Overhauling the thresholds and mixing proportions for mfqe postprocessor.

Makes the thresholds for the multiframe quality enhancement module
depend on the difference between the base quantizers. Also modifies
the mixing function to weigh the current low quality frame less if
the difference in quantizer is large. With the above modifications
mfqe works well for both scalable patterns as well as low quality
key frames.

Change-Id: If24e94f63f3c292f939eea94f627e7ebfb27cb75

1 files changed, 49 insertions, 45 deletions

diff --git a/vp8/common/postproc.c b/vp8/common/postproc.c
index cb81cb52a..d6223f493 100644
--- a/vp8/common/postproc.c
+++ b/vp8/common/postproc.c
@@ -714,7 +714,7 @@ static void multiframe_quality_enhance_block
          0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
     };
     int blksizeby2 = blksize >> 1;
-    int blksizesq = blksize * blksize;
+    int qdiff = qcurr - qprev;
 
     int i, j;
     unsigned char *yp;
@@ -727,27 +727,28 @@ static void multiframe_quality_enhance_block
     unsigned int act, sse, sad, thr;
     if (blksize == 16)
     {
-        act = vp8_variance_var16x16(y, y_stride, VP8_ZEROS, 0, &sse);
-        sad = vp8_variance_sad16x16(y, y_stride, yd, yd_stride, 0);
+        act = (vp8_variance_var16x16(yd, yd_stride, VP8_ZEROS, 0, &sse)+128)>>8;
+        sad = (vp8_variance_sad16x16(y, y_stride, yd, yd_stride, 0)+128)>>8;
     }
     else if (blksize == 8)
     {
-        act = vp8_variance_var8x8(y, y_stride, VP8_ZEROS, 0, &sse);
-        sad = vp8_variance_sad8x8(y, y_stride, yd, yd_stride, 0);
+        act = (vp8_variance_var8x8(yd, yd_stride, VP8_ZEROS, 0, &sse)+32)>>6;
+        sad = (vp8_variance_sad8x8(y, y_stride, yd, yd_stride, 0)+32)>>6;
     }
     else
     {
-        act = vp8_variance_var4x4(y, y_stride, VP8_ZEROS, 0, &sse);
-        sad = vp8_variance_sad4x4(y, y_stride, yd, yd_stride, 0);
+        act = (vp8_variance_var4x4(yd, yd_stride, VP8_ZEROS, 0, &sse)+8)>>4;
+        sad = (vp8_variance_sad4x4(y, y_stride, yd, yd_stride, 0)+8)>>4;
     }
-
-    thr = 6 * blksizesq + (act >> 3);
-    if (thr > 12 * blksizesq) thr = 12 * blksizesq;
-    // These thresholds should be adapted later based on qcurr and qprev
+    /* thr = qdiff/8 + log2(act) + log4(qprev) */
+    thr = (qdiff>>3);
+    while (act>>=1) thr++;
+    while (qprev>>=2) thr++;
     if (sad < thr)
     {
         static const int roundoff = (1 << (MFQE_PRECISION - 1));
         int ifactor = (sad << MFQE_PRECISION) / thr;
+        ifactor >>= (qdiff >> 5);
         // TODO: SIMD optimize this section
         if (ifactor)
         {
@@ -839,41 +840,44 @@ void vp8_multiframe_quality_enhance
             if (((frame_type == INTER_FRAME &&
                   abs(mode_info_context->mbmi.mv.as_mv.row) <= 10 &&
                   abs(mode_info_context->mbmi.mv.as_mv.col) <= 10) ||
-                 (frame_type == KEY_FRAME)) &&
-                mode_info_context->mbmi.mode != B_PRED)
-            {
-                multiframe_quality_enhance_block(16,
-                                                 qcurr,
-                                                 qprev,
-                                                 y_ptr,
-                                                 u_ptr,
-                                                 v_ptr,
-                                                 show->y_stride,
-                                                 show->uv_stride,
-                                                 yd_ptr,
-                                                 ud_ptr,
-                                                 vd_ptr,
-                                                 dest->y_stride,
-                                                 dest->uv_stride);
-            }
-            else if (mode_info_context->mbmi.mode == B_PRED)
+                 (frame_type == KEY_FRAME)))
             {
-                int i, j;
-                for (i=0; i<2; ++i)
-                    for (j=0; j<2; ++j)
-                        multiframe_quality_enhance_block(8,
-                                                         qcurr,
-                                                         qprev,
-                                                         y_ptr + 8*(i*show->y_stride+j),
-                                                         u_ptr + 4*(i*show->uv_stride+j),
-                                                         v_ptr + 4*(i*show->uv_stride+j),
-                                                         show->y_stride,
-                                                         show->uv_stride,
-                                                         yd_ptr + 8*(i*dest->y_stride+j),
-                                                         ud_ptr + 4*(i*dest->uv_stride+j),
-                                                         vd_ptr + 4*(i*dest->uv_stride+j),
-                                                         dest->y_stride,
-                                                         dest->uv_stride);
+                if (mode_info_context->mbmi.mode == B_PRED || mode_info_context->mbmi.mode == SPLITMV)
+                {
+                    int i, j;
+                    for (i=0; i<2; ++i)
+                        for (j=0; j<2; ++j)
+                            multiframe_quality_enhance_block(8,
+                                                             qcurr,
+                                                             qprev,
+                                                             y_ptr + 8*(i*show->y_stride+j),
+                                                             u_ptr + 4*(i*show->uv_stride+j),
+                                                             v_ptr + 4*(i*show->uv_stride+j),
+                                                             show->y_stride,
+                                                             show->uv_stride,
+                                                             yd_ptr + 8*(i*dest->y_stride+j),
+                                                             ud_ptr + 4*(i*dest->uv_stride+j),
+                                                             vd_ptr + 4*(i*dest->uv_stride+j),
+                                                             dest->y_stride,
+                                                             dest->uv_stride);
+                }
+                else
+                {
+                    multiframe_quality_enhance_block(16,
+                                                     qcurr,
+                                                     qprev,
+                                                     y_ptr,
+                                                     u_ptr,
+                                                     v_ptr,
+                                                     show->y_stride,
+                                                     show->uv_stride,
+                                                     yd_ptr,
+                                                     ud_ptr,
+                                                     vd_ptr,
+                                                     dest->y_stride,
+                                                     dest->uv_stride);
+
+                }
             }
             else
             {