Function testLimiterCeiling

tests/client_comp_test.cpp:246–272

Brickwall limiter must clamp peaks to ceiling even with comp off.

// Brickwall limiter must clamp peaks to ceiling even with comp off.
void testLimiterCeiling()
{
    ClientComp comp;
    comp.prepare(kSampleRate);
    comp.setEnabled(false);  // comp off, only limiter active
    comp.setLimiterEnabled(true);
    comp.setLimiterCeilingDb(-6.0f);  // ceiling at 0.5012 linear

    const float ceilingLin = std::pow(10.0f, -6.0f / 20.0f);
    const int frames = static_cast<int>(kSampleRate);
    auto buf = makeTone(1000.0, frames, 0.9f);  // well above ceiling

    // Warmup pass so limiter envelope is primed
    auto warm = makeTone(1000.0, frames, 0.9f);
    processBlocks(comp, warm.data(), frames);

    processBlocks(comp, buf.data(), frames);
    const float peak = peakAbsStereo(buf.data(), frames);

    // Allow a tiny overshoot (≤ +0.5 dB) for limiter settling between sine peaks.
    const float peakDb    = 20.0f * std::log10(peak);
    const float ceilingDb = 20.0f * std::log10(ceilingLin);
    report("limiter clamps 0.9 peak to -6 dBFS ceiling",
           peakDb - ceilingDb < 0.5f,
           "peak=" + std::to_string(peakDb) + " dBFS (ceiling="
               + std::to_string(ceilingDb) + ")");
}

// Stereo linking: max(|L|,|R|) drives envelope, and the same gain is
// applied to both. Feed L-only signal and check R remains silent (no