[richiemcilroy]

Gated Instant recordings start their audio at the start gate's arm time (#2650), but the screen track started at its first admitted frame, 17 to 25 ms later. Instant merges its tracks by timestamp, so the screen played early by that delay.

Fix

The gated Instant video track now starts where its audio starts: the arm point, or the pipeline epoch if the gate armed before it (audio_epoch, the Linux composite-camera path can create its epoch late). The first admitted frame is shown from that origin, and every later frame is muxed at its capture time relative to it.

// crates/recording/src/output_pipeline/core.rs
fn shift_from_origin(duration: Duration, is_first_frame: bool, origin_lead: Option<(Instant, Duration)>) -> Duration {
    match origin_lead {
        Some((_, lead)) if !is_first_frame => duration + lead,
        _ => duration,
    }
}

• RecordingStartGate::video_origin_lead (crates/recording/src/output_pipeline/start_gate.rs) gives the first frame's lead over that origin. primed_instant_video_armed_before_the_epoch_starts_at_the_epoch covers a gate armed before the epoch. Only the Instant pipeline turns it on (set_video_origin_at_arm in instant_recording.rs), behind a gate.
• Capture times go through clock remapping and drift tracking unchanged; only the muxed timeline moves. The first version stamped the first frame with the arm instant instead, which the drift tracker read as 20 ms of hand-off lag, so it pulled the second frame back by the same amount (frames captured 20, 53 and 86 ms after the arm muxed at 0, 33 and 86 ms). primed_instant_video_starts_at_the_arm_point checks 0, 53 and 86 ms and fails with the shift disabled.
• The recorded first timestamp, the encoder-pair start and the static tail use the arm point as the origin. The live path and the stop-time drain share the rule.
• Studio aligns its tracks with each track's recorded start time and is unchanged.

Measured

recording/instant/gated (the app's start), real capture on a MacBook Pro, 5 recordings each:

	main	This PR
Screen vs microphone	-4.4, -4.5, -3.8, -10.1, -20.1 ms	+15.3, +15.1, +13.1, +15.7, +12.8 ms
Spread	16.3 ms	2.9 ms
Inside the -10 to +75 ms window	3 of 5	5 of 5

• Blacksmith macOS 26: +18.6 ms, against -19.0, +8.8 and +14.1 ms on main's last run (one recording per run).
• The flaky recording/instant/gated sync entry stays until more runner runs show it no longer fires.

Confidence Score: 5/5

The PR appears safe to merge; no actionable new issues were found.

Summary

Gated Instant recordings now start video at the same origin as audio.

• Gated Instant screen video starts where its audio starts.

No new actionable issues were found. The earlier test-coverage thread has an explanatory reply and regression coverage. Tests were inspected but not run.

_{Reviews (3) · Last reviewed commit: "fix(recording): start gated Instant vide..." · Reviewed by Greptile}

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Project	Deployment	Actions	Updated
cap-status	Ready	Preview	Oct 17, 2026 2:53am UTC

[richiemcilroy]

@greptileai review

[capy-ai]

Capy found no issues.

View 1 other finding in Capy.

[richiemcilroy]

@greptileai review

[capy-ai]

Capy found 1 potential issue (1 medium).

[richiemcilroy]

@greptileai review

[capy-ai]

Capy found no issues.