Test Signal Generator

Test Signal Generator input properties for Script Engine. Virtual input that synthesises video test patterns (SMPTE/EBU/100% colour bars, grayscale ramp/steps, grid, checkerboard, concentric circles, solid colour, animated frame counter, and primary fills) and audio test signals (silence, sine/square/sawtooth tones, white/pink noise, log frequency sweep, and L/R channel-ID tones). Designed for pipeline diagnostics: verifying colour and levels end-to-end, tuning encoder settings, measuring round-trip latency, and confirming channel routing.

Property	Type	Access	Description
`ShowAdvancedOptions`	`bool`	`get/set`	Show or hide the input's advanced settings in the editor UI. [default=false].
`AutoStart`	`bool`	`get/set`	Whether the generator starts producing output as soon as the project loads. [default=true]. When true, `StartCommand` is invoked automatically during input initialisation, so the input goes straight to `Running`. Disable to require an explicit start (useful when the signal should only begin on operator action or via a script trigger).
`EnableVideo`	`bool`	`get/set`	Whether the video pattern is rendered each frame. [default=true]. When false, no video pattern is produced — useful when this input is only being used as an audio source. Re-enabling redraws the pattern on the next frame.
`EnableAudio`	`bool`	`get/set`	Whether the audio test signal is produced each frame. [default=true]. When false, the input outputs silence on all channels instead of the configured `AudioSignalType`. Use this when only the video pattern is needed, or to mute the test tone temporarily without changing the selected signal type.
`PlaybackState`	`PlaybackState`	`get`	Current playback state of the generator (read-only). Reflects whether the input is `Stopped` or `Running`. Set indirectly via `StartCommand` / `StopCommand` (or `AutoStart` at load time). Scripts should read this to decide whether the signal is live; the property also drives the running indicator and the enabled state of the Start/Stop buttons.
`StartCommand`	`Command`	`get`	Begin generating the configured video pattern and audio signal. Invokable command. Transitions `PlaybackState` to `Running` and starts output from a clean state — frame counter, sweep, and noise are all reset, and the first video frame is drawn fresh from the current settings. No-op if already running.
`StopCommand`	`Command`	`get`	Stop generating video and audio output. Invokable command. Transitions `PlaybackState` to `Stopped`, silences the audio output, and resets the audio meters. Video output is no longer produced until `StartCommand` is invoked again. No-op if already stopped.
`VideoPatternType`	`VideoPattern`	`get/set`	Which video test pattern to render. [default=SmpteColorBars]. Selects the pattern produced each frame. Most patterns are static and only redrawn when settings change; `FrameCounter` is animated and updates every frame (it also drives a flash marker for latency measurement). Pattern-specific properties only take effect for the matching pattern (e.g. `GridSpacing` for `Grid`, `CheckerSize` for `Checkerboard`, `SolidColorRed/Green/Blue` for `SolidColor`).
`OutputWidth`	`int`	`get/set`	Output frame width in pixels. [min=128, max=3840, default=1920]. Controls the horizontal resolution of the generated video pattern. Combine with `OutputHeight` to test specific aspect ratios (e.g. 1920x1080 for 16:9, 3840x2160 for UHD).
`OutputHeight`	`int`	`get/set`	Output frame height in pixels. [min=128, max=2160, default=1080]. Controls the vertical resolution of the generated video pattern. See `OutputWidth` for typical resolution pairings.
`GridSpacing`	`int`	`get/set`	Spacing between grid lines, in pixels. [min=8, max=256, default=64]. Only used by the `Grid` pattern. Smaller values produce a denser crosshatch (useful for inspecting fine geometric distortion or scaler artefacts); larger values give a sparser grid suitable for general framing checks. The outer frame border is always drawn regardless.
`CheckerSize`	`int`	`get/set`	Side length of one checkerboard square, in pixels. [min=4, max=128, default=32]. Only used by the `Checkerboard` pattern. Small sizes are useful for stressing scalers, chroma subsampling, and codec block boundaries; large sizes are easier to read for level and contrast verification.
`ShowCenterCross`	`bool`	`get/set`	Whether to overlay a small red centre cross on the rendered pattern. [default=true]. Drawn on top of every pattern after generation. Useful for confirming framing, centring, and pixel-aspect handling through downstream operators and encoders. Disable for clean test patterns when you don't want the overlay to interfere with measurement.
`ShowSafeAreas`	`bool`	`get/set`	Whether to overlay the broadcast title-safe and action-safe markers. [default=false]. When enabled, draws two dashed rectangles on top of the pattern: a yellow action-safe boundary at 90% of the frame and a green title-safe boundary at 80% of the frame. Use to verify that graphics, captions, and key visuals stay within the expected safe areas after downstream scaling or cropping.
`CircleLineWidth`	`int`	`get/set`	Line thickness for the circle/aspect-ratio pattern, in pixels. [min=1, max=8, default=2]. Only used by the `Circle` pattern. Controls how thick the concentric reference circles and the horizontal/vertical/diagonal centre lines are drawn. Increase for higher-resolution outputs so the lines remain visible after downscaling or compression.
`SolidColorRed`	`int`	`get/set`	Red channel of the solid-fill colour, 0–255. [min=0, max=255, default=0]. Only used by the `SolidColor` pattern. Combined with `SolidColorGreen` and `SolidColorBlue` to produce an arbitrary 8-bit-per-channel BGRA fill. Useful for level checks (e.g. pure 255 red to inspect chroma clipping) or for driving chroma keyers with a known backdrop.
`SolidColorGreen`	`int`	`get/set`	Green channel of the solid-fill colour, 0–255. [min=0, max=255, default=128]. Only used by the `SolidColor` pattern. See `SolidColorRed` for general usage; pure 255 green is the standard chroma-key reference colour.
`SolidColorBlue`	`int`	`get/set`	Blue channel of the solid-fill colour, 0–255. [min=0, max=255, default=255]. Only used by the `SolidColor` pattern. See `SolidColorRed` for general usage.
`AudioSignalType`	`AudioTestSignal`	`get/set`	Which audio test signal to generate. [default=Sine]. `Silence` outputs nothing (level reference). `Sine`/`Square`/`Sawtooth` produce a tone at `AudioFrequency` with `AudioGainDB` applied. `WhiteNoise` outputs flat-spectrum noise. `PinkNoise` outputs noise with the perceptually flat (−3 dB/octave) slope used for room and system tuning. `Sweep` is a logarithmic frequency sweep between `SweepLowFrequency` and `SweepHighFrequency` over `SweepDurationSeconds`, repeating per `AudioSweepMode`. `ChannelId` plays `ChannelIdFrequencyLeft` and `ChannelIdFrequencyRight` alternately on each channel every half-second to confirm L/R routing.
`AudioFrequency`	`int`	`get/set`	Tone frequency for the periodic audio signals, in Hz. [min=20, max=20000, default=1000]. Applies to `Sine`, `Square`, and `Sawtooth` signal types only (ignored by noise, sweep, and channel-ID modes). 1000 Hz is the standard EBU/SMPTE reference tone; 440 Hz is musical A4. The range covers the full audible band — values above ~20 kHz are clamped, and frequencies near the Nyquist of the 48 kHz output may alias for non-sine waveforms.
`AudioGainDB`	`int`	`get/set`	Output level for the audio signal, in decibels relative to full-scale. [min=-60, max=6, default=-20]. Applies to all audio signal types. −20 dBFS matches the common EBU/SMPTE alignment level and is safe against clipping when downstream stages add gain. Values above 0 dBFS will clip in fixed-point targets — only use the positive headroom for deliberate overload tests.
`SweepDurationSeconds`	`int`	`get/set`	Length of one full low→high frequency sweep, in seconds. [min=1, max=30, default=5]. Only used when `AudioSignalType` is `Sweep`. Shorter durations are useful for quick spectrum checks; longer durations reveal frequency-dependent issues (resonances, comb filtering, codec artefacts) with finer resolution. Combine with `AudioSweepMode` to control whether the sweep stops, repeats, or ping-pongs at the end.
`SweepLowFrequency`	`int`	`get/set`	Lower bound of the frequency sweep, in Hz. [min=20, max=1000, default=20]. Only used when `AudioSignalType` is `Sweep`. Sets the starting (and, in `PingPong` mode, returning) frequency of the logarithmic sweep. Must be less than `SweepHighFrequency` for the sweep to run in the expected direction.
`SweepHighFrequency`	`int`	`get/set`	Upper bound of the frequency sweep, in Hz. [min=1000, max=20000, default=20000]. Only used when `AudioSignalType` is `Sweep`. Sets the peak frequency of the logarithmic sweep. Keep below the Nyquist limit (24 kHz at 48 kHz sample rate) to avoid aliasing — 20 kHz covers the full audible band.
`AudioSweepMode`	`SweepMode`	`get/set`	How the frequency sweep behaves at the end of one pass. [default=PingPong]. Only used when `AudioSignalType` is `Sweep`. `OneShot` sweeps once from low to high and then holds at the high frequency. `Repeat` snaps back to the low frequency and runs again (audible discontinuity). `PingPong` reverses direction at each end for a continuous low↔high motion with no jumps — usually the most pleasant for spectrum-by-ear inspection.
`ChannelIdFrequencyLeft`	`int`	`get/set`	Tone frequency played on the left channel during channel identification, in Hz. [min=100, max=4000, default=440]. Only used when `AudioSignalType` is `ChannelId`. Left and right take turns every half-second: during the left half the right channel is silent, and vice versa. Pick a frequency clearly distinct from `ChannelIdFrequencyRight` so you can tell them apart by ear (e.g. 440 vs 880 Hz — musical A4 and A5).
`ChannelIdFrequencyRight`	`int`	`get/set`	Tone frequency played on the right channel during channel identification, in Hz. [min=100, max=4000, default=880]. Only used when `AudioSignalType` is `ChannelId`. See `ChannelIdFrequencyLeft` for full behaviour — keep this distinct from the left frequency so the channels are unambiguous by ear.
`CurrentFrameCount`	`long`	`get`	Number of video frames rendered since the last `StartCommand` (read-only). Increments by one per rendered frame while `PlaybackState` is `Running`, and resets to 0 when the generator is restarted. Drives the binary visualisation in the `FrameCounter` pattern, and can be polled from scripts to gate timing-sensitive logic or measure throughput.

Inherits from: AbstractInput, AbstractAudioProcessing, AbstractAudioMetering.

See also: Test Signal Generator in Inputs — user-facing introduction, screenshots, and section summaries.