1 files changed, 96 insertions, 0 deletions
diff --git a/webrtc/modules/video_coding/codec_timer.cc b/webrtc/modules/video_coding/codec_timer.cc
new file mode 100644
index 0000000000..60add8fc4b
--- /dev/null
+++ b/webrtc/modules/video_coding/codec_timer.cc
@@ -0,0 +1,96 @@
+/*
+ *  Copyright (c) 2011 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_coding/codec_timer.h"
+
+#include <assert.h>
+
+namespace webrtc {
+
+// The first kIgnoredSampleCount samples will be ignored.
+static const int32_t kIgnoredSampleCount = 5;
+
+VCMCodecTimer::VCMCodecTimer()
+    : _filteredMax(0), _ignoredSampleCount(0), _shortMax(0), _history() {
+  Reset();
+}
+
+void VCMCodecTimer::Reset() {
+  _filteredMax = 0;
+  _ignoredSampleCount = 0;
+  _shortMax = 0;
+  for (int i = 0; i < MAX_HISTORY_SIZE; i++) {
+    _history[i].shortMax = 0;
+    _history[i].timeMs = -1;
+  }
+}
+
+// Update the max-value filter
+void VCMCodecTimer::MaxFilter(int32_t decodeTime, int64_t nowMs) {
+  if (_ignoredSampleCount >= kIgnoredSampleCount) {
+    UpdateMaxHistory(decodeTime, nowMs);
+    ProcessHistory(nowMs);
+  } else {
+    _ignoredSampleCount++;
+  }
+}
+
+void VCMCodecTimer::UpdateMaxHistory(int32_t decodeTime, int64_t now) {
+  if (_history[0].timeMs >= 0 && now - _history[0].timeMs < SHORT_FILTER_MS) {
+    if (decodeTime > _shortMax) {
+      _shortMax = decodeTime;
+    }
+  } else {
+    // Only add a new value to the history once a second
+    if (_history[0].timeMs == -1) {
+      // First, no shift
+      _shortMax = decodeTime;
+    } else {
+      // Shift
+      for (int i = (MAX_HISTORY_SIZE - 2); i >= 0; i--) {
+        _history[i + 1].shortMax = _history[i].shortMax;
+        _history[i + 1].timeMs = _history[i].timeMs;
+      }
+    }
+    if (_shortMax == 0) {
+      _shortMax = decodeTime;
+    }
+
+    _history[0].shortMax = _shortMax;
+    _history[0].timeMs = now;
+    _shortMax = 0;
+  }
+}
+
+void VCMCodecTimer::ProcessHistory(int64_t nowMs) {
+  _filteredMax = _shortMax;
+  if (_history[0].timeMs == -1) {
+    return;
+  }
+  for (int i = 0; i < MAX_HISTORY_SIZE; i++) {
+    if (_history[i].timeMs == -1) {
+      break;
+    }
+    if (nowMs - _history[i].timeMs > MAX_HISTORY_SIZE * SHORT_FILTER_MS) {
+      // This sample (and all samples after this) is too old
+      break;
+    }
+    if (_history[i].shortMax > _filteredMax) {
+      // This sample is the largest one this far into the history
+      _filteredMax = _history[i].shortMax;
+    }
+  }
+}
+
+// Get the maximum observed time within a time window
+int32_t VCMCodecTimer::RequiredDecodeTimeMs(FrameType /*frameType*/) const {
+  return _filteredMax;
+}
+}  // namespace webrtc