[fix] fix congestion control module

src/qos/congestion_window_pushback_controller.cc

@@ -0,0 +1,70 @@
+/*
+ *  Copyright (c) 2018 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 "congestion_window_pushback_controller.h"
+
+#include <algorithm>
+#include <cstdint>
+
+#include "api/units/data_size.h"
+
+namespace webrtc {
+
+const int kDefaultMinPushbackTargetBitrateBps = 30000;
+
+CongestionWindowPushbackController::CongestionWindowPushbackController()
+    : add_pacing_(false),
+      min_pushback_target_bitrate_bps_(kDefaultMinPushbackTargetBitrateBps),
+      current_data_window_(
+          DataSize::Bytes(kDefaultMinPushbackTargetBitrateBps)) {}
+
+void CongestionWindowPushbackController::UpdateOutstandingData(
+    int64_t outstanding_bytes) {
+  outstanding_bytes_ = outstanding_bytes;
+}
+void CongestionWindowPushbackController::UpdatePacingQueue(
+    int64_t pacing_bytes) {
+  pacing_bytes_ = pacing_bytes;
+}
+
+void CongestionWindowPushbackController::SetDataWindow(DataSize data_window) {
+  current_data_window_ = data_window;
+}
+
+uint32_t CongestionWindowPushbackController::UpdateTargetBitrate(
+    uint32_t bitrate_bps) {
+  if (!current_data_window_ || current_data_window_->IsZero())
+    return bitrate_bps;
+  int64_t total_bytes = outstanding_bytes_;
+  if (add_pacing_) total_bytes += pacing_bytes_;
+  double fill_ratio =
+      total_bytes / static_cast<double>(current_data_window_->bytes());
+  if (fill_ratio > 1.5) {
+    encoding_rate_ratio_ *= 0.9;
+  } else if (fill_ratio > 1) {
+    encoding_rate_ratio_ *= 0.95;
+  } else if (fill_ratio < 0.1) {
+    encoding_rate_ratio_ = 1.0;
+  } else {
+    encoding_rate_ratio_ *= 1.05;
+    encoding_rate_ratio_ = std::min(encoding_rate_ratio_, 1.0);
+  }
+  uint32_t adjusted_target_bitrate_bps =
+      static_cast<uint32_t>(bitrate_bps * encoding_rate_ratio_);
+
+  // Do not adjust below the minimum pushback bitrate but do obey if the
+  // original estimate is below it.
+  bitrate_bps = adjusted_target_bitrate_bps < min_pushback_target_bitrate_bps_
+                    ? std::min(bitrate_bps, min_pushback_target_bitrate_bps_)
+                    : adjusted_target_bitrate_bps;
+  return bitrate_bps;
+}
+
+}  // namespace webrtc