Index: 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 |
new file mode 100644 |
index 0000000000000000000000000000000000000000..87beac38ae582e265fe35c0541aaf2c15b729179 |
--- /dev/null |
+++ b/webrtc/modules/video_processing/util/noise_estimation.cc |
@@ -0,0 +1,95 @@ |
+/* |
+ * Copyright (c) 2016 The WebRTC project authors. All Rights Reserved. |
+ * |
+ * Use of this source code is governed by a BSD-style license |
+ * that can be found in the LICENSE file in the root of the source |
+ * tree. An additional intellectual property rights grant can be found |
+ * in the file PATENTS. All contributing project authors may |
+ * be found in the AUTHORS file in the root of the source tree. |
+ */ |
+ |
+#include "webrtc/modules/video_processing/util/noise_estimation.h" |
+ |
+namespace webrtc { |
+ |
+void NoiseEstimation::Init(int width, int height, CpuType cpu_type) { |
+ int mb_cols = width >> 4; |
+ int mb_rows = height >> 4; |
+ consec_low_var_.reset(new uint32_t[mb_cols * mb_rows]()); |
+ width_ = width; |
+ height_ = height; |
+ mb_cols_ = width_ >> 4; |
+ mb_rows_ = height_ >> 4; |
+ cpu_type_ = cpu_type; |
+} |
+ |
+void NoiseEstimation::GetNoise(int mb_index, uint32_t var, uint32_t luma) { |
+ consec_low_var_[mb_index]++; |
+ num_static_block_++; |
+ if (consec_low_var_[mb_index] >= kConsecLowVarFrame && |
+ (luma >> 8) < kAverageLumaMax && (luma >> 8) > kAverageLumaMin) { |
+ // Normalized var by the average luma value, this gives more weight to |
+ // darker blocks. |
+ int nor_var = var / (luma >> 12); |
+ noise_var_ += |
+ nor_var > kBlockSelectionVarMax ? kBlockSelectionVarMax : nor_var; |
+ num_noisy_block_++; |
+ } |
+} |
+ |
+void NoiseEstimation::ResetConsecLowVar(int mb_index) { |
+ consec_low_var_[mb_index] = 0; |
+} |
+ |
+void NoiseEstimation::UpdateNoiseLevel() { |
+ // TODO(jackychen): Tune a threshold for numb_noisy_block > T to make the |
+ // 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_) { |
+ noise_var_ = 0; |
+ noise_var_accum_ = 0; |
+ num_static_block_ = 0; |
+ num_noisy_block_ = 0; |
+#if DISPLAY |
+ printf("Not enough samples.\n"); |
+#endif |
+ return; |
+ } else { |
+ // 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 |
+ num_noisy_block_ = 0; |
+ num_static_block_ = 0; |
+ } |
+ // For the first frame just update the value with current noise_var_, |
+ // otherwise, use the averaging window. |
+ if (noise_var_accum_ == 0) { |
+ noise_var_accum_ = noise_var_; |
+ } 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 |
+} |
+ |
+uint8_t NoiseEstimation::GetNoiseLevel() { |
+ int noise_thr = cpu_type_ ? kNoiseThreshold : kNoiseThresholdNeon; |
+ UpdateNoiseLevel(); |
+ if (noise_var_accum_ > noise_thr) { |
+ return 1; |
+ } |
+ return 0; |
+} |
+ |
+} // namespace webrtc |