Re-factor some duplicate code.

Change-Id: I89a1dbea39c50c7633f746d9c93fec3a289f1b42

vp9/encoder/vp9_firstpass.c

diff --git a/vp9/encoder/vp9_firstpass.c b/vp9/encoder/vp9_firstpass.c
index 5c71a64..cde7ab9 100644
--- a/vp9/encoder/vp9_firstpass.c
+++ b/vp9/encoder/vp9_firstpass.c
@@ -1578,7 +1578,7 @@
 
     // Break out conditions.
     if (
-      // Break at cpi->max_gf_interval unless almost totally static.
+      // Break at active_max_gf_interval unless almost totally static.
       (i >= active_max_gf_interval && (zero_motion_accumulator < 0.995)) ||
       (
         // Don't break out with a very short interval.

vp9/encoder/vp9_ratectrl.c

diff --git a/vp9/encoder/vp9_ratectrl.c b/vp9/encoder/vp9_ratectrl.c
index 9ad8517..38eec88 100644
--- a/vp9/encoder/vp9_ratectrl.c
+++ b/vp9/encoder/vp9_ratectrl.c
@@ -1390,6 +1390,24 @@
   return target_index - qindex;
 }
 
+void vp9_rc_set_gf_max_interval(const VP9EncoderConfig *const oxcf,
+                                RATE_CONTROL *const rc) {
+  // Set Maximum gf/arf interval
+  rc->max_gf_interval = 16;
+
+  // Extended interval for genuinely static scenes
+  rc->static_scene_max_gf_interval = oxcf->key_freq >> 1;
+
+  // Special conditions when alt ref frame enabled
+  if (oxcf->play_alternate && oxcf->lag_in_frames) {
+    if (rc->static_scene_max_gf_interval > oxcf->lag_in_frames - 1)
+      rc->static_scene_max_gf_interval = oxcf->lag_in_frames - 1;
+  }
+
+  if (rc->max_gf_interval > rc->static_scene_max_gf_interval)
+    rc->max_gf_interval = rc->static_scene_max_gf_interval;
+}
+
 void vp9_rc_update_framerate(VP9_COMP *cpi) {
   const VP9_COMMON *const cm = &cpi->common;
   const VP9EncoderConfig *const oxcf = &cpi->oxcf;
@@ -1414,21 +1432,5 @@
   rc->max_frame_bandwidth = MAX(MAX((cm->MBs * MAX_MB_RATE), MAXRATE_1080P),
                                     vbr_max_bits);
 
-  // Set Maximum gf/arf interval
-  rc->max_gf_interval = 16;
-
-  // Extended interval for genuinely static scenes
-  rc->static_scene_max_gf_interval = cpi->oxcf.key_freq >> 1;
-
-  // Special conditions when alt ref frame enabled in lagged compress mode
-  if (oxcf->play_alternate && oxcf->lag_in_frames) {
-    if (rc->max_gf_interval > oxcf->lag_in_frames - 1)
-      rc->max_gf_interval = oxcf->lag_in_frames - 1;
-
-    if (rc->static_scene_max_gf_interval > oxcf->lag_in_frames - 1)
-      rc->static_scene_max_gf_interval = oxcf->lag_in_frames - 1;
-  }
-
-  if (rc->max_gf_interval > rc->static_scene_max_gf_interval)
-    rc->max_gf_interval = rc->static_scene_max_gf_interval;
+  vp9_rc_set_gf_max_interval(oxcf, rc);
 }

vp9/encoder/vp9_ratectrl.h

diff --git a/vp9/encoder/vp9_ratectrl.h b/vp9/encoder/vp9_ratectrl.h
index b1cc676..75e31e3 100644
--- a/vp9/encoder/vp9_ratectrl.h
+++ b/vp9/encoder/vp9_ratectrl.h
@@ -178,6 +178,9 @@
 
 void vp9_rc_update_framerate(struct VP9_COMP *cpi);
 
+void vp9_rc_set_gf_max_interval(const struct VP9EncoderConfig *const oxcf,
+                                RATE_CONTROL *const rc);
+
 #ifdef __cplusplus
 }  // extern "C"
 #endif

vp9/encoder/vp9_svc_layercontext.c

diff --git a/vp9/encoder/vp9_svc_layercontext.c b/vp9/encoder/vp9_svc_layercontext.c
index 48aa64c..97241db 100644
--- a/vp9/encoder/vp9_svc_layercontext.c
+++ b/vp9/encoder/vp9_svc_layercontext.c
@@ -150,20 +150,7 @@
                                    oxcf->two_pass_vbrmin_section / 100);
   lrc->max_frame_bandwidth = (int)(((int64_t)lrc->avg_frame_bandwidth *
                                    oxcf->two_pass_vbrmax_section) / 100);
-  lrc->max_gf_interval = 16;
-
-  lrc->static_scene_max_gf_interval = cpi->oxcf.key_freq >> 1;
-
-  if (oxcf->play_alternate && oxcf->lag_in_frames) {
-    if (lrc->max_gf_interval > oxcf->lag_in_frames - 1)
-      lrc->max_gf_interval = oxcf->lag_in_frames - 1;
-
-    if (lrc->static_scene_max_gf_interval > oxcf->lag_in_frames - 1)
-      lrc->static_scene_max_gf_interval = oxcf->lag_in_frames - 1;
-  }
-
-  if (lrc->max_gf_interval > lrc->static_scene_max_gf_interval)
-    lrc->max_gf_interval = lrc->static_scene_max_gf_interval;
+  vp9_rc_set_gf_max_interval(oxcf, lrc);
 }
 
 void vp9_restore_layer_context(VP9_COMP *const cpi) {