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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
* Copyright (C) 2019, Google Inc.
*
* timeline.cpp - Timeline for per-frame control
*/
#include "timeline.h"
#include "libcamera/internal/log.h"
/**
* \file timeline.h
* \brief Timeline for per-frame control
*/
namespace libcamera {
LOG_DEFINE_CATEGORY(Timeline)
/**
* \class FrameAction
* \brief Action that can be schedule on a Timeline
*
* A frame action is an event schedule to be executed on a Timeline. A frame
* action has two primal attributes a frame number and a type.
*
* The frame number describes the frame to which the action is associated. The
* type is a numerical ID which identifies the action within the pipeline and
* IPA protocol.
*/
/**
* \class Timeline
* \brief Executor of FrameAction
*
* The timeline has three primary functions:
*
* 1. Keep track of the Start of Exposure (SOE) for every frame processed by
* the hardware. Using this information it shall keep an up-to-date estimate
* of the frame interval (time between two consecutive SOE events).
*
* The estimated frame interval together with recorded SOE events are the
* foundation for how the timeline schedule FrameAction at specific points
* in time.
* \todo Improve the frame interval estimation algorithm.
*
* 2. Keep track of current delays for different types of actions. The delays
* for different actions might differ during a capture session. Exposure time
* effects the over all FPS and different ISP parameters might impacts its
* processing time.
*
* The action type delays shall be updated by the IPA in conjunction with
* how it changes the capture parameters.
*
* 3. Schedule actions on the timeline. This is the process of taking a
* FrameAction which contains an abstract description of what frame and
* what type of action it contains and turning that into an time point
* and make sure the action is executed at that time.
*/
Timeline::Timeline()
: frameInterval_(0)
{
timer_.timeout.connect(this, &Timeline::timeout);
}
/**
* \brief Reset and stop the timeline
*
* The timeline needs to be reset when the timeline should no longer execute
* actions. A timeline should be reset between two capture sessions to prevent
* the old capture session to effect the second one.
*/
void Timeline::reset()
{
timer_.stop();
actions_.clear();
history_.clear();
}
/**
* \brief Schedule an action on the timeline
* \param[in] action FrameAction to schedule
*
* The act of scheduling an action to the timeline is the process of taking
* the properties of the action (type, frame and time offsets) and translating
* that to a time point using the current values for the action type timings
* value recorded in the timeline. If an action is scheduled too late, execute
* it immediately.
*/
void Timeline::scheduleAction(std::unique_ptr<FrameAction> action)
{
unsigned int lastFrame;
utils::time_point lastTime;
if (history_.empty()) {
lastFrame = 0;
lastTime = std::chrono::steady_clock::now();
} else {
lastFrame = history_.back().first;
lastTime = history_.back().second;
}
/*
* Calculate when the action shall be schedule by first finding out how
* many frames in the future the action acts on and then add the actions
* frame offset. After the spatial frame offset is found out translate
* that to a time point by using the last estimated start of exposure
* (SOE) as the fixed offset. Lastly add the action time offset to the
* time point.
*/
int frame = action->frame() - lastFrame + frameOffset(action->type());
utils::time_point deadline = lastTime + frame * frameInterval_
+ timeOffset(action->type());
utils::time_point now = std::chrono::steady_clock::now();
if (deadline < now) {
LOG(Timeline, Warning)
<< "Action scheduled too late "
<< utils::time_point_to_string(deadline)
<< ", run now " << utils::time_point_to_string(now);
action->run();
} else {
actions_.emplace(deadline, std::move(action));
updateDeadline();
}
}
void Timeline::notifyStartOfExposure(unsigned int frame, utils::time_point time)
{
history_.push_back(std::make_pair(frame, time));
if (history_.size() <= HISTORY_DEPTH / 2)
return;
while (history_.size() > HISTORY_DEPTH)
history_.pop_front();
/* Update esitmated time between two start of exposures. */
utils::duration sumExposures(0);
unsigned int numExposures = 0;
utils::time_point lastTime;
for (auto it = history_.begin(); it != history_.end(); it++) {
if (it != history_.begin()) {
sumExposures += it->second - lastTime;
numExposures++;
}
lastTime = it->second;
}
frameInterval_ = sumExposures;
if (numExposures)
frameInterval_ /= numExposures;
}
int Timeline::frameOffset(unsigned int type) const
{
const auto it = delays_.find(type);
if (it == delays_.end()) {
LOG(Timeline, Error)
<< "No frame offset set for action type " << type;
return 0;
}
return it->second.first;
}
utils::duration Timeline::timeOffset(unsigned int type) const
{
const auto it = delays_.find(type);
if (it == delays_.end()) {
LOG(Timeline, Error)
<< "No time offset set for action type " << type;
return utils::duration::zero();
}
return it->second.second;
}
void Timeline::setRawDelay(unsigned int type, int frame, utils::duration time)
{
delays_[type] = std::make_pair(frame, time);
}
void Timeline::updateDeadline()
{
if (actions_.empty())
return;
const utils::time_point &deadline = actions_.begin()->first;
if (timer_.isRunning() && deadline >= timer_.deadline())
return;
if (deadline <= std::chrono::steady_clock::now()) {
timeout(&timer_);
return;
}
timer_.start(deadline);
}
void Timeline::timeout(Timer *timer)
{
utils::time_point now = std::chrono::steady_clock::now();
for (auto it = actions_.begin(); it != actions_.end();) {
const utils::time_point &sched = it->first;
if (sched > now)
break;
FrameAction *action = it->second.get();
action->run();
it = actions_.erase(it);
}
updateDeadline();
}
} /* namespace libcamera */
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