7 @@ int vp9_rc_regulate_q(const VP9_COMP *cpi, int target_bits_per_frame, const VP9_COMMON *const cm = &cpi->common; int q = active_worst_quality; int last_error = INT_MAX; - int i, target_bits_per_mb; + int i, target_bits_per_mb, bits_per_mb_at_this_q; const double correction_factor = get_rate_correction_factor(cpi); // Calculate required scaling factor based on target frame size and size of @@ -488,9 +494,14 @@ int vp9_rc_regulate_q(const VP9_COMP *cpi, int target_bits_per_frame, i = active_best_quality; do { - const int bits_per_mb_at_this_q = (int)vp9_rc_bits_per_mb(cm->frame_type, i, - correction_factor, - cm->bit_depth); + if (cpi->oxcf.aq_mode == CYCLIC_REFRESH_AQ && cm->seg.enabled) { + bits_per_mb_at_this_q = + (int)vp9_cyclic_refresh_rc_bits_per_mb(cpi, i, correction_factor); + } else { + bits_per_mb_at_this_q = (int)vp9_rc_bits_per_mb(cm->frame_type, i, + correction_factor, + cm->bit_depth); + } if (bits_per_mb_at_this_q <= target_bits_per_mb) { if ((target_bits_per_mb - bits_per_mb_at_this_q) <= last_error) @@ -1203,6 +1214,10 @@ void vp9_rc_postencode_update(VP9_COMP *cpi, uint64_t bytes_used) { RATE_CONTROL *const rc = &cpi->rc; const int qindex = cm->base_qindex; + if (cpi->oxcf.aq_mode == CYCLIC_REFRESH_AQ && cm->seg.enabled) { + vp9_cyclic_refresh_update_actual_count(cpi); + } + // Update rate control heuristics rc->projected_frame_size = (int)(bytes_used << 3); diff --git a/vp9/encoder/vp9_ratectrl.h b/vp9/encoder/vp9_ratectrl.h index 6200b396c..cf709274d 100644 --- a/vp9/encoder/vp9_ratectrl.h +++ b/vp9/encoder/vp9_ratectrl.h @@ -115,6 +115,10 @@ struct VP9EncoderConfig; void vp9_rc_init(const struct VP9EncoderConfig *oxcf, int pass, RATE_CONTROL *rc); +int vp9_estimate_bits_at_q(FRAME_TYPE frame_kind, int q, int mbs, + double correction_factor, + vpx_bit_depth_t bit_depth); + double vp9_convert_qindex_to_q(int qindex, vpx_bit_depth_t bit_depth); void vp9_rc_init_minq_luts();