If the array size is even, the median should be average of its two middlemost elements.
NADA unittests updated accordingly.
BUG=webrtc:4550
R=stefan@webrtc.org
Review URL: https://codereview.webrtc.org/1246083006 .
Cr-Commit-Position: refs/heads/master@{#9607}
diff --git a/webrtc/modules/remote_bitrate_estimator/test/estimators/nada.cc b/webrtc/modules/remote_bitrate_estimator/test/estimators/nada.cc
index 2500679..d77447f 100644
--- a/webrtc/modules/remote_bitrate_estimator/test/estimators/nada.cc
+++ b/webrtc/modules/remote_bitrate_estimator/test/estimators/nada.cc
@@ -124,12 +124,20 @@
derivative, RecentKbps(), corrected_send_time_ms);
}
+// If size is even, the median is the average of the two middlemost numbers.
int64_t NadaBweReceiver::MedianFilter(int64_t* last_delays_ms, int size) {
- // Typically, size = 5.
std::vector<int64_t> array_copy(last_delays_ms, last_delays_ms + size);
std::nth_element(array_copy.begin(), array_copy.begin() + size / 2,
array_copy.end());
- return array_copy.at(size / 2);
+ if (size % 2 == 1) {
+ // Typically, size = 5. For odd size values, right and left are equal.
+ return array_copy.at(size / 2);
+ }
+ int64_t right = array_copy.at(size / 2);
+ std::nth_element(array_copy.begin(), array_copy.begin() + (size - 1) / 2,
+ array_copy.end());
+ int64_t left = array_copy.at((size - 1) / 2);
+ return (left + right + 1) / 2;
}
int64_t NadaBweReceiver::ExponentialSmoothingFilter(int64_t new_value,
diff --git a/webrtc/modules/remote_bitrate_estimator/test/estimators/nada_unittest.cc b/webrtc/modules/remote_bitrate_estimator/test/estimators/nada_unittest.cc
index 8076896..a0f56b7 100644
--- a/webrtc/modules/remote_bitrate_estimator/test/estimators/nada_unittest.cc
+++ b/webrtc/modules/remote_bitrate_estimator/test/estimators/nada_unittest.cc
@@ -356,7 +356,7 @@
// Raw delays are = [10 20 30 40 50 60 70 80] ms.
// Baseline delay will be 50 ms.
// Delay signals should be: [0 10 20 30 40 50 60 70] ms.
- const int64_t kMedianFilteredDelaysMs[] = {0, 10, 10, 20, 20, 30, 40, 50};
+ const int64_t kMedianFilteredDelaysMs[] = {0, 5, 10, 15, 20, 30, 40, 50};
const int kNumPackets = ARRAY_SIZE(kMedianFilteredDelaysMs);
const float kAlpha = 0.1f; // Used for exponential smoothing.
@@ -425,7 +425,7 @@
// Baseline delay will be 50 ms.
// Delay signals should be: [0 200 400 600 800 1000 1200 1400] ms.
const int64_t kMedianFilteredDelaysMs[] = {
- 0, 200, 200, 400, 400, 600, 800, 1000};
+ 0, 100, 200, 300, 400, 600, 800, 1000};
const int kNumPackets = ARRAY_SIZE(kMedianFilteredDelaysMs);
const float kAlpha = 0.1f; // Used for exponential smoothing.