Remove refresh_last_frame flag

refresh_last_frame flag is present in both AV1_COMP
and EncodeFrameParams structs, and is unused. This CL
removes the flag from both the structures.

BUG=aomedia:2610

Change-Id: Ib55cddef18ae3e9333f639631081dfc7d25746f9

av1/encoder/encode_strategy.c

diff --git a/av1/encoder/encode_strategy.c b/av1/encoder/encode_strategy.c
index 4791e55..3bba79a 100644
--- a/av1/encoder/encode_strategy.c
+++ b/av1/encoder/encode_strategy.c
@@ -47,28 +47,24 @@
 
   switch (type) {
     case KF_UPDATE:
-      frame_params->refresh_last_frame = 1;
       frame_params->refresh_golden_frame = 1;
       frame_params->refresh_bwd_ref_frame = 1;
       frame_params->refresh_alt_ref_frame = 1;
       break;
 
     case LF_UPDATE:
-      frame_params->refresh_last_frame = 1;
       frame_params->refresh_golden_frame = 0;
       frame_params->refresh_bwd_ref_frame = 0;
       frame_params->refresh_alt_ref_frame = 0;
       break;
 
     case GF_UPDATE:
-      frame_params->refresh_last_frame = 0;
       frame_params->refresh_golden_frame = 1;
       frame_params->refresh_bwd_ref_frame = 0;
       frame_params->refresh_alt_ref_frame = 0;
       break;
 
     case OVERLAY_UPDATE:
-      frame_params->refresh_last_frame = 0;
       frame_params->refresh_golden_frame = 1;
       frame_params->refresh_bwd_ref_frame = 0;
       frame_params->refresh_alt_ref_frame = 0;
@@ -77,7 +73,6 @@
       break;
 
     case ARF_UPDATE:
-      frame_params->refresh_last_frame = 0;
       frame_params->refresh_golden_frame = 0;
       // NOTE: BWDREF does not get updated along with ALTREF_FRAME.
       frame_params->refresh_bwd_ref_frame = 0;
@@ -85,7 +80,6 @@
       break;
 
     case INTNL_OVERLAY_UPDATE:
-      frame_params->refresh_last_frame = 1;
       frame_params->refresh_golden_frame = 0;
       frame_params->refresh_bwd_ref_frame = 0;
       frame_params->refresh_alt_ref_frame = 0;
@@ -94,7 +88,6 @@
       break;
 
     case INTNL_ARF_UPDATE:
-      frame_params->refresh_last_frame = 0;
       frame_params->refresh_golden_frame = 0;
       frame_params->refresh_bwd_ref_frame = 1;
       frame_params->refresh_alt_ref_frame = 0;
@@ -105,14 +98,12 @@
 
   if (cpi->ext_refresh_frame_flags_pending &&
       (!is_stat_generation_stage(cpi))) {
-    frame_params->refresh_last_frame = cpi->ext_refresh_last_frame;
     frame_params->refresh_golden_frame = cpi->ext_refresh_golden_frame;
     frame_params->refresh_alt_ref_frame = cpi->ext_refresh_alt_ref_frame;
     frame_params->refresh_bwd_ref_frame = cpi->ext_refresh_bwd_ref_frame;
   }
 
   if (force_refresh_all) {
-    frame_params->refresh_last_frame = 1;
     frame_params->refresh_golden_frame = 1;
     frame_params->refresh_bwd_ref_frame = 1;
     frame_params->refresh_alt_ref_frame = 1;

av1/encoder/encoder.c

diff --git a/av1/encoder/encoder.c b/av1/encoder/encoder.c
index dfb7fa9..d5435ee 100644
--- a/av1/encoder/encoder.c
+++ b/av1/encoder/encoder.c
@@ -2838,7 +2838,6 @@
     rc->baseline_gf_interval = (MIN_GF_INTERVAL + MAX_GF_INTERVAL) / 2;
   }
 
-  cpi->refresh_last_frame = 1;
   cpi->refresh_golden_frame = 0;
   cpi->refresh_bwd_ref_frame = 0;
 
@@ -6515,7 +6514,6 @@
   memcpy(cm->remapped_ref_idx, frame_params->remapped_ref_idx,
          REF_FRAMES * sizeof(*cm->remapped_ref_idx));
 
-  cpi->refresh_last_frame = frame_params->refresh_last_frame;
   cpi->refresh_golden_frame = frame_params->refresh_golden_frame;
   cpi->refresh_bwd_ref_frame = frame_params->refresh_bwd_ref_frame;
   cpi->refresh_alt_ref_frame = frame_params->refresh_alt_ref_frame;

av1/encoder/encoder.h

diff --git a/av1/encoder/encoder.h b/av1/encoder/encoder.h
index 628ca9a..cd41b76 100644
--- a/av1/encoder/encoder.h
+++ b/av1/encoder/encoder.h
@@ -872,14 +872,8 @@
   // after the current frame is encoded, the XYZ reference frame gets refreshed
   // (updated) to be the current frame.
   //
-  // Special case: 'refresh_last_frame' specifies that:
-  // - LAST_FRAME reference should be updated to be the current frame (as usual)
-  // - Also, LAST2_FRAME and LAST3_FRAME references are implicitly updated to be
-  // the two past reference frames just before LAST_FRAME that are available.
-  //
   // Note: Usually at most one of these refresh flags is true at a time.
   // But a key-frame is special, for which all the flags are true at once.
-  int refresh_last_frame;
   int refresh_golden_frame;
   int refresh_bwd_ref_frame;
   int refresh_alt_ref_frame;
@@ -1223,7 +1217,6 @@
   int remapped_ref_idx[REF_FRAMES];
 
   // Flags which determine which reference buffers are refreshed by this frame
-  int refresh_last_frame;
   int refresh_golden_frame;
   int refresh_bwd_ref_frame;
   int refresh_alt_ref_frame;

av1/encoder/tpl_model.c

diff --git a/av1/encoder/tpl_model.c b/av1/encoder/tpl_model.c
index b722c7b..f06708c 100644
--- a/av1/encoder/tpl_model.c
+++ b/av1/encoder/tpl_model.c
@@ -979,7 +979,6 @@
     av1_configure_buffer_updates(cpi, &this_frame_params,
                                  gf_group->update_type[gf_index], 0);
 
-    cpi->refresh_last_frame = this_frame_params.refresh_last_frame;
     cpi->refresh_golden_frame = this_frame_params.refresh_golden_frame;
     cpi->refresh_bwd_ref_frame = this_frame_params.refresh_bwd_ref_frame;
     cpi->refresh_alt_ref_frame = this_frame_params.refresh_alt_ref_frame;