Two things came up on the new tab. Floated and sized down, it spilled
its knobs out of its window, and sized up it left the window empty.
Auto-gain lifted far too much: it brought 0 dB back to 0 dB, which at
-40 dB, 4:1 and knee 6 is +28.1 dB, so a sound at -24 dB came out at
-6 dB. And as a knob from 0 to 1 it blended between makeup and
auto-gain, so at 1 the makeup knob did nothing.
Layout:
- The knobs stay on the bottom line, centred, with the help line
above them.
- The levels fill the height left above. The curve is a square at
their right, centred up and down. It grows with the tab from 180 to
360 px and takes no more than 40 % of its width (picturesLayout).
- A floated window cannot be sized below what its pane needs. A pane
says so in its minWidth and minHeight, and the Compressor's is every
knob and the smallest pictures. Other panes keep 320 x 200.
- A pane put into an open window that is too small grows the window.
Auto-gain, as decided in #378:
- A Compressor's auto-gain gives back what it takes from a sound at
-18 dB, so that one comes out as loud as it went in. At the numbers
above that is +14.6 dB.
- Auto-gain is a switch on the Compressor, the Limiter and the
Saturation alike, a setting and no longer an input. The makeup or
output is added on top of it instead of being blended with it.
- A project from before reads a number as on above 0. Nodes never
set keep their defaults: off on the Compressor, on on the other two.
- The tab shows the switch at the right of the knobs, with the dB it
gives below it. With it on, the curve has a line at -18 dB from the
curve up to the diagonal.
- Every level reading keeps the gain of its time. Before, the whole
picture was read by the current makeup, so after a change the
tinting of the last seconds was wrong or missing.
Findings:
- My first e2e run of the layout clicked Dock where it was before the
window was sized up, so the window stayed open and the next check
went red. The check reads the button again.
Tests:
- Gate (melektaus-atx): 282 files, 4344 tests (6 new)
- e2e 34 (melektaus-atx): ALL PASSED, 118 checks (2 new)
- Offline in Chrome: a sine at -18 dB through -24 dB and 4:1 came out
at -17.92 dB with auto-gain on and -22.42 dB with it off.
- Counter-checks: the curve set at the top instead of the middle, and
every reading read at a gain of 0, each fail exactly their test.
- Looked at the window in screenshots: at its least every knob and
the switch show. At 1280 x 797 the levels fill the height, the
curve is centred at the right and the knobs are at the bottom.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A sound FX could not control dynamics. A Compressor squeezes the
loudness together, and a Limiter keeps every peak below a line. Both
work on a voice and on a bus, where they tame everything at once.
- Compressor: DynamicsCompressorNode with Threshold, Ratio, Knee,
Attack and Release, then Makeup and Auto-gain from 0 to 1. After the
node the sound gets (1 - w) * makeup + w * A dB. A is what the curve
takes off at 0 dBFS.
- The node adds 0.6 of A by itself, as the spec says. That gain is
taken back out, so 0 really means no makeup.
- The knee shape is left to the browser by the spec. dynamics.ts ports
Chromium's curve. It gives the gain Chrome was measured to add at
four settings to three places.
- Limiter: a class on the FX worklet with Threshold, Ceiling, Release
and Auto-gain. It looks 5 ms ahead: the smallest gain of the window
ahead, averaged over the window, then a release. No sample passes the
lower of threshold and ceiling. Auto-gain raises it toward the
ceiling.
- Deviation from the plan in the issue: the Limiter has a Threshold as
well. Without it Auto-gain has nothing to measure against.
- Latency is made up on voices now too. A voice starts as much earlier
as its stages are late (Compressor 6 ms, Limiter 5 ms). The other
way of a Mix and the other layers of a note are held back to the
latest, and a bus counts it into its latency.
- A voice with a Limiter counts as ringing, so the worklet is stopped
only after what it still holds is out.
Tests:
- Unit dynamics (new) 8, soundfx 49 (3 new), sound-library 100 (4 new),
green.
- Counter-checks, each turns tests red: no look-ahead in the Limiter
(3), no taking back of the node's gain (1), a voice not started
earlier (1), no stage latency on a bus (1), no hold-back in a Mix (1).
- e2e 34 (melektaus-atx): ALL PASSED, 78 checks (1 new). Chrome
offline: Compressor 288 samples late, Limiter 240. Full scale through
-12 dB 4:1 hard knee: +0.19 dB with full auto-gain, -8.81 dB without.
A sine at 2 through the Limiter at -6 dB peaks at -6.00 dB, with
auto-gain 1 at -1.00 dB.
- The gate runs once on the last commit of this series.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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