README

EdgeAudio (VAD & Talkover)

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• Introduction
• Quick Start
• Dependencies
• Key Features
• Things You Should Know
• License
• Going further

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Mini‑lab Delphi/VCL to integrate mic capture, audio playback, and filtering (VAD + Talkover) via WebView2, with a bidirectional JS bridge and event‑driven orchestration. Architecture centered on TEdgeAudioControl + TAudioSettings, applied in real time on the WebAudio side.

Built with Delphi 12 Community Edition (v12.1 Patch 1)
The wrapper itself is MIT-licensed.
You can compile and test it free of charge with Delphi CE; any recent commercial Delphi edition works as well.

Introduction

• Pipeline: mic capture, player, high‑pass filter, VAD, and Talkover, synchronized Delphi ↔ JS via WebView2.

• Virtual host to serve web assets and avoid CORS; clean VCL integration in TEdgeBrowser.

• Typed events and a dispatch engine on the Delphi side (play, pause, ended, segments, etc.).

  

Quick Start

Component Installation (TEdgeAudioControl)

• Load the EdgeAudioDesign.dproj package in the IDE.

• Compile or Build the package.

• Install the package to register the component in the Palette.

  

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Case 1 — Project already has a TEdgeBrowser (use the Edge.Audio unit)

• Add the source folder to the project search path (File search).
• Copy the web (HTML/JS/CSS) and tools folders into your project’s source folder; the control checks for web at runtime and shows a dedicated message if missing.
• Before the first run, copy WebView2Loader.dll (32/64‑bit per target) next to the executable; a built‑in message explicitly reminds this.
• Drive capture/VAD/Talkover/filter and playback through the WebView2 bridge (chrome.webview).

[!NOTE] The sample code AudioEdgeTest1.zip, located in the sample folder, demonstrates this use case.

[!WARNING] If you use AudioEdgeTest1.zip, make sure to specify the search paths in the project options ("EDGEAUDIO\SOURCE" and "OPENAI\SOURCE").

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Case 2 — Using the TEdgeAudioControl component

• Add the source folder to the project search path.
• Copy the web and tools folders into your project’s source folder; default ffmpegPath = ....\tools (override as needed).
• Before the first run, copy WebView2Loader.dll (32/64‑bit) next to the executable.

[!NOTE] The sample code AudioEdgeTest2.zip, located in the sample folder, demonstrates this use case.

[!WARNING] If you use AudioEdgeTest2.zip, make sure to specify the search paths in the project options ("EDGEAUDIO\SOURCE" and "OPENAI\SOURCE").

Settings in the object inspector

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Redistribution (common to both cases)

• Place the web folder next to the executable; an automatic message appears if it’s missing.
• Ship WebView2Loader.dll (32/64‑bit) with the executable.
• If you rely on audio conversion via ffmpeg: redistribute tools/ffmpeg or set ffmpegPath accordingly.

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Dependencies

• Delphi 12 (Athens) or later.
• WebView2 Runtime (Edge) for VCL; ship WebView2Loader.dll next to your EXE (x86/x64 as appropriate) .
• ffmpeg if audio conversion is required; path configurable via ffmpegPath (default ....\tools). See also : https://ffmpeg.org/

[!NOTE]

1. The provided code examples use an OpenAI model to process audio input and produce audio output; install the DelphiGenAI wrapper v1.2.1: https://github.com/MaxiDonkey/DelphiGenAII
2. The code examples use the Windows 11 MineShaft custom VCL theme.

Key Features

• Capture + VAD: adjustable threshold/silenceMs/timeslice; audio segments sent back to Delphi; start/stop from Delphi.
• Talkover: auto‑pause playback on speech with fine‑grained parameters (ratio, relative/absolute thresholds, cooldown, anti “ping‑pong”).
• Playback/Streaming: play/pause/seek/stop, MediaSource streaming, >1 volume boost via WebAudio, setSinkId if supported, energy metrics feeding Talkover logic.
• High‑pass filter: hot‑adjustable; Delphi receives notifications on changes.
• WebView2 bridge: Delphi → JS commands (setTalkoverParams, setHighpassFrequency, etc.) and JS → Delphi events (audio_play, audio_pause, audio_ended, audio_segment…).
• Built‑in UX: “toast” notifications and animations (waveform, processing) controlled from Delphi.

Things You Should Know

• Consider enabling autoBlockCaptureDuringPlayback to avoid echo while playing; tune Talkover cooldown/thresholds on the fly via JS commands.
• WebView2 navigation uses a local “virtual host” to serve assets and avoid CORS.

License

This project is licensed under the MIT License.

Going further

• Architecture and event flow: see the “Dev note – Architecture & Mechanics” sections (Audio, Control, Events) in the source for diagrams and extension points (interfaces, handlers). Refer to Deep-dive section.