vp9-rtc: Fixes to resizer for real-timem84-4147

Reduce the time before sampling begins (after key)
and reduce averaging window, to make resize act
faster.

Reset RC paramaters for temporal layers on resize.

Add per-frame-bandwidth thresholds to force
downsize for extreme case, for HD input.

Bug: 1097494

Change-Id: I8e08580b2216a2e6981502552025370703cd206c
(cherry picked from commit e9c6cb64744f6df31ba52501d4759b50ba832df2)

2 files changed, 33 insertions, 6 deletions

diff --git a/test/resize_test.cc b/test/resize_test.cc
index d996cbe1b..a2dc5d7a7 100644
--- a/test/resize_test.cc
+++ b/test/resize_test.cc
@@ -672,11 +672,11 @@ TEST_P(ResizeRealtimeTest, TestInternalResizeDownUpChangeBitRate) {
     ASSERT_EQ(info->h, GetFrameHeight(idx));
     if (info->w != last_w || info->h != last_h) {
       resize_count++;
-      if (resize_count == 1) {
+      if (resize_count <= 2) {
         // Verify that resize down occurs.
         ASSERT_LT(info->w, last_w);
         ASSERT_LT(info->h, last_h);
-      } else if (resize_count == 2) {
+      } else if (resize_count > 2) {
         // Verify that resize up occurs.
         ASSERT_GT(info->w, last_w);
         ASSERT_GT(info->h, last_h);
@@ -687,8 +687,8 @@ TEST_P(ResizeRealtimeTest, TestInternalResizeDownUpChangeBitRate) {
   }
 
 #if CONFIG_VP9_DECODER
-  // Verify that we get 2 resize events in this test.
-  ASSERT_EQ(resize_count, 2) << "Resizing should occur twice.";
+  // Verify that we get 4 resize events in this test.
+  ASSERT_EQ(resize_count, 4) << "Resizing should occur twice.";
   EXPECT_EQ(static_cast<unsigned int>(0), GetMismatchFrames());
 #else
   printf("Warning: VP9 decoder unavailable, unable to check resize count!\n");
diff --git a/vp9/encoder/vp9_ratectrl.c b/vp9/encoder/vp9_ratectrl.c
index 5dd745f3a..9debc01ef 100644
--- a/vp9/encoder/vp9_ratectrl.c
+++ b/vp9/encoder/vp9_ratectrl.c
@@ -2385,6 +2385,11 @@ void vp9_rc_get_svc_params(VP9_COMP *cpi) {
             cpi->resize_scale_num * lc->scaling_factor_num;
         lc->scaling_factor_den_resize =
             cpi->resize_scale_den * lc->scaling_factor_den;
+        // Reset rate control for all temporal layers.
+        lc->rc.buffer_level = lc->rc.optimal_buffer_level;
+        lc->rc.bits_off_target = lc->rc.optimal_buffer_level;
+        lc->rc.rate_correction_factors[INTER_FRAME] =
+            rc->rate_correction_factors[INTER_FRAME];
       }
       // Set the size for this current temporal layer.
       lc = &svc->layer_context[svc->spatial_layer_id *
@@ -2657,6 +2662,7 @@ int vp9_resize_one_pass_cbr(VP9_COMP *cpi) {
   int min_width = (320 * 4) / 3;
   int min_height = (180 * 4) / 3;
   int down_size_on = 1;
+  int force_downsize_rate = 0;
   cpi->resize_scale_num = 1;
   cpi->resize_scale_den = 1;
   // Don't resize on key frame; reset the counters on key frame.
@@ -2677,10 +2683,31 @@ int vp9_resize_one_pass_cbr(VP9_COMP *cpi) {
   }
 #endif
 
+  // Force downsize based on per-frame-bandwidth, for extreme case,
+  // for HD input.
+  if (cpi->resize_state == ORIG && cm->width * cm->height >= 1280 * 720) {
+    if (rc->avg_frame_bandwidth < (int)(300000 / 30)) {
+      resize_action = DOWN_ONEHALF;
+      cpi->resize_state = ONE_HALF;
+      force_downsize_rate = 1;
+    } else if (rc->avg_frame_bandwidth < (int)(400000 / 30)) {
+      resize_action = ONEHALFONLY_RESIZE ? DOWN_ONEHALF : DOWN_THREEFOUR;
+      cpi->resize_state = ONEHALFONLY_RESIZE ? ONE_HALF : THREE_QUARTER;
+      force_downsize_rate = 1;
+    }
+  } else if (cpi->resize_state == THREE_QUARTER &&
+             cm->width * cm->height >= 960 * 540) {
+    if (rc->avg_frame_bandwidth < (int)(300000 / 30)) {
+      resize_action = DOWN_ONEHALF;
+      cpi->resize_state = ONE_HALF;
+      force_downsize_rate = 1;
+    }
+  }
+
   // Resize based on average buffer underflow and QP over some window.
   // Ignore samples close to key frame, since QP is usually high after key.
-  if (cpi->rc.frames_since_key > 2 * cpi->framerate) {
-    const int window = (int)(4 * cpi->framerate);
+  if (!force_downsize_rate && cpi->rc.frames_since_key > cpi->framerate) {
+    const int window = VPXMIN(30, (int)(2 * cpi->framerate));
     cpi->resize_avg_qp += cm->base_qindex;
     if (cpi->rc.buffer_level < (int)(30 * rc->optimal_buffer_level / 100))
       ++cpi->resize_buffer_underflow;