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Thaumic Cast

Video sync

Sonos speakers play a moment behind your browser. A song does not mind; a film looks badly dubbed. Video sync puts the words back where the lips are.

What it does

Section titled “What it does”

Video sync plays each page’s sound early by as much as the speakers play late, inside the site’s own player. The picture stays where it is. How late the speakers play comes from the companion, which measures it.

If it still sounds early or late to you, fine-tune it in the cast’s card, up to half a second either way in 10 ms steps. Thaumic Cast remembers the fine-tune for each room.

Extension · try it

Fine-tune for Kitchen0 ms

Pretend speakers: nothing plays, nothing is saved.

Turn it on

Section titled “Turn it on”
  1. In the extension’s Settings, under Finer points, turn on Video sync.
  2. Your browser asks to let Thaumic Cast onto every site. Allow it (see the permission).
  3. Reload any page that was open before.
  4. Start a new cast. In the cast’s card, the row says Locking on…, then In step.

The permission it asks for

Section titled “The permission it asks for”

Video sync works inside each site’s own player, so your browser has to let it onto every site. Until it does, video sync does nothing, and switching it on asks again.

Limits

Section titled “Limits”

Tried on YouTube, Netflix and Prime Video. It cannot help everywhere, and it says why in the cast’s card:

Limit Why
PCM casts only Only PCM keeps good enough time. The default quality, Luxurious, is PCM.
Not with browser-wide capture Video sync needs a cast of one tab, not of the whole browser.
Companion out of date It is too old to say how late the speakers play. Update it.
Some players cannot be synced A player that keeps sound and picture in one stream, works where the extension cannot reach, or sends its sound in a form that cannot be moved.
Live broadcasts A broadcast too near live has no sound to play early.
Browser pages Browser pages, the Web Store and local files are out of bounds to extensions.
The video stuck The sound goes back where it was, and the row offers Try again.
Pages already open A page open before video sync was on needs a reload.
Switching it on or off On some players it can take a few seconds to take effect.

What the row says

Section titled “What the row says”
The row says It means
Locking on… Measuring and moving the sound.
In step Sound and picture agree.
Nothing to watch No video on the page yet.
Cannot sync One of the limits above; the reason is underneath.
Turned off Something went wrong in the player (the video stuck, for example), so the sound went back where it was. Try again has another go.
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