Add packetization and coding/decoding of feedback message format.

webrtc/modules/rtp_rtcp/source/rtcp_packet/feedback_packet_unittest.cc

+/*
+ *  Copyright (c) 2015 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 <limits>
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/feedback_packet.h"
+#include "webrtc/modules/rtp_rtcp/source/byte_io.h"
+
+using webrtc::rtcp::FeedbackPacket;
+
+namespace webrtc {
+namespace {
+
+static const int kHeaderSize = 20;
+static const int kStatusChunkSize = 2;
+static const int kSmallDeltaSize = 1;
+static const int kLargeDeltaSize = 2;
+
+static const int64_t kDeltaLimit = 0xFF * FeedbackPacket::kDeltaScaleFactor;
+
+class FeedbackTester {
+ public:
+  FeedbackTester()
+      : expected_size_(kAnySize),
+        default_delta_(FeedbackPacket::kDeltaScaleFactor * 4) {}
+
+  void WithExpectedSize(size_t expected_size) {
+    expected_size_ = expected_size;
+  }
+
+  void WithDefaultDelta(int64_t delta) { default_delta_ = delta; }
+
+  void WithInput(const uint16_t received_seq[],
+                 const int64_t received_ts[],
+                 uint16_t length) {
+    rtc::scoped_ptr<int64_t[]> temp_deltas;
+    if (received_ts == nullptr) {
+      temp_deltas.reset(new int64_t[length]);
+      GenerateDeltas(received_seq, length, temp_deltas.get());
+      received_ts = temp_deltas.get();
+    }
+
+    expected_seq_.clear();
+    expected_deltas_.clear();
+    feedback_.reset(new FeedbackPacket());
+
+    feedback_->WithBase(received_seq[0], received_ts[0]);
+    int64_t last_time = feedback_->GetBaseTimeUs();
+    for (int i = 0; i < length; ++i) {
+      int64_t time = received_ts[i];
+      EXPECT_TRUE(feedback_->WithReceivedPacket(received_seq[i], time));
+
+      if (last_time != -1) {
+        int64_t delta = time - last_time;
+        expected_deltas_.push_back(delta);
+      }
+      last_time = time;
+    }
+    expected_seq_.insert(expected_seq_.begin(), &received_seq[0],
+                         &received_seq[length]);
+  }
+
+  void VerifyPacket() {
+    serialized_ = feedback_->Build();
+    VerifyInternal();
+    feedback_ =
+        FeedbackPacket::ParseFrom(serialized_->Buffer(), serialized_->Length());
+    ASSERT_NE(nullptr, feedback_.get());
+    VerifyInternal();
+  }
+
+  static const size_t kAnySize = static_cast<size_t>(0) - 1;
+
+ private:
+  void VerifyInternal() {
+    if (expected_size_ != kAnySize) {
+      // Round up to whole 32-bit words.
+      size_t expected_size_words = (expected_size_ + 3) / 4;
+      size_t expected_size_bytes = expected_size_words * 4;
+      EXPECT_EQ(expected_size_bytes, serialized_->Length());
+    }
+
+    std::vector<FeedbackPacket::StatusSymbol> symbols =
+        feedback_->GetStatusVector();
+    uint16_t seq = feedback_->GetBaseSequence();
+    auto seq_it = expected_seq_.begin();
+    for (FeedbackPacket::StatusSymbol symbol : symbols) {
+      bool received =
+          (symbol == FeedbackPacket::StatusSymbol::kReceivedSmallDelta ||
+           symbol == FeedbackPacket::StatusSymbol::kReceivedLargeDelta);
+      if (seq_it != expected_seq_.end()) {
+        if (seq == *seq_it) {
+          ASSERT_NE(expected_seq_.end(), seq_it);
+          ASSERT_TRUE(received) << "Expected received packet @ " << seq;
+          ++seq_it;
+        } else {
+          ASSERT_FALSE(received) << "Did not expect received packet @ " << seq;
+        }
+      }
+      ++seq;
+    }
+    ASSERT_EQ(expected_seq_.end(), seq_it);
+
+    std::vector<int64_t> deltas = feedback_->GetReceiveDeltasUs();
+    ASSERT_EQ(expected_deltas_.size(), deltas.size());
+    for (size_t i = 0; i < expected_deltas_.size(); ++i)
+      EXPECT_EQ(expected_deltas_[i], deltas[i]) << "Delta mismatch @ " << i;
+  }
+
+  void GenerateDeltas(const uint16_t seq[],
+                      const size_t length,
+                      int64_t* deltas) {
+    uint16_t last_seq = seq[0];
+    int64_t offset = 0;
+
+    for (size_t i = 0; i < length; ++i) {
+      if (seq[i] < last_seq)
+        offset += 0x10000 * default_delta_;
+      last_seq = seq[i];
+
+      deltas[i] = offset + (last_seq * default_delta_);
+    }
+  }
+
+  std::vector<uint16_t> expected_seq_;
+  std::vector<int64_t> expected_deltas_;
+  size_t expected_size_;
+  int64_t default_delta_;
+  rtc::scoped_ptr<FeedbackPacket> feedback_;
+  rtc::scoped_ptr<rtcp::RawPacket> serialized_;
+};
+
+TEST(RtcpPacketTest, FeedbackPacket_OneBitVector) {
+  const uint16_t kReceived[] = {1, 2, 7, 8, 9, 10, 13};
+  const size_t kLength = sizeof(kReceived) / sizeof(uint16_t);
+  const size_t kExpectedSizeBytes =
+      kHeaderSize + kStatusChunkSize + (kLength * kSmallDeltaSize);
+
+  FeedbackTester test;
+  test.WithExpectedSize(kExpectedSizeBytes);
+  test.WithInput(kReceived, nullptr, kLength);
+  test.VerifyPacket();
+}
+
+TEST(RtcpPacketTest, FeedbackPacket_FullOneBitVector) {
+  const uint16_t kReceived[] = {1, 2, 7, 8, 9, 10, 13, 14};
+  const size_t kLength = sizeof(kReceived) / sizeof(uint16_t);
+  const size_t kExpectedSizeBytes =
+      kHeaderSize + kStatusChunkSize + (kLength * kSmallDeltaSize);
+
+  FeedbackTester test;
+  test.WithExpectedSize(kExpectedSizeBytes);
+  test.WithInput(kReceived, nullptr, kLength);
+  test.VerifyPacket();
+}
+
+TEST(RtcpPacketTest, FeedbackPacket_OneBitVector_WrapReceived) {
+  const uint16_t kMax = 0xFFFF;
+  const uint16_t kReceived[] = {kMax - 2, kMax - 1, kMax, 0, 1, 2};
+  const size_t kLength = sizeof(kReceived) / sizeof(uint16_t);
+  const size_t kExpectedSizeBytes =
+      kHeaderSize + kStatusChunkSize + (kLength * kSmallDeltaSize);
+
+  FeedbackTester test;
+  test.WithExpectedSize(kExpectedSizeBytes);
+  test.WithInput(kReceived, nullptr, kLength);
+  test.VerifyPacket();
+}
+
+TEST(RtcpPacketTest, FeedbackPacket_OneBitVector_WrapMissing) {
+  const uint16_t kMax = 0xFFFF;
+  const uint16_t kReceived[] = {kMax - 2, kMax - 1, 1, 2};
+  const size_t kLength = sizeof(kReceived) / sizeof(uint16_t);
+  const size_t kExpectedSizeBytes =
+      kHeaderSize + kStatusChunkSize + (kLength * kSmallDeltaSize);
+
+  FeedbackTester test;
+  test.WithExpectedSize(kExpectedSizeBytes);
+  test.WithInput(kReceived, nullptr, kLength);
+  test.VerifyPacket();
+}
+
+TEST(RtcpPacketTest, FeedbackPacket_TwoBitVector) {
+  const uint16_t kReceived[] = {1, 2, 6, 7};
+  const size_t kLength = sizeof(kReceived) / sizeof(uint16_t);
+  const size_t kExpectedSizeBytes =
+      kHeaderSize + kStatusChunkSize + (kLength * kLargeDeltaSize);
+
+  FeedbackTester test;
+  test.WithExpectedSize(kExpectedSizeBytes);
+  test.WithDefaultDelta(kDeltaLimit + FeedbackPacket::kDeltaScaleFactor);
+  test.WithInput(kReceived, nullptr, kLength);
+  test.VerifyPacket();
+}
+
+TEST(RtcpPacketTest, FeedbackPacket_TwoBitVectorFull) {
+  const uint16_t kReceived[] = {1, 2, 6, 7, 8};
+  const size_t kLength = sizeof(kReceived) / sizeof(uint16_t);
+  const size_t kExpectedSizeBytes =
+      kHeaderSize + (2 * kStatusChunkSize) + (kLength * kLargeDeltaSize);
+
+  FeedbackTester test;
+  test.WithExpectedSize(kExpectedSizeBytes);
+  test.WithDefaultDelta(kDeltaLimit + FeedbackPacket::kDeltaScaleFactor);
+  test.WithInput(kReceived, nullptr, kLength);
+  test.VerifyPacket();
+}
+
+TEST(RtcpPacketTest, FeedbackPacket_LargeAndNegativeDeltas) {
+  const uint16_t kReceived[] = {1, 2, 6, 7, 8};
+  const int64_t kReceiveTimes[] = {
+      2000,
+      1000,
+      4000,
+      3000,
+      3000 + FeedbackPacket::kDeltaScaleFactor * (1 << 8)};
+  const size_t kLength = sizeof(kReceived) / sizeof(uint16_t);
+  const size_t kExpectedSizeBytes =
+      kHeaderSize + kStatusChunkSize + (3 * kLargeDeltaSize) + kSmallDeltaSize;
+
+  FeedbackTester test;
+  test.WithExpectedSize(kExpectedSizeBytes);
+  test.WithInput(kReceived, kReceiveTimes, kLength);
+  test.VerifyPacket();
+}
+
+TEST(RtcpPacketTest, FeedbackPacket_MaxRle) {
+  // Expected chunks created:
+  // * 1-bit vector chunk (1xreceived + 13xdropped)
+  // * RLE chunk of max length for dropped symbol
+  // * 1-bit vector chunk (1xreceived + 13xdropped)
+
+  const size_t kPacketCount = (1 << 13) - 1 + 14;
+  const uint16_t kReceived[] = {0, kPacketCount};
+  const int64_t kReceiveTimes[] = {1000, 2000};
+  const size_t kLength = sizeof(kReceived) / sizeof(uint16_t);
+  const size_t kExpectedSizeBytes =
+      kHeaderSize + (3 * kStatusChunkSize) + (kLength * kSmallDeltaSize);
+
+  FeedbackTester test;
+  test.WithExpectedSize(kExpectedSizeBytes);
+  test.WithInput(kReceived, kReceiveTimes, kLength);
+  test.VerifyPacket();
+}
+
+TEST(RtcpPacketTest, FeedbackPacket_MinRle) {
+  // Expected chunks created:
+  // * 1-bit vector chunk (1xreceived + 13xdropped)
+  // * RLE chunk of length 15 for dropped symbol
+  // * 1-bit vector chunk (1xreceived + 13xdropped)
+
+  const uint16_t kReceived[] = {0, (14 * 2) + 1};
+  const int64_t kReceiveTimes[] = {1000, 2000};
+  const size_t kLength = sizeof(kReceived) / sizeof(uint16_t);
+  const size_t kExpectedSizeBytes =
+      kHeaderSize + (3 * kStatusChunkSize) + (kLength * kSmallDeltaSize);
+
+  FeedbackTester test;
+  test.WithExpectedSize(kExpectedSizeBytes);
+  test.WithInput(kReceived, kReceiveTimes, kLength);
+  test.VerifyPacket();
+}
+
+TEST(RtcpPacketTest, FeedbackPacket_OneToTwoBitVector) {
+  const size_t kTwoBitVectorCapacity = 7;
+  const uint16_t kReceived[] = {0, kTwoBitVectorCapacity - 1};
+  const int64_t kReceiveTimes[] = {
+      0, kDeltaLimit + FeedbackPacket::kDeltaScaleFactor};
+  const size_t kLength = sizeof(kReceived) / sizeof(uint16_t);
+  const size_t kExpectedSizeBytes =
+      kHeaderSize + kStatusChunkSize + kSmallDeltaSize + kLargeDeltaSize;
+
+  FeedbackTester test;
+  test.WithExpectedSize(kExpectedSizeBytes);
+  test.WithInput(kReceived, kReceiveTimes, kLength);
+  test.VerifyPacket();
+}
+
+TEST(RtcpPacketTest, FeedbackPacket_OneToTwoBitVectorSplit) {
+  const size_t kTwoBitVectorCapacity = 7;
+  const uint16_t kReceived[] = {0, kTwoBitVectorCapacity};
+  const int64_t kReceiveTimes[] = {
+      0, kDeltaLimit + FeedbackPacket::kDeltaScaleFactor};
+  const size_t kLength = sizeof(kReceived) / sizeof(uint16_t);
+  const size_t kExpectedSizeBytes =
+      kHeaderSize + (kStatusChunkSize * 2) + kSmallDeltaSize + kLargeDeltaSize;
+
+  FeedbackTester test;
+  test.WithExpectedSize(kExpectedSizeBytes);
+  test.WithInput(kReceived, kReceiveTimes, kLength);
+  test.VerifyPacket();
+}
+
+TEST(RtcpPacketTest, FeedbackPacket_Aliasing) {
+  FeedbackPacket feedback;
+  feedback.WithBase(0, 0);
+
+  const int kSamples = 100;
+  const int64_t kTooSmallDelta = FeedbackPacket::kDeltaScaleFactor / 3;
+
+  for (int i = 0; i < kSamples; ++i)
+    feedback.WithReceivedPacket(i, i * kTooSmallDelta);
+
+  feedback.Build();
+  std::vector<int64_t> deltas = feedback.GetReceiveDeltasUs();
+
+  int64_t accumulated_delta = 0;
+  int num_samples = 0;
+  for (int64_t delta : deltas) {
+    accumulated_delta += delta;
+    int64_t expected_time = num_samples * kTooSmallDelta;
+    ++num_samples;
+
+    EXPECT_NEAR(expected_time, accumulated_delta,
+                FeedbackPacket::kDeltaScaleFactor / 2);
+  }
+}
+
+TEST(RtcpPacketTest, FeedbackPacket_Limits) {
+  // Sequence number wrap above 0x8000.
+  rtc::scoped_ptr<FeedbackPacket> packet(new FeedbackPacket());
+  packet->WithBase(0, 0);
+  EXPECT_TRUE(packet->WithReceivedPacket(0x8000, 1000));
+
+  packet.reset(new FeedbackPacket());
+  packet->WithBase(0, 0);
+  EXPECT_FALSE(packet->WithReceivedPacket(0x8000 + 1, 1000));
+
+  // Packet status count max 0xFFFF.
+  packet.reset(new FeedbackPacket());
+  packet->WithBase(0, 0);
+  EXPECT_TRUE(packet->WithReceivedPacket(0x8000, 1000));
+  EXPECT_TRUE(packet->WithReceivedPacket(0xFFFF, 2000));
+  EXPECT_FALSE(packet->WithReceivedPacket(0, 3000));
+
+  // Too large delta.
+  packet.reset(new FeedbackPacket());
+  packet->WithBase(0, 0);
+  int64_t kMaxPositiveTimeDelta =
+      std::numeric_limits<int16_t>::max() * FeedbackPacket::kDeltaScaleFactor;
+  EXPECT_FALSE(packet->WithReceivedPacket(
+      1, kMaxPositiveTimeDelta + FeedbackPacket::kDeltaScaleFactor));
+  EXPECT_TRUE(packet->WithReceivedPacket(1, kMaxPositiveTimeDelta));
+
+  // Too large negative delta.
+  packet.reset(new FeedbackPacket());
+  packet->WithBase(0, 0);
+  int64_t kMaxNegativeTimeDelta =
+      std::numeric_limits<int16_t>::min() * FeedbackPacket::kDeltaScaleFactor;
+  EXPECT_FALSE(packet->WithReceivedPacket(
+      1, kMaxNegativeTimeDelta - FeedbackPacket::kDeltaScaleFactor));
+  EXPECT_TRUE(packet->WithReceivedPacket(1, kMaxNegativeTimeDelta));
+
+  // TODO(sprang): Once we support max length lower than RTCP length limit,
+  // add back test for max size in bytes.
+}
+
+TEST(RtcpPacketTest, FeedbackPacket_Padding) {
+  const size_t kExpectedSizeBytes =
+      kHeaderSize + kStatusChunkSize + kSmallDeltaSize;
+  const size_t kExpectedSizeWords = (kExpectedSizeBytes + 3) / 4;
+
+  FeedbackPacket feedback;
+  feedback.WithBase(0, 0);
+  EXPECT_TRUE(feedback.WithReceivedPacket(0, 0));
+
+  rtc::scoped_ptr<rtcp::RawPacket> packet(feedback.Build());
+  EXPECT_EQ(kExpectedSizeWords * 4, packet->Length());
+  ASSERT_GT(kExpectedSizeWords * 4, kExpectedSizeBytes);
+  for (size_t i = kExpectedSizeBytes; i < kExpectedSizeWords * 4; ++i)
+    EXPECT_EQ(0u, packet->Buffer()[i]);
+
+  // Modify packet by adding 4 bytes of padding at the end. Not currently used
+  // when we're sending, but need to be able to handle it when receiving.
+
+  const int kPaddingBytes = 4;
+  const size_t kExpectedSizeWithPadding =
+      (kExpectedSizeWords * 4) + kPaddingBytes;
+  uint8_t mod_buffer[kExpectedSizeWithPadding];
+  memcpy(mod_buffer, packet->Buffer(), kExpectedSizeWords * 4);
+  memset(&mod_buffer[kExpectedSizeWords * 4], 0, kPaddingBytes - 1);
+  mod_buffer[kExpectedSizeWithPadding - 1] = kPaddingBytes;
+  const uint8_t padding_flag = 1 << 5;
+  mod_buffer[0] |= padding_flag;
+  ByteWriter<uint16_t>::WriteBigEndian(
+      &mod_buffer[2], ByteReader<uint16_t>::ReadBigEndian(&mod_buffer[2]) +
+                          ((kPaddingBytes + 3) / 4));
+
+  rtc::scoped_ptr<FeedbackPacket> parsed_packet(
+      FeedbackPacket::ParseFrom(mod_buffer, kExpectedSizeWithPadding));
+  ASSERT_TRUE(parsed_packet.get() != nullptr);
+  EXPECT_EQ(kExpectedSizeWords * 4, packet->Length());  // Padding not included.
+}
+
+}  // namespace
+}  // namespace webrtc