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/*
* 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.
*/
// Test to verify correct operation when using the decoder-internal PLC.
#include <memory>
#include <utility>
#include <vector>
#include "absl/types/optional.h"
#include "modules/audio_coding/codecs/pcm16b/audio_encoder_pcm16b.h"
#include "modules/audio_coding/neteq/tools/audio_checksum.h"
#include "modules/audio_coding/neteq/tools/audio_sink.h"
#include "modules/audio_coding/neteq/tools/encode_neteq_input.h"
#include "modules/audio_coding/neteq/tools/fake_decode_from_file.h"
#include "modules/audio_coding/neteq/tools/input_audio_file.h"
#include "modules/audio_coding/neteq/tools/neteq_test.h"
#include "rtc_base/numerics/safe_conversions.h"
#include "test/audio_decoder_proxy_factory.h"
#include "test/gtest.h"
#include "test/testsupport/file_utils.h"
namespace webrtc {
namespace test {
namespace {
constexpr int kSampleRateHz = 32000;
constexpr int kRunTimeMs = 10000;
// This class implements a fake decoder. The decoder will read audio from a file
// and present as output, both for regular decoding and for PLC.
class AudioDecoderPlc : public AudioDecoder {
public:
AudioDecoderPlc(std::unique_ptr<InputAudioFile> input, int sample_rate_hz)
: input_(std::move(input)), sample_rate_hz_(sample_rate_hz) {}
void Reset() override {}
int SampleRateHz() const override { return sample_rate_hz_; }
size_t Channels() const override { return 1; }
int DecodeInternal(const uint8_t* /*encoded*/,
size_t encoded_len,
int sample_rate_hz,
int16_t* decoded,
SpeechType* speech_type) override {
RTC_CHECK_GE(encoded_len / 2, 10 * sample_rate_hz_ / 1000);
RTC_CHECK_LE(encoded_len / 2, 2 * 10 * sample_rate_hz_ / 1000);
RTC_CHECK_EQ(sample_rate_hz, sample_rate_hz_);
RTC_CHECK(decoded);
RTC_CHECK(speech_type);
RTC_CHECK(input_->Read(encoded_len / 2, decoded));
*speech_type = kSpeech;
last_was_plc_ = false;
return encoded_len / 2;
}
void GeneratePlc(size_t requested_samples_per_channel,
rtc::BufferT<int16_t>* concealment_audio) override {
// Instead of generating random data for GeneratePlc we use the same data as
// the input, so we can check that we produce the same result independently
// of the losses.
RTC_DCHECK_EQ(requested_samples_per_channel, 10 * sample_rate_hz_ / 1000);
// Must keep a local copy of this since DecodeInternal sets it to false.
const bool last_was_plc = last_was_plc_;
std::vector<int16_t> decoded(5760);
SpeechType speech_type;
int dec_len = DecodeInternal(nullptr, 2 * 10 * sample_rate_hz_ / 1000,
sample_rate_hz_, decoded.data(), &speech_type);
concealment_audio->AppendData(decoded.data(), dec_len);
concealed_samples_ += rtc::checked_cast<size_t>(dec_len);
if (!last_was_plc) {
++concealment_events_;
}
last_was_plc_ = true;
}
size_t concealed_samples() { return concealed_samples_; }
size_t concealment_events() { return concealment_events_; }
private:
const std::unique_ptr<InputAudioFile> input_;
const int sample_rate_hz_;
size_t concealed_samples_ = 0;
size_t concealment_events_ = 0;
bool last_was_plc_ = false;
};
// An input sample generator which generates only zero-samples.
class ZeroSampleGenerator : public EncodeNetEqInput::Generator {
public:
rtc::ArrayView<const int16_t> Generate(size_t num_samples) override {
vec.resize(num_samples, 0);
rtc::ArrayView<const int16_t> view(vec);
RTC_DCHECK_EQ(view.size(), num_samples);
return view;
}
private:
std::vector<int16_t> vec;
};
// A NetEqInput which connects to another NetEqInput, but drops a number of
// consecutive packets on the way
class LossyInput : public NetEqInput {
public:
LossyInput(int loss_cadence,
int burst_length,
std::unique_ptr<NetEqInput> input)
: loss_cadence_(loss_cadence),
burst_length_(burst_length),
input_(std::move(input)) {}
absl::optional<int64_t> NextPacketTime() const override {
return input_->NextPacketTime();
}
absl::optional<int64_t> NextOutputEventTime() const override {
return input_->NextOutputEventTime();
}
absl::optional<SetMinimumDelayInfo> NextSetMinimumDelayInfo() const override {
return input_->NextSetMinimumDelayInfo();
}
std::unique_ptr<PacketData> PopPacket() override {
if (loss_cadence_ != 0 && (++count_ % loss_cadence_) == 0) {
// Pop `burst_length_` packets to create the loss.
auto packet_to_return = input_->PopPacket();
for (int i = 0; i < burst_length_; i++) {
input_->PopPacket();
}
return packet_to_return;
}
return input_->PopPacket();
}
void AdvanceOutputEvent() override { return input_->AdvanceOutputEvent(); }
void AdvanceSetMinimumDelay() override {
return input_->AdvanceSetMinimumDelay();
}
bool ended() const override { return input_->ended(); }
absl::optional<RTPHeader> NextHeader() const override {
return input_->NextHeader();
}
private:
const int loss_cadence_;
const int burst_length_;
int count_ = 0;
const std::unique_ptr<NetEqInput> input_;
};
class AudioChecksumWithOutput : public AudioChecksum {
public:
explicit AudioChecksumWithOutput(std::string* output_str)
: output_str_(*output_str) {}
~AudioChecksumWithOutput() { output_str_ = Finish(); }
private:
std::string& output_str_;
};
struct TestStatistics {
NetEqNetworkStatistics network;
NetEqLifetimeStatistics lifetime;
};
TestStatistics RunTest(int loss_cadence,
int burst_length,
std::string* checksum) {
NetEq::Config config;
config.for_test_no_time_stretching = true;
// The input is mostly useless. It sends zero-samples to a PCM16b encoder,
// but the actual encoded samples will never be used by the decoder in the
// test. See below about the decoder.
auto generator = std::make_unique<ZeroSampleGenerator>();
constexpr int kPayloadType = 100;
AudioEncoderPcm16B::Config encoder_config;
encoder_config.sample_rate_hz = kSampleRateHz;
encoder_config.payload_type = kPayloadType;
auto encoder = std::make_unique<AudioEncoderPcm16B>(encoder_config);
auto input = std::make_unique<EncodeNetEqInput>(
std::move(generator), std::move(encoder), kRunTimeMs);
// Wrap the input in a loss function.
auto lossy_input = std::make_unique<LossyInput>(loss_cadence, burst_length,
std::move(input));
// Setting up decoders.
NetEqTest::DecoderMap decoders;
// Using a fake decoder which simply reads the output audio from a file.
auto input_file = std::make_unique<InputAudioFile>(
webrtc::test::ResourcePath("audio_coding/testfile32kHz", "pcm"));
AudioDecoderPlc dec(std::move(input_file), kSampleRateHz);
// Masquerading as a PCM16b decoder.
decoders.emplace(kPayloadType, SdpAudioFormat("l16", 32000, 1));
// Output is simply a checksum calculator.
auto output = std::make_unique<AudioChecksumWithOutput>(checksum);
// No callback objects.
NetEqTest::Callbacks callbacks;
NetEqTest neteq_test(
config, /*decoder_factory=*/
rtc::make_ref_counted<test::AudioDecoderProxyFactory>(&dec),
/*codecs=*/decoders, /*text_log=*/nullptr, /*neteq_factory=*/nullptr,
/*input=*/std::move(lossy_input), std::move(output), callbacks);
EXPECT_LE(kRunTimeMs, neteq_test.Run());
auto lifetime_stats = neteq_test.LifetimeStats();
EXPECT_EQ(dec.concealed_samples(), lifetime_stats.concealed_samples);
EXPECT_EQ(dec.concealment_events(), lifetime_stats.concealment_events);
return {neteq_test.SimulationStats(), neteq_test.LifetimeStats()};
}
} // namespace
// Check that some basic metrics are produced in the right direction. In
// particular, expand_rate should only increase if there are losses present. Our
// dummy decoder is designed such as the checksum should always be the same
// regardless of the losses given that calls are executed in the right order.
TEST(NetEqDecoderPlc, BasicMetrics) {
std::string checksum;
// Drop 1 packet every 10 packets.
auto stats = RunTest(10, 1, &checksum);
std::string checksum_no_loss;
auto stats_no_loss = RunTest(0, 0, &checksum_no_loss);
EXPECT_EQ(checksum, checksum_no_loss);
EXPECT_EQ(stats.network.preemptive_rate,
stats_no_loss.network.preemptive_rate);
EXPECT_EQ(stats.network.accelerate_rate,
stats_no_loss.network.accelerate_rate);
EXPECT_EQ(0, stats_no_loss.network.expand_rate);
EXPECT_GT(stats.network.expand_rate, 0);
}
// Checks that interruptions are not counted in small losses but they are
// correctly counted in long interruptions.
TEST(NetEqDecoderPlc, CountInterruptions) {
std::string checksum;
std::string checksum_2;
std::string checksum_3;
// Half of the packets lost but in short interruptions.
auto stats_no_interruptions = RunTest(1, 1, &checksum);
// One lost of 500 ms (250 packets).
auto stats_one_interruption = RunTest(200, 250, &checksum_2);
// Two losses of 250ms each (125 packets).
auto stats_two_interruptions = RunTest(125, 125, &checksum_3);
EXPECT_EQ(checksum, checksum_2);
EXPECT_EQ(checksum, checksum_3);
EXPECT_GT(stats_no_interruptions.network.expand_rate, 0);
EXPECT_EQ(stats_no_interruptions.lifetime.total_interruption_duration_ms, 0);
EXPECT_EQ(stats_no_interruptions.lifetime.interruption_count, 0);
EXPECT_GT(stats_one_interruption.network.expand_rate, 0);
EXPECT_EQ(stats_one_interruption.lifetime.total_interruption_duration_ms,
5000);
EXPECT_EQ(stats_one_interruption.lifetime.interruption_count, 1);
EXPECT_GT(stats_two_interruptions.network.expand_rate, 0);
EXPECT_EQ(stats_two_interruptions.lifetime.total_interruption_duration_ms,
5000);
EXPECT_EQ(stats_two_interruptions.lifetime.interruption_count, 2);
}
// Checks that small losses do not produce interruptions.
TEST(NetEqDecoderPlc, NoInterruptionsInSmallLosses) {
std::string checksum_1;
std::string checksum_4;
auto stats_1 = RunTest(300, 1, &checksum_1);
auto stats_4 = RunTest(300, 4, &checksum_4);
EXPECT_EQ(checksum_1, checksum_4);
EXPECT_EQ(stats_1.lifetime.interruption_count, 0);
EXPECT_EQ(stats_1.lifetime.total_interruption_duration_ms, 0);
EXPECT_EQ(stats_1.lifetime.concealed_samples, 640u); // 20ms of concealment.
EXPECT_EQ(stats_1.lifetime.concealment_events, 1u); // in just one event.
EXPECT_EQ(stats_4.lifetime.interruption_count, 0);
EXPECT_EQ(stats_4.lifetime.total_interruption_duration_ms, 0);
EXPECT_EQ(stats_4.lifetime.concealed_samples, 2560u); // 80ms of concealment.
EXPECT_EQ(stats_4.lifetime.concealment_events, 1u); // in just one event.
}
// Checks that interruptions of different sizes report correct duration.
TEST(NetEqDecoderPlc, InterruptionsReportCorrectSize) {
std::string checksum;
for (int burst_length = 5; burst_length < 10; burst_length++) {
auto stats = RunTest(300, burst_length, &checksum);
auto duration = stats.lifetime.total_interruption_duration_ms;
if (burst_length < 8) {
EXPECT_EQ(duration, 0);
} else {
EXPECT_EQ(duration, burst_length * 20);
}
}
}
} // namespace test
} // namespace webrtc