ref: 9f9d4f8dc9888d3b4d6c793d031f3ce5d407bd65
parent: 90ce21e519505986c413aa493c13128a451df61a
author: Marco <marpan@google.com>
date: Fri Dec 1 10:20:41 EST 2017
vp9-svc: Allow for nonzero motion on spatial reference. For nonrd pickmode on a given spatial layer, the spatial (golden) reference was always only using zeromv for prediction. In this patch if the downsampling filter used for generating the lower spatial layer is an averaging filter (nonzero phase), we allow for subpel motion on the spatial (golden) reference to compensate for the shift. This is done by forcing the testing of nonzero motion mode to compensate for spatial downsampling shift. Improvement for cases where the downsampling is averaging filter. In the current code this is only done for generating resolutions <= QVGA. Improvement for avgPSNR/SSIM on RTC set for speed 7: ~1.2%. Gain is larger (~2-3%) for VGA clips with 2 spatial layers. ~1% speed slowdown for 3 layer SVC on mac. Change-Id: I9ec4fa20a38947934fc650594596c25280c3b289
--- a/vp9/encoder/vp9_pickmode.c
+++ b/vp9/encoder/vp9_pickmode.c
@@ -1498,6 +1498,9 @@
MV_REFERENCE_FRAME best_second_ref_frame = NONE;
int comp_modes = 0;
int num_inter_modes = (cpi->use_svc) ? RT_INTER_MODES_SVC : RT_INTER_MODES;
+ int flag_svc_subpel = 0;
+ int svc_mv_col = 0;
+ int svc_mv_row = 0;
init_ref_frame_cost(cm, xd, ref_frame_cost);
@@ -1647,6 +1650,18 @@
if (cpi->use_svc || cpi->oxcf.speed <= 7 || bsize < BLOCK_32X32)
x->sb_use_mv_part = 0;
+ // Set the flag_svc_subpel to 1 for SVC if the lower spatial layer used
+ // an averaging filter for downsampling (phase = 8). If so, we will test
+ // a nonzero motion mode on the spatial (goldeen) reference.
+ // The nonzero motion is half pixel shifted to left and top (-4, -4).
+ if (cpi->use_svc && cpi->svc.spatial_layer_id > 0 &&
+ svc_force_zero_mode[GOLDEN_FRAME - 1] &&
+ cpi->svc.downsample_filter_phase[cpi->svc.spatial_layer_id - 1] == 8) {+ svc_mv_col = -4;
+ svc_mv_row = -4;
+ flag_svc_subpel = 1;
+ }
+
for (idx = 0; idx < num_inter_modes + comp_modes; ++idx) {int rate_mv = 0;
int mode_rd_thresh;
@@ -1660,6 +1675,7 @@
int inter_mv_mode = 0;
int skip_this_mv = 0;
int comp_pred = 0;
+ int force_gf_mv = 0;
PREDICTION_MODE this_mode;
second_ref_frame = NONE;
@@ -1680,6 +1696,19 @@
comp_pred = 1;
}
+ if (flag_svc_subpel && ref_frame == GOLDEN_FRAME) {+ force_gf_mv = 1;
+ // Only test mode if NEARESTMV/NEARMV is (svc_mv_col, svc_mv_row),
+ // otherwise set NEWMV to (svc_mv_col, svc_mv_row).
+ if (this_mode == NEWMV) {+ frame_mv[this_mode][ref_frame].as_mv.col = svc_mv_col;
+ frame_mv[this_mode][ref_frame].as_mv.row = svc_mv_row;
+ } else if (frame_mv[this_mode][ref_frame].as_mv.col != svc_mv_col ||
+ frame_mv[this_mode][ref_frame].as_mv.row != svc_mv_row) {+ continue;
+ }
+ }
+
if (comp_pred) {const struct segmentation *const seg = &cm->seg;
if (!cpi->allow_comp_inter_inter) continue;
@@ -1737,7 +1766,7 @@
// Skip non-zeromv mode search for golden frame if force_skip_low_temp_var
// is set. If nearestmv for golden frame is 0, zeromv mode will be skipped
// later.
- if (force_skip_low_temp_var && ref_frame == GOLDEN_FRAME &&
+ if (!force_gf_mv && force_skip_low_temp_var && ref_frame == GOLDEN_FRAME &&
frame_mv[this_mode][ref_frame].as_int != 0) {continue;
}
@@ -1751,7 +1780,7 @@
}
if (cpi->use_svc) {- if (svc_force_zero_mode[ref_frame - 1] &&
+ if (!force_gf_mv && svc_force_zero_mode[ref_frame - 1] &&
frame_mv[this_mode][ref_frame].as_int != 0)
continue;
}
@@ -1808,7 +1837,7 @@
&rd_thresh_freq_fact[mode_index])))
continue;
- if (this_mode == NEWMV) {+ if (this_mode == NEWMV && !force_gf_mv) {if (ref_frame > LAST_FRAME && !cpi->use_svc &&
cpi->oxcf.rc_mode == VPX_CBR) {int tmp_sad;
@@ -1949,7 +1978,7 @@
if ((this_mode == NEWMV || filter_ref == SWITCHABLE) &&
pred_filter_search &&
(ref_frame == LAST_FRAME ||
- (ref_frame == GOLDEN_FRAME &&
+ (ref_frame == GOLDEN_FRAME && !force_gf_mv &&
(cpi->use_svc || cpi->oxcf.rc_mode == VPX_VBR))) &&
(((mi->mv[0].as_mv.row | mi->mv[0].as_mv.col) & 0x07) != 0)) {int pf_rate[3];