Audio Noise GateApply a noise gate to reduce background noise in quiet sections.

The noise gate processes audio sample-by-sample, analyzing the signal amplitude against the user-defined threshold. When the signal level falls below the threshold, the gate closes by reducing the gain to near-zero. When the signal exceeds the threshold, the gate opens to full volume. To prevent artifacts, the gate implements smooth transitions using an envelope follower: the attack time controls how quickly the gate opens when signal exceeds threshold, and the release time controls how gradually the gate closes. The amplitude is measured using a sliding RMS window (typically 10-50ms) to avoid triggering on individual sample spikes. The gating is applied directly to the PCM sample data in the AudioBuffer. The result is encoded as a 16-bit WAV file.