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LibVideo: Check whether it's time to present frames before doing so

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Previously, we assumed the timer was hitting at the correct time. This
meant that if we changed states and the previous state handler had
prepared a next frame, we would immediately display it without checking
the timestamp.
This commit is contained in:
Zaggy1024 2023-02-12 02:00:59 -06:00 • committed by Andreas Kling
parent 5da0c6f916
commit f9a65c1502
1 changed files with 14 additions and 5 deletions
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19
Userland/Libraries/LibVideo/PlaybackManager.cpp
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@ -313,6 +313,19 @@ private:
ErrorOr<void> on_timer_callback() override
{
auto set_presentation_timer = [&]() {
auto frame_time_ms = (manager().m_next_frame->timestamp() - current_time()).to_milliseconds();
VERIFY(frame_time_ms <= NumericLimits<int>::max());
dbgln_if(PLAYBACK_MANAGER_DEBUG, "Time until next frame is {}ms", frame_time_ms);
manager().start_timer(max(static_cast<int>(frame_time_ms), 0));
};
if (manager().m_next_frame.has_value() && manager().m_next_frame->timestamp() < current_time()) {
dbgln_if(PLAYBACK_MANAGER_DEBUG, "Current time {}ms is too early to present the next frame at {}ms, delaying", current_time().to_milliseconds(), manager().m_next_frame->timestamp().to_milliseconds());
set_presentation_timer();
return {};
}
Optional<FrameQueueItem> future_frame_item;
bool should_present_frame = false;
@ -381,11 +394,7 @@ private:
// The future frame item becomes the next one to present.
manager().m_next_frame.emplace(future_frame_item.release_value());
auto frame_time_ms = (manager().m_next_frame->timestamp() - current_time()).to_milliseconds();
VERIFY(frame_time_ms <= NumericLimits<int>::max());
dbgln_if(PLAYBACK_MANAGER_DEBUG, "Time until next frame is {}ms", frame_time_ms);
manager().start_timer(max(static_cast<int>(frame_time_ms), 0));
set_presentation_timer();
return {};
}