Facilitation for VBR using LAP - Modify KF and GF group bits.

In case of single pass VBR using LAP, calculate kf_group_bits and
gf_group_bits based on average frame bandwidth.

Change-Id: Ia1c59b2a8dd888444ee7c927e586c453d65b597f

av1/encoder/pass2_strategy.c

diff --git a/av1/encoder/pass2_strategy.c b/av1/encoder/pass2_strategy.c
index 6adc1fb..0c73e99 100644
--- a/av1/encoder/pass2_strategy.c
+++ b/av1/encoder/pass2_strategy.c
@@ -704,6 +704,11 @@
   const int max_bits = frame_max_bits(rc, &cpi->oxcf);
   int64_t total_group_bits;
 
+  if (cpi->lap_enabled) {
+    total_group_bits = rc->avg_frame_bandwidth * rc->baseline_gf_interval;
+    return total_group_bits;
+  }
+
   // Calculate the bits to be allocated to the group as a whole.
   if ((twopass->kf_group_bits > 0) && (twopass->kf_group_error_left > 0)) {
     total_group_bits = (int64_t)(twopass->kf_group_bits *
@@ -2157,6 +2162,19 @@
   return frames_to_key;
 }
 
+static int64_t get_kf_group_bits(AV1_COMP *cpi, double kf_group_err) {
+  RATE_CONTROL *const rc = &cpi->rc;
+  TWO_PASS *const twopass = &cpi->twopass;
+  int64_t kf_group_bits;
+  if (cpi->lap_enabled)
+    kf_group_bits = (int64_t)(rc->frames_to_key * rc->avg_frame_bandwidth);
+  else
+    kf_group_bits = (int64_t)(twopass->bits_left *
+                              (kf_group_err / twopass->modified_error_left));
+
+  return kf_group_bits;
+}
+
 static void find_next_key_frame(AV1_COMP *cpi, FIRSTPASS_STATS *this_frame) {
   RATE_CONTROL *const rc = &cpi->rc;
   TWO_PASS *const twopass = &cpi->twopass;
@@ -2263,7 +2281,8 @@
   }
 
   // Calculate the number of bits that should be assigned to the kf group.
-  if (twopass->bits_left > 0 && twopass->modified_error_left > 0.0) {
+  if ((twopass->bits_left > 0 && twopass->modified_error_left > 0.0) ||
+      (cpi->lap_enabled && cpi->oxcf.rc_mode != AOM_Q)) {
     // Maximum number of bits for a single normal frame (not key frame).
     const int max_bits = frame_max_bits(rc, &cpi->oxcf);
 
@@ -2272,9 +2291,7 @@
 
     // Default allocation based on bits left and relative
     // complexity of the section.
-    twopass->kf_group_bits = (int64_t)(
-        twopass->bits_left * (kf_group_err / twopass->modified_error_left));
-
+    twopass->kf_group_bits = get_kf_group_bits(cpi, kf_group_err);
     // Clip based on maximum per frame rate defined by the user.
     max_grp_bits = (int64_t)max_bits * (int64_t)rc->frames_to_key;
     if (twopass->kf_group_bits > max_grp_bits)
@@ -2402,6 +2419,21 @@
 #endif
 #define DEFAULT_GRP_WEIGHT 1.0
 
+static int get_section_target_bandwidth(AV1_COMP *cpi) {
+  AV1_COMMON *const cm = &cpi->common;
+  CurrentFrame *const current_frame = &cm->current_frame;
+  RATE_CONTROL *const rc = &cpi->rc;
+  TWO_PASS *const twopass = &cpi->twopass;
+  int section_target_bandwidth;
+  const int frames_left = (int)(twopass->stats_buf_ctx->total_stats->count -
+                                current_frame->frame_number);
+  if (cpi->lap_enabled)
+    section_target_bandwidth = (int)rc->avg_frame_bandwidth;
+  else
+    section_target_bandwidth = (int)(twopass->bits_left / frames_left);
+  return section_target_bandwidth;
+}
+
 static void process_first_pass_stats(AV1_COMP *cpi,
                                      FIRSTPASS_STATS *this_frame) {
   AV1_COMMON *const cm = &cpi->common;
@@ -2420,12 +2452,8 @@
       *cpi->twopass.stats_buf_ctx->total_left_stats =
           *cpi->twopass.stats_buf_ctx->total_stats;
     }
-    const int frames_left = (int)(twopass->stats_buf_ctx->total_stats->count -
-                                  current_frame->frame_number);
-
     // Special case code for first frame.
-    const int section_target_bandwidth =
-        (int)(twopass->bits_left / frames_left);
+    const int section_target_bandwidth = get_section_target_bandwidth(cpi);
     const double section_length =
         twopass->stats_buf_ctx->total_left_stats->count;
     const double section_error =

av1/encoder/speed_features.c

diff --git a/av1/encoder/speed_features.c b/av1/encoder/speed_features.c
index 4a69840..e6d25f3 100644
--- a/av1/encoder/speed_features.c
+++ b/av1/encoder/speed_features.c
@@ -1213,7 +1213,8 @@
     sf->rd_sf.optimize_coefficients = NO_TRELLIS_OPT;
 
   // No recode or trellis for 1 pass.
-  if (oxcf->pass == 0) sf->hl_sf.recode_loop = DISALLOW_RECODE;
+  if (oxcf->pass == 0 && has_no_stats_stage(cpi))
+    sf->hl_sf.recode_loop = DISALLOW_RECODE;
 
   MotionVectorSearchParams *const mv_search_params = &cpi->mv_search_params;
   if (sf->mv_sf.subpel_search_method == SUBPEL_TREE) {