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// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "cc/trees/frame_rate_estimator.h"
#include "base/feature_list.h"
#include "base/strings/stringprintf.h"
#include "base/task/sequenced_task_runner.h"
#include "base/time/time.h"
#include "base/trace_event/trace_event.h"
#include "cc/base/features.h"
#include "components/viz/common/frame_sinks/begin_frame_args.h"
namespace cc {
namespace {
constexpr auto kInputPriorityDelay = base::Milliseconds(250);
} // namespace
FrameRateEstimator::FrameRateEstimator(base::SequencedTaskRunner* task_runner)
: notifier_(
task_runner,
base::BindRepeating(&FrameRateEstimator::OnExitInputPriorityMode,
base::Unretained(this)),
kInputPriorityDelay) {}
FrameRateEstimator::~FrameRateEstimator() = default;
void FrameRateEstimator::SetVideoConferenceMode(bool enabled) {
if (enabled == in_video_conference_mode_) {
return;
}
in_video_conference_mode_ = enabled;
last_draw_time_in_video_conference_mode_ = base::TimeTicks();
num_of_consecutive_frames_with_min_delta_ = 0u;
}
void FrameRateEstimator::WillDraw(base::TimeTicks now) {
TRACE_EVENT1(
"cc,benchmark", "FrameRateEstimator::WillDraw", "Info",
base::StringPrintf("\nin_video_conference_mode: %d\ninput_priority_mode: "
"%d",
in_video_conference_mode_, input_priority_mode_));
if (!in_video_conference_mode_ || input_priority_mode_) {
return;
}
if (last_draw_time_in_video_conference_mode_ == base::TimeTicks()) {
last_draw_time_in_video_conference_mode_ = now;
return;
}
auto draw_delta = now - last_draw_time_in_video_conference_mode_;
last_draw_time_in_video_conference_mode_ = now;
// If we see that the page is animating consistently at 30 fps or more, then
// we assume that BeginFrames can not be throttled. But if the animation
// frequency is lower than that, then using a lower frame rate is permitted.
// The delta below is to account for minor offsets in frame times.
constexpr auto kFudgeDelta = base::Milliseconds(1);
constexpr auto kMinDelta =
(viz::BeginFrameArgs::DefaultInterval() * 2) - kFudgeDelta;
if (draw_delta < kMinDelta)
num_of_consecutive_frames_with_min_delta_++;
else
num_of_consecutive_frames_with_min_delta_ = 0u;
}
base::TimeDelta FrameRateEstimator::GetPreferredInterval() const {
if (input_priority_mode_) {
return viz::BeginFrameArgs::MinInterval();
}
constexpr size_t kMinNumOfFramesWithMinDelta = 4u;
if (in_video_conference_mode_ &&
num_of_consecutive_frames_with_min_delta_ < kMinNumOfFramesWithMinDelta) {
return viz::BeginFrameArgs::DefaultInterval() * 2;
}
return viz::BeginFrameArgs::MinInterval();
}
void FrameRateEstimator::NotifyInputEvent() {
input_priority_mode_ = true;
notifier_.Schedule();
}
void FrameRateEstimator::OnExitInputPriorityMode() {
input_priority_mode_ = false;
last_draw_time_in_video_conference_mode_ = base::TimeTicks();
num_of_consecutive_frames_with_min_delta_ = 0u;
}
void FrameRateEstimator::DidNotProduceFrame() {
num_of_consecutive_frames_with_min_delta_ = 0u;
}
} // namespace cc
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