wasapi-development

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name: wasapi-development description: Design, implement, review, debug, and optimize Windows Audio Session API (WASAPI) and Core Audio code on Windows 10/11. Use for audio rendering, microphone capture, system loopback, process loopback, low-latency audio, shared/exclusive streams, IAudioClient/IAudioClient2/IAudioClient3, IAudioRenderClient, IAudioCaptureClient, MMDevice endpoint selection, audio sessions, device switching, stream recovery, format negotiation, buffer processing, MMCSS, and native interop from C++, C#, .NET, WinUI 3, WPF, or other Windows desktop applications. compatibility: Windows desktop development targeting Windows 10 or Windows 11. Some capabilities require specific Windows builds; verify the project's minimum supported OS before selecting APIs. metadata: domain: windows-audio version: "1.0"

WASAPI Development

Use this skill when working directly with WASAPI, Core Audio, MMDevice, audio sessions, endpoint volume, or low-level Windows audio streams.

Treat audio streaming code as real-time, stateful, resource-sensitive systems code, not ordinary application code.

Reference documents

This skill is split across modular reference files in references/. Load only the document(s) relevant to the current task.

Reference	Contents	Load when
references/overview.md	Goals, when to use WASAPI, inspect the existing system, core optimization principle.	Starting any WASAPI work; orientation.
references/scenario-and-architecture.md	Classify direction/endpoint/mode/latency/processing; Core Audio object chain; recommended class responsibilities.	Selecting the stream scenario; designing structure.
references/modes-latency-scheduling.md	Shared vs exclusive mode; IAudioClient3; latency as negotiated; event-driven streaming; real-time bounds; MMCSS.	Choosing mode/latency; scheduling the audio worker.
references/audio-formats.md	Format negotiation, GetMixFormat / IsFormatSupported, format ownership, sample conversion, multichannel.	Negotiating or converting audio formats.
references/render-and-capture.md	IAudioRenderClient / IAudioCaptureClient buffer protocol; priming; capture flags; timing/positions.	Implementing render or capture loops.
references/loopback.md	Endpoint loopback, process loopback, RAW mode, MATCH_FORMAT.	Capturing system/process audio or bypassing processing.
references/devices-routing-changes.md	MMDevice endpoint selection, default routing, IMMNotificationClient, invalidation/recovery.	Choosing devices; handling device changes.
references/sessions-and-volume.md	Audio categories, sessions, endpoint vs session volume.	Session/volume control.
references/threading-and-lifecycle.md	COM/threading, async activation, lifecycle state machine, Start/Stop/Reset, cancellation, locking.	Stream lifecycle and concurrency.
references/data-flow.md	Backpressure, buffer ownership across threads, silence, discontinuities.	Connecting a slow consumer; handing off audio data.
references/diagnostics-and-performance.md	Structured diagnostics; investigating glitches/underruns.	Debugging or optimizing audio.
references/managed-and-errors.md	C#/.NET guidance, error categorization, fallback policy.	Managed implementations; error handling.
references/testing.md	Unit vs integration testing, review checklist, anti-patterns.	Testing and reviewing WASAPI code.
references/workflow.md	Step-by-step implementation workflow; source-of-truth policy.	Implementing a new or modified audio feature.

How to use

1. Read references/overview.md for orientation.
2. Read the specific references/*.md documents for the task (format selection, capture loop, device handling, etc.).
3. Apply the guidance to the host project, preserving its existing abstractions and conventions.