Performance HUD

The Performance HUD is a debugging tool that shows real-time diagnostic information about how Orbit is performing on your system. It's especially useful with large, complex sessions: if something doesn't sound right — glitches, dropouts, or audio that isn't behaving as expected — the HUD can give an indication as to why.

Opening the HUD

• Orbit → Toggle Performance HUD (⇧⌘P) — opens a floating window with real-time performance metrics.

Next to the Performance HUD title, a status pill reads OK, WARN or FAIL as an at-a-glance health summary.

Metrics to watch

Metric	What it means	Healthy range / guidance
CPU Usage	Host CPU usage sample	Low and steady; spikes with render time suggest contention
Memory	Orbit's memory use	Steady during playback; continuous growth is worth reporting
Sample Rate / Buffer Size	Device clock and buffer length	Buffer 128–512 frames typical; unexpected changes = device switch
Render avg/p95/max (ms)	Engine render time per buffer	Stay well below buffer duration (<25% is comfortable); p95/max near buffer size risk underruns
Load (%)	Render time as % of buffer duration	<50% steady is good; >75% sustained or spiky warrants attention
Underruns	Buffer underrun count	0 and not increasing. A single blip might be benign; rising counts during playback need attention
Faults	Engine fault count	0; investigate any non-zero value
Active Objects	Objects currently contributing	Matches ADM expectation; big jumps without timeline changes suggest ADM/mute/solo issues
Event/Prep/Log Queues	Internal queue depths	Near zero or stable; growth correlates with contention or I/O stalls
Blocks	Total buffers rendered	Reference counter to align timing between runs
Transport	Engine transport time (s)	Should track playback; sanity check HUD sync

Video

Below the audio metrics, a Video section reports picture playback:

Metric	What it means
Present fps	Frames presented per second
Interval p99	99th-percentile time between presented frames (ms)
Jitter CoV	How uneven the frame cadence is (lower is smoother)
Scrub→pic p99	99th-percentile time from a scrub to the new picture appearing (ms)
Holds	Frames where the same picture was held
Drops	Dropped frames
Path mix	Share of recent frames drawn from the background render cache (B), composited live (L), or with no video at that point (G)
Held-skip	Share of recent frames that were unchanged, so no new picture was needed

When to use

• Investigate glitches: watch underruns and render p95/max.
• Compare routing/mode changes: ensure active object counts and queues stay stable.