modules/rtp_rtcp/source/rtp_format_h264_unittest.cc - src - Git at Google

 /*
  *  Copyright (c) 2014 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/rtp_rtcp/source/rtp_format_h264.h"

 #include <memory>
 #include <vector>

 #include "absl/algorithm/container.h"
 #include "api/array_view.h"
 #include "common_video/h264/h264_common.h"
 #include "modules/rtp_rtcp/mocks/mock_rtp_rtcp.h"
 #include "modules/rtp_rtcp/source/byte_io.h"
 #include "modules/rtp_rtcp/source/rtp_packet_to_send.h"
 #include "test/gmock.h"
 #include "test/gtest.h"

 namespace webrtc {
 namespace {

 using ::testing::Each;
 using ::testing::ElementsAre;
 using ::testing::ElementsAreArray;
 using ::testing::Eq;
 using ::testing::IsEmpty;
 using ::testing::SizeIs;

 constexpr RtpPacketToSend::ExtensionManager* kNoExtensions = nullptr;
 constexpr size_t kMaxPayloadSize = 1200;
 constexpr size_t kLengthFieldLength = 2;
 constexpr RtpPacketizer::PayloadSizeLimits kNoLimits;

 enum Nalu {
   kSlice = 1,
   kIdr = 5,
   kSei = 6,
   kSps = 7,
   kPps = 8,
   kStapA = 24,
   kFuA = 28
 };

 static const size_t kNalHeaderSize = 1;
 static const size_t kFuAHeaderSize = 2;

 // Bit masks for FU (A and B) indicators.
 enum NalDefs { kFBit = 0x80, kNriMask = 0x60, kTypeMask = 0x1F };

 // Bit masks for FU (A and B) headers.
 enum FuDefs { kSBit = 0x80, kEBit = 0x40, kRBit = 0x20 };

 // Creates Buffer that looks like nal unit of given size.
 rtc::Buffer GenerateNalUnit(size_t size) {
   RTC_CHECK_GT(size, 0);
   rtc::Buffer buffer(size);
   // Set some valid header.
   buffer[0] = kSlice;
   for (size_t i = 1; i < size; ++i) {
     buffer[i] = static_cast<uint8_t>(i);
   }
   // Last byte shouldn't be 0, or it may be counted as part of next 4-byte start
   // sequence.
   buffer[size - 1] |= 0x10;
   return buffer;
 }

 // Create frame consisting of nalus of given size.
 rtc::Buffer CreateFrame(std::initializer_list<size_t> nalu_sizes) {
   static constexpr int kStartCodeSize = 3;
   rtc::Buffer frame(absl::c_accumulate(nalu_sizes, 0) +
                     kStartCodeSize * nalu_sizes.size());
   size_t offset = 0;
   for (size_t nalu_size : nalu_sizes) {
     EXPECT_GE(nalu_size, 1u);
     // Insert nalu start code
     frame[offset] = 0;
     frame[offset + 1] = 0;
     frame[offset + 2] = 1;
     // Set some valid header.
     frame[offset + 3] = 1;
     // Fill payload avoiding accidental start codes
     if (nalu_size > 1) {
       memset(frame.data() + offset + 4, 0x3f, nalu_size - 1);
     }
     offset += (kStartCodeSize + nalu_size);
   }
   return frame;
 }

 // Create frame consisting of given nalus.
 rtc::Buffer CreateFrame(rtc::ArrayView<const rtc::Buffer> nalus) {
   static constexpr int kStartCodeSize = 3;
   int frame_size = 0;
   for (const rtc::Buffer& nalu : nalus) {
     frame_size += (kStartCodeSize + nalu.size());
   }
   rtc::Buffer frame(frame_size);
   size_t offset = 0;
   for (const rtc::Buffer& nalu : nalus) {
     // Insert nalu start code
     frame[offset] = 0;
     frame[offset + 1] = 0;
     frame[offset + 2] = 1;
     // Copy the nalu unit.
     memcpy(frame.data() + offset + 3, nalu.data(), nalu.size());
     offset += (kStartCodeSize + nalu.size());
   }
   return frame;
 }

 std::vector<RtpPacketToSend> FetchAllPackets(RtpPacketizerH264* packetizer) {
   std::vector<RtpPacketToSend> result;
   size_t num_packets = packetizer->NumPackets();
   result.reserve(num_packets);
   RtpPacketToSend packet(kNoExtensions);
   while (packetizer->NextPacket(&packet)) {
     result.push_back(packet);
   }
   EXPECT_THAT(result, SizeIs(num_packets));
   return result;
 }

 // Tests that should work with both packetization mode 0 and
 // packetization mode 1.
 class RtpPacketizerH264ModeTest
     : public ::testing::TestWithParam<H264PacketizationMode> {};

 TEST_P(RtpPacketizerH264ModeTest, SingleNalu) {
   const uint8_t frame[] = {0, 0, 1, kIdr, 0xFF};

   RtpPacketizerH264 packetizer(frame, kNoLimits, GetParam());
   std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

   ASSERT_THAT(packets, SizeIs(1));
   EXPECT_THAT(packets[0].payload(), ElementsAre(kIdr, 0xFF));
 }

 TEST_P(RtpPacketizerH264ModeTest, SingleNaluTwoPackets) {
   RtpPacketizer::PayloadSizeLimits limits;
   limits.max_payload_len = kMaxPayloadSize;
   rtc::Buffer nalus[] = {GenerateNalUnit(kMaxPayloadSize),
                          GenerateNalUnit(100)};
   rtc::Buffer frame = CreateFrame(nalus);

   RtpPacketizerH264 packetizer(frame, limits, GetParam());
   std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

   ASSERT_THAT(packets, SizeIs(2));
   EXPECT_THAT(packets[0].payload(), ElementsAreArray(nalus[0]));
   EXPECT_THAT(packets[1].payload(), ElementsAreArray(nalus[1]));
 }

 TEST_P(RtpPacketizerH264ModeTest,
        SingleNaluFirstPacketReductionAppliesOnlyToFirstFragment) {
   RtpPacketizer::PayloadSizeLimits limits;
   limits.max_payload_len = 200;
   limits.first_packet_reduction_len = 5;
   rtc::Buffer nalus[] = {GenerateNalUnit(/*size=*/195),
                          GenerateNalUnit(/*size=*/200),
                          GenerateNalUnit(/*size=*/200)};
   rtc::Buffer frame = CreateFrame(nalus);

   RtpPacketizerH264 packetizer(frame, limits, GetParam());
   std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

   ASSERT_THAT(packets, SizeIs(3));
   EXPECT_THAT(packets[0].payload(), ElementsAreArray(nalus[0]));
   EXPECT_THAT(packets[1].payload(), ElementsAreArray(nalus[1]));
   EXPECT_THAT(packets[2].payload(), ElementsAreArray(nalus[2]));
 }

 TEST_P(RtpPacketizerH264ModeTest,
        SingleNaluLastPacketReductionAppliesOnlyToLastFragment) {
   RtpPacketizer::PayloadSizeLimits limits;
   limits.max_payload_len = 200;
   limits.last_packet_reduction_len = 5;
   rtc::Buffer nalus[] = {GenerateNalUnit(/*size=*/200),
                          GenerateNalUnit(/*size=*/200),
                          GenerateNalUnit(/*size=*/195)};
   rtc::Buffer frame = CreateFrame(nalus);

   RtpPacketizerH264 packetizer(frame, limits, GetParam());
   std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

   ASSERT_THAT(packets, SizeIs(3));
   EXPECT_THAT(packets[0].payload(), ElementsAreArray(nalus[0]));
   EXPECT_THAT(packets[1].payload(), ElementsAreArray(nalus[1]));
   EXPECT_THAT(packets[2].payload(), ElementsAreArray(nalus[2]));
 }

 TEST_P(RtpPacketizerH264ModeTest,
        SingleNaluFirstAndLastPacketReductionSumsForSinglePacket) {
   RtpPacketizer::PayloadSizeLimits limits;
   limits.max_payload_len = 200;
   limits.first_packet_reduction_len = 20;
   limits.last_packet_reduction_len = 30;
   rtc::Buffer frame = CreateFrame({150});

   RtpPacketizerH264 packetizer(frame, limits, GetParam());
   std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

   EXPECT_THAT(packets, SizeIs(1));
 }

 INSTANTIATE_TEST_SUITE_P(
     PacketMode,
     RtpPacketizerH264ModeTest,
     ::testing::Values(H264PacketizationMode::SingleNalUnit,
                       H264PacketizationMode::NonInterleaved));

 // Aggregation tests.
 TEST(RtpPacketizerH264Test, StapA) {
   rtc::Buffer nalus[] = {GenerateNalUnit(/*size=*/2),
                          GenerateNalUnit(/*size=*/2),
                          GenerateNalUnit(/*size=*/0x123)};
   rtc::Buffer frame = CreateFrame(nalus);

   RtpPacketizerH264 packetizer(frame, kNoLimits,
                                H264PacketizationMode::NonInterleaved);
   std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

   ASSERT_THAT(packets, SizeIs(1));
   auto payload = packets[0].payload();
   EXPECT_EQ(payload.size(),
             kNalHeaderSize + 3 * kLengthFieldLength + 2 + 2 + 0x123);

   EXPECT_EQ(payload[0], kStapA);
   payload = payload.subview(kNalHeaderSize);
   // 1st fragment.
   EXPECT_THAT(payload.subview(0, kLengthFieldLength),
               ElementsAre(0, 2));  // Size.
   EXPECT_THAT(payload.subview(kLengthFieldLength, 2),
               ElementsAreArray(nalus[0]));
   payload = payload.subview(kLengthFieldLength + 2);
   // 2nd fragment.
   EXPECT_THAT(payload.subview(0, kLengthFieldLength),
               ElementsAre(0, 2));  // Size.
   EXPECT_THAT(payload.subview(kLengthFieldLength, 2),
               ElementsAreArray(nalus[1]));
   payload = payload.subview(kLengthFieldLength + 2);
   // 3rd fragment.
   EXPECT_THAT(payload.subview(0, kLengthFieldLength),
               ElementsAre(0x1, 0x23));  // Size.
   EXPECT_THAT(payload.subview(kLengthFieldLength), ElementsAreArray(nalus[2]));
 }

 TEST(RtpPacketizerH264Test, SingleNalUnitModeHasNoStapA) {
   // This is the same setup as for the StapA test.
   rtc::Buffer frame = CreateFrame({2, 2, 0x123});

   RtpPacketizerH264 packetizer(frame, kNoLimits,
                                H264PacketizationMode::SingleNalUnit);
   std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

   // The three fragments should be returned as three packets.
   ASSERT_THAT(packets, SizeIs(3));
   EXPECT_EQ(packets[0].payload_size(), 2u);
   EXPECT_EQ(packets[1].payload_size(), 2u);
   EXPECT_EQ(packets[2].payload_size(), 0x123u);
 }

 TEST(RtpPacketizerH264Test, StapARespectsFirstPacketReduction) {
   RtpPacketizer::PayloadSizeLimits limits;
   limits.max_payload_len = 1000;
   limits.first_packet_reduction_len = 100;
   const size_t kFirstFragmentSize =
       limits.max_payload_len - limits.first_packet_reduction_len;
   rtc::Buffer nalus[] = {GenerateNalUnit(/*size=*/kFirstFragmentSize),
                          GenerateNalUnit(/*size=*/2),
                          GenerateNalUnit(/*size=*/2)};
   rtc::Buffer frame = CreateFrame(nalus);

   RtpPacketizerH264 packetizer(frame, limits,
                                H264PacketizationMode::NonInterleaved);
   std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

   ASSERT_THAT(packets, SizeIs(2));
   // Expect 1st packet is single nalu.
   EXPECT_THAT(packets[0].payload(), ElementsAreArray(nalus[0]));
   // Expect 2nd packet is aggregate of last two fragments.
   EXPECT_THAT(packets[1].payload(),
               ElementsAre(kStapA,                          //
                           0, 2, nalus[1][0], nalus[1][1],  //
                           0, 2, nalus[2][0], nalus[2][1]));
 }

 TEST(RtpPacketizerH264Test, StapARespectsLastPacketReduction) {
   RtpPacketizer::PayloadSizeLimits limits;
   limits.max_payload_len = 1000;
   limits.last_packet_reduction_len = 100;
   const size_t kLastFragmentSize =
       limits.max_payload_len - limits.last_packet_reduction_len;
   rtc::Buffer nalus[] = {GenerateNalUnit(/*size=*/2),
                          GenerateNalUnit(/*size=*/2),
                          GenerateNalUnit(/*size=*/kLastFragmentSize)};
   rtc::Buffer frame = CreateFrame(nalus);

   RtpPacketizerH264 packetizer(frame, limits,
                                H264PacketizationMode::NonInterleaved);
   std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

   ASSERT_THAT(packets, SizeIs(2));
   // Expect 1st packet is aggregate of 1st two fragments.
   EXPECT_THAT(packets[0].payload(),
               ElementsAre(kStapA,                          //
                           0, 2, nalus[0][0], nalus[0][1],  //
                           0, 2, nalus[1][0], nalus[1][1]));
   // Expect 2nd packet is single nalu.
   EXPECT_THAT(packets[1].payload(), ElementsAreArray(nalus[2]));
 }

 TEST(RtpPacketizerH264Test, TooSmallForStapAHeaders) {
   RtpPacketizer::PayloadSizeLimits limits;
   limits.max_payload_len = 1000;
   const size_t kLastFragmentSize =
       limits.max_payload_len - 3 * kLengthFieldLength - 4;
   rtc::Buffer nalus[] = {GenerateNalUnit(/*size=*/2),
                          GenerateNalUnit(/*size=*/2),
                          GenerateNalUnit(/*size=*/kLastFragmentSize)};
   rtc::Buffer frame = CreateFrame(nalus);

   RtpPacketizerH264 packetizer(frame, limits,
                                H264PacketizationMode::NonInterleaved);
   std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

   ASSERT_THAT(packets, SizeIs(2));
   // Expect 1st packet is aggregate of 1st two fragments.
   EXPECT_THAT(packets[0].payload(),
               ElementsAre(kStapA,                          //
                           0, 2, nalus[0][0], nalus[0][1],  //
                           0, 2, nalus[1][0], nalus[1][1]));
   // Expect 2nd packet is single nalu.
   EXPECT_THAT(packets[1].payload(), ElementsAreArray(nalus[2]));
 }

 // Fragmentation + aggregation.
 TEST(RtpPacketizerH264Test, MixedStapAFUA) {
   RtpPacketizer::PayloadSizeLimits limits;
   limits.max_payload_len = 100;
   const size_t kFuaPayloadSize = 70;
   const size_t kFuaNaluSize = kNalHeaderSize + 2 * kFuaPayloadSize;
   const size_t kStapANaluSize = 20;
   rtc::Buffer nalus[] = {GenerateNalUnit(kFuaNaluSize),
                          GenerateNalUnit(kStapANaluSize),
                          GenerateNalUnit(kStapANaluSize)};
   rtc::Buffer frame = CreateFrame(nalus);

   RtpPacketizerH264 packetizer(frame, limits,
                                H264PacketizationMode::NonInterleaved);
   std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

   ASSERT_THAT(packets, SizeIs(3));
   // First expect two FU-A packets.
   EXPECT_THAT(packets[0].payload().subview(0, kFuAHeaderSize),
               ElementsAre(kFuA, FuDefs::kSBit | nalus[0][0]));
   EXPECT_THAT(
       packets[0].payload().subview(kFuAHeaderSize),
       ElementsAreArray(nalus[0].data() + kNalHeaderSize, kFuaPayloadSize));

   EXPECT_THAT(packets[1].payload().subview(0, kFuAHeaderSize),
               ElementsAre(kFuA, FuDefs::kEBit | nalus[0][0]));
   EXPECT_THAT(
       packets[1].payload().subview(kFuAHeaderSize),
       ElementsAreArray(nalus[0].data() + kNalHeaderSize + kFuaPayloadSize,
                        kFuaPayloadSize));

   // Then expect one STAP-A packet with two nal units.
   EXPECT_THAT(packets[2].payload()[0], kStapA);
   auto payload = packets[2].payload().subview(kNalHeaderSize);
   EXPECT_THAT(payload.subview(0, kLengthFieldLength),
               ElementsAre(0, kStapANaluSize));
   EXPECT_THAT(payload.subview(kLengthFieldLength, kStapANaluSize),
               ElementsAreArray(nalus[1]));
   payload = payload.subview(kLengthFieldLength + kStapANaluSize);
   EXPECT_THAT(payload.subview(0, kLengthFieldLength),
               ElementsAre(0, kStapANaluSize));
   EXPECT_THAT(payload.subview(kLengthFieldLength), ElementsAreArray(nalus[2]));
 }

 TEST(RtpPacketizerH264Test, LastFragmentFitsInSingleButNotLastPacket) {
   RtpPacketizer::PayloadSizeLimits limits;
   limits.max_payload_len = 1178;
   limits.first_packet_reduction_len = 0;
   limits.last_packet_reduction_len = 20;
   limits.single_packet_reduction_len = 20;
   // Actual sizes, which triggered this bug.
   rtc::Buffer frame = CreateFrame({20, 8, 18, 1161});

   RtpPacketizerH264 packetizer(frame, limits,
                                H264PacketizationMode::NonInterleaved);
   std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

   // Last packet has to be of correct size.
   // Incorrect implementation might miss this constraint and not split the last
   // fragment in two packets.
   EXPECT_LE(static_cast<int>(packets.back().payload_size()),
             limits.max_payload_len - limits.last_packet_reduction_len);
 }

 // Splits frame with payload size `frame_payload_size` without fragmentation,
 // Returns sizes of the payloads excluding fua headers.
 std::vector<int> TestFua(size_t frame_payload_size,
                          const RtpPacketizer::PayloadSizeLimits& limits) {
   rtc::Buffer nalu[] = {GenerateNalUnit(kNalHeaderSize + frame_payload_size)};
   rtc::Buffer frame = CreateFrame(nalu);

   RtpPacketizerH264 packetizer(frame, limits,
                                H264PacketizationMode::NonInterleaved);
   std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

   EXPECT_GE(packets.size(), 2u);  // Single packet indicates it is not FuA.
   std::vector<uint16_t> fua_header;
   std::vector<int> payload_sizes;

   for (const RtpPacketToSend& packet : packets) {
     auto payload = packet.payload();
     EXPECT_GT(payload.size(), kFuAHeaderSize);
     fua_header.push_back((payload[0] << 8) | payload[1]);
     payload_sizes.push_back(payload.size() - kFuAHeaderSize);
   }

   EXPECT_TRUE(fua_header.front() & FuDefs::kSBit);
   EXPECT_TRUE(fua_header.back() & FuDefs::kEBit);
   // Clear S and E bits before testing all are duplicating same original header.
   fua_header.front() &= ~FuDefs::kSBit;
   fua_header.back() &= ~FuDefs::kEBit;
   EXPECT_THAT(fua_header, Each(Eq((kFuA << 8) | nalu[0][0])));

   return payload_sizes;
 }

 // Fragmentation tests.
 TEST(RtpPacketizerH264Test, FUAOddSize) {
   RtpPacketizer::PayloadSizeLimits limits;
   limits.max_payload_len = 1200;
   EXPECT_THAT(TestFua(1200, limits), ElementsAre(600, 600));
 }

 TEST(RtpPacketizerH264Test, FUAWithFirstPacketReduction) {
   RtpPacketizer::PayloadSizeLimits limits;
   limits.max_payload_len = 1200;
   limits.first_packet_reduction_len = 4;
   limits.single_packet_reduction_len = 4;
   EXPECT_THAT(TestFua(1198, limits), ElementsAre(597, 601));
 }

 TEST(RtpPacketizerH264Test, FUAWithLastPacketReduction) {
   RtpPacketizer::PayloadSizeLimits limits;
   limits.max_payload_len = 1200;
   limits.last_packet_reduction_len = 4;
   limits.single_packet_reduction_len = 4;
   EXPECT_THAT(TestFua(1198, limits), ElementsAre(601, 597));
 }

 TEST(RtpPacketizerH264Test, FUAWithSinglePacketReduction) {
   RtpPacketizer::PayloadSizeLimits limits;
   limits.max_payload_len = 1199;
   limits.single_packet_reduction_len = 200;
   EXPECT_THAT(TestFua(1000, limits), ElementsAre(500, 500));
 }

 TEST(RtpPacketizerH264Test, FUAEvenSize) {
   RtpPacketizer::PayloadSizeLimits limits;
   limits.max_payload_len = 1200;
   EXPECT_THAT(TestFua(1201, limits), ElementsAre(600, 601));
 }

 TEST(RtpPacketizerH264Test, FUARounding) {
   RtpPacketizer::PayloadSizeLimits limits;
   limits.max_payload_len = 1448;
   EXPECT_THAT(TestFua(10123, limits),
               ElementsAre(1265, 1265, 1265, 1265, 1265, 1266, 1266, 1266));
 }

 TEST(RtpPacketizerH264Test, FUABig) {
   RtpPacketizer::PayloadSizeLimits limits;
   limits.max_payload_len = 1200;
   // Generate 10 full sized packets, leave room for FU-A headers.
   EXPECT_THAT(
       TestFua(10 * (1200 - kFuAHeaderSize), limits),
       ElementsAre(1198, 1198, 1198, 1198, 1198, 1198, 1198, 1198, 1198, 1198));
 }

 TEST(RtpPacketizerH264Test, RejectsOverlongDataInPacketizationMode0) {
   RtpPacketizer::PayloadSizeLimits limits;
   rtc::Buffer frame = CreateFrame({kMaxPayloadSize + 1});

   RtpPacketizerH264 packetizer(frame, limits,
                                H264PacketizationMode::SingleNalUnit);
   std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

   EXPECT_THAT(packets, IsEmpty());
 }
 }  // namespace
 }  // namespace webrtc
	/*
	* Copyright (c) 2014 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/rtp_rtcp/source/rtp_format_h264.h"

	#include <memory>
	#include <vector>

	#include "absl/algorithm/container.h"
	#include "api/array_view.h"
	#include "common_video/h264/h264_common.h"
	#include "modules/rtp_rtcp/mocks/mock_rtp_rtcp.h"
	#include "modules/rtp_rtcp/source/byte_io.h"
	#include "modules/rtp_rtcp/source/rtp_packet_to_send.h"
	#include "test/gmock.h"
	#include "test/gtest.h"

	namespace webrtc {
	namespace {

	using ::testing::Each;
	using ::testing::ElementsAre;
	using ::testing::ElementsAreArray;
	using ::testing::Eq;
	using ::testing::IsEmpty;
	using ::testing::SizeIs;

	constexpr RtpPacketToSend::ExtensionManager* kNoExtensions = nullptr;
	constexpr size_t kMaxPayloadSize = 1200;
	constexpr size_t kLengthFieldLength = 2;
	constexpr RtpPacketizer::PayloadSizeLimits kNoLimits;

	enum Nalu {
	kSlice = 1,
	kIdr = 5,
	kSei = 6,
	kSps = 7,
	kPps = 8,
	kStapA = 24,
	kFuA = 28
	};

	static const size_t kNalHeaderSize = 1;
	static const size_t kFuAHeaderSize = 2;

	// Bit masks for FU (A and B) indicators.
	enum NalDefs { kFBit = 0x80, kNriMask = 0x60, kTypeMask = 0x1F };

	// Bit masks for FU (A and B) headers.
	enum FuDefs { kSBit = 0x80, kEBit = 0x40, kRBit = 0x20 };

	// Creates Buffer that looks like nal unit of given size.
	rtc::Buffer GenerateNalUnit(size_t size) {
	RTC_CHECK_GT(size, 0);
	rtc::Buffer buffer(size);
	// Set some valid header.
	buffer[0] = kSlice;
	for (size_t i = 1; i < size; ++i) {
	buffer[i] = static_cast<uint8_t>(i);
	}
	// Last byte shouldn't be 0, or it may be counted as part of next 4-byte start
	// sequence.
	buffer[size - 1] \|= 0x10;
	return buffer;
	}

	// Create frame consisting of nalus of given size.
	rtc::Buffer CreateFrame(std::initializer_list<size_t> nalu_sizes) {
	static constexpr int kStartCodeSize = 3;
	rtc::Buffer frame(absl::c_accumulate(nalu_sizes, 0) +
	kStartCodeSize * nalu_sizes.size());
	size_t offset = 0;
	for (size_t nalu_size : nalu_sizes) {
	EXPECT_GE(nalu_size, 1u);
	// Insert nalu start code
	frame[offset] = 0;
	frame[offset + 1] = 0;
	frame[offset + 2] = 1;
	// Set some valid header.
	frame[offset + 3] = 1;
	// Fill payload avoiding accidental start codes
	if (nalu_size > 1) {
	memset(frame.data() + offset + 4, 0x3f, nalu_size - 1);
	}
	offset += (kStartCodeSize + nalu_size);
	}
	return frame;
	}

	// Create frame consisting of given nalus.
	rtc::Buffer CreateFrame(rtc::ArrayView<const rtc::Buffer> nalus) {
	static constexpr int kStartCodeSize = 3;
	int frame_size = 0;
	for (const rtc::Buffer& nalu : nalus) {
	frame_size += (kStartCodeSize + nalu.size());
	}
	rtc::Buffer frame(frame_size);
	size_t offset = 0;
	for (const rtc::Buffer& nalu : nalus) {
	// Insert nalu start code
	frame[offset] = 0;
	frame[offset + 1] = 0;
	frame[offset + 2] = 1;
	// Copy the nalu unit.
	memcpy(frame.data() + offset + 3, nalu.data(), nalu.size());
	offset += (kStartCodeSize + nalu.size());
	}
	return frame;
	}

	std::vector<RtpPacketToSend> FetchAllPackets(RtpPacketizerH264* packetizer) {
	std::vector<RtpPacketToSend> result;
	size_t num_packets = packetizer->NumPackets();
	result.reserve(num_packets);
	RtpPacketToSend packet(kNoExtensions);
	while (packetizer->NextPacket(&packet)) {
	result.push_back(packet);
	}
	EXPECT_THAT(result, SizeIs(num_packets));
	return result;
	}

	// Tests that should work with both packetization mode 0 and
	// packetization mode 1.
	class RtpPacketizerH264ModeTest
	: public ::testing::TestWithParam<H264PacketizationMode> {};

	TEST_P(RtpPacketizerH264ModeTest, SingleNalu) {
	const uint8_t frame[] = {0, 0, 1, kIdr, 0xFF};

	RtpPacketizerH264 packetizer(frame, kNoLimits, GetParam());
	std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

	ASSERT_THAT(packets, SizeIs(1));
	EXPECT_THAT(packets[0].payload(), ElementsAre(kIdr, 0xFF));
	}

	TEST_P(RtpPacketizerH264ModeTest, SingleNaluTwoPackets) {
	RtpPacketizer::PayloadSizeLimits limits;
	limits.max_payload_len = kMaxPayloadSize;
	rtc::Buffer nalus[] = {GenerateNalUnit(kMaxPayloadSize),
	GenerateNalUnit(100)};
	rtc::Buffer frame = CreateFrame(nalus);

	RtpPacketizerH264 packetizer(frame, limits, GetParam());
	std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

	ASSERT_THAT(packets, SizeIs(2));
	EXPECT_THAT(packets[0].payload(), ElementsAreArray(nalus[0]));
	EXPECT_THAT(packets[1].payload(), ElementsAreArray(nalus[1]));
	}

	TEST_P(RtpPacketizerH264ModeTest,
	SingleNaluFirstPacketReductionAppliesOnlyToFirstFragment) {
	RtpPacketizer::PayloadSizeLimits limits;
	limits.max_payload_len = 200;
	limits.first_packet_reduction_len = 5;
	rtc::Buffer nalus[] = {GenerateNalUnit(/size=/195),
	GenerateNalUnit(/size=/200),
	GenerateNalUnit(/size=/200)};
	rtc::Buffer frame = CreateFrame(nalus);

	RtpPacketizerH264 packetizer(frame, limits, GetParam());
	std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

	ASSERT_THAT(packets, SizeIs(3));
	EXPECT_THAT(packets[0].payload(), ElementsAreArray(nalus[0]));
	EXPECT_THAT(packets[1].payload(), ElementsAreArray(nalus[1]));
	EXPECT_THAT(packets[2].payload(), ElementsAreArray(nalus[2]));
	}

	TEST_P(RtpPacketizerH264ModeTest,
	SingleNaluLastPacketReductionAppliesOnlyToLastFragment) {
	RtpPacketizer::PayloadSizeLimits limits;
	limits.max_payload_len = 200;
	limits.last_packet_reduction_len = 5;
	rtc::Buffer nalus[] = {GenerateNalUnit(/size=/200),
	GenerateNalUnit(/size=/200),
	GenerateNalUnit(/size=/195)};
	rtc::Buffer frame = CreateFrame(nalus);

	RtpPacketizerH264 packetizer(frame, limits, GetParam());
	std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

	ASSERT_THAT(packets, SizeIs(3));
	EXPECT_THAT(packets[0].payload(), ElementsAreArray(nalus[0]));
	EXPECT_THAT(packets[1].payload(), ElementsAreArray(nalus[1]));
	EXPECT_THAT(packets[2].payload(), ElementsAreArray(nalus[2]));
	}

	TEST_P(RtpPacketizerH264ModeTest,
	SingleNaluFirstAndLastPacketReductionSumsForSinglePacket) {
	RtpPacketizer::PayloadSizeLimits limits;
	limits.max_payload_len = 200;
	limits.first_packet_reduction_len = 20;
	limits.last_packet_reduction_len = 30;
	rtc::Buffer frame = CreateFrame({150});

	RtpPacketizerH264 packetizer(frame, limits, GetParam());
	std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

	EXPECT_THAT(packets, SizeIs(1));
	}

	INSTANTIATE_TEST_SUITE_P(
	PacketMode,
	RtpPacketizerH264ModeTest,
	::testing::Values(H264PacketizationMode::SingleNalUnit,
	H264PacketizationMode::NonInterleaved));

	// Aggregation tests.
	TEST(RtpPacketizerH264Test, StapA) {
	rtc::Buffer nalus[] = {GenerateNalUnit(/size=/2),
	GenerateNalUnit(/size=/2),
	GenerateNalUnit(/size=/0x123)};
	rtc::Buffer frame = CreateFrame(nalus);

	RtpPacketizerH264 packetizer(frame, kNoLimits,
	H264PacketizationMode::NonInterleaved);
	std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

	ASSERT_THAT(packets, SizeIs(1));
	auto payload = packets[0].payload();
	EXPECT_EQ(payload.size(),
	kNalHeaderSize + 3 * kLengthFieldLength + 2 + 2 + 0x123);

	EXPECT_EQ(payload[0], kStapA);
	payload = payload.subview(kNalHeaderSize);
	// 1st fragment.
	EXPECT_THAT(payload.subview(0, kLengthFieldLength),
	ElementsAre(0, 2)); // Size.
	EXPECT_THAT(payload.subview(kLengthFieldLength, 2),
	ElementsAreArray(nalus[0]));
	payload = payload.subview(kLengthFieldLength + 2);
	// 2nd fragment.
	EXPECT_THAT(payload.subview(0, kLengthFieldLength),
	ElementsAre(0, 2)); // Size.
	EXPECT_THAT(payload.subview(kLengthFieldLength, 2),
	ElementsAreArray(nalus[1]));
	payload = payload.subview(kLengthFieldLength + 2);
	// 3rd fragment.
	EXPECT_THAT(payload.subview(0, kLengthFieldLength),
	ElementsAre(0x1, 0x23)); // Size.
	EXPECT_THAT(payload.subview(kLengthFieldLength), ElementsAreArray(nalus[2]));
	}

	TEST(RtpPacketizerH264Test, SingleNalUnitModeHasNoStapA) {
	// This is the same setup as for the StapA test.
	rtc::Buffer frame = CreateFrame({2, 2, 0x123});

	RtpPacketizerH264 packetizer(frame, kNoLimits,
	H264PacketizationMode::SingleNalUnit);
	std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

	// The three fragments should be returned as three packets.
	ASSERT_THAT(packets, SizeIs(3));
	EXPECT_EQ(packets[0].payload_size(), 2u);
	EXPECT_EQ(packets[1].payload_size(), 2u);
	EXPECT_EQ(packets[2].payload_size(), 0x123u);
	}

	TEST(RtpPacketizerH264Test, StapARespectsFirstPacketReduction) {
	RtpPacketizer::PayloadSizeLimits limits;
	limits.max_payload_len = 1000;
	limits.first_packet_reduction_len = 100;
	const size_t kFirstFragmentSize =
	limits.max_payload_len - limits.first_packet_reduction_len;
	rtc::Buffer nalus[] = {GenerateNalUnit(/size=/kFirstFragmentSize),
	GenerateNalUnit(/size=/2),
	GenerateNalUnit(/size=/2)};
	rtc::Buffer frame = CreateFrame(nalus);

	RtpPacketizerH264 packetizer(frame, limits,
	H264PacketizationMode::NonInterleaved);
	std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

	ASSERT_THAT(packets, SizeIs(2));
	// Expect 1st packet is single nalu.
	EXPECT_THAT(packets[0].payload(), ElementsAreArray(nalus[0]));
	// Expect 2nd packet is aggregate of last two fragments.
	EXPECT_THAT(packets[1].payload(),
	ElementsAre(kStapA, //
	0, 2, nalus[1][0], nalus[1][1], //
	0, 2, nalus[2][0], nalus[2][1]));
	}

	TEST(RtpPacketizerH264Test, StapARespectsLastPacketReduction) {
	RtpPacketizer::PayloadSizeLimits limits;
	limits.max_payload_len = 1000;
	limits.last_packet_reduction_len = 100;
	const size_t kLastFragmentSize =
	limits.max_payload_len - limits.last_packet_reduction_len;
	rtc::Buffer nalus[] = {GenerateNalUnit(/size=/2),
	GenerateNalUnit(/size=/2),
	GenerateNalUnit(/size=/kLastFragmentSize)};
	rtc::Buffer frame = CreateFrame(nalus);

	RtpPacketizerH264 packetizer(frame, limits,
	H264PacketizationMode::NonInterleaved);
	std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

	ASSERT_THAT(packets, SizeIs(2));
	// Expect 1st packet is aggregate of 1st two fragments.
	EXPECT_THAT(packets[0].payload(),
	ElementsAre(kStapA, //
	0, 2, nalus[0][0], nalus[0][1], //
	0, 2, nalus[1][0], nalus[1][1]));
	// Expect 2nd packet is single nalu.
	EXPECT_THAT(packets[1].payload(), ElementsAreArray(nalus[2]));
	}

	TEST(RtpPacketizerH264Test, TooSmallForStapAHeaders) {
	RtpPacketizer::PayloadSizeLimits limits;
	limits.max_payload_len = 1000;
	const size_t kLastFragmentSize =
	limits.max_payload_len - 3 * kLengthFieldLength - 4;
	rtc::Buffer nalus[] = {GenerateNalUnit(/size=/2),
	GenerateNalUnit(/size=/2),
	GenerateNalUnit(/size=/kLastFragmentSize)};
	rtc::Buffer frame = CreateFrame(nalus);

	RtpPacketizerH264 packetizer(frame, limits,
	H264PacketizationMode::NonInterleaved);
	std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

	ASSERT_THAT(packets, SizeIs(2));
	// Expect 1st packet is aggregate of 1st two fragments.
	EXPECT_THAT(packets[0].payload(),
	ElementsAre(kStapA, //
	0, 2, nalus[0][0], nalus[0][1], //
	0, 2, nalus[1][0], nalus[1][1]));
	// Expect 2nd packet is single nalu.
	EXPECT_THAT(packets[1].payload(), ElementsAreArray(nalus[2]));
	}

	// Fragmentation + aggregation.
	TEST(RtpPacketizerH264Test, MixedStapAFUA) {
	RtpPacketizer::PayloadSizeLimits limits;
	limits.max_payload_len = 100;
	const size_t kFuaPayloadSize = 70;
	const size_t kFuaNaluSize = kNalHeaderSize + 2 * kFuaPayloadSize;
	const size_t kStapANaluSize = 20;
	rtc::Buffer nalus[] = {GenerateNalUnit(kFuaNaluSize),
	GenerateNalUnit(kStapANaluSize),
	GenerateNalUnit(kStapANaluSize)};
	rtc::Buffer frame = CreateFrame(nalus);

	RtpPacketizerH264 packetizer(frame, limits,
	H264PacketizationMode::NonInterleaved);
	std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

	ASSERT_THAT(packets, SizeIs(3));
	// First expect two FU-A packets.
	EXPECT_THAT(packets[0].payload().subview(0, kFuAHeaderSize),
	ElementsAre(kFuA, FuDefs::kSBit \| nalus[0][0]));
	EXPECT_THAT(
	packets[0].payload().subview(kFuAHeaderSize),
	ElementsAreArray(nalus[0].data() + kNalHeaderSize, kFuaPayloadSize));

	EXPECT_THAT(packets[1].payload().subview(0, kFuAHeaderSize),
	ElementsAre(kFuA, FuDefs::kEBit \| nalus[0][0]));
	EXPECT_THAT(
	packets[1].payload().subview(kFuAHeaderSize),
	ElementsAreArray(nalus[0].data() + kNalHeaderSize + kFuaPayloadSize,
	kFuaPayloadSize));

	// Then expect one STAP-A packet with two nal units.
	EXPECT_THAT(packets[2].payload()[0], kStapA);
	auto payload = packets[2].payload().subview(kNalHeaderSize);
	EXPECT_THAT(payload.subview(0, kLengthFieldLength),
	ElementsAre(0, kStapANaluSize));
	EXPECT_THAT(payload.subview(kLengthFieldLength, kStapANaluSize),
	ElementsAreArray(nalus[1]));
	payload = payload.subview(kLengthFieldLength + kStapANaluSize);
	EXPECT_THAT(payload.subview(0, kLengthFieldLength),
	ElementsAre(0, kStapANaluSize));
	EXPECT_THAT(payload.subview(kLengthFieldLength), ElementsAreArray(nalus[2]));
	}

	TEST(RtpPacketizerH264Test, LastFragmentFitsInSingleButNotLastPacket) {
	RtpPacketizer::PayloadSizeLimits limits;
	limits.max_payload_len = 1178;
	limits.first_packet_reduction_len = 0;
	limits.last_packet_reduction_len = 20;
	limits.single_packet_reduction_len = 20;
	// Actual sizes, which triggered this bug.
	rtc::Buffer frame = CreateFrame({20, 8, 18, 1161});

	RtpPacketizerH264 packetizer(frame, limits,
	H264PacketizationMode::NonInterleaved);
	std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

	// Last packet has to be of correct size.
	// Incorrect implementation might miss this constraint and not split the last
	// fragment in two packets.
	EXPECT_LE(static_cast<int>(packets.back().payload_size()),
	limits.max_payload_len - limits.last_packet_reduction_len);
	}

	// Splits frame with payload size `frame_payload_size` without fragmentation,
	// Returns sizes of the payloads excluding fua headers.
	std::vector<int> TestFua(size_t frame_payload_size,
	const RtpPacketizer::PayloadSizeLimits& limits) {
	rtc::Buffer nalu[] = {GenerateNalUnit(kNalHeaderSize + frame_payload_size)};
	rtc::Buffer frame = CreateFrame(nalu);

	RtpPacketizerH264 packetizer(frame, limits,
	H264PacketizationMode::NonInterleaved);
	std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

	EXPECT_GE(packets.size(), 2u); // Single packet indicates it is not FuA.
	std::vector<uint16_t> fua_header;
	std::vector<int> payload_sizes;

	for (const RtpPacketToSend& packet : packets) {
	auto payload = packet.payload();
	EXPECT_GT(payload.size(), kFuAHeaderSize);
	fua_header.push_back((payload[0] << 8) \| payload[1]);
	payload_sizes.push_back(payload.size() - kFuAHeaderSize);
	}

	EXPECT_TRUE(fua_header.front() & FuDefs::kSBit);
	EXPECT_TRUE(fua_header.back() & FuDefs::kEBit);
	// Clear S and E bits before testing all are duplicating same original header.
	fua_header.front() &= ~FuDefs::kSBit;
	fua_header.back() &= ~FuDefs::kEBit;
	EXPECT_THAT(fua_header, Each(Eq((kFuA << 8) \| nalu[0][0])));

	return payload_sizes;
	}

	// Fragmentation tests.
	TEST(RtpPacketizerH264Test, FUAOddSize) {
	RtpPacketizer::PayloadSizeLimits limits;
	limits.max_payload_len = 1200;
	EXPECT_THAT(TestFua(1200, limits), ElementsAre(600, 600));
	}

	TEST(RtpPacketizerH264Test, FUAWithFirstPacketReduction) {
	RtpPacketizer::PayloadSizeLimits limits;
	limits.max_payload_len = 1200;
	limits.first_packet_reduction_len = 4;
	limits.single_packet_reduction_len = 4;
	EXPECT_THAT(TestFua(1198, limits), ElementsAre(597, 601));
	}

	TEST(RtpPacketizerH264Test, FUAWithLastPacketReduction) {
	RtpPacketizer::PayloadSizeLimits limits;
	limits.max_payload_len = 1200;
	limits.last_packet_reduction_len = 4;
	limits.single_packet_reduction_len = 4;
	EXPECT_THAT(TestFua(1198, limits), ElementsAre(601, 597));
	}

	TEST(RtpPacketizerH264Test, FUAWithSinglePacketReduction) {
	RtpPacketizer::PayloadSizeLimits limits;
	limits.max_payload_len = 1199;
	limits.single_packet_reduction_len = 200;
	EXPECT_THAT(TestFua(1000, limits), ElementsAre(500, 500));
	}

	TEST(RtpPacketizerH264Test, FUAEvenSize) {
	RtpPacketizer::PayloadSizeLimits limits;
	limits.max_payload_len = 1200;
	EXPECT_THAT(TestFua(1201, limits), ElementsAre(600, 601));
	}

	TEST(RtpPacketizerH264Test, FUARounding) {
	RtpPacketizer::PayloadSizeLimits limits;
	limits.max_payload_len = 1448;
	EXPECT_THAT(TestFua(10123, limits),
	ElementsAre(1265, 1265, 1265, 1265, 1265, 1266, 1266, 1266));
	}

	TEST(RtpPacketizerH264Test, FUABig) {
	RtpPacketizer::PayloadSizeLimits limits;
	limits.max_payload_len = 1200;
	// Generate 10 full sized packets, leave room for FU-A headers.
	EXPECT_THAT(
	TestFua(10 * (1200 - kFuAHeaderSize), limits),
	ElementsAre(1198, 1198, 1198, 1198, 1198, 1198, 1198, 1198, 1198, 1198));
	}

	TEST(RtpPacketizerH264Test, RejectsOverlongDataInPacketizationMode0) {
	RtpPacketizer::PayloadSizeLimits limits;
	rtc::Buffer frame = CreateFrame({kMaxPayloadSize + 1});

	RtpPacketizerH264 packetizer(frame, limits,
	H264PacketizationMode::SingleNalUnit);
	std::vector<RtpPacketToSend> packets = FetchAllPackets(&packetizer);

	EXPECT_THAT(packets, IsEmpty());
	}
	} // namespace
	} // namespace webrtc