{
  "schema": "sync-performance-measurements-v1",
  "reportId": "research-2026-09-19-windows-sustained-delivery",
  "generated": "2026-09-19T18:35:00Z",
  "platform": {
    "os": "Windows 11 Pro 64-bit (Build 26200)",
    "runner": "largeboi-sync-camera",
    "architecture": "x86_64",
    "videoFramework": "Windows Media Foundation Virtual Camera (IMFMediaSourceEx, IMFMediaStream2)",
    "frameServerHost": "FSCS.exe (Windows Camera Frame Server)",
    "audioSubsystem": "WASAPI Shared Mode (RtAudio 6)"
  },
  "benchmarks": {
    "baseline60s": {
      "label": "Baseline unoptimized camera delivery (60s)",
      "targetFps": 60,
      "durationSeconds": 60,
      "submittedFrames": 3600,
      "totalNewDelivered": 3445,
      "totalRepeatsDelivered": 10001,
      "totalEmpties": 5,
      "totalOutOfOrder": 0,
      "droppedFrames": 155,
      "dropRatePercent": 4.305,
      "meanDeliveredFps": 57.42,
      "minSecondFps": 54,
      "maxSecondFps": 59,
      "firstThirdFps": 57.30,
      "lastThirdFps": 57.50,
      "sustainedTarget": false,
      "limitingFactors": [
        "Windows default 15.6 ms timer interrupt resolution",
        "100% CPU lockup on uncached NV12 color conversion per repeat sample request"
      ]
    },
    "sustained600s": {
      "label": "Optimized sustained camera delivery (600s)",
      "targetFps": 60,
      "durationSeconds": 600,
      "submittedFrames": 36001,
      "totalNewDelivered": 35998,
      "totalRepeatsDelivered": 199140,
      "totalEmpties": 8,
      "totalOutOfOrder": 0,
      "steadyStateDroppedFrames": 0,
      "steadyStateEmpties": 0,
      "meanDeliveredFps": 60.00,
      "exactMeanFps": 59.9967,
      "medianSecondFps": 60.0,
      "minSecondFps": 59,
      "maxSecondFps": 61,
      "firstThirdFps": 59.99,
      "lastThirdFps": 59.99,
      "sustainedTarget": true,
      "secondsDistribution": {
        "exactly60Fps": 596,
        "seconds59Fps": 3,
        "seconds61Fps": 1,
        "secondsBelow59Fps": 0,
        "secondsAbove61Fps": 0
      },
      "boundaryAnomalies": [
        {"second": 0, "fps": 59, "empties": 8, "reason": "Initial startup negotiation before writer pipeline priming"},
        {"second": 536, "fps": 61, "empties": 0, "reason": "1-frame second-boundary tick shift (+1 frame)"},
        {"second": 537, "fps": 59, "empties": 0, "reason": "1-frame second-boundary tick shift (-1 frame, net 120 frames in 2s)"},
        {"second": 599, "fps": 59, "empties": 0, "reason": "Final shutdown second boundary"}
      ],
      "optimizationsApplied": [
        "timeBeginPeriod(1) multimedia timer precision (1.0 ms interrupt cadence)",
        "converted_dirty_ NV12 dirty caching in SyncCameraStream::WrapAsSample"
      ]
    },
    "wasapiLoopbackQualification": {
      "label": "WASAPI automated CI loopback capture qualification",
      "driver": "VB-Audio Virtual Cable (VBAudioVACWDM)",
      "sourceName": "CABLE Output (VB-Audio Virtual Cable) (WASAPI)",
      "sourceId": "audio_5e3e4e5871985b2d83dec7f116f492e5a15ba75058a8f9dbbfb7a1f98614371a",
      "channels": 2,
      "sampleRate": 48000,
      "captureMilliseconds": 2000,
      "finiteSamplesRatio": 1.0,
      "nonfiniteSamples": 0,
      "cursorDiscontinuities": 0,
      "droppedFrames": 0,
      "startupDiscontinuityHandling": "Initial AUDCLNT_BUFFERFLAGS_DATA_DISCONTINUITY consumed without stream abort",
      "qualified": true
    }
  }
}