shithub: libvpx

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Adopt weighted averaging in MFQE.

By using weighted averaging in the calculation of the frames to be
displayed, we get an average gain of more than 1 db for key frames
whose base qp are 20 higher than non-key frames.

Change-Id: I7bcb2e7b9c6420ea3f73f33204d18b072dffd17c

--- a/vp9/common/vp9_mfqe.c

+++ b/vp9/common/vp9_mfqe.c

@@ -167,10 +167,10 @@

   // it might be a lighting change in smooth area. When there is a

   // lighting change in smooth area, it is dangerous to do MFQE.

   if (sad > 1 && sad < sad_thr && vdiff > sad * 3 && vdiff < 150) {

-    // TODO(jackychen): Add weighted average in the calculation.

-    // Currently, the data is copied from last frame without averaging.

+    int weight = ((float)sad / (sad_thr - 1)) * ((float)vdiff / (150 - 1)) *

+                 (1 << MFQE_PRECISION);

     apply_ifactor(y, y_stride, yd, yd_stride, u, v, uv_stride,

-                  ud, vd, uvd_stride, bs, 0);

+                  ud, vd, uvd_stride, bs, weight);

   } else {

     // Copy the block from current frame (i.e., no mfqe is done).

     copy_block(y, u, v, y_stride, uv_stride, yd, ud, vd,