/*
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* Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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// Unit tests for BufferLevelFilter class.
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#include "webrtc/modules/audio_coding/neteq/buffer_level_filter.h"
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#include <math.h> // Access to pow function.
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#include "testing/gtest/include/gtest/gtest.h"
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namespace webrtc {
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TEST(BufferLevelFilter, CreateAndDestroy) {
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BufferLevelFilter* filter = new BufferLevelFilter();
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EXPECT_EQ(0, filter->filtered_current_level());
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delete filter;
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}
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TEST(BufferLevelFilter, ConvergenceTest) {
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BufferLevelFilter filter;
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for (int times = 10; times <= 50; times += 10) {
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for (int value = 100; value <= 200; value += 10) {
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filter.Reset();
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filter.SetTargetBufferLevel(1); // Makes filter coefficient 251/256.
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std::ostringstream ss;
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ss << "times = " << times << ", value = " << value;
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SCOPED_TRACE(ss.str()); // Print out the parameter values on failure.
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for (int i = 0; i < times; ++i) {
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filter.Update(value, 0 /* time_stretched_samples */,
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160 /* packet_len_samples */);
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}
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// Expect the filtered value to be (theoretically)
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// (1 - (251/256) ^ |times|) * |value|.
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double expected_value_double =
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(1 - pow(251.0 / 256.0, times)) * value;
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int expected_value = static_cast<int>(expected_value_double);
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// filtered_current_level() returns the value in Q8.
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// The actual value may differ slightly from the expected value due to
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// intermediate-stage rounding errors in the filter implementation.
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// This is why we have to use EXPECT_NEAR with a tolerance of +/-1.
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EXPECT_NEAR(expected_value, filter.filtered_current_level() >> 8, 1);
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}
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}
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}
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// Verify that target buffer level impacts on the filter convergence.
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TEST(BufferLevelFilter, FilterFactor) {
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BufferLevelFilter filter;
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// Update 10 times with value 100.
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const int kTimes = 10;
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const int kValue = 100;
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filter.SetTargetBufferLevel(3); // Makes filter coefficient 252/256.
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for (int i = 0; i < kTimes; ++i) {
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filter.Update(kValue, 0 /* time_stretched_samples */,
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160 /* packet_len_samples */);
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}
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// Expect the filtered value to be
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// (1 - (252/256) ^ |kTimes|) * |kValue|.
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int expected_value = 14;
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// filtered_current_level() returns the value in Q8.
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EXPECT_EQ(expected_value, filter.filtered_current_level() >> 8);
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filter.Reset();
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filter.SetTargetBufferLevel(7); // Makes filter coefficient 253/256.
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for (int i = 0; i < kTimes; ++i) {
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filter.Update(kValue, 0 /* time_stretched_samples */,
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160 /* packet_len_samples */);
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}
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// Expect the filtered value to be
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// (1 - (253/256) ^ |kTimes|) * |kValue|.
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expected_value = 11;
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// filtered_current_level() returns the value in Q8.
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EXPECT_EQ(expected_value, filter.filtered_current_level() >> 8);
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filter.Reset();
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filter.SetTargetBufferLevel(8); // Makes filter coefficient 254/256.
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for (int i = 0; i < kTimes; ++i) {
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filter.Update(kValue, 0 /* time_stretched_samples */,
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160 /* packet_len_samples */);
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}
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// Expect the filtered value to be
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// (1 - (254/256) ^ |kTimes|) * |kValue|.
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expected_value = 7;
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// filtered_current_level() returns the value in Q8.
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EXPECT_EQ(expected_value, filter.filtered_current_level() >> 8);
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}
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TEST(BufferLevelFilter, TimeStretchedSamples) {
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BufferLevelFilter filter;
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filter.SetTargetBufferLevel(1); // Makes filter coefficient 251/256.
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// Update 10 times with value 100.
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const int kTimes = 10;
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const int kValue = 100;
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const int kPacketSizeSamples = 160;
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const int kNumPacketsStretched = 2;
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const int kTimeStretchedSamples = kNumPacketsStretched * kPacketSizeSamples;
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for (int i = 0; i < kTimes; ++i) {
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// Packet size set to 0. Do not expect the parameter
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// |kTimeStretchedSamples| to have any effect.
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filter.Update(kValue, kTimeStretchedSamples, 0 /* packet_len_samples */);
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}
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// Expect the filtered value to be
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// (1 - (251/256) ^ |kTimes|) * |kValue|.
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const int kExpectedValue = 17;
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// filtered_current_level() returns the value in Q8.
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EXPECT_EQ(kExpectedValue, filter.filtered_current_level() >> 8);
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// Update filter again, now with non-zero value for packet length.
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// Set the current filtered value to be the input, in order to isolate the
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// impact of |kTimeStretchedSamples|.
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filter.Update(filter.filtered_current_level() >> 8, kTimeStretchedSamples,
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kPacketSizeSamples);
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EXPECT_EQ(kExpectedValue - kNumPacketsStretched,
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filter.filtered_current_level() >> 8);
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// Try negative value and verify that we come back to the previous result.
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filter.Update(filter.filtered_current_level() >> 8, -kTimeStretchedSamples,
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kPacketSizeSamples);
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EXPECT_EQ(kExpectedValue, filter.filtered_current_level() >> 8);
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}
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TEST(BufferLevelFilter, TimeStretchedSamplesNegativeUnevenFrames) {
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BufferLevelFilter filter;
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filter.SetTargetBufferLevel(1); // Makes filter coefficient 251/256.
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// Update 10 times with value 100.
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const int kTimes = 10;
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const int kValue = 100;
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const int kPacketSizeSamples = 160;
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const int kTimeStretchedSamples = -3.1415 * kPacketSizeSamples;
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for (int i = 0; i < kTimes; ++i) {
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// Packet size set to 0. Do not expect the parameter
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// |kTimeStretchedSamples| to have any effect.
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filter.Update(kValue, kTimeStretchedSamples, 0 /* packet_len_samples */);
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}
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// Expect the filtered value to be
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// (1 - (251/256) ^ |kTimes|) * |kValue|.
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const int kExpectedValue = 17;
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// filtered_current_level() returns the value in Q8.
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EXPECT_EQ(kExpectedValue, filter.filtered_current_level() >> 8);
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// Update filter again, now with non-zero value for packet length.
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// Set the current filtered value to be the input, in order to isolate the
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// impact of |kTimeStretchedSamples|.
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filter.Update(filter.filtered_current_level() >> 8, kTimeStretchedSamples,
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kPacketSizeSamples);
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EXPECT_EQ(21, filter.filtered_current_level() >> 8);
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// Try negative value and verify that we come back to the previous result.
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filter.Update(filter.filtered_current_level() >> 8, -kTimeStretchedSamples,
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kPacketSizeSamples);
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EXPECT_EQ(kExpectedValue, filter.filtered_current_level() >> 8);
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}
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} // namespace webrtc
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