Preserve the previous golden frame on golden updates

This commit restores the quality lost when the buffer-to-buffer copy
logic was removed. Note that this is specific to the current use of
golden frames and will need rework when RTC functionality is added.

Change-Id: I7324a75acd96eafd9e0f9b8633d782e390d5dc21

2 files changed, 14 insertions, 6 deletions

diff --git a/vp9/common/vp9_alloccommon.c b/vp9/common/vp9_alloccommon.c
index 895928b90..f2107d7aa 100644
--- a/vp9/common/vp9_alloccommon.c
+++ b/vp9/common/vp9_alloccommon.c
@@ -87,14 +87,16 @@ int vp9_alloc_frame_buffers(VP9_COMMON *oci, int width, int height) {
     }
   }
 
-  oci->new_fb_idx = 0;
+  oci->new_fb_idx = NUM_YV12_BUFFERS - 1;
+  oci->fb_idx_ref_cnt[oci->new_fb_idx] = 1;
+
   for (i = 0; i < 3; i++)
-    oci->active_ref_idx[i] = i + 1;
+    oci->active_ref_idx[i] = i;
 
-  oci->fb_idx_ref_cnt[0] = 1;
-  oci->fb_idx_ref_cnt[1] = 1;
-  oci->fb_idx_ref_cnt[2] = 1;
-  oci->fb_idx_ref_cnt[3] = 1;
+  for (i = 0; i < NUM_REF_FRAMES; i++) {
+    oci->ref_frame_map[i] = i;
+    oci->fb_idx_ref_cnt[i] = 1;
+  }
 
   if (vp8_yv12_alloc_frame_buffer(&oci->temp_scale_frame, width, 16,
                                   VP9BORDERINPIXELS) < 0) {
diff --git a/vp9/common/vp9_onyxc_int.h b/vp9/common/vp9_onyxc_int.h
index 46a9ff781..0f40e9faa 100644
--- a/vp9/common/vp9_onyxc_int.h
+++ b/vp9/common/vp9_onyxc_int.h
@@ -38,6 +38,7 @@ void vp9_initialize_common(void);
 #define QINDEX_RANGE (MAXQ + 1)
 
 #define NUM_REF_FRAMES 3
+#define NUM_REF_FRAMES_LG2 2
 #define NUM_YV12_BUFFERS (NUM_REF_FRAMES + 1)
 
 #define NUM_FRAME_CONTEXTS_LG2 2
@@ -147,6 +148,11 @@ typedef struct VP9Common {
 
   YV12_BUFFER_CONFIG yv12_fb[NUM_YV12_BUFFERS];
   int fb_idx_ref_cnt[NUM_YV12_BUFFERS]; /* reference counts */
+  int ref_frame_map[NUM_REF_FRAMES]; /* maps fb_idx to reference slot */
+
+  /* TODO(jkoleszar): could expand active_ref_idx to 4, with 0 as intra, and
+   * roll new_fb_idx into it.
+   */
   int active_ref_idx[3]; /* each frame can reference 3 buffers */
   int new_fb_idx;