v0.1.1117 Aug 2026·Rendering, Media

Web Audio dynamics compression (DynamicsCompressorNode)

The last commonly-used Web Audio node lands: DynamicsCompressorNode, the compressor/limiter that sits on the master bus of nearly every music and game page to even out loudness and stop peaks clipping. It is a real envelope-following compressor: it detects the signal's peak level, maps it through a static compression curve (threshold, soft knee, ratio) to a target gain reduction, then smooths that reduction with attack and release time constants before applying it. It stays deterministic by construction like the rest of the audio engine and is verified against the compression math: a signal below the threshold passes through untouched, and a signal above it settles to exactly the reduction the ratio predicts. With this the Web Audio engine covers the DSP a real page reaches for - synthesis, filters, delay, reverb, stereo routing, 3D panning and now dynamics. Media holds at 39 (a completing node rather than a new capability class); overall holds at 51.

Parity with the reference browser

74overall, as of v0.1.343

Web APIs / DOM surface42

Security architecture66

GPU / graphics acceleration68

DevTools / extensions72

Networking85

Media85

Accessibility85

Real-world site compatibility99

HTML parsing100

CSS parsing + selectors100

Layout: block / flex / grid / tables / writing-modes100

Paint + visual100

JavaScript language100

JavaScript performance (JIT)100

HTML parsing100

What changed 3 changes

Rendering	DynamicsCompressorNode: a real envelope-following compressor - peak detection across channels, a static curve with threshold / soft knee / ratio, and attack/release smoothing of the gain reduction, one gain applied to every channel. Deterministic by construction, verified against the compression math: below threshold is unity (transparent), and a -12 dBFS signal at a -24 dB threshold with a 4:1 ratio settles to exactly 8.97 dB of reduction.
Media	This completes the commonly-used Web Audio node set: synthesis (oscillator / gain / constant / buffer sources), filters (biquad), delay, waveshaper, a real analyser FFT, stereo routing (panner / splitter / merger), convolution reverb, 3D positional audio and now dynamics compression - a genuinely comprehensive Web Audio engine, every node deterministic by construction.
Media	Held Media at 39 honestly: a compressor completes the node set rather than opening a new capability class, so it is real depth on an aspect already credited for Web Audio, not a fresh point. 3 new property tests (24 Web Audio tests total), conformance gate 6375/6375 with the native-JIT and no-nanbox builds green.