Rework frame context selection
Make the primary reference frame selection dependent on the GOP
layer depth. Remove the dependency on frame update types.
It changes the coding stats. Tested in speed 0 and 1, the compression
performance is improved by 0.05% - 0.09% across different test sets.
STATS_CHANGED
Change-Id: I1ab3dc51afc6902809a4aab2f151eefe8b040f03
diff --git a/av1/encoder/encode_strategy.c b/av1/encoder/encode_strategy.c
index 281d871..d6dc11d 100644
--- a/av1/encoder/encode_strategy.c
+++ b/av1/encoder/encode_strategy.c
@@ -365,23 +365,17 @@
// just used to choose the primary_ref_frame (as the most recent reference
// buffer of the same reference-type as the current frame)
- const int intra_only = frame_params->frame_type == KEY_FRAME ||
- frame_params->frame_type == INTRA_ONLY_FRAME;
- if (intra_only || frame_params->error_resilient_mode ||
- cpi->ext_use_primary_ref_none)
- return REGULAR_FRAME;
- else if (get_frame_update_type(cpi) == INTNL_ARF_UPDATE)
- return INTERNAL_ARF_FRAME;
- else if (frame_params->refresh_alt_ref_frame)
- return ARF_FRAME;
- else if (cpi->rc.is_src_frame_alt_ref)
- return OVERLAY_FRAME;
- else if (frame_params->refresh_golden_frame)
- return GLD_FRAME;
- else if (frame_params->refresh_bwd_ref_frame)
- return BRF_FRAME;
- else
- return REGULAR_FRAME;
+ (void)frame_params;
+ // TODO(jingning): This table should be a lot simpler with the new
+ // ARF system in place. Keep frame_params for the time being as we are
+ // still evaluating a few design options.
+ switch (cpi->gf_group.layer_depth[cpi->gf_group.index]) {
+ case 0: return 0;
+ case 1: return 1;
+ case MAX_ARF_LAYERS:
+ case MAX_ARF_LAYERS + 1: return 4;
+ default: return 7;
+ }
}
static int choose_primary_ref_frame(
@@ -397,7 +391,7 @@
// Find the most recent reference frame with the same reference type as the
// current frame
- const FRAME_CONTEXT_INDEX current_ref_type =
+ FRAME_CONTEXT_INDEX current_ref_type =
get_current_frame_ref_type(cpi, frame_params);
int wanted_fb = cpi->fb_of_context_type[current_ref_type];
@@ -407,6 +401,7 @@
primary_ref_frame = ref_frame - LAST_FRAME;
}
}
+
return primary_ref_frame;
}
@@ -414,13 +409,15 @@
const AV1_COMP *const cpi, const EncodeFrameParams *const frame_params,
int *const fb_of_context_type) {
const AV1_COMMON *const cm = &cpi->common;
+ const int current_frame_ref_type =
+ get_current_frame_ref_type(cpi, frame_params);
if (frame_is_intra_only(cm) || cm->error_resilient_mode ||
cpi->ext_use_primary_ref_none) {
for (int i = 0; i < REF_FRAMES; i++) {
fb_of_context_type[i] = -1;
}
- fb_of_context_type[REGULAR_FRAME] =
+ fb_of_context_type[current_frame_ref_type] =
cm->show_frame ? get_ref_frame_map_idx(cm, GOLDEN_FRAME)
: get_ref_frame_map_idx(cm, ALTREF_FRAME);
}
@@ -429,12 +426,11 @@
// Refresh fb_of_context_type[]: see encoder.h for explanation
if (cm->current_frame.frame_type == KEY_FRAME) {
// All ref frames are refreshed, pick one that will live long enough
- fb_of_context_type[REGULAR_FRAME] = 0;
+ fb_of_context_type[current_frame_ref_type] = 0;
} else {
// If more than one frame is refreshed, it doesn't matter which one we
// pick so pick the first. LST sometimes doesn't refresh any: this is ok
- const int current_frame_ref_type =
- get_current_frame_ref_type(cpi, frame_params);
+
for (int i = 0; i < REF_FRAMES; i++) {
if (cm->current_frame.refresh_frame_flags & (1 << i)) {
fb_of_context_type[current_frame_ref_type] = i;
diff --git a/av1/encoder/firstpass.h b/av1/encoder/firstpass.h
index cfee3a8..9c02849 100644
--- a/av1/encoder/firstpass.h
+++ b/av1/encoder/firstpass.h
@@ -131,6 +131,9 @@
int ref_frame_gop_idx[MAX_STATIC_GF_GROUP_LENGTH][REF_FRAMES];
unsigned char pyramid_height;
unsigned char pyramid_lvl_nodes[MAX_PYRAMID_LVL];
+
+ // TODO(jingning): Unify the data structure used here after the new control
+ // mechanism is in place.
int layer_depth[MAX_STATIC_GF_GROUP_LENGTH];
// This is currently only populated for AOM_Q mode
unsigned char q_val[MAX_STATIC_GF_GROUP_LENGTH];
diff --git a/av1/encoder/gop_structure.c b/av1/encoder/gop_structure.c
index df7ef23..eb4f3a8 100644
--- a/av1/encoder/gop_structure.c
+++ b/av1/encoder/gop_structure.c
@@ -96,12 +96,14 @@
assert(first_frame_update_type == KF_UPDATE ||
first_frame_update_type == OVERLAY_UPDATE ||
first_frame_update_type == GF_UPDATE);
+
gf_group->update_type[frame_index] = first_frame_update_type;
gf_group->arf_src_offset[frame_index] = 0;
gf_group->arf_pos_in_gf[frame_index] = 0;
gf_group->arf_update_idx[frame_index] = 0;
gf_group->pyramid_level[frame_index] = MIN_PYRAMID_LVL;
- gf_group->layer_depth[frame_index] = 0;
+ gf_group->layer_depth[frame_index] =
+ first_frame_update_type == OVERLAY_UPDATE ? MAX_ARF_LAYERS + 1 : 0;
++frame_index;
// ALTREF.
