fix(windows): initialize COM on audio threads

[n1net4il]

Description

On some Windows environments, as observed in a VMware Windows 11 guest, audio initialization could fail because the existing code did not guarantee that COM was initialized on the audio worker thread before accessing WASAPI COM interfaces.

Couldn't create audio policy config: [0x800401F0]
There will be no audio
Unable to initialize audio capture. The stream will not have audio.

0x800401F0 corresponds to CO_E_NOTINITIALIZED, indicating that COM was not initialized on the calling thread.

This change ensures that COM is initialized on the Windows audio worker thread before audio policy and WASAPI operations, and keeps it initialized for the thread’s lifetime. It also handles existing COM apartments safely, balances successful initialization calls with CoUninitialize(), and adds unit tests for the relevant HRESULT cases.

AI tools assisted with identifying the root cause and developing the patch. The fix was manually verified in the original VMware Windows 11 reproduction environment.

Successful audio initialization after applying the patch:

Audio mixer format is 32-bit, 48000 Hz, no resampling needed
Audio capture format is [F32 48000 2.0]
Opus initialized: 48 kHz, 2 channels, 96 kbps (total), LOWDELAY

References

• Microsoft: CoInitializeEx function
• Microsoft: CoUninitialize function

Screenshot

Issues Fixed or Closed

Fixes #4847

Roadmap Issues

Type of Change

• feat: New feature (non-breaking change which adds functionality)
• fix: Bug fix (non-breaking change which fixes an issue)
• docs: Documentation only changes
• style: Changes that do not affect the meaning of the code (white-space, formatting, missing semicolons, etc.)
• refactor: Code change that neither fixes a bug nor adds a feature
• perf: Code change that improves performance
• test: Adding missing tests or correcting existing tests
• build: Changes that affect the build system or external dependencies
• ci: Changes to CI configuration files and scripts
• chore: Other changes that don't modify src or test files
• revert: Reverts a previous commit
• BREAKING CHANGE: Introduces a breaking change (can be combined with any type above)

Checklist

• Code follows the style guidelines of this project
• Code has been self-reviewed
• Code has been commented, particularly in hard-to-understand areas
• Code docstring/documentation-blocks for new or existing methods/components have been added or updated
• Unit tests have been added or updated for any new or modified functionality

AI Usage

See our AI usage policy.

• None: No AI tools were used in creating this PR
• Light: AI provided minor assistance (formatting, simple suggestions)
• Moderate: AI helped with code generation or debugging specific parts
• Heavy: AI generated most or all of the code changes

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud