gramps
5e78065c2d
The recording is 60fps but WebView2 capture was a blind 100ms DispatcherTimer = 10Hz; each captured web frame repeated ~6x into the file caps web animation at the capture rate, not the page's (user: 'the animation appears to be too slow'). - New CaptureScheduler (Services/CaptureScheduler.cs): per-session dispatcher timer that DROPS a tick while a capture is in flight (latest-wins, never queues) — the guard that makes a higher cadence safe: concurrent full-HD PNG CapturePreviewAsync calls (~10-30ms each, slow per WebView2Feedback#20) would stack CPU and publish stale-after-fresh. Effective cadence = max(interval, capture duration). - Cadence: SetCaptureInterval(33) on record/stream start, (200) idle — applied via MainViewModel.Streaming.Operations.cs. - De-throttle the hidden page: shared CoreWebView2Environment created BEFORE EnsureCoreWebView2Async with --disable-backgrounding-occluded-windows --disable-renderer-backgrounding --disable-features=CalculateNativeWinOcclusion. Off-screen WebView2 is a hidden page when the host window is unfocused/covered and Chromium then parks rAF and clamps timers to ~1s (WebView2Feedback#1172/#3070, Chrome-88 timer-throttling blog). - Telemetry: first 30 captures per session log elapsed ms (PNG encode + decode) to startup.log — that decides whether ~30Hz stays or drops to ~20Hz; the FramePump drops frames (never time-lapses, slice 10) if UI-thread GC churn starves it. - ONE test: CaptureScheduler_Drops_Ticks_While_Capture_InFlight_And_Resumes (deterministic TCS-driven, no WebView2 runtime). Suite 290/291 — sole failure the pre-existing compositor pixel test. - Docs same-commit: ai.md slice 11, MyMistakes.md, HANDOFF. References: https://github.com/MicrosoftEdge/WebView2Feedback/issues/1172 https://github.com/MicrosoftEdge/WebView2Feedback/issues/3070 https://github.com/MicrosoftEdge/WebView2Feedback/issues/20 https://developer.chrome.com/blog/timer-throttling-in-chrome-88
73 lines
2.3 KiB
C#
73 lines
2.3 KiB
C#
using System;
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using System.Threading.Tasks;
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using System.Windows.Threading;
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namespace ytLive.Services;
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/// <summary>Per-session web capture pace: a DispatcherTimer that drops ticks while a
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/// capture is in flight (latest-wins). Raising the naive 10Hz cadence to ~30Hz would
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/// stack concurrent CapturePreviewAsync calls (a full 1920×1080 PNG encode costs
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/// ~10-30ms), so overlapping ticks are dropped, never queued; the effective cadence
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/// is max(interval, capture duration). The interval and the in-flight drop live here,
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/// not in the manager, so the scheduler is unit-testable without a WebView2 runtime.</summary>
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internal sealed class CaptureScheduler
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{
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private readonly Dispatcher _dispatcher;
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private readonly Func<Task> _capture;
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private DispatcherTimer? _timer;
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private int _intervalMs;
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private bool _inFlight;
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private Task _pending = Task.CompletedTask;
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public CaptureScheduler(Dispatcher dispatcher, int intervalMs, Func<Task> capture)
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{
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_dispatcher = dispatcher;
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_intervalMs = Math.Max(16, intervalMs);
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_capture = capture;
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}
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/// <summary>The task of the capture currently in flight, or a completed task when
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/// idle. Test seam: lets the caller await exactly the running capture.</summary>
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internal Task Pending => _pending;
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public void Start()
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{
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if (_timer != null) return;
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_timer = new DispatcherTimer(
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TimeSpan.FromMilliseconds(_intervalMs),
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DispatcherPriority.Background,
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(_, _) => Tick(),
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_dispatcher);
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_timer.Start();
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}
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public void Stop() => _timer?.Stop();
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public void SetInterval(int milliseconds)
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{
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_intervalMs = Math.Max(16, milliseconds);
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if (_timer != null) _timer.Interval = TimeSpan.FromMilliseconds(_intervalMs);
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}
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/// <summary>Runs the capture unless one is already in flight — the dropped tick is
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/// the latest-wins policy. Tick runs on the dispatcher thread (timer + test), so
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/// _inFlight needs no locking.</summary>
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internal void Tick()
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{
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if (_inFlight) return;
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_inFlight = true;
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_pending = RunCapture();
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}
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private async Task RunCapture()
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{
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try
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{
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await _capture();
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}
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finally
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{
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_inFlight = false;
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}
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}
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} |