Ext RC: Only advance GOP on second define_gf_group

define_gf_group() is called twice in av1_get_second_pass_params()
with is_final_pass being 0 and 1 separately. This caused ext RC to
advance 2 GOPs which is wrong.

Change-Id: I19ccbe3b95541029e8d2a1199b9942d3b1470e00

av1/encoder/gop_structure.c

diff --git a/av1/encoder/gop_structure.c b/av1/encoder/gop_structure.c
index a366d1f..079b8ea 100644
--- a/av1/encoder/gop_structure.c
+++ b/av1/encoder/gop_structure.c
@@ -873,7 +873,7 @@
   }
 }
 
-void av1_gop_setup_structure(AV1_COMP *cpi) {
+void av1_gop_setup_structure(AV1_COMP *cpi, const int is_final_pass) {
   RATE_CONTROL *const rc = &cpi->rc;
   PRIMARY_RATE_CONTROL *const p_rc = &cpi->ppi->p_rc;
   GF_GROUP *const gf_group = &cpi->ppi->gf_group;
@@ -882,9 +882,12 @@
   const int key_frame = rc->frames_since_key == 0;
   FRAME_UPDATE_TYPE first_frame_update_type = ARF_UPDATE;
 
+  // define_gf_group() is called twice in av1_set_second_pass_params() with
+  // `is_final_pass` being 0 and 1 separately. But only one GOP can be advanced
+  // with the external RC. That is only done when `is_final_pass` is true.
   if (cpi->ext_ratectrl.ready &&
       (cpi->ext_ratectrl.funcs.rc_type & AOM_RC_GOP) != 0 &&
-      cpi->ext_ratectrl.funcs.get_gop_decision != NULL) {
+      cpi->ext_ratectrl.funcs.get_gop_decision != NULL && is_final_pass) {
     aom_rc_gop_decision_t gop_decision;
     aom_codec_err_t codec_status =
         av1_extrc_get_gop_decision(&cpi->ext_ratectrl, &gop_decision);

av1/encoder/gop_structure.h

diff --git a/av1/encoder/gop_structure.h b/av1/encoder/gop_structure.h
index 92380ab..14ef5bf 100644
--- a/av1/encoder/gop_structure.h
+++ b/av1/encoder/gop_structure.h
@@ -36,11 +36,13 @@
  * the group. It does this primarily by updateing entries in
  * cpi->twopass.gf_group.update_type[].
  *
- * \param[in]    cpi          Top - level encoder instance structure
+ * \param[in]    cpi            Top - level encoder instance structure
+ * \param[in]    is_final_pass  Whether it is the second call to
+ *                              define_gf_group().
  *
  * \remark No return value but this function updates group data structures.
  */
-void av1_gop_setup_structure(struct AV1_COMP *cpi);
+void av1_gop_setup_structure(struct AV1_COMP *cpi, const int is_final_pass);
 
 /*!\brief Check whether a frame in the GOP is a forward key frame
  *

av1/encoder/pass2_strategy.c

diff --git a/av1/encoder/pass2_strategy.c b/av1/encoder/pass2_strategy.c
index 202ebae..be22b63 100644
--- a/av1/encoder/pass2_strategy.c
+++ b/av1/encoder/pass2_strategy.c
@@ -2179,10 +2179,12 @@
  * case of one pass encoding where no lookahead stats are avialable.
  *
  * \param[in]    cpi             Top-level encoder structure
+ * \param[in]    is_final_pass   Whether it is the second call to
+ *                               define_gf_group().
  *
  * \remark Nothing is returned. Instead, cpi->ppi->gf_group is changed.
  */
-static void define_gf_group_pass0(AV1_COMP *cpi) {
+static void define_gf_group_pass0(AV1_COMP *cpi, const int is_final_pass) {
   RATE_CONTROL *const rc = &cpi->rc;
   PRIMARY_RATE_CONTROL *const p_rc = &cpi->ppi->p_rc;
   GF_GROUP *const gf_group = &cpi->ppi->gf_group;
@@ -2220,7 +2222,7 @@
     gf_group->max_layer_depth_allowed = 0;
 
   // Set up the structure of this Group-Of-Pictures (same as GF_GROUP)
-  av1_gop_setup_structure(cpi);
+  av1_gop_setup_structure(cpi, is_final_pass);
 
   // Allocate bits to each of the frames in the GF group.
   // TODO(sarahparker) Extend this to work with pyramid structure.
@@ -2544,7 +2546,7 @@
   }
 
   if (has_no_stats_stage(cpi)) {
-    define_gf_group_pass0(cpi);
+    define_gf_group_pass0(cpi, is_final_pass);
     return;
   }
 
@@ -2645,7 +2647,7 @@
   update_gop_length(rc, p_rc, i, is_final_pass);
 
   // Set up the structure of this Group-Of-Pictures (same as GF_GROUP)
-  av1_gop_setup_structure(cpi);
+  av1_gop_setup_structure(cpi, is_final_pass);
 
   set_gop_bits_boost(cpi, i, is_intra_only, is_final_pass, use_alt_ref,
                      alt_offset, start_pos, &gf_stats);
@@ -2721,7 +2723,7 @@
   update_gop_length(rc, p_rc, i, is_final_pass);
 
   // Set up the structure of this Group-Of-Pictures (same as GF_GROUP)
-  av1_gop_setup_structure(cpi);
+  av1_gop_setup_structure(cpi, is_final_pass);
 
   set_gop_bits_boost(cpi, i, is_intra_only, is_final_pass, use_alt_ref, 0,
                      start_pos, &gf_stats);