What conditions must hold to record Unity Recorder Accumulation successfully, so a render does not silently fail or show a progress bar?

Problem. Accumulation recordings can capture nothing or show artifacts if setup rules are missed. Conditions. Recorder 5.1.7. Method (checklist). HDRP only; Movie or Image Sequence recorder only; Source = Game View or Targeted Camera; keep Game View visible for the whole recording; only one active recorder (disable all others, and no overlapping Recorder Clips in Timeline); path tracing needs DX12. Frame Interval recording with Start above 0 still plays and renders all earlier frames, to keep physics and procedural noise deterministic. For film hand-off, set Playback to Constant with Target FPS (variable is for gameplay; ProRes cannot use variable). Failure modes. If Game View is hidden, the simulation clock keeps running while no frames are recorded, and a progress bar can appear in frames. Cannot run in -batchmode. Limitations. Cinemachine-driven Timeline shots (C3-B721-05) must keep any Recorder Clip with Accumulation alone in its time range. Version/date. Recorder 5.1.7 docs, fetched 2026-10-24. Curator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources. Limitations: Pre-checks only restate the docs; no run was performed. Constant-versus-variable detail overlaps prior C2-B15-F2-10, which this extends only for the Frame Interval and Timeline points. Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

{
  "citations": [
    {
      "url": "https://docs.unity3d.com/Packages/com.unity.recorder@5.1/manual/RecordingAccumulation.html",
      "note": "Game View must be visible; Timeline Recorder Clips; Recording Mode: Frame Interval; Known issues: batch mode"
    },
    {
      "url": "https://docs.unity3d.com/Packages/com.unity.recorder@5.1/manual/RecorderWindowRecordingProperties.html",
      "note": "Game View must be visible; Timeline Recorder Clips; Recording Mode: Frame Interval; Known issues: batch mode"
    },
    {
      "url": "https://docs.unity3d.com/Packages/com.unity.recorder@5.1/manual/KnownIssues.html",
      "note": "Game View must be visible; Timeline Recorder Clips; Recording Mode: Frame Interval; Known issues: batch mode"
    }
  ]
}