commit afaae0d15132161a9ef88ade6da9a27d8f9049eb
author jackychen <jackychen@google.com> Tue Apr 12 23:02:55 2016 -0700
committer Commit bot <commit-bot@chromium.org> Wed Apr 13 06:03:11 2016 +0000
tree ff00e52b534ad42b45bdbc292ac98dac44adab1b
parent a31fb75e4439b9f5b5b2b86cabb4bf3b97a5057a

External VNR speed improvement.

Improved visual quality with 3x times speed-up.
Change list:
 1. Remove second chance filter in temporal denoising filter to mitigate trailing artifact.
 2. Add swap buffer to save one whole-frame memcpy.
 3. Do noise estimation on every N blocks.
 4. Adopt a faster moving object detection algorithm (change the structure).
 5. Refactor the for loops and PositionCheck().
 6. Refactor the function ReduceFalseDetection (RFD).
 7. Fix a bug in TrailingBlock() which causes a mismatch.
 8. Change unit test to support swap buffer test.
 9. Remove CopyMem8x8, use memcpy to copy U/V plane which can be optimized future.
 10. Remove DenoiseMetrics.

Review URL: https://codereview.webrtc.org/1871853003

Cr-Commit-Position: refs/heads/master@{#12340}

webrtc/modules/video_processing/util/noise_estimation.cc

diff --git a/webrtc/modules/video_processing/util/noise_estimation.cc b/webrtc/modules/video_processing/util/noise_estimation.cc
index 87beac3..a0ae2c4 100644
--- a/webrtc/modules/video_processing/util/noise_estimation.cc
+++ b/webrtc/modules/video_processing/util/noise_estimation.cc
@@ -27,10 +27,10 @@
   consec_low_var_[mb_index]++;
   num_static_block_++;
   if (consec_low_var_[mb_index] >= kConsecLowVarFrame &&
-      (luma >> 8) < kAverageLumaMax && (luma >> 8) > kAverageLumaMin) {
+      (luma >> 6) < kAverageLumaMax && (luma >> 6) > kAverageLumaMin) {
     // Normalized var by the average luma value, this gives more weight to
     // darker blocks.
-    int nor_var = var / (luma >> 12);
+    int nor_var = var / (luma >> 10);
     noise_var_ +=
         nor_var > kBlockSelectionVarMax ? kBlockSelectionVarMax : nor_var;
     num_noisy_block_++;
@@ -46,25 +46,28 @@
   // condition more reasonable.
   // No enough samples implies the motion of the camera or too many moving
   // objects in the frame.
-  if (num_static_block_ < (0.65 * mb_cols_ * mb_rows_) || !num_noisy_block_) {
+  if (num_static_block_ <
+          (0.65 * mb_cols_ * mb_rows_ / NOISE_SUBSAMPLE_INTERVAL) ||
+      !num_noisy_block_) {
+#if DISPLAY
+    printf("Not enough samples. %d \n", num_static_block_);
+#endif
     noise_var_ = 0;
     noise_var_accum_ = 0;
-    num_static_block_ = 0;
     num_noisy_block_ = 0;
-#if DISPLAY
-    printf("Not enough samples.\n");
-#endif
+    num_static_block_ = 0;
     return;
   } else {
+#if DISPLAY
+    printf("%d %d fraction = %.3f\n", num_static_block_,
+           mb_cols_ * mb_rows_ / NOISE_SUBSAMPLE_INTERVAL,
+           percent_static_block_);
+#endif
     // Normalized by the number of noisy blocks.
     noise_var_ /= num_noisy_block_;
     // Get the percentage of static blocks.
-    percent_static_block_ =
-        static_cast<double>(num_static_block_) / (mb_cols_ * mb_rows_);
-#if DISPLAY
-    printf("%d %d fraction = %.3f\n", num_static_block_, mb_cols_ * mb_rows_,
-           percent_static_block_);
-#endif
+    percent_static_block_ = static_cast<double>(num_static_block_) /
+                            (mb_cols_ * mb_rows_ / NOISE_SUBSAMPLE_INTERVAL);
     num_noisy_block_ = 0;
     num_static_block_ = 0;
   }
@@ -75,12 +78,12 @@
   } else {
     noise_var_accum_ = (noise_var_accum_ * 15 + noise_var_) / 16;
   }
-  // Reset noise_var_ for the next frame.
-  noise_var_ = 0;
 #if DISPLAY
   printf("noise_var_accum_ = %.1f, noise_var_ = %d.\n", noise_var_accum_,
          noise_var_);
 #endif
+  // Reset noise_var_ for the next frame.
+  noise_var_ = 0;
 }
 
 uint8_t NoiseEstimation::GetNoiseLevel() {