commit ea72639373c664746453c13d036032f5975c6136
author Yunqing Wang <yunqingwang@google.com> Wed Jan 18 15:41:16 2023 -0800
committer Yunqing Wang <yunqingwang@google.com> Fri Jan 20 04:37:15 2023 +0000
tree 66e079cdcd8fa27021897e447ebdb328f30b4c06
parent 6ebcbc15a1bfbae00af78e5050855be45a2c9452

Improve frame interpolation filter resetting

In current code base, the frame interpolation filter is allowed to be
reset only for EIGHTTAP_REGULAR filter type. This condition is overly
strict and would miss opportunities for bit saving. This CL modifies
the way that the filter type counts are recorded to ensure the correct
frame filter type resetting decision, and also loosens the condition
for frame filter resetting. This change will help some RTC encoding,
which will be implemented in the following CL.

STATS_CHANGED

Change-Id: I34e7e0faffcb80344468294c0b59cc03e1e6d58c

av1/encoder/encodeframe_utils.c

diff --git a/av1/encoder/encodeframe_utils.c b/av1/encoder/encodeframe_utils.c
index c478ef6..80b0f3c 100644
--- a/av1/encoder/encodeframe_utils.c
+++ b/av1/encoder/encodeframe_utils.c
@@ -193,6 +193,9 @@
   for (dir = 0; dir < 2; ++dir) {
     const int ctx = av1_get_pred_context_switchable_interp(xd, dir);
     InterpFilter filter = av1_extract_interp_filter(mbmi->interp_filters, dir);
+
+    // Only allow the 3 valid SWITCHABLE_FILTERS.
+    assert(filter < SWITCHABLE_FILTERS);
     ++counts->switchable_interp[ctx][filter];
   }
 }
@@ -369,9 +372,12 @@
   }
 #endif
   if (!frame_is_intra_only(cm)) {
-    if (cm->features.interp_filter == SWITCHABLE &&
-        mi_addr->motion_mode != WARPED_CAUSAL &&
-        !is_nontrans_global_motion(xd, xd->mi[0])) {
+    if (is_inter_block(mi) && cm->features.interp_filter == SWITCHABLE) {
+      // When the frame interp filter is SWITCHABLE, several cases that always
+      // use the default type (EIGHTTAP_REGULAR) are described in
+      // av1_is_interp_needed(). Here, we should keep the counts for all
+      // applicable blocks, so the frame filter resetting decision in
+      // fix_interp_filter() is made correctly.
       update_filter_type_count(td->counts, xd, mi_addr);
     }
   }

av1/encoder/encoder_utils.c

diff --git a/av1/encoder/encoder_utils.c b/av1/encoder/encoder_utils.c
index e2240cd..3181b78 100644
--- a/av1/encoder/encoder_utils.c
+++ b/av1/encoder/encoder_utils.c
@@ -1121,7 +1121,7 @@
       // Only one filter is used. So set the filter at frame level
       for (int i = 0; i < SWITCHABLE_FILTERS; ++i) {
         if (count[i]) {
-          if (i == EIGHTTAP_REGULAR) *interp_filter = i;
+          *interp_filter = i;
           break;
         }
       }
@@ -1171,7 +1171,8 @@
     }
   }
 
-  fix_interp_filter(&cm->features.interp_filter, cpi->td.counts);
+  if (!frame_is_intra_only(cm))
+    fix_interp_filter(&cm->features.interp_filter, cpi->td.counts);
 }
 
 int av1_is_integer_mv(const YV12_BUFFER_CONFIG *cur_picture,