Hovercraft is a virtual camera, which means everything you put on it travels through whatever app you’re using to take the call — Zoom, FaceTime, Webex, Teams, Discord, a browser. Most of the time this is invisible. Sometimes the call app does something on top of our output that surprises you. This page documents the cases we’ve seen, what’s actually happening, and what to do about each one.
None of these are Hovercraft bugs. They’re properties of the host app. Knowing which is which gets you back on a clean call quickly.
My slide looks flipped to me on the call
You’re on a video call. You load a PDF or share a window with Hovercraft. The slide looks correct in the Hovercraft preview window on your screen, but in your own video tile in Zoom / FaceTime / Webex, it appears horizontally flipped. Text is backwards. You think you’re shipping a broken slide to your audience.
What’s actually happening
Almost every video conferencing app on macOS — FaceTime, Zoom, Webex, Microsoft Teams, Discord, Google Meet — mirrors your own self-view tile by default. The intent is for your video to read like looking in a bathroom mirror so it feels natural to see yourself. The stream the other person on the call receives is the correctly-oriented version. The mirror only applies to the small picture-in-picture of yourself in your own window. Almost no one notices this until they share a slide with text on it — suddenly the mirroring becomes very obvious in your self-view, and very alarming.
Verify in 30 seconds
Hop on a quick call with a friend or colleague and ask them what they see. Your slide should read correctly to them, even though it still looks flipped to you in your own self-view tile. We have heard from three customers in our first week of launch who were certain they were shipping flipped slides to their audience; in every case the audience saw them correctly oriented.
Disable self-view mirroring (optional)
Most apps let you turn off the mirror in your own tile, in case seeing your slide flipped is too distracting to ignore even when you know it’s only happening locally:
Zoom: Settings → Video → uncheck Mirror my video.
FaceTime: during a call, hover over your own tile and use the menu options that appear; on recent macOS versions there is a mirror toggle.
Microsoft Teams: ... → Device settings → Camera → Mirror my video.
Webex: Video preview → Mirror my video.
Discord: User Settings → Voice & Video → Mirror video.
If after disabling the mirror in your conferencing app the slide still appears flipped to the other participant, please write to us — that would be a real bug and we want to dig in.
Hovercraft isn’t in my browser’s camera list
You join a call in a browser tab and the camera picker shows your built-in FaceTime camera, your iPhone Continuity Camera, and any plugged-in webcams, but not Hovercraft.
What’s actually happening
Almost always, this is Safari holding a stale camera list. When Safari launches it asks macOS once for the available cameras and then keeps that list for the lifetime of the Safari process. If Safari was already running when you installed Hovercraft (or when an update swapped its camera helper), Safari has no idea Hovercraft exists yet and won’t offer it to any site’s camera picker.
Chromium-family browsers (Chrome, Brave, Arc, Edge, Vivaldi) subscribe to camera-list-change notifications from macOS and pick up Hovercraft live, which is why this only ever shows up in Safari.
What to do
Fully quit Safari (⌘Q, not just close the window) and reopen it. Hovercraft will be in every site’s camera picker after that. You only need to do this once per Safari session, not before every meeting.
The cases where you’ll need to restart Safari again:
The first time after installing Hovercraft on a Mac where Safari was already open.
After any Hovercraft update, if Hovercraft stops appearing in Meet or Teams. Quitting and reopening Safari once always fixes it.
After uninstalling and reinstalling Hovercraft.
A macOS reboot resets all of this. The first Safari launch after a reboot will pick Hovercraft up correctly without any extra step.
If Hovercraft still isn’t in Safari’s picker after a clean restart, switch to Chrome, Brave, Arc, or Edge for that meeting (every Chromium browser sees Hovercraft without any setup), or use the conferencing service’s native Mac app. Webex, Zoom, Teams, Google Meet, and Discord all ship native Mac clients that pick up Hovercraft without any of this.
Zoom is mangling the text on my slide
You share a slide with text on it through Hovercraft on Zoom. The audience sees the text rendered as garbled non-Latin glyphs — a customer described it as “Mesopotamian characters” — even though the slide reads cleanly in your Hovercraft preview.
What’s actually happening
Zoom’s Studio Effects / Video Filters run a generative pass on the camera feed before it leaves your machine — smoothing skin, adjusting lighting, applying cosmetic touch-ups. That pass treats the entire frame as a face and runs an enhancement model on it. When part of the frame is text rather than skin, the model hallucinates it into something that looks like text but isn’t. The text never leaves Zoom in a readable form because Zoom transformed it before transit. We see Hovercraft’s output go in clean and Zoom’s output go out garbled. Hovercraft already disables macOS Reactions on its own capture for related reasons, but Zoom’s effects run inside Zoom’s process and we can’t reach them.
Zoom → Settings → Video → uncheck Touch up my appearance and Adjust for low light.
With every Zoom video effect off, the feed Zoom transmits is byte-clean from Hovercraft. Text renders as text.
Videos in my Keynote deck don’t play
You share a Keynote presentation as a window source through Hovercraft. Static slide content captures fine, but embedded videos inside the deck appear as a still frame — the video doesn’t play in the captured stream even though it’s playing in Keynote on your screen.
What’s actually happening
Hovercraft uses macOS’s ScreenCaptureKit to capture individual application windows. Keynote renders embedded video through a separate hardware overlay layer (likely an AVPlayerLayer composited on top of the window) that ScreenCaptureKit’s window-content composition doesn’t pick up. The same limitation affects other tools that use ScreenCaptureKit for window capture. We are tracking the issue and exploring whether there’s a capture-API path that includes overlay layers.
What to do
For decks with embedded video, the cleanest workaround today is to export the deck as a movie (Keynote → File → Export To → Movie), then play that movie back through your usual screen-share path or open the resulting .mov in QuickTime and share the QuickTime window through Hovercraft instead. Native PDF export from Keynote also captures cleanly for slides that don’t need motion.
See something not covered here? support@sandwich.vision. We add to this page as patterns emerge.
Looking for what shipped recently? See the release notes.