gramps
09a866e6a1
Take 9's numbers were decisive: paste cache moved work to ~25ms/frame but the period stayed ~37ms. The missing ~12ms per tick is Task.Delay rounding every sub-tick request up to the Windows system-clock tick (~15.6ms default — documented: learn.microsoft.com/en-us/dotnet/api/system.threading.tasks.task.delay). A frame finishing 3ms early requested 3ms and slept 15.6. Producer capped at ~27fps no matter how fast the compositor got — which is why two real render fixes read as 'zero change' in playback. Game-loop/OBS canon for this (stackoverflow.com/questions/5441464; learn.microsoft.com/en-us/windows/win32/ api/timeapi/nf-timeapi-timebeginperiod): raise the timer resolution for the session, sleep only the bulk of the remainder, and SPIN the last ~2ms across the deadline. - FramePump: timeBeginPeriod(1) on entering the pump loop, timeEndPeriod(1) in the finally; pacing = bulk _pacingDelay(ahead - 2ms) + bounded Thread.SpinWait tail; blown deadlines rebase unchanged (never burst). - Stats now report avg wait: render+submit+wait must equal the period — the accounting is closed, no stage can hide in an unmeasured gap again. - Webcam dropped its IsOpaque paste-cache bypass: it re-sampled ~156k px every tick even between identical device frames; cached paste beats the sampler on hits, costs the same on misses. 52/52 per-class green (pacing + pixel suites unchanged — output byte-stable), clean build 0 warnings. Docs same commit (ai.md slice 6, TASKS.md take-10 gate, MyMistakes #3 + renumber, HANDOFF). User's top-bar spec remains next in queue (Unit B) — re-sent many times, captured, no open questions.
479 lines
21 KiB
C#
479 lines
21 KiB
C#
using System;
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using System.Threading;
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using System.Threading.Tasks;
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using ytLive.Models;
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using ytLive.Services.Compositor;
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namespace ytLive.Services.Encoder;
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/// <summary>
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/// The live frame producer (TASK 4 ship step 5): the bridge between the capture
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/// managers + compositor and the encoder. While live it snapshots the active
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/// scene each tick, resolves every element to its latest frame, composites it
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/// into the tier's output frame, and paces frames into the encoder at the tier's
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/// FPS. All collaborators are constructor-injected seams (scene, resolver,
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/// options, encoder factory, pacing delay) so the pump stays free of WPF and of
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/// the capture managers and is fully hermetic in tests.
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///
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/// The RTMP URL comes from the options provider: until the live-stream create
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/// flow lands (TASK 5) it yields null, so go-live runs the existing visual flow
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/// without actually pushing.
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/// </summary>
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public sealed class FramePump : IDisposable
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{
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private readonly Func<Scene?> _sceneProvider;
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private readonly Func<SceneElement, VideoFrame?> _frameResolver;
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private readonly Func<CompositorOptions> _compositorOptions;
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private readonly Func<EncoderOptions?> _encoderOptions;
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private readonly Func<IFfmpegEncoder> _encoderFactory;
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private readonly Action<string>? _log;
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private readonly Func<TimeSpan, CancellationToken, Task> _pacingDelay;
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private readonly Func<(VideoFrame? Frame, SocialBarPosition Position)>? _socialBar;
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private readonly TransitionService? _transition;
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private readonly SceneGraph? _sceneGraph;
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private readonly SceneCompositor _compositor = new();
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// Master-buffer scratch pool (take-4 starvation fix, slice 2 of 2): a fresh
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// 8.3MB byte[] every tick is ~500MB/s of LOH churn — GC stalls masquerading
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// as render cost. The pump pools ONLY buffers it handed out (reference-equality
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// set), so bake-cache / social-bar / static-cache frames are never touched;
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// SubmitFrameAsync copies the bytes to the encoder's stdin before returning,
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// so recycling after submit is safe (MyMistakes recipe).
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private readonly HashSet<byte[]> _ownedScratch = new(ReferenceEqualityComparer.Instance);
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private readonly List<byte[]> _freeScratch = new();
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private const int MaxScratchPooled = 4;
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private byte[] AcquireScratch(int size)
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{
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for (var i = _freeScratch.Count - 1; i >= 0; i--)
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{
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if (_freeScratch[i].Length != size) continue;
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var buffer = _freeScratch[i];
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_freeScratch.RemoveAt(i);
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return buffer;
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}
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var fresh = new byte[size];
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_ownedScratch.Add(fresh);
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return fresh;
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}
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private void ReleaseScratch(byte[]? buffer)
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{
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if (buffer == null || !_ownedScratch.Contains(buffer)) return;
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if (_freeScratch.Count >= MaxScratchPooled || _freeScratch.Contains(buffer)) return;
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_freeScratch.Add(buffer);
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}
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// Windows sleep quantum (take-9 finding, 2026-09-04): Task.Delay rounds every
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// request up to the system clock tick (~15.6ms default — learn.microsoft.com/en-us/
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// dotnet/api/system.threading.tasks.task.delay: "approximately 15 milliseconds on
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// Windows systems"), so a pacer requesting 3-15ms actually sleeps 15.6ms. Takes
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// 5-9 measured work ~25ms but period ~37ms: one padded wait per frame hid every
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// compositor improvement. Established media-app practice (game-loop/OBS canon —
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// stackoverflow.com/questions/5441464; and raise the resolution for the session —
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// learn.microsoft.com/en-us/windows/win32/api/timeapi/nf-timeapi-timebeginperiod):
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// timeBeginPeriod(1) while the pump runs, sleep only the BULK of the remainder,
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// and spin the last ~2ms across the deadline.
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[System.Runtime.InteropServices.DllImport("winmm.dll")]
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private static extern uint timeBeginPeriod(uint uMilliseconds);
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[System.Runtime.InteropServices.DllImport("winmm.dll")]
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private static extern uint timeEndPeriod(uint uMilliseconds);
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private static readonly long SpinTailTicks = System.Diagnostics.Stopwatch.Frequency * 2 / 1000; // 2ms
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private readonly object _gate = new();
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private IFfmpegEncoder? _encoder;
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private CancellationTokenSource? _cts;
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private Task? _pumpTask;
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private bool _started;
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/// <summary>Forwards the encoder's parsed health — ship step 6 binds this to the bottom bar.</summary>
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public event EventHandler<StreamHealth>? HealthUpdated;
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/// <summary>Raised when the encoder cannot start or dies mid-stream. The pump stops itself.</summary>
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public event EventHandler<string>? Failed;
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public FramePump(
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Func<Scene?> sceneProvider,
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Func<SceneElement, VideoFrame?> frameResolver,
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Func<CompositorOptions> compositorOptions,
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Func<EncoderOptions?> encoderOptions,
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Func<IFfmpegEncoder> encoderFactory,
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Action<string>? log = null,
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Func<TimeSpan, CancellationToken, Task>? pacingDelay = null,
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Func<(VideoFrame? Frame, SocialBarPosition Position)>? socialBar = null,
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TransitionService? transition = null,
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SceneGraph? sceneGraph = null)
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{
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_sceneProvider = sceneProvider ?? throw new ArgumentNullException(nameof(sceneProvider));
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_frameResolver = frameResolver ?? throw new ArgumentNullException(nameof(frameResolver));
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_compositorOptions = compositorOptions ?? throw new ArgumentNullException(nameof(compositorOptions));
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_encoderOptions = encoderOptions ?? throw new ArgumentNullException(nameof(encoderOptions));
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_encoderFactory = encoderFactory ?? throw new ArgumentNullException(nameof(encoderFactory));
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_log = log;
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_pacingDelay = pacingDelay ?? ((delay, ct) => Task.Delay(delay, ct));
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_socialBar = socialBar;
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_transition = transition;
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_sceneGraph = sceneGraph;
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}
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public bool IsRunning { get; private set; }
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/// <summary>Never throws: failures are logged and surfaced via <see cref="Failed"/>,
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/// so the VM can fire-and-forget it from a sync command handler.</summary>
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public async Task StartAsync(CancellationToken cancellationToken = default)
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{
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lock (_gate)
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{
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if (_started) return;
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_started = true;
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}
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IFfmpegEncoder? encoder = null;
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try
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{
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var options = _encoderOptions();
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if (options == null)
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{
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_log?.Invoke("FramePump: no output configured (neither streaming nor recording) — encoder skipped");
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lock (_gate) _started = false;
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return;
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}
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encoder = _encoderFactory();
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encoder.HealthUpdated += OnHealthUpdated;
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encoder.ProcessFailed += OnProcessFailed;
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await encoder.StartAsync(options, cancellationToken);
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lock (_gate)
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{
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_encoder = encoder;
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}
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// IsRunning must be true before the loop starts: the loop reads it on
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// its first iteration, and with a completed-task delay it can run
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// synchronously on this thread before PumpAsync even returns.
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IsRunning = true;
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_cts = new CancellationTokenSource();
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_pumpTask = PumpAsync(options, _cts.Token);
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_log?.Invoke($"FramePump started ({options.Width}×{options.Height} @ {options.Fps} fps)");
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}
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catch (Exception ex)
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{
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_log?.Invoke($"FramePump: start failed: {ex.Message}");
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if (encoder != null)
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{
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encoder.HealthUpdated -= OnHealthUpdated;
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encoder.ProcessFailed -= OnProcessFailed;
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try
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{
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encoder.Dispose();
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}
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catch (Exception disposeEx)
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{
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_log?.Invoke($"FramePump: disposing failed encoder: {disposeEx.Message}");
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}
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}
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lock (_gate)
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{
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_started = false;
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IsRunning = false;
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}
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Failed?.Invoke(this, ex.Message);
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}
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}
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public async Task StopAsync(CancellationToken cancellationToken = default)
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{
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IFfmpegEncoder? encoder;
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Task? pump;
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lock (_gate)
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{
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if (!_started && _encoder == null) return;
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_started = false;
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IsRunning = false;
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encoder = _encoder;
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pump = _pumpTask;
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_cts?.Cancel();
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}
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// Stop the encoder BEFORE awaiting the pump: closing its stdin unblocks a
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// write stuck on pipe backpressure, otherwise the pump could await forever.
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if (encoder != null)
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{
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try
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{
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await encoder.StopAsync(cancellationToken);
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}
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catch (Exception ex)
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{
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_log?.Invoke($"FramePump: encoder stop failed: {ex.Message}");
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}
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}
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if (pump != null)
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{
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try
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{
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await pump;
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}
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catch (Exception ex)
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{
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_log?.Invoke($"FramePump: pump loop faulted during stop: {ex.Message}");
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}
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}
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if (encoder != null)
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{
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encoder.HealthUpdated -= OnHealthUpdated;
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encoder.ProcessFailed -= OnProcessFailed;
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try
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{
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encoder.Dispose();
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}
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catch (Exception ex)
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{
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_log?.Invoke($"FramePump: encoder dispose failed: {ex.Message}");
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}
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}
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lock (_gate)
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{
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_encoder = null;
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_cts = null;
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_pumpTask = null;
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}
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_log?.Invoke("FramePump stopped");
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}
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public void Dispose()
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{
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try
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{
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StopAsync().GetAwaiter().GetResult();
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}
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catch (Exception ex)
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{
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_log?.Invoke($"FramePump: dispose failed: {ex.Message}");
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}
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_freeScratch.Clear();
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_ownedScratch.Clear();
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}
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private async Task PumpAsync(EncoderOptions options, CancellationToken ct)
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{
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var interval = TimeSpan.FromSeconds(1d / Math.Max(1, options.Fps));
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var lastTick = System.Diagnostics.Stopwatch.StartNew();
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// Deadline pacing (2026-09-03, take-3 fix): the frame interval is a DEADLINE,
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// not an afterthought sleep — the OBS libobs video-io.c pattern (researched
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// before coding; see https://github.com/obsproject/obs-studio/blob/master/
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// libobs/media-io/video-io.c). The old loop slept the FULL interval after
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// each render, so period = render + submit + interval: at take-3's 258ms
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// render that was 3.6fps stamped into a 60fps container — rawvideo stamps by
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// arrival, so 30 wall-seconds muxed as a 2.1s time-lapse, no error anywhere.
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var intervalTicks = Math.Max(1, (long)Math.Round(interval.TotalSeconds * System.Diagnostics.Stopwatch.Frequency));
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var nextTick = System.Diagnostics.Stopwatch.GetTimestamp();
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// Stage timing (2026-09-01, take two): rawvideo carries no per-frame
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// timestamps — ffmpeg stamps frames by ARRIVAL at the declared fps. A producer
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// slower than the declared rate yields a time-lapsed, short file (observed:
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// 39 frames in 27 wall-seconds ≈ 30x at 60fps) with no error anywhere.
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// Log the render/submit split every 5s so the next take names the stage.
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var renderSw = new System.Diagnostics.Stopwatch();
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var submitSw = new System.Diagnostics.Stopwatch();
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var waitSw = new System.Diagnostics.Stopwatch();
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// Resolve-vs-composite split (2026-09-04, take-6 ambiguity): "render" was a
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// black box — the stats line now reports resolver time separately so a take
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// names the stage (get-frame vs blit) instead of feeding another guess.
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var resolveSw = new System.Diagnostics.Stopwatch();
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long renderTicks = 0, submitTicks = 0, resolveTicks = 0, waitTicks = 0;
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int statFrames = 0;
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var statsNext = DateTime.UtcNow + TimeSpan.FromSeconds(5);
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void ReportStats()
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{
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if (DateTime.UtcNow < statsNext) return;
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var target = 5d / interval.TotalSeconds; // frames expected per window
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_log?.Invoke(statFrames == 0
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? "FramePump stats: NO frames produced in 5s (loop stalled?)"
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: $"FramePump stats: {statFrames}/{target:F0} frames per 5s, " +
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$"avg render {renderTicks / (double)System.Diagnostics.Stopwatch.Frequency * 1000 / statFrames:F1}ms " +
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$"(resolve {resolveTicks / (double)System.Diagnostics.Stopwatch.Frequency * 1000 / statFrames:F1}), " +
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$"avg submit {submitTicks / (double)System.Diagnostics.Stopwatch.Frequency * 1000 / statFrames:F1}ms, "
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+ $"avg wait {waitTicks / (double)System.Diagnostics.Stopwatch.Frequency * 1000 / statFrames:F1}ms");
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renderTicks = submitTicks = resolveTicks = waitTicks = 0;
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statFrames = 0;
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statsNext = DateTime.UtcNow + TimeSpan.FromSeconds(5);
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}
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// One wrapper shared by every render of the run — resolve time accumulates
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// inside the render measurement, and the stats line reports the split.
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timeBeginPeriod(1); // pairs with timeEndPeriod in the finally — see field note
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VideoFrame? TimedResolver(SceneElement element)
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{
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resolveSw.Restart();
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var frame = _frameResolver(element);
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resolveSw.Stop();
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resolveTicks += resolveSw.ElapsedTicks;
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return frame;
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}
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try
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{
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while (!ct.IsCancellationRequested)
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{
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var scene = _sceneProvider();
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if (scene != null)
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{
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var compositorOptions = _compositorOptions();
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VideoFrame? socialBarFrame = null;
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var socialBarTop = 0;
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if (_socialBar != null)
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{
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var (barFrame, position) = _socialBar();
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socialBarFrame = barFrame;
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if (barFrame != null)
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socialBarTop = position == SocialBarPosition.Top
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? 0
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: compositorOptions.SourceRectHeight - barFrame.Height;
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}
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VideoFrame frame;
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var scratchSize = compositorOptions.SourceRectWidth
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* compositorOptions.SourceRectHeight * 4;
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// The transition "from" frame lives in TransitionService.FromFrame
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// (captured at Start by the VM). The old per-tick fromScene render
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// here was dead weight — a full extra scene composite every
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// transition tick that BlendFrame never read; removed with the
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// pooling change because its buffer's only consumer was its own release.
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renderSw.Restart();
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var scratch = AcquireScratch(scratchSize);
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frame = RenderScene(scene, compositorOptions, socialBarFrame, socialBarTop, scratch, TimedResolver);
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if (_transition is { Active: true } transition)
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{
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frame = transition.BlendFrame(frame);
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transition.Tick(lastTick.Elapsed.TotalMilliseconds);
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}
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// Restarted EVERY frame (transition or not): a transition begun
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// after idle must not inherit a giant ElapsedMs and complete
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// instantly on its first Tick.
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lastTick.Restart();
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renderSw.Stop();
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renderTicks += renderSw.ElapsedTicks;
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IFfmpegEncoder? encoder;
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lock (_gate) encoder = _encoder;
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if (encoder == null) break;
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submitSw.Restart();
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await encoder.SubmitFrameAsync(frame, ct);
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submitSw.Stop();
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submitTicks += submitSw.ElapsedTicks;
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// Submit copied the bytes — everything from this tick is recyclable.
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// Release AFTER submit, and the free-list Contains guard makes the
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// Cut path (BlendFrame returns toFrame itself, aliasing scratch) safe.
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ReleaseScratch(frame.BgraPixels);
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ReleaseScratch(scratch);
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statFrames++;
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ReportStats();
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// Advance the deadline; cost already spent is not slept again.
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// Blew the frame budget: skip the wait AND the missed ticks —
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// rebase rather than bursting a catch-up pile (OBS rewinds its
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// tick; a burst only queues stale frames). Otherwise sleep the
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// BULK and SPIN the 2ms tail — never hand a sub-tick remainder
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// to the sleep quantum (see the timeBeginPeriod note).
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nextTick += intervalTicks;
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waitSw.Restart();
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var ahead = nextTick - System.Diagnostics.Stopwatch.GetTimestamp();
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if (ahead <= 0)
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{
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nextTick = System.Diagnostics.Stopwatch.GetTimestamp() + intervalTicks;
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}
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else
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{
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if (ahead > SpinTailTicks)
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await _pacingDelay(TimeSpan.FromSeconds(
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(ahead - SpinTailTicks) / (double)System.Diagnostics.Stopwatch.Frequency), ct);
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while (!ct.IsCancellationRequested
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&& System.Diagnostics.Stopwatch.GetTimestamp() < nextTick)
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Thread.SpinWait(400);
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}
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waitSw.Stop();
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waitTicks += waitSw.ElapsedTicks;
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}
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}
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}
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catch (OperationCanceledException)
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{
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// normal stop
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}
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catch (Exception ex)
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{
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// A failure while the pump is supposed to run (encoder died under us,
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// scene provider faulted, ...) stops the pump and surfaces once.
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if (ct.IsCancellationRequested)
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{
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_log?.Invoke($"FramePump: pump exited during stop: {ex.Message}");
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}
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else
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{
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_log?.Invoke($"FramePump: pump loop faulted: {ex.Message}");
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Failed?.Invoke(this, ex.Message);
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}
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}
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finally
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{
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timeEndPeriod(1);
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lock (_gate) IsRunning = false;
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}
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}
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private void OnHealthUpdated(object? sender, StreamHealth health) => HealthUpdated?.Invoke(this, health);
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/// <summary>Render a scene, using the baked-crust optimization when a <see cref="SceneGraph"/>
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/// is wired in: bake/cache the static layers below the split point, then composite the
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/// dynamic/above-split layers per frame. Without a SceneGraph, falls back to a full render
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/// (identical output — see SceneCompositorTests). <paramref name="scratch"/> is a pooled
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/// master buffer when supplied; the fully-static path returns the bake-cache frame itself
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/// (never pooled — the release side checks owned-by-reference).</summary>
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private VideoFrame RenderScene(
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Scene scene,
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CompositorOptions options,
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VideoFrame? socialBarFrame,
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int socialBarTop,
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byte[]? scratch = null,
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Func<SceneElement, VideoFrame?>? resolver = null)
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{
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// per-tick composites use the (timed) resolver; the rare bake uses the raw one
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// so bake cost lands in "render" but not "resolve".
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resolver ??= _frameResolver;
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if (_sceneGraph == null)
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return _compositor.Render(scene, resolver, null, options, socialBarFrame, socialBarTop, scratch: scratch);
|
||
|
||
var split = _sceneGraph.GetSplitPoint(scene);
|
||
if (split == scene.Elements.Count)
|
||
{
|
||
// Fully static scene: bake once, reuse.
|
||
var baked = _sceneGraph.GetBakedBase(scene, _frameResolver, _compositorOptions);
|
||
if (baked != null)
|
||
return StretchMath.BilinearScale(baked, options.OutputWidth, options.OutputHeight);
|
||
}
|
||
|
||
var baseFrame = _sceneGraph.GetBakedBase(scene, _frameResolver, _compositorOptions);
|
||
if (baseFrame != null)
|
||
{
|
||
return SceneCompositor.CompositeLayers(
|
||
baseFrame, scene, split, resolver, options, socialBarFrame, socialBarTop, scratch: scratch);
|
||
}
|
||
|
||
// No static base (first layer is dynamic or empty scene) — full render.
|
||
return _compositor.Render(scene, resolver, null, options, socialBarFrame, socialBarTop, scratch: scratch);
|
||
}
|
||
|
||
private void OnProcessFailed(object? sender, string message)
|
||
{
|
||
_log?.Invoke($"FramePump: encoder process failed: {message}");
|
||
Failed?.Invoke(this, message);
|
||
_ = StopAsync();
|
||
}
|
||
}
|