Performance and troubleshooting

Smooth frame rates

Adaptive quality (on by default, Settings → Performance) watches the frame rate and lowers the rendering resolution, then effect detail, when your computer can't keep up — and raises them again when it can.

Setting	What it does
Target frame rate	Auto (your screen's refresh rate), or a fixed 144, 120, 60 or 30. A lower target saves power and heat.
Lowest resolution	How far adaptive quality may reduce resolution.

Press ` for the performance HUD: frame rate, CPU time, quality level, the GPU in use and more.

If a visualization is far too heavy for your graphics card, the app switches that layer off and tells you, rather than letting the screen freeze. Visualizations with a Detail control (black hole, nebula, fractals) get much faster when you lower it.

Tips for slower computers: fewer layers, fewer overall effects (bloom and trails cost the most), a lower target frame rate, and plug laptops in.

Common problems

The visuals don't react to the music

• Check the source in the Audio tab is playing; the Live pane's beat dots and the HUD's level should be moving.
• With a microphone, make sure the browser has permission, the right input is chosen under Devices, and raise Input gain.
• With tab capture, make sure sharing the tab's audio was ticked when you chose the tab.

Microphone or tab capture isn't offered

Tab capture needs Chrome or Edge. Phones and tablets only offer the microphone. If permission was refused, allow it again in the browser's site settings (the icon at the left of the address bar).

The beat is off

Use Tap, Beat 1, ½× / 2× and the nudge buttons in Audio → Beat, or set the tempo range in Settings. If bars land in the wrong place, set the Time signature yourself. Once it's right, turn Beat detection off (Auto/Hold in the Live pane, or Alt T) and it will stay put. See Beat, tempo and sync.

Chrome's "sharing this tab" bar shows over the visuals

When you capture a tab's sound, Chrome shows a bar saying the tab is being shared, and it has no button to hide it. The browser's own full screen (the green button, ⌃ ⌘ F or F11) keeps it. Use Glowtrope's full screen instead, Alt Enter or , which hides it. Output windows don't show it either.

To avoid it entirely, don't capture a tab. On a Mac, install the free BlackHole driver. In Audio MIDI Setup, make a Multi-Output Device with your speakers and BlackHole and set it as the system output, then choose BlackHole as the input in Audio → Source. You can then use the Apple Music app too. Glowtrope already turns off echo cancellation, noise suppression and automatic gain for inputs, so the analysis hears the music unprocessed.

Flashes come before or after the sound

Run Audio → Sync → Calibrate… for this screen and these speakers. See Sync.

Black screen, or "This browser can’t run Glowtrope"

The app needs WebGL 2. Make sure hardware acceleration is on in your browser's settings, update the browser, and try Chrome or Edge.

"The GPU context was lost; recovering…"

The graphics driver reset (it can happen when a laptop switches graphics cards or wakes from sleep). The app rebuilds everything and carries on by itself.

No sound from files

Some browsers block sound until you've clicked the page. Click anywhere, or press play in the Audio tab.

My presets are gone

They're stored in the browser, so they belong to this browser on this computer, and clearing site data removes them. Keep an export as a backup: Presets → Export everything.

Browsers

	Chrome / Edge	Firefox	Safari
Visuals, files, microphone	✓	✓	✓
Tab and system audio capture	✓	—	—
Choosing the output device	✓	—	—
Placing output windows on screens automatically	✓	—	—
MIDI	✓	✓	—
Recording	✓ (WebM)	✓ (WebM)	✓ (MP4)

Privacy

There's no account, no tracking and no server. Music is analysed on your device and never uploaded. Presets and settings stay in your browser. Share links carry the scene in the part of the address that's never sent to a server. The only download is the optional MilkDrop pack, which comes from a public library mirror and is checked before it's used.