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/*
* Copyright (C) 2018 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
// Unit tests for Isochronous Clock Model
#include <math.h>
#include <stdlib.h>
#include <aaudio/AAudio.h>
#include <audio_utils/clock.h>
#include <client/IsochronousClockModel.h>
#include <gtest/gtest.h>
using namespace aaudio;
// We can use arbitrary values here because we are not opening a real audio stream.
#define SAMPLE_RATE 48000
#define HW_FRAMES_PER_BURST 48
// Sometimes we need a (double) value to avoid misguided Build warnings.
#define NANOS_PER_BURST ((double) NANOS_PER_SECOND * HW_FRAMES_PER_BURST / SAMPLE_RATE)
class ClockModelTestFixture: public ::testing::Test {
public:
ClockModelTestFixture() {
}
void SetUp() {
model.setSampleRate(SAMPLE_RATE);
model.setFramesPerBurst(HW_FRAMES_PER_BURST);
}
void TearDown() {
}
~ClockModelTestFixture() {
// cleanup any pending stuff, but no exceptions allowed
}
/** Test processing of timestamps when the hardware may be slightly off from
* the expected sample rate.
* @param hardwareFramesPerSecond sample rate that may be slightly off
* @param numLoops number of iterations
* @param hardwarePauseTime number of seconds to jump forward at halfway point
*/
void checkDriftingClock(double hardwareFramesPerSecond,
int numLoops,
double hardwarePauseTime = 0.0) {
int checksToSkip = 0;
const int64_t startTimeNanos = 500000000; // arbitrary
int64_t jumpOffsetNanos = 0;
srand48(123456); // arbitrary seed for repeatable test results
model.start(startTimeNanos);
const int64_t startPositionFrames = HW_FRAMES_PER_BURST; // hardware
// arbitrary time for first burst
const int64_t markerTime = startTimeNanos + NANOS_PER_MILLISECOND
+ (200 * NANOS_PER_MICROSECOND);
// Should set initial marker.
model.processTimestamp(startPositionFrames, markerTime);
ASSERT_EQ(startPositionFrames, model.convertTimeToPosition(markerTime));
double elapsedTimeSeconds = 0.0;
for (int i = 0; i < numLoops; i++) {
// Calculate random delay over several bursts.
const double timeDelaySeconds = 10.0 * drand48() * NANOS_PER_BURST / NANOS_PER_SECOND;
elapsedTimeSeconds += timeDelaySeconds;
const int64_t elapsedTimeNanos = (int64_t)(elapsedTimeSeconds * NANOS_PER_SECOND);
const int64_t currentTimeNanos = startTimeNanos + elapsedTimeNanos;
// Simulate DSP running at the specified rate.
const int64_t currentTimeFrames = startPositionFrames +
(int64_t)(hardwareFramesPerSecond * elapsedTimeSeconds);
const int64_t numBursts = currentTimeFrames / HW_FRAMES_PER_BURST;
const int64_t hardwarePosition = startPositionFrames
+ (numBursts * HW_FRAMES_PER_BURST);
// Simulate a pause in the DSP where the position freezes for a length of time.
if (i == numLoops / 2) {
jumpOffsetNanos = (int64_t)(hardwarePauseTime * NANOS_PER_SECOND);
checksToSkip = 5; // Give the model some time to catch up.
}
// Apply drifting timestamp. Add a random time to simulate the
// random sampling of the clock that occurs when polling the DSP clock.
int64_t sampledTimeNanos = (int64_t) (currentTimeNanos
+ jumpOffsetNanos
+ (drand48() * NANOS_PER_BURST));
model.processTimestamp(hardwarePosition, sampledTimeNanos);
if (checksToSkip > 0) {
checksToSkip--;
} else {
// When the model is drifting it may be pushed forward or backward.
const int64_t modelPosition = model.convertTimeToPosition(sampledTimeNanos);
if (hardwareFramesPerSecond >= SAMPLE_RATE) { // fast hardware
ASSERT_LE(hardwarePosition - HW_FRAMES_PER_BURST, modelPosition);
ASSERT_GE(hardwarePosition + HW_FRAMES_PER_BURST, modelPosition);
} else {
// Slow hardware. If this fails then the model may be drifting
// forward in time too slowly. Increase kDriftNanos.
ASSERT_LE(hardwarePosition, modelPosition);
ASSERT_GE(hardwarePosition + (2 * HW_FRAMES_PER_BURST), modelPosition);
}
}
}
}
IsochronousClockModel model;
};
// Check default setup.
TEST_F(ClockModelTestFixture, clock_setup) {
ASSERT_EQ(SAMPLE_RATE, model.getSampleRate());
ASSERT_EQ(HW_FRAMES_PER_BURST, model.getFramesPerBurst());
}
// Test delta calculations.
TEST_F(ClockModelTestFixture, clock_deltas) {
int64_t position = model.convertDeltaTimeToPosition(NANOS_PER_SECOND);
ASSERT_EQ(SAMPLE_RATE, position);
// Deltas are not quantized.
// Compare time to the equivalent position in frames.
constexpr int64_t kNanosPerBurst = HW_FRAMES_PER_BURST * NANOS_PER_SECOND / SAMPLE_RATE;
position = model.convertDeltaTimeToPosition(NANOS_PER_SECOND + (kNanosPerBurst / 2));
ASSERT_EQ(SAMPLE_RATE + (HW_FRAMES_PER_BURST / 2), position);
int64_t time = model.convertDeltaPositionToTime(SAMPLE_RATE);
ASSERT_EQ(NANOS_PER_SECOND, time);
// Compare position in frames to the equivalent time.
time = model.convertDeltaPositionToTime(SAMPLE_RATE + (HW_FRAMES_PER_BURST / 2));
ASSERT_EQ(NANOS_PER_SECOND + (kNanosPerBurst / 2), time);
}
// start() should force the internal markers
TEST_F(ClockModelTestFixture, clock_start) {
const int64_t startTime = 100000;
model.start(startTime);
int64_t position = model.convertTimeToPosition(startTime);
EXPECT_EQ(0, position);
int64_t time = model.convertPositionToTime(position);
EXPECT_EQ(startTime, time);
time = startTime + (500 * NANOS_PER_MICROSECOND);
position = model.convertTimeToPosition(time);
EXPECT_EQ(0, position);
}
// timestamps moves the window if outside the bounds
TEST_F(ClockModelTestFixture, clock_timestamp) {
const int64_t startTime = 100000000;
model.start(startTime);
const int64_t position = HW_FRAMES_PER_BURST; // hardware
int64_t markerTime = startTime + NANOS_PER_MILLISECOND + (200 * NANOS_PER_MICROSECOND);
// Should set marker.
model.processTimestamp(position, markerTime);
EXPECT_EQ(position, model.convertTimeToPosition(markerTime));
// convertTimeToPosition rounds down
EXPECT_EQ(position, model.convertTimeToPosition(markerTime + (73 * NANOS_PER_MICROSECOND)));
// convertPositionToTime rounds up
EXPECT_EQ(markerTime + (int64_t)NANOS_PER_BURST, model.convertPositionToTime(position + 17));
}
#define NUM_LOOPS_DRIFT 200000
TEST_F(ClockModelTestFixture, clock_no_drift) {
checkDriftingClock(SAMPLE_RATE, NUM_LOOPS_DRIFT);
}
// Test drifting hardware clocks.
// It is unlikely that real hardware would be off by more than this amount.
// Test a slow clock. This will cause the times to be later than expected.
// This will push the clock model window forward and cause it to drift.
TEST_F(ClockModelTestFixture, clock_slow_drift) {
checkDriftingClock(0.99998 * SAMPLE_RATE, NUM_LOOPS_DRIFT);
}
// Test a fast hardware clock. This will cause the times to be earlier
// than expected. This will cause the clock model to jump backwards quickly.
TEST_F(ClockModelTestFixture, clock_fast_drift) {
checkDriftingClock(1.00002 * SAMPLE_RATE, NUM_LOOPS_DRIFT);
}
// Simulate a pause in the DSP, which can occur if the DSP reroutes the audio.
TEST_F(ClockModelTestFixture, clock_jump_forward_500) {
checkDriftingClock(SAMPLE_RATE, NUM_LOOPS_DRIFT, 0.500);
}