Request preparation

• I used an AI assistant to help structure this request
• I checked for existing issues covering the same feature

What would you like?

What

A client-side Digital Voice Keyer (DVK) that plays locally stored audio files as transmitted speech — without requiring audio files to be stored on the FlexRadio hardware and without needing an upgraded SmartSDR license (e.g. the Maestro or SSDR DVK feature).

The user loads a set of WAV/FLAC files (e.g. CQ calls, contest exchanges, 73 messages) into AetherSDR, assigns them to numbered slots, and triggers playback with a button click or keyboard shortcut. AetherSDR keys the radio's PTT via the TX audio path, streams the audio, then unkeys when the file ends.

A prior art implementation by K9DUR for SmartSDR on Windows demonstrates the concept and community demand: it injected PC audio into the DAX TX channel to achieve the same result client-side.

Why

• The FlexRadio hardware-side DVK (CWX DVK macros) requires an upgraded SmartSDR license tier not available to all users
• Contest and DX operation benefits enormously from repeatable, consistent TX audio for CQ calls and exchanges
• Linux users have no access to third-party DVK utilities written for Windows
• A client-side implementation stores files locally, keeps operation fully offline, and requires zero radio firmware changes

How Other Clients Do It

The direct VITA-49 path (feeding AudioEngine's TX buffer directly) is preferred: it avoids PipeWire, works in all modes, and uses the already-wired r8brain-free-src resampler for sample rate conversion.

Audio format requirements (from existing AudioEngine): float32, big-endian, 24 kHz stereo. The Resampler class (r8brain-free-src) already handles arbitrary-rate → 24 kHz conversion for RN2 and RADE — the same pipeline can be reused here.

Acceptance Criteria

• User can assign a local audio file (WAV/FLAC) to each of 8 DVK slots via the UI; assignments survive application restart (stored in AppSettings)
• Pressing a slot button keys the radio (xmit 1), streams the audio file through the existing TX audio path at the correct sample rate, and automatically unkeys (xmit 0) when playback ends
• Pressing Stop or Esc at any time during playback immediately stops audio and sends xmit 0
• Repeat mode continuously retransmits a slot with a configurable inter-transmission gap until stopped
• The DVK is disabled (buttons greyed out) when the radio is not connected or when the active slice mode is CW (to avoid accidental phone transmission on a CW QSO)

Suggested labels: enhancement, audio, GUI