VINAIscope — Manual

01Overview

VINAIscope is an analysis tool, not a processor. It taps the signal and renders a real-time waveform through the Phosphor Display Engine — a CRT you'd actually want in the rack. Persistence trails paint a glowing afterimage of the waveform, FOCUS adds trace bloom, scanlines and phosphor decay give you the old-school read, and the moment a sample crosses full-scale the overflow indicator flares. Everything is redrawn at up to 120 Hz with none of the lag of real glass.

The audio leaves exactly as it arrived — bit-transparent, sample-accurate, zero added latency. Park it anywhere in the chain, leave it on the master, A/B with it inserted: the sound never changes, only your view of it does. One logarithmic TIME control sweeps the window from a single kick transient out to whole phrases, and a rising zero-cross trigger locks the trace dead still when you need to read fine detail.

02The interface

• Scope display (center) — the live phosphor waveform with persistence trails, focus bloom, scanlines and the CRT graticule.
• Overflow indicator — flares the instant a sample crosses full-scale, so you catch the clip the moment it happens.
• Control row (TRIM · TIME · PERSISTENCE · FOCUS) — the four knobs that scale, window and shape the trace.
• FREEZE — holds the current frame on screen so you can study a captured moment.

03Knobs & buttons

04Under the hood

VINAIscope is deliberately all display, no DSP. There is no filter, no gain stage, no oversampling and no processing of any kind on the audio path — the analyzer reads the signal and hands the original samples straight back to the host, bit-for-bit. Everything you see happens downstream, on the GUI thread, decoupled from audio entirely.

Signal flow

• Bit-transparent tap. On each audio block the input is copied — not routed — into a lock-free, single-producer / single-consumer FIFO and then passed through untouched. The output buffer is the input buffer: no summing, no scaling, no rounding, so the signal is bit-exact in and out.
• Power-of-two waveform FIFO. The capture ring holds 2¹⁷ samples (131,072). A power-of-two length lets the read/write indices wrap with a single bitmask instead of a modulo, keeping the audio-thread write to a couple of branch-free instructions and zero locks.
• No audio-thread allocation or DSP. The render path never touches the audio callback — the FIFO is the only point of contact. Because nothing is filtered, resampled or smoothed, there is no group delay to report and nothing to latency-compensate: PDC is reported as zero.
• 120 Hz GUI redraw. The Phosphor Display Engine drains the FIFO and repaints at up to 120 Hz on the message thread, fully asynchronous to the audio block size — buffer changes in the host don't alter what you see, only how often it updates.
• Zero-cross triggering. For windows ≤ 200 ms the engine searches the captured buffer for a rising zero-crossing and aligns the draw origin to it, so periodic material stands dead still. Above 200 ms — where a static lock would fight long-form movement — it free-runs.
• Catmull-Rom trace. The sampled points are interpolated with a Catmull-Rom spline for a smooth, anti-aliased waveform rather than hard polylines between samples — the curve passes through every captured point with no overshoot artefacts on the displayed line.
• Phosphor-persistence ring. Previous frames are retained in a persistence ring buffer and decayed frame-over-frame, building the CRT afterimage; FOCUS drives a bloom pass on the live trace, scanlines and an overflow glow are composited on top — all purely visual.
• Metering / overflow. The overflow flag is raised whenever a captured sample reaches or crosses full-scale (|x| ≥ 1.0). It is a read-only observation of the tapped signal — VINAIscope never clamps, limits or otherwise alters the sample it flagged.

The net result: zero latency, zero coloration, zero self-noise. You can leave it inserted on the master through mixdown and bounce — the render is bit-identical with the analyzer in or out of the chain.

05Measured

Measured in-house (headless host + numpy/scipy), 48 kHz.

06Specifications