Virtual Audio Routing vs CoreAudio Loopbacks: Capturing Meeting Audio Without Leaks
Architectural breakdown of system audio loopbacks on macOS and Windows. Learn how BlackHole, CoreAudio TAPs, and WASAPI capture meeting audio without echo.
To provide real-time AI transcription of interview questions, an assistant must capture incoming speaker audio directly from Zoom or Teams with zero acoustic echo and under 50ms latency.
The Problem: Capturing Interviewer Speech for AI Transcription
In technical interviews, interviewers explain problems verbally. Without low-latency audio ingestion, candidates must manually transcribe complex requirements. Direct digital loopback automates this process seamlessly.
macOS CoreAudio: AudioServerPlugIns vs. CATapDescription
macOS Sonoma introduced CATapDescription, enabling user-space process-isolated audio tapping without requiring external virtual audio drivers like Soundflower or BlackHole.
Windows WASAPI Loopback Capture Architecture
On Windows, the Windows Audio Session API (WASAPI) supports AUDCLNT_STREAMFLAGS_LOOPBACK, capturing the master audio render endpoint before it reaches DAC speakers.
Echo Cancellation & Acoustic Feedback Elimination
By segregating audio channels, incoming interviewer speech is routed directly to the AI whisper engine without re-injecting into the candidate's outgoing microphone line.