Gainshift por MarshallPascal

Every tab gets its own volume.

Firefox can mute a tab. It can't turn one down. Gainshift gives you the
level in between — drop a noisy tab to 1% and leave everything else
alone, or push a quiet one up to 600%.

WHY THIS ONE WORKS WHERE OTHERS DON'T

Most volume extensions go looking for <video> and <audio> tags. That is
fine on YouTube. It fails on a surprising amount of the web, because
plenty of pages make sound without ever creating one: browser games,
emulators and custom players push audio straight through the Web Audio
API, or through Audio objects built in JavaScript and never added to
the page at all. On those, a DOM-scanning extension reports "no audio
found" while the page is plainly making noise.

Gainshift works in three places instead:

• the Web Audio graph, which is where game and engine audio lives
• ordinary <video> and <audio> elements in the page
• detached Audio objects, created in code and never inserted

It also follows audio into nested cross-origin frames, so a game
embedded three or four iframes deep inside a page still answers.

WHAT YOU GET

• A slider and a typed box, 0 to 600% in 1% steps. Arrow keys nudge by
one either way.
• One-click presets: 0, 25, 50, 100 and 200%.
• Levels remembered per site, not per page. Set a site to 40% once and
every page on it opens there. One click on Forget clears it again.
• The toolbar button shows the current level, and becomes a mute icon
when a tab is silenced.
• A per-frame readout showing where the sound was actually found —
worth having when a page has a dozen frames and only one of them is
making noise.
• A panel that follows your browser's light or dark theme.

BELOW 100%, AND ABOVE IT

These are two different mechanisms, and the difference is worth knowing.

Below 100%, media elements are turned down through their own volume
control, and Web Audio is scaled in the graph. Both are exact
multiplications. No media element is re-routed, nothing is re-encoded,
and nothing is degraded — quiet is simply quiet.

Above 100% there is no such shortcut: to make a media element louder
than its own maximum, the audio has to be routed through Web Audio and
amplified. That works on most sites. It does not work on media served
from another domain without CORS headers, where the browser blocks the
route and the tab goes silent instead of loud. Returning to 100% and
reloading recovers it.

The panel tells you this the moment you cross 100%, and if amplification
does fail it names the actual reason rather than guessing.

PRIVACY

Gainshift makes no network requests of any kind. Nothing is collected,
nothing is transmitted, and there is no analytics, no telemetry and no
server to send anything to.

The only thing stored is the list of sites you chose a level for, and
the number you chose. It stays in your own browser.

THE PERMISSIONS, AND WHY EACH ONE

• Access to all sites — audio can be on any site, and inside frames
loaded from other domains. The only thing looked for in a page is its
video and audio elements: no text, no form data, no cookies, no
browsing history.
• Tabs and webNavigation — to find every frame in a tab, including the
deeply nested ones that games load.
• Storage — to remember your per-site levels.

ONE HONEST LIMIT

This is interception, not magic. It covers the ways a page normally
produces sound, and those cover a great deal — but something reaching
audio by a route nobody has run into yet would slip past it. If you hit
a site where it comes up empty, that is worth reporting rather than
assuming it can't be fixed.