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/*
* Copyright (c) 2012 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.
*/
/*
* Test application for core FEC algorithm. Calls encoding and decoding
* functions in ForwardErrorCorrection directly.
*/
#include <string.h>
#include <time.h>
#include <list>
#include "webrtc/modules/rtp_rtcp/source/byte_io.h"
#include "webrtc/modules/rtp_rtcp/source/forward_error_correction.h"
#include "webrtc/modules/rtp_rtcp/source/forward_error_correction_internal.h"
#include "webrtc/rtc_base/random.h"
#include "webrtc/test/gtest.h"
#include "webrtc/test/testsupport/fileutils.h"
// #define VERBOSE_OUTPUT
namespace webrtc {
namespace fec_private_tables {
extern const uint8_t** kPacketMaskBurstyTbl[12];
}
namespace test {
using fec_private_tables::kPacketMaskBurstyTbl;
void ReceivePackets(
ForwardErrorCorrection::ReceivedPacketList* to_decode_list,
ForwardErrorCorrection::ReceivedPacketList* received_packet_list,
size_t num_packets_to_decode,
float reorder_rate,
float duplicate_rate,
Random* random) {
RTC_DCHECK(to_decode_list->empty());
RTC_DCHECK_LE(num_packets_to_decode, received_packet_list->size());
for (size_t i = 0; i < num_packets_to_decode; i++) {
auto it = received_packet_list->begin();
// Reorder packets.
float random_variable = random->Rand<float>();
while (random_variable < reorder_rate) {
++it;
if (it == received_packet_list->end()) {
--it;
break;
}
random_variable = random->Rand<float>();
}
to_decode_list->push_back(std::move(*it));
received_packet_list->erase(it);
// Duplicate packets.
ForwardErrorCorrection::ReceivedPacket* received_packet =
to_decode_list->back().get();
random_variable = random->Rand<float>();
while (random_variable < duplicate_rate) {
std::unique_ptr<ForwardErrorCorrection::ReceivedPacket> duplicate_packet(
new ForwardErrorCorrection::ReceivedPacket());
*duplicate_packet = *received_packet;
duplicate_packet->pkt = new ForwardErrorCorrection::Packet();
memcpy(duplicate_packet->pkt->data, received_packet->pkt->data,
received_packet->pkt->length);
duplicate_packet->pkt->length = received_packet->pkt->length;
to_decode_list->push_back(std::move(duplicate_packet));
random_variable = random->Rand<float>();
}
}
}
void RunTest(bool use_flexfec) {
// TODO(marpan): Split this function into subroutines/helper functions.
enum { kMaxNumberMediaPackets = 48 };
enum { kMaxNumberFecPackets = 48 };
const uint32_t kNumMaskBytesL0 = 2;
const uint32_t kNumMaskBytesL1 = 6;
// FOR UEP
const bool kUseUnequalProtection = true;
// FEC mask types.
const FecMaskType kMaskTypes[] = {kFecMaskRandom, kFecMaskBursty};
const int kNumFecMaskTypes = sizeof(kMaskTypes) / sizeof(*kMaskTypes);
// Maximum number of media packets allowed for the mask type.
const uint16_t kMaxMediaPackets[] = {
kMaxNumberMediaPackets,
sizeof(kPacketMaskBurstyTbl) / sizeof(*kPacketMaskBurstyTbl)};
ASSERT_EQ(12, kMaxMediaPackets[1]) << "Max media packets for bursty mode not "
<< "equal to 12.";
ForwardErrorCorrection::PacketList media_packet_list;
std::list<ForwardErrorCorrection::Packet*> fec_packet_list;
ForwardErrorCorrection::ReceivedPacketList to_decode_list;
ForwardErrorCorrection::ReceivedPacketList received_packet_list;
ForwardErrorCorrection::RecoveredPacketList recovered_packet_list;
std::list<uint8_t*> fec_mask_list;
// Running over only two loss rates to limit execution time.
const float loss_rate[] = {0.05f, 0.01f};
const uint32_t loss_rate_size = sizeof(loss_rate) / sizeof(*loss_rate);
const float reorder_rate = 0.1f;
const float duplicate_rate = 0.1f;
uint8_t media_loss_mask[kMaxNumberMediaPackets];
uint8_t fec_loss_mask[kMaxNumberFecPackets];
uint8_t fec_packet_masks[kMaxNumberFecPackets][kMaxNumberMediaPackets];
// Seed the random number generator, storing the seed to file in order to
// reproduce past results.
const unsigned int random_seed = static_cast<unsigned int>(time(nullptr));
Random random(random_seed);
std::string filename = webrtc::test::OutputPath() + "randomSeedLog.txt";
FILE* random_seed_file = fopen(filename.c_str(), "a");
fprintf(random_seed_file, "%u\n", random_seed);
fclose(random_seed_file);
random_seed_file = nullptr;
uint16_t seq_num = 0;
uint32_t timestamp = random.Rand<uint32_t>();
const uint32_t media_ssrc = random.Rand(1u, 0xfffffffe);
uint32_t fec_ssrc;
uint16_t fec_seq_num_offset;
if (use_flexfec) {
fec_ssrc = random.Rand(1u, 0xfffffffe);
fec_seq_num_offset = random.Rand(0, 1 << 15);
} else {
fec_ssrc = media_ssrc;
fec_seq_num_offset = 0;
}
std::unique_ptr<ForwardErrorCorrection> fec;
if (use_flexfec) {
fec = ForwardErrorCorrection::CreateFlexfec(fec_ssrc, media_ssrc);
} else {
RTC_DCHECK_EQ(media_ssrc, fec_ssrc);
fec = ForwardErrorCorrection::CreateUlpfec(fec_ssrc);
}
// Loop over the mask types: random and bursty.
for (int mask_type_idx = 0; mask_type_idx < kNumFecMaskTypes;
++mask_type_idx) {
for (uint32_t loss_rate_idx = 0; loss_rate_idx < loss_rate_size;
++loss_rate_idx) {
printf("Loss rate: %.2f, Mask type %d \n", loss_rate[loss_rate_idx],
mask_type_idx);
const uint32_t packet_mask_max = kMaxMediaPackets[mask_type_idx];
std::unique_ptr<uint8_t[]> packet_mask(
new uint8_t[packet_mask_max * kNumMaskBytesL1]);
FecMaskType fec_mask_type = kMaskTypes[mask_type_idx];
for (uint32_t num_media_packets = 1; num_media_packets <= packet_mask_max;
num_media_packets++) {
internal::PacketMaskTable mask_table(fec_mask_type, num_media_packets);
for (uint32_t num_fec_packets = 1;
num_fec_packets <= num_media_packets &&
num_fec_packets <= packet_mask_max;
num_fec_packets++) {
// Loop over num_imp_packets: usually <= (0.3*num_media_packets).
// For this test we check up to ~ (num_media_packets / 4).
uint32_t max_num_imp_packets = num_media_packets / 4 + 1;
for (uint32_t num_imp_packets = 0;
num_imp_packets <= max_num_imp_packets &&
num_imp_packets <= packet_mask_max;
num_imp_packets++) {
uint8_t protection_factor =
static_cast<uint8_t>(num_fec_packets * 255 / num_media_packets);
const uint32_t mask_bytes_per_fec_packet =
(num_media_packets > 16) ? kNumMaskBytesL1 : kNumMaskBytesL0;
memset(packet_mask.get(), 0,
num_media_packets * mask_bytes_per_fec_packet);
// Transfer packet masks from bit-mask to byte-mask.
internal::GeneratePacketMasks(num_media_packets, num_fec_packets,
num_imp_packets,
kUseUnequalProtection,
mask_table, packet_mask.get());
#ifdef VERBOSE_OUTPUT
printf(
"%u media packets, %u FEC packets, %u num_imp_packets, "
"loss rate = %.2f \n",
num_media_packets, num_fec_packets, num_imp_packets,
loss_rate[loss_rate_idx]);
printf("Packet mask matrix \n");
#endif
for (uint32_t i = 0; i < num_fec_packets; i++) {
for (uint32_t j = 0; j < num_media_packets; j++) {
const uint8_t byte_mask =
packet_mask[i * mask_bytes_per_fec_packet + j / 8];
const uint32_t bit_position = (7 - j % 8);
fec_packet_masks[i][j] =
(byte_mask & (1 << bit_position)) >> bit_position;
#ifdef VERBOSE_OUTPUT
printf("%u ", fec_packet_masks[i][j]);
#endif
}
#ifdef VERBOSE_OUTPUT
printf("\n");
#endif
}
#ifdef VERBOSE_OUTPUT
printf("\n");
#endif
// Check for all zero rows or columns: indicates incorrect mask.
uint32_t row_limit = num_media_packets;
for (uint32_t i = 0; i < num_fec_packets; ++i) {
uint32_t row_sum = 0;
for (uint32_t j = 0; j < row_limit; ++j) {
row_sum += fec_packet_masks[i][j];
}
ASSERT_NE(0u, row_sum) << "Row is all zero " << i;
}
for (uint32_t j = 0; j < row_limit; ++j) {
uint32_t column_sum = 0;
for (uint32_t i = 0; i < num_fec_packets; ++i) {
column_sum += fec_packet_masks[i][j];
}
ASSERT_NE(0u, column_sum) << "Column is all zero " << j;
}
// Construct media packets.
// Reset the sequence number here for each FEC code/mask tested
// below, to avoid sequence number wrap-around. In actual decoding,
// old FEC packets in list are dropped if sequence number wrap
// around is detected. This case is currently not handled below.
seq_num = 0;
for (uint32_t i = 0; i < num_media_packets; ++i) {
std::unique_ptr<ForwardErrorCorrection::Packet> media_packet(
new ForwardErrorCorrection::Packet());
const uint32_t kMinPacketSize = 12;
const uint32_t kMaxPacketSize = static_cast<uint32_t>(
IP_PACKET_SIZE - 12 - 28 - fec->MaxPacketOverhead());
media_packet->length = random.Rand(kMinPacketSize,
kMaxPacketSize);
// Generate random values for the first 2 bytes.
media_packet->data[0] = random.Rand<uint8_t>();
media_packet->data[1] = random.Rand<uint8_t>();
// The first two bits are assumed to be 10 by the
// FEC encoder. In fact the FEC decoder will set the
// two first bits to 10 regardless of what they
// actually were. Set the first two bits to 10
// so that a memcmp can be performed for the
// whole restored packet.
media_packet->data[0] |= 0x80;
media_packet->data[0] &= 0xbf;
// FEC is applied to a whole frame.
// A frame is signaled by multiple packets without
// the marker bit set followed by the last packet of
// the frame for which the marker bit is set.
// Only push one (fake) frame to the FEC.
media_packet->data[1] &= 0x7f;
ByteWriter<uint16_t>::WriteBigEndian(&media_packet->data[2],
seq_num);
ByteWriter<uint32_t>::WriteBigEndian(&media_packet->data[4],
timestamp);
ByteWriter<uint32_t>::WriteBigEndian(&media_packet->data[8],
media_ssrc);
// Generate random values for payload
for (size_t j = 12; j < media_packet->length; ++j) {
media_packet->data[j] = random.Rand<uint8_t>();
}
media_packet_list.push_back(std::move(media_packet));
seq_num++;
}
media_packet_list.back()->data[1] |= 0x80;
ASSERT_EQ(0, fec->EncodeFec(media_packet_list, protection_factor,
num_imp_packets, kUseUnequalProtection,
fec_mask_type, &fec_packet_list))
<< "EncodeFec() failed";
ASSERT_EQ(num_fec_packets, fec_packet_list.size())
<< "We requested " << num_fec_packets << " FEC packets, but "
<< "EncodeFec() produced " << fec_packet_list.size();
memset(media_loss_mask, 0, sizeof(media_loss_mask));
uint32_t media_packet_idx = 0;
for (const auto& media_packet : media_packet_list) {
// We want a value between 0 and 1.
const float loss_random_variable = random.Rand<float>();
if (loss_random_variable >= loss_rate[loss_rate_idx]) {
media_loss_mask[media_packet_idx] = 1;
std::unique_ptr<ForwardErrorCorrection::ReceivedPacket>
received_packet(
new ForwardErrorCorrection::ReceivedPacket());
received_packet->pkt = new ForwardErrorCorrection::Packet();
received_packet->pkt->length = media_packet->length;
memcpy(received_packet->pkt->data, media_packet->data,
media_packet->length);
received_packet->ssrc = media_ssrc;
received_packet->seq_num =
ByteReader<uint16_t>::ReadBigEndian(&media_packet->data[2]);
received_packet->is_fec = false;
received_packet_list.push_back(std::move(received_packet));
}
media_packet_idx++;
}
memset(fec_loss_mask, 0, sizeof(fec_loss_mask));
uint32_t fec_packet_idx = 0;
for (auto* fec_packet : fec_packet_list) {
const float loss_random_variable = random.Rand<float>();
if (loss_random_variable >= loss_rate[loss_rate_idx]) {
fec_loss_mask[fec_packet_idx] = 1;
std::unique_ptr<ForwardErrorCorrection::ReceivedPacket>
received_packet(
new ForwardErrorCorrection::ReceivedPacket());
received_packet->pkt = new ForwardErrorCorrection::Packet();
received_packet->pkt->length = fec_packet->length;
memcpy(received_packet->pkt->data, fec_packet->data,
fec_packet->length);
received_packet->seq_num = fec_seq_num_offset + seq_num;
received_packet->is_fec = true;
received_packet->ssrc = fec_ssrc;
received_packet_list.push_back(std::move(received_packet));
fec_mask_list.push_back(fec_packet_masks[fec_packet_idx]);
}
++fec_packet_idx;
++seq_num;
}
#ifdef VERBOSE_OUTPUT
printf("Media loss mask:\n");
for (uint32_t i = 0; i < num_media_packets; i++) {
printf("%u ", media_loss_mask[i]);
}
printf("\n\n");
printf("FEC loss mask:\n");
for (uint32_t i = 0; i < num_fec_packets; i++) {
printf("%u ", fec_loss_mask[i]);
}
printf("\n\n");
#endif
auto fec_mask_it = fec_mask_list.begin();
while (fec_mask_it != fec_mask_list.end()) {
uint32_t hamming_dist = 0;
uint32_t recovery_position = 0;
for (uint32_t i = 0; i < num_media_packets; i++) {
if (media_loss_mask[i] == 0 && (*fec_mask_it)[i] == 1) {
recovery_position = i;
++hamming_dist;
}
}
auto item_to_delete = fec_mask_it;
++fec_mask_it;
if (hamming_dist == 1) {
// Recovery possible. Restart search.
media_loss_mask[recovery_position] = 1;
fec_mask_it = fec_mask_list.begin();
} else if (hamming_dist == 0) {
// FEC packet cannot provide further recovery.
fec_mask_list.erase(item_to_delete);
}
}
#ifdef VERBOSE_OUTPUT
printf("Recovery mask:\n");
for (uint32_t i = 0; i < num_media_packets; ++i) {
printf("%u ", media_loss_mask[i]);
}
printf("\n\n");
#endif
// For error-checking frame completion.
bool fec_packet_received = false;
while (!received_packet_list.empty()) {
size_t num_packets_to_decode = random.Rand(
1u, static_cast<uint32_t>(received_packet_list.size()));
ReceivePackets(&to_decode_list, &received_packet_list,
num_packets_to_decode, reorder_rate,
duplicate_rate, &random);
if (fec_packet_received == false) {
for (const auto& received_packet : to_decode_list) {
if (received_packet->is_fec) {
fec_packet_received = true;
}
}
}
ASSERT_EQ(0,
fec->DecodeFec(&to_decode_list, &recovered_packet_list))
<< "DecodeFec() failed";
ASSERT_TRUE(to_decode_list.empty())
<< "Received packet list is not empty.";
}
media_packet_idx = 0;
for (const auto& media_packet : media_packet_list) {
if (media_loss_mask[media_packet_idx] == 1) {
// Should have recovered this packet.
auto recovered_packet_list_it = recovered_packet_list.cbegin();
ASSERT_FALSE(recovered_packet_list_it ==
recovered_packet_list.end())
<< "Insufficient number of recovered packets.";
ForwardErrorCorrection::RecoveredPacket* recovered_packet =
recovered_packet_list_it->get();
ASSERT_EQ(recovered_packet->pkt->length, media_packet->length)
<< "Recovered packet length not identical to original "
<< "media packet";
ASSERT_EQ(0, memcmp(recovered_packet->pkt->data,
media_packet->data, media_packet->length))
<< "Recovered packet payload not identical to original "
<< "media packet";
recovered_packet_list.pop_front();
}
++media_packet_idx;
}
fec->ResetState(&recovered_packet_list);
ASSERT_TRUE(recovered_packet_list.empty())
<< "Excessive number of recovered packets.\t size is: "
<< recovered_packet_list.size();
// -- Teardown --
media_packet_list.clear();
// Clear FEC packet list, so we don't pass in a non-empty
// list in the next call to DecodeFec().
fec_packet_list.clear();
// Delete received packets we didn't pass to DecodeFec(), due to
// early frame completion.
received_packet_list.clear();
while (!fec_mask_list.empty()) {
fec_mask_list.pop_front();
}
timestamp += 90000 / 30;
} // loop over num_imp_packets
} // loop over FecPackets
} // loop over num_media_packets
} // loop over loss rates
} // loop over mask types
// Have DecodeFec clear the recovered packet list.
fec->ResetState(&recovered_packet_list);
ASSERT_TRUE(recovered_packet_list.empty())
<< "Recovered packet list is not empty";
}
TEST(FecTest, UlpfecTest) {
RunTest(false);
}
TEST(FecTest, FlexfecTest) {
RunTest(true);
}
} // namespace test
} // namespace webrtc