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2ddc39e2b9
When pacing is enabled for the low latency rendering path, frames are sent to the decoder in regular intervals. In case of a jitter, these frames intervals could add up to create a large latency. Hence, disable frame pacing if the pre-decode queue grows beyond the threshold. The threshold for when to disable frame pacing is set through a field trial. The default value is high enough so that the behavior is not changed unless the field trial is specified. Bug: chromium:1237402 Change-Id: I901fd579f68da286eca3d654118f60d3c55e21ce Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/228241 Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org> Commit-Queue: Johannes Kron <kron@webrtc.org> Cr-Commit-Position: refs/heads/master@{#34705}
282 lines
12 KiB
C++
282 lines
12 KiB
C++
/*
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* Copyright (c) 2011 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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#include "modules/video_coding/timing.h"
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#include "system_wrappers/include/clock.h"
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#include "test/field_trial.h"
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#include "test/gtest.h"
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namespace webrtc {
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namespace {
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const int kFps = 25;
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} // namespace
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TEST(ReceiverTimingTest, JitterDelay) {
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SimulatedClock clock(0);
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VCMTiming timing(&clock);
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timing.Reset();
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uint32_t timestamp = 0;
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timing.UpdateCurrentDelay(timestamp);
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timing.Reset();
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timing.IncomingTimestamp(timestamp, clock.TimeInMilliseconds());
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uint32_t jitter_delay_ms = 20;
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timing.SetJitterDelay(jitter_delay_ms);
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timing.UpdateCurrentDelay(timestamp);
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timing.set_render_delay(0);
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uint32_t wait_time_ms = timing.MaxWaitingTime(
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timing.RenderTimeMs(timestamp, clock.TimeInMilliseconds()),
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clock.TimeInMilliseconds(), /*too_many_frames_queued=*/false);
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// First update initializes the render time. Since we have no decode delay
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// we get wait_time_ms = renderTime - now - renderDelay = jitter.
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EXPECT_EQ(jitter_delay_ms, wait_time_ms);
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jitter_delay_ms += VCMTiming::kDelayMaxChangeMsPerS + 10;
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timestamp += 90000;
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clock.AdvanceTimeMilliseconds(1000);
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timing.SetJitterDelay(jitter_delay_ms);
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timing.UpdateCurrentDelay(timestamp);
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wait_time_ms = timing.MaxWaitingTime(
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timing.RenderTimeMs(timestamp, clock.TimeInMilliseconds()),
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clock.TimeInMilliseconds(), /*too_many_frames_queued=*/false);
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// Since we gradually increase the delay we only get 100 ms every second.
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EXPECT_EQ(jitter_delay_ms - 10, wait_time_ms);
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timestamp += 90000;
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clock.AdvanceTimeMilliseconds(1000);
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timing.UpdateCurrentDelay(timestamp);
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wait_time_ms = timing.MaxWaitingTime(
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timing.RenderTimeMs(timestamp, clock.TimeInMilliseconds()),
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clock.TimeInMilliseconds(), /*too_many_frames_queued=*/false);
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EXPECT_EQ(jitter_delay_ms, wait_time_ms);
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// Insert frames without jitter, verify that this gives the exact wait time.
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const int kNumFrames = 300;
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for (int i = 0; i < kNumFrames; i++) {
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clock.AdvanceTimeMilliseconds(1000 / kFps);
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timestamp += 90000 / kFps;
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timing.IncomingTimestamp(timestamp, clock.TimeInMilliseconds());
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}
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timing.UpdateCurrentDelay(timestamp);
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wait_time_ms = timing.MaxWaitingTime(
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timing.RenderTimeMs(timestamp, clock.TimeInMilliseconds()),
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clock.TimeInMilliseconds(), /*too_many_frames_queued=*/false);
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EXPECT_EQ(jitter_delay_ms, wait_time_ms);
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// Add decode time estimates for 1 second.
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const uint32_t kDecodeTimeMs = 10;
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for (int i = 0; i < kFps; i++) {
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clock.AdvanceTimeMilliseconds(kDecodeTimeMs);
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timing.StopDecodeTimer(kDecodeTimeMs, clock.TimeInMilliseconds());
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timestamp += 90000 / kFps;
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clock.AdvanceTimeMilliseconds(1000 / kFps - kDecodeTimeMs);
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timing.IncomingTimestamp(timestamp, clock.TimeInMilliseconds());
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}
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timing.UpdateCurrentDelay(timestamp);
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wait_time_ms = timing.MaxWaitingTime(
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timing.RenderTimeMs(timestamp, clock.TimeInMilliseconds()),
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clock.TimeInMilliseconds(), /*too_many_frames_queued=*/false);
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EXPECT_EQ(jitter_delay_ms, wait_time_ms);
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const int kMinTotalDelayMs = 200;
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timing.set_min_playout_delay(kMinTotalDelayMs);
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clock.AdvanceTimeMilliseconds(5000);
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timestamp += 5 * 90000;
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timing.UpdateCurrentDelay(timestamp);
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const int kRenderDelayMs = 10;
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timing.set_render_delay(kRenderDelayMs);
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wait_time_ms = timing.MaxWaitingTime(
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timing.RenderTimeMs(timestamp, clock.TimeInMilliseconds()),
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clock.TimeInMilliseconds(), /*too_many_frames_queued=*/false);
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// We should at least have kMinTotalDelayMs - decodeTime (10) - renderTime
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// (10) to wait.
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EXPECT_EQ(kMinTotalDelayMs - kDecodeTimeMs - kRenderDelayMs, wait_time_ms);
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// The total video delay should be equal to the min total delay.
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EXPECT_EQ(kMinTotalDelayMs, timing.TargetVideoDelay());
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// Reset playout delay.
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timing.set_min_playout_delay(0);
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clock.AdvanceTimeMilliseconds(5000);
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timestamp += 5 * 90000;
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timing.UpdateCurrentDelay(timestamp);
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}
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TEST(ReceiverTimingTest, TimestampWrapAround) {
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SimulatedClock clock(0);
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VCMTiming timing(&clock);
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// Provoke a wrap-around. The fifth frame will have wrapped at 25 fps.
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uint32_t timestamp = 0xFFFFFFFFu - 3 * 90000 / kFps;
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for (int i = 0; i < 5; ++i) {
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timing.IncomingTimestamp(timestamp, clock.TimeInMilliseconds());
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clock.AdvanceTimeMilliseconds(1000 / kFps);
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timestamp += 90000 / kFps;
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EXPECT_EQ(3 * 1000 / kFps,
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timing.RenderTimeMs(0xFFFFFFFFu, clock.TimeInMilliseconds()));
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EXPECT_EQ(3 * 1000 / kFps + 1,
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timing.RenderTimeMs(89u, // One ms later in 90 kHz.
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clock.TimeInMilliseconds()));
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}
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}
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TEST(ReceiverTimingTest, MaxWaitingTimeIsZeroForZeroRenderTime) {
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// This is the default path when the RTP playout delay header extension is set
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// to min==0.
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constexpr int64_t kStartTimeUs = 3.15e13; // About one year in us.
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constexpr int64_t kTimeDeltaMs = 1000.0 / 60.0;
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constexpr int64_t kZeroRenderTimeMs = 0;
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SimulatedClock clock(kStartTimeUs);
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VCMTiming timing(&clock);
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timing.Reset();
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for (int i = 0; i < 10; ++i) {
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clock.AdvanceTimeMilliseconds(kTimeDeltaMs);
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int64_t now_ms = clock.TimeInMilliseconds();
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EXPECT_LT(timing.MaxWaitingTime(kZeroRenderTimeMs, now_ms,
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/*too_many_frames_queued=*/false),
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0);
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}
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// Another frame submitted at the same time also returns a negative max
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// waiting time.
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int64_t now_ms = clock.TimeInMilliseconds();
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EXPECT_LT(timing.MaxWaitingTime(kZeroRenderTimeMs, now_ms,
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/*too_many_frames_queued=*/false),
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0);
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// MaxWaitingTime should be less than zero even if there's a burst of frames.
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EXPECT_LT(timing.MaxWaitingTime(kZeroRenderTimeMs, now_ms,
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/*too_many_frames_queued=*/false),
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0);
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EXPECT_LT(timing.MaxWaitingTime(kZeroRenderTimeMs, now_ms,
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/*too_many_frames_queued=*/false),
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0);
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EXPECT_LT(timing.MaxWaitingTime(kZeroRenderTimeMs, now_ms,
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/*too_many_frames_queued=*/false),
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0);
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}
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TEST(ReceiverTimingTest, MaxWaitingTimeZeroDelayPacingExperiment) {
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// The minimum pacing is enabled by a field trial and active if the RTP
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// playout delay header extension is set to min==0.
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constexpr int64_t kMinPacingMs = 3;
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test::ScopedFieldTrials override_field_trials(
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"WebRTC-ZeroPlayoutDelay/min_pacing:3ms/");
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constexpr int64_t kStartTimeUs = 3.15e13; // About one year in us.
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constexpr int64_t kTimeDeltaMs = 1000.0 / 60.0;
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constexpr int64_t kZeroRenderTimeMs = 0;
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SimulatedClock clock(kStartTimeUs);
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VCMTiming timing(&clock);
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timing.Reset();
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// MaxWaitingTime() returns zero for evenly spaced video frames.
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for (int i = 0; i < 10; ++i) {
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clock.AdvanceTimeMilliseconds(kTimeDeltaMs);
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int64_t now_ms = clock.TimeInMilliseconds();
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EXPECT_EQ(timing.MaxWaitingTime(kZeroRenderTimeMs, now_ms,
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/*too_many_frames_queued=*/false),
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0);
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timing.SetLastDecodeScheduledTimestamp(now_ms);
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}
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// Another frame submitted at the same time is paced according to the field
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// trial setting.
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int64_t now_ms = clock.TimeInMilliseconds();
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EXPECT_EQ(timing.MaxWaitingTime(kZeroRenderTimeMs, now_ms,
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/*too_many_frames_queued=*/false),
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kMinPacingMs);
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// If there's a burst of frames, the wait time is calculated based on next
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// decode time.
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EXPECT_EQ(timing.MaxWaitingTime(kZeroRenderTimeMs, now_ms,
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/*too_many_frames_queued=*/false),
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kMinPacingMs);
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EXPECT_EQ(timing.MaxWaitingTime(kZeroRenderTimeMs, now_ms,
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/*too_many_frames_queued=*/false),
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kMinPacingMs);
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// Allow a few ms to pass, this should be subtracted from the MaxWaitingTime.
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constexpr int64_t kTwoMs = 2;
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clock.AdvanceTimeMilliseconds(kTwoMs);
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now_ms = clock.TimeInMilliseconds();
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EXPECT_EQ(timing.MaxWaitingTime(kZeroRenderTimeMs, now_ms,
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/*too_many_frames_queued=*/false),
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kMinPacingMs - kTwoMs);
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// A frame is decoded at the current time, the wait time should be restored to
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// pacing delay.
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timing.SetLastDecodeScheduledTimestamp(now_ms);
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EXPECT_EQ(timing.MaxWaitingTime(kZeroRenderTimeMs, now_ms,
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/*too_many_frames_queued=*/false),
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kMinPacingMs);
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}
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TEST(ReceiverTimingTest, DefaultMaxWaitingTimeUnaffectedByPacingExperiment) {
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// The minimum pacing is enabled by a field trial but should not have any
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// effect if render_time_ms is greater than 0;
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test::ScopedFieldTrials override_field_trials(
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"WebRTC-ZeroPlayoutDelay/min_pacing:3ms/");
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constexpr int64_t kStartTimeUs = 3.15e13; // About one year in us.
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constexpr int64_t kTimeDeltaMs = 1000.0 / 60.0;
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SimulatedClock clock(kStartTimeUs);
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VCMTiming timing(&clock);
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timing.Reset();
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clock.AdvanceTimeMilliseconds(kTimeDeltaMs);
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int64_t now_ms = clock.TimeInMilliseconds();
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int64_t render_time_ms = now_ms + 30;
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// Estimate the internal processing delay from the first frame.
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int64_t estimated_processing_delay =
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(render_time_ms - now_ms) -
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timing.MaxWaitingTime(render_time_ms, now_ms,
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/*too_many_frames_queued=*/false);
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EXPECT_GT(estimated_processing_delay, 0);
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// Any other frame submitted at the same time should be scheduled according to
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// its render time.
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for (int i = 0; i < 5; ++i) {
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render_time_ms += kTimeDeltaMs;
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EXPECT_EQ(timing.MaxWaitingTime(render_time_ms, now_ms,
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/*too_many_frames_queued=*/false),
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render_time_ms - now_ms - estimated_processing_delay);
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}
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}
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TEST(ReceiverTiminTest, MaxWaitingTimeReturnsZeroIfTooManyFramesQueuedIsTrue) {
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// The minimum pacing is enabled by a field trial and active if the RTP
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// playout delay header extension is set to min==0.
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constexpr int64_t kMinPacingMs = 3;
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test::ScopedFieldTrials override_field_trials(
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"WebRTC-ZeroPlayoutDelay/min_pacing:3ms/");
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constexpr int64_t kStartTimeUs = 3.15e13; // About one year in us.
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constexpr int64_t kTimeDeltaMs = 1000.0 / 60.0;
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constexpr int64_t kZeroRenderTimeMs = 0;
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SimulatedClock clock(kStartTimeUs);
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VCMTiming timing(&clock);
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timing.Reset();
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// MaxWaitingTime() returns zero for evenly spaced video frames.
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for (int i = 0; i < 10; ++i) {
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clock.AdvanceTimeMilliseconds(kTimeDeltaMs);
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int64_t now_ms = clock.TimeInMilliseconds();
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EXPECT_EQ(timing.MaxWaitingTime(kZeroRenderTimeMs, now_ms,
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/*too_many_frames_queued=*/false),
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0);
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timing.SetLastDecodeScheduledTimestamp(now_ms);
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}
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// Another frame submitted at the same time is paced according to the field
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// trial setting.
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int64_t now_ms = clock.TimeInMilliseconds();
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EXPECT_EQ(timing.MaxWaitingTime(kZeroRenderTimeMs, now_ms,
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/*too_many_frames_queued=*/false),
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kMinPacingMs);
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// MaxWaitingTime returns 0 even if there's a burst of frames if
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// too_many_frames_queued is set to true.
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EXPECT_EQ(timing.MaxWaitingTime(kZeroRenderTimeMs, now_ms,
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/*too_many_frames_queued=*/true),
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0);
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EXPECT_EQ(timing.MaxWaitingTime(kZeroRenderTimeMs, now_ms,
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/*too_many_frames_queued=*/true),
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0);
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}
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} // namespace webrtc
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