Fix multi player with same frame rates.

Telegram/SourceFiles/lottie/lottie_frame_renderer.cpp

@@ -298,8 +298,6 @@ void SharedState::renderFrame(
 void SharedState::init(QImage cover, const FrameRequest &request) {
 	Expects(!initialized());
 
-	_duration = crl::time(1000) * _framesCount / _frameRate;
-
 	_frames[0].request = request;
 	_frames[0].original = std::move(cover);
 	_frames[0].position = 0;
@@ -307,13 +305,20 @@ void SharedState::init(QImage cover, const FrameRequest &request) {
 	// Usually main thread sets displayed time before _counter increment.
 	// But in this case we update _counter, so we set a fake displayed time.
 	_frames[0].displayed = kDisplaySkipped;
-
-	_counter.store(0, std::memory_order_release);
 }
 
-void SharedState::start(not_null<Player*> owner, crl::time now) {
+void SharedState::start(
+		not_null<Player*> owner,
+		crl::time started,
+		crl::time delay,
+		int skippedFrames) {
 	_owner = owner;
-	_started = now;
+	_started = started;
+	_delay = delay;
+	_skippedFrames = skippedFrames;
+
+	_frames[0].position = currentFramePosition();
+	_counter.store(0, std::memory_order_release);
 }
 
 bool IsRendered(not_null<const Frame*> frame) {
@@ -328,10 +333,14 @@ void SharedState::renderNextFrame(
 
 	renderFrame(frame->original, request, (++_frameIndex) % _framesCount);
 	PrepareFrameByRequest(frame);
-	frame->position = crl::time(1000) * _frameIndex / _frameRate;
+	frame->position = currentFramePosition();
 	frame->displayed = kTimeUnknown;
 }
 
+crl::time SharedState::currentFramePosition() const {
+	return crl::time(1000) * (_skippedFrames + _frameIndex) / _frameRate;
+}
+
 auto SharedState::renderNextFrame(const FrameRequest &request)
 -> RenderResult {
 	const auto prerender = [&](int index) -> RenderResult {
@@ -351,7 +360,7 @@ auto SharedState::renderNextFrame(const FrameRequest &request)
 		if (!IsRendered(frame)) {
 			renderNextFrame(frame, request);
 		}
-		frame->display = _started + _accumulatedDelayMs + frame->position;
+		frame->display = _started + _delay + frame->position;
 
 		// Release this frame to the main thread for rendering.
 		_counter.store(
@@ -441,7 +450,16 @@ crl::time SharedState::nextFrameDisplayTime() const {
 	Unexpected("Counter value in VideoTrack::Shared::nextFrameDisplayTime.");
 }
 
-crl::time SharedState::markFrameDisplayed(crl::time now, crl::time delayed) {
+void SharedState::addTimelineDelay(crl::time delayed) {
+	if (!delayed) {
+		return;
+	}
+
+	Assert(counter() % 2 == 1);
+	_delay += delayed;
+}
+
+crl::time SharedState::markFrameDisplayed(crl::time now) {
 	const auto mark = [&](int counter) {
 		const auto next = (counter + 1) % (2 * kFramesCount);
 		const auto index = next / 2;
@@ -455,15 +473,14 @@ crl::time SharedState::markFrameDisplayed(crl::time now, crl::time delayed) {
 		return frame->position;
 	};
 
-	_accumulatedDelayMs += delayed;
 	switch (counter()) {
-	case 0: return kTimeUnknown;
+	case 0: Unexpected("Value 0 in SharedState::markFrameDisplayed.");
 	case 1: return mark(1);
-	case 2: return kTimeUnknown;
+	case 2: Unexpected("Value 2 in SharedState::markFrameDisplayed.");
 	case 3: return mark(3);
-	case 4: return kTimeUnknown;
+	case 4: Unexpected("Value 4 in SharedState::markFrameDisplayed.");
 	case 5: return mark(5);
-	case 6: return kTimeUnknown;
+	case 6: Unexpected("Value 6 in SharedState::markFrameDisplayed.");
 	case 7: return mark(7);
 	}
 	Unexpected("Counter value in Lottie::SharedState::markFrameDisplayed.");

Telegram/SourceFiles/lottie/lottie_frame_renderer.h

@@ -57,14 +57,19 @@ public:
 		std::unique_ptr<Cache> cache,
 		const FrameRequest &request);
 
-	void start(not_null<Player*> owner, crl::time now);
+	void start(
+		not_null<Player*> owner,
+		crl::time now,
+		crl::time delay = 0,
+		int skippedFrames = 0);
 
 	[[nodiscard]] Information information() const;
 	[[nodiscard]] bool initialized() const;
 
 	[[nodiscard]] not_null<Frame*> frameForPaint();
 	[[nodiscard]] crl::time nextFrameDisplayTime() const;
-	crl::time markFrameDisplayed(crl::time now, crl::time delayed);
+	void addTimelineDelay(crl::time delayed);
+	crl::time markFrameDisplayed(crl::time now);
 	crl::time markFrameShown();
 
 	void renderFrame(QImage &image, const FrameRequest &request, int index);
@@ -88,10 +93,13 @@ private:
 	[[nodiscard]] not_null<Frame*> getFrame(int index);
 	[[nodiscard]] not_null<const Frame*> getFrame(int index) const;
 	[[nodiscard]] int counter() const;
+	[[nodiscard]] crl::time currentFramePosition() const;
 
 	QByteArray _content;
 	std::unique_ptr<rlottie::Animation> _animation;
 
+	// crl::queue changes 0,2,4,6 to 1,3,5,7.
+	// main thread changes 1,3,5,7 to 2,4,6,0.
 	static constexpr auto kCounterUninitialized = -1;
 	std::atomic<int> _counter = kCounterUninitialized;
 
@@ -100,12 +108,16 @@ private:
 
 	base::weak_ptr<Player> _owner;
 	crl::time _started = kTimeUnknown;
-	crl::time _duration = kTimeUnknown;
+
+	// (_counter % 2) == 1 main thread can write _delay.
+	// (_counter % 2) == 0 crl::queue can read _delay.
+	crl::time _delay = kTimeUnknown;
+
 	int _frameIndex = 0;
+	int _skippedFrames = 0;
 	int _framesCount = 0;
 	int _frameRate = 0;
 	QSize _size;
-	std::atomic<int> _accumulatedDelayMs = 0;
 
 	std::unique_ptr<Cache> _cache;
 

Telegram/SourceFiles/lottie/lottie_multi_player.cpp

@@ -22,6 +22,10 @@ std::shared_ptr<FrameRenderer> MakeFrameRenderer() {
 MultiPlayer::MultiPlayer(std::shared_ptr<FrameRenderer> renderer)
 : _timer([=] { checkNextFrameRender(); })
 , _renderer(renderer ? std::move(renderer) : FrameRenderer::Instance()) {
+	crl::on_main_update_requests(
+	) | rpl::start_with_next([=] {
+		checkStep();
+	}, _lifetime);
 }
 
 MultiPlayer::~MultiPlayer() {
@@ -54,26 +58,22 @@ not_null<Animation*> MultiPlayer::append(
 	return _animations.back().get();
 }
 
-crl::time MultiPlayer::startAtRightTime(not_null<SharedState*> state) {
+void MultiPlayer::startAtRightTime(not_null<SharedState*> state) {
 	Expects(!_active.empty());
 	Expects((_active.size() == 1) == (_started == kTimeUnknown));
 
+	const auto now = crl::now();
 	if (_active.size() == 1) {
-		_started = crl::now();
-		state->start(this, _started);
-		return _started;
+		_started = now;
 	}
 
-	const auto now = crl::now();
 	const auto rate = state->information().frameRate;
 	Assert(rate != 0);
 
-	const auto started = _started + _accumulatedDelay;
+	const auto started = _started + _delay;
 	const auto skipFrames = (now - started) * rate / 1000;
-	const auto startAt = started + (1000 * skipFrames / rate);
 
-	state->start(this, startAt);
-	return startAt;
+	state->start(this, _started, _delay, skipFrames);
 }
 
 void MultiPlayer::start(
@@ -81,21 +81,32 @@ void MultiPlayer::start(
 		std::unique_ptr<SharedState> state) {
 	Expects(state != nullptr);
 
+	if (_nextFrameTime == kTimeUnknown) {
+		appendToActive(animation, std::move(state));
+	} else {
+		// We always try to mark as shown at the same time, so we start a new
+		// animation at the same time we mark all existing as shown.
+		_pendingToStart.emplace(animation, std::move(state));
+	}
+}
+
+void MultiPlayer::appendPendingToActive() {
+	for (auto &[animation, state] : base::take(_pendingToStart)) {
+		appendToActive(animation, std::move(state));
+	}
+}
+
+void MultiPlayer::appendToActive(
+		not_null<Animation*> animation,
+		std::unique_ptr<SharedState> state) {
+	Expects(_nextFrameTime == kTimeUnknown);
+
 	_active.emplace(animation, state.get());
 
 	auto information = state->information();
 	startAtRightTime(state.get());
 	_renderer->append(std::move(state));
 	_updates.fire({});
-
-	crl::on_main_update_requests(
-	) | rpl::start_with_next([=] {
-		checkStep();
-	}, _lifetime);
-
-	_nextFrameTime = kTimeUnknown;
-	_timer.cancel();
-	checkStep();
 }
 
 void MultiPlayer::remove(not_null<Animation*> animation) {
@@ -112,7 +123,7 @@ void MultiPlayer::remove(not_null<Animation*> animation) {
 
 	if (_active.empty()) {
 		_started = kTimeUnknown;
-		_accumulatedDelay = 0;
+		_delay = 0;
 		_nextFrameTime = kTimeUnknown;
 		_timer.cancel();
 	}
@@ -127,7 +138,7 @@ rpl::producer<MultiUpdate> MultiPlayer::updates() const {
 }
 
 void MultiPlayer::checkStep() {
-	if (_nextFrameTime == kFrameDisplayTimeAlreadyDone) {
+	if (_active.empty() || _nextFrameTime == kFrameDisplayTimeAlreadyDone) {
 		return;
 	} else if (_nextFrameTime != kTimeUnknown) {
 		checkNextFrameRender();
@@ -139,9 +150,6 @@ void MultiPlayer::checkStep() {
 void MultiPlayer::checkNextFrameAvailability() {
 	Expects(_nextFrameTime == kTimeUnknown);
 
-	if (_active.empty()) {
-		return;
-	}
 	auto next = kTimeUnknown;
 	for (const auto &[animation, state] : _active) {
 		const auto time = state->nextFrameDisplayTime();
@@ -181,10 +189,10 @@ void MultiPlayer::checkNextFrameRender() {
 	} else {
 		_timer.cancel();
 
-		const auto exact = std::exchange(
-			_nextFrameTime,
-			kFrameDisplayTimeAlreadyDone);
-		markFrameDisplayed(now, now - exact);
+		markFrameDisplayed(now);
+		addTimelineDelay(now - _nextFrameTime);
+
+		_nextFrameTime = kFrameDisplayTimeAlreadyDone;
 		_updates.fire({});
 	}
 }
@@ -198,7 +206,7 @@ void MultiPlayer::updateFrameRequest(
 	_renderer->updateFrameRequest(i->second, request);
 }
 
-void MultiPlayer::markFrameDisplayed(crl::time now, crl::time delayed) {
+void MultiPlayer::markFrameDisplayed(crl::time now) {
 	Expects(!_active.empty());
 
 	auto displayed = 0;
@@ -210,17 +218,27 @@ void MultiPlayer::markFrameDisplayed(crl::time now, crl::time delayed) {
 			continue;
 		} else if (now >= time) {
 			++displayed;
-			state->markFrameDisplayed(now, delayed);
+			state->markFrameDisplayed(now);
 		} else {
 			++waiting;
 		}
 	}
-	PROFILE_LOG(("PLAYER FRAME DISPLAYED AT: %1, DELAYED: %2, (MARKED %3, WAITING %4)").arg(now).arg(delayed).arg(displayed).arg(waiting));
+	PROFILE_LOG(("PLAYER FRAME DISPLAYED AT: %1 (MARKED %2, WAITING %3)").arg(now).arg(displayed).arg(waiting));
+}
+
+void MultiPlayer::addTimelineDelay(crl::time delayed) {
+	Expects(!_active.empty());
+
+	for (const auto &[animation, state] : _active) {
+		state->addTimelineDelay(delayed);
+	}
+	_delay += delayed;
 }
 
 void MultiPlayer::markFrameShown() {
 	if (_nextFrameTime == kFrameDisplayTimeAlreadyDone) {
 		_nextFrameTime = kTimeUnknown;
+		appendPendingToActive();
 	}
 	auto count = 0;
 	for (const auto &[animation, state] : _active) {

Telegram/SourceFiles/lottie/lottie_multi_player.h

@@ -56,8 +56,13 @@ public:
 	void remove(not_null<Animation*> animation);
 
 private:
-	crl::time startAtRightTime(not_null<SharedState*> state);
-	void markFrameDisplayed(crl::time now, crl::time delayed);
+	void appendToActive(
+		not_null<Animation*> animation,
+		std::unique_ptr<SharedState> state);
+	void startAtRightTime(not_null<SharedState*> state);
+	void appendPendingToActive();
+	void markFrameDisplayed(crl::time now);
+	void addTimelineDelay(crl::time delayed);
 	void checkNextFrameAvailability();
 	void checkNextFrameRender();
 
@@ -65,9 +70,12 @@ private:
 	const std::shared_ptr<FrameRenderer> _renderer;
 	std::vector<std::unique_ptr<Animation>> _animations;
 	base::flat_map<not_null<Animation*>, not_null<SharedState*>> _active;
+	base::flat_map<
+		not_null<Animation*>,
+		std::unique_ptr<SharedState>> _pendingToStart;
 	//base::flat_map<not_null<Animation*>, not_null<SharedState*>> _paused;
 	crl::time _started = kTimeUnknown;
-	crl::time _accumulatedDelay = 0;
+	crl::time _delay = 0;
 	crl::time _nextFrameTime = kTimeUnknown;
 	rpl::event_stream<MultiUpdate> _updates;
 	rpl::lifetime _lifetime;

Telegram/SourceFiles/lottie/lottie_single_player.cpp

@@ -102,10 +102,10 @@ void SinglePlayer::checkNextFrameRender() {
 	} else {
 		_timer.cancel();
 
-		const auto exact = std::exchange(
-			_nextFrameTime,
-			kFrameDisplayTimeAlreadyDone);
-		const auto position = _state->markFrameDisplayed(now, now - exact);
+		const auto position = _state->markFrameDisplayed(now);
+		_state->addTimelineDelay(now - _nextFrameTime);
+
+		_nextFrameTime = kFrameDisplayTimeAlreadyDone;
 		_updates.fire({ DisplayFrameRequest{ position } });
 	}
 }