The picture is fine but there is no sound

Audio travels further than video: the glasses must announce themselves as a sound card, the system must select that card, and the player must be playing a track that still exists. Each hop fails in a different way, and the failure names the fix. Three questions find which hop broke.

Why "select the right output device" is not enough

The advice you will find everywhere is to switch the default output. It helps in exactly one of the four cases, which is why it feels unreliable. The four are:

1. The sound card never appeared. Glasses carry audio over the same USB-C connection as the picture, but as a separate USB function. If the audio function does not enumerate, there is nothing to select and no setting will help — the cable is usually the culprit, and charge-only USB-C cables are indistinguishable by feel from data cables.

2. The endpoint exists but is silent. The device is listed, you can select it, and the level meter stays flat. That means the audio is going somewhere else, or another application holds the endpoint exclusively. Meeting apps and some players do exactly this and do not say so.

3. The signal is there but the level is not. The meter moves and you hear nothing. Glasses keep their own volume, separate from the system slider, and that value persists across reboots — a device left at zero looks completely dead while the system reports playback.

4. The device is fine and the file is not. System sounds come through the glasses, but your film is silent. Files remuxed to add a stereo flag sometimes lose their audio stream in the process, and players will happily render a silent video rather than complain.

What you can verify here, without trusting anyone

The device check enumerates every audio output the browser can see, names the ones that look like the glasses, and can play a short quiet tone straight at the chosen device. That separates "not enumerated" from "enumerated but unreachable" in one step — which is the difference between replacing a cable and changing a setting.

• Device check — audio outputs, a test tone, plus display mode, refresh rate and sensor status.
• Built-in player — shows the tracks it finds in a file, so a missing audio stream is visible rather than guessed.
• Player setup notes — which Windows and macOS settings silently take the device over.

Nothing is uploaded and nothing is installed; the audio test is a 0.12-second tone at low volume, so it will not surprise you.

DepthSnap — free browser-based 2D to 3D SBS converter. No upload, no signup, no watermark.