Audio histogram in Wisp

Linear: AUT-106

The seam works. media quantizes audio into an AudioHistogram, media::waveform::mono_bars lays it out as rectangle geometry, and wisp's graphics pipeline draws those rectangles. Wisp never imports media.

A 440 Hz sine at amplitude 0.6, sampled at 48 kHz for 1 second, quantized at 50 ms (20 bars), mirrored about the centerline. Every bar is roughly the same height — that's the constant-amplitude sine made visible.

End-to-end path

sequenceDiagram
    participant Mock as media::SineWaveSource
    participant Hist as media::histogram::quantize
    participant Geom as media::waveform::mono_bars
    participant Wisp as wisp::Graphics

    Mock->>Hist: AudioChunk (1s, 48 kHz mono)
    Hist->>Geom: AudioHistogram (20 × peak, rms)
    Geom->>Wisp: Vec<WaveformBarRect>
    Wisp->>Wisp: graphics.draw_rect(x, y, w, h) ×20

Story code (excerpt)

#![allow(unused)]
fn main() {
use media::{audio::AudioFormat, clock::MediaDuration,
            histogram::quantize, mock_audio::SineWaveSource,
            waveform::{mono_bars, BarMetric, WaveformDisplayMode, WaveformLayout}};
use wisp::{Color, Fill, Graphics, math::Rect};

let mut src = SineWaveSource::new(AudioFormat::mono_f32(48_000), 440.0, 0.6);
let chunk = src.next_chunk(48_000);                       // 1 s
let histogram = quantize(&chunk, MediaDuration::from_millis(50)); // 20 bars

let layout = WaveformLayout {
    origin_x: -0.85, baseline_y: 0.0,
    bar_width: 0.075, bar_gap: 0.012,
    max_height: 1.1,
    color: [1.0, 0.74, 0.30, 1.0],
    metric: BarMetric::Peak,
    mode: WaveformDisplayMode::Mirrored,
};
let rects = mono_bars(&histogram, &layout);

let mut bars = Graphics::new();
let [r, g, b, a] = layout.color;
bars.fill(Fill::Solid(Color::rgba(r, g, b, a)));
for rect in &rects {
    bars.draw_rect(Rect::new(rect.x, rect.y, rect.width, rect.height));
}
}

The full story is in crates/wisp-storybook/src/stories/s_audio_histogram.rs.

Next

GStreamer audio → histogram example swaps the mock source for a real GStreamer-captured audio chunk so the same renderer can draw real microphone input.