Rework two_pass_first_group_inter()

This function is used to in part decide if to trigger recode loop
for the first normal P frame in a GOP. Rework its design logic to
support the GOP with multi-layer ARF. Allow recode when there is
a transition from ARF/OVERLAY/USE_BUF to normal P frame.

The overall coding performance for multi-ARF gets slightly better
(less than 0.1% for show_existing_frame case). Tested on a few
clips, the encoding speed remains similar too. This change primarily
serves to help integration of multi-layer ARF and dual-ARF systems.

Change-Id: Ia44e44526b05029b1546985b3eb649e767d5444f

1 files changed, 6 insertions, 3 deletions

diff --git a/vp9/encoder/vp9_encoder.c b/vp9/encoder/vp9_encoder.c
index 69ab0445c..dae718b99 100644
--- a/vp9/encoder/vp9_encoder.c
+++ b/vp9/encoder/vp9_encoder.c
@@ -2921,9 +2921,12 @@ static int big_rate_miss(VP9_COMP *cpi) {
 static int two_pass_first_group_inter(VP9_COMP *cpi) {
   TWO_PASS *const twopass = &cpi->twopass;
   GF_GROUP *const gf_group = &twopass->gf_group;
-  if ((cpi->oxcf.pass == 2) &&
-      (gf_group->index == gf_group->first_inter_index)) {
-    return 1;
+  const int gfg_index = gf_group->index;
+
+  if (cpi->oxcf.pass == 2) {
+    if (gfg_index == 0) return gf_group->update_type[gfg_index] == LF_UPDATE;
+    return gf_group->update_type[gfg_index - 1] != LF_UPDATE &&
+           gf_group->update_type[gfg_index] == LF_UPDATE;
   } else {
     return 0;
   }