Make fec controller plug-able.

Bug: webrtc:8656
Change-Id: I3d42ffc92a7c95266e5d53bab03f388bd0de2592
Reviewed-on: https://webrtc-review.googlesource.com/39760
Reviewed-by: Stefan Holmer <stefan@webrtc.org>
Commit-Queue: Ying Wang <yinwa@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21710}

modules/video_coding/fec_controller_unittest.cc

@@ -0,0 +1,107 @@
+/*
+ *  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 "modules/video_coding/fec_controller_default.h"
+#include "system_wrappers/include/clock.h"
+#include "test/gtest.h"
+
+namespace webrtc {
+
+static const int kCodecBitrateBps = 100000;
+
+class ProtectionBitrateCalculatorTest : public ::testing::Test {
+ protected:
+  enum {
+    kSampleRate = 90000  // RTP timestamps per second.
+  };
+
+  class ProtectionCallback : public VCMProtectionCallback {
+   public:
+    int ProtectionRequest(const FecProtectionParams* delta_params,
+                          const FecProtectionParams* key_params,
+                          uint32_t* sent_video_rate_bps,
+                          uint32_t* sent_nack_rate_bps,
+                          uint32_t* sent_fec_rate_bps) override {
+      *sent_video_rate_bps = kCodecBitrateBps;
+      *sent_nack_rate_bps = nack_rate_bps_;
+      *sent_fec_rate_bps = fec_rate_bps_;
+      return 0;
+    }
+
+    uint32_t fec_rate_bps_ = 0;
+    uint32_t nack_rate_bps_ = 0;
+  };
+
+  // Note: simulated clock starts at 1 seconds, since parts of webrtc use 0 as
+  // a special case (e.g. frame rate in media optimization).
+  ProtectionBitrateCalculatorTest()
+      : clock_(1000), fec_controller_(&clock_, &protection_callback_) {}
+
+  SimulatedClock clock_;
+  ProtectionCallback protection_callback_;
+  FecControllerDefault fec_controller_;
+};
+
+TEST_F(ProtectionBitrateCalculatorTest, ProtectsUsingFecBitrate) {
+  static const uint32_t kMaxBitrateBps = 130000;
+
+  fec_controller_.SetProtectionMethod(true /*enable_fec*/,
+                                      false /* enable_nack */);
+  fec_controller_.SetEncodingData(640, 480, 1, 1000);
+
+  // Using 10% of codec bitrate for FEC.
+  protection_callback_.fec_rate_bps_ = kCodecBitrateBps / 10;
+  uint32_t target_bitrate = fec_controller_.UpdateFecRates(
+      kMaxBitrateBps, 30, 0, std::vector<bool>(1, false), 0);
+
+  EXPECT_GT(target_bitrate, 0u);
+  EXPECT_GT(kMaxBitrateBps, target_bitrate);
+
+  // Using as much for codec bitrate as fec rate, new target rate should share
+  // both equally, but only be half of max (since that ceiling should be hit).
+  protection_callback_.fec_rate_bps_ = kCodecBitrateBps;
+  target_bitrate = fec_controller_.UpdateFecRates(
+      kMaxBitrateBps, 30, 128, std::vector<bool>(1, false), 100);
+  EXPECT_EQ(kMaxBitrateBps / 2, target_bitrate);
+}
+
+TEST_F(ProtectionBitrateCalculatorTest, ProtectsUsingNackBitrate) {
+  static const uint32_t kMaxBitrateBps = 130000;
+
+  fec_controller_.SetProtectionMethod(false /*enable_fec*/,
+                                      true /* enable_nack */);
+  fec_controller_.SetEncodingData(640, 480, 1, 1000);
+
+  uint32_t target_bitrate = fec_controller_.UpdateFecRates(
+      kMaxBitrateBps, 30, 0, std::vector<bool>(1, false), 0);
+
+  EXPECT_EQ(kMaxBitrateBps, target_bitrate);
+
+  // Using as much for codec bitrate as nack rate, new target rate should share
+  // both equally, but only be half of max (since that ceiling should be hit).
+  protection_callback_.nack_rate_bps_ = kMaxBitrateBps;
+  target_bitrate = fec_controller_.UpdateFecRates(
+      kMaxBitrateBps, 30, 128, std::vector<bool>(1, false), 100);
+  EXPECT_EQ(kMaxBitrateBps / 2, target_bitrate);
+}
+
+TEST_F(ProtectionBitrateCalculatorTest, NoProtection) {
+  static const uint32_t kMaxBitrateBps = 130000;
+
+  fec_controller_.SetProtectionMethod(false /*enable_fec*/,
+                                      false /* enable_nack */);
+  fec_controller_.SetEncodingData(640, 480, 1, 1000);
+
+  uint32_t target_bitrate = fec_controller_.UpdateFecRates(
+      kMaxBitrateBps, 30, 128, std::vector<bool>(1, false), 100);
+  EXPECT_EQ(kMaxBitrateBps, target_bitrate);
+}
+
+}  // namespace webrtc