Fix Windows DirectShow: Add virtual camera support and friendly names #657
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Fix three critical issues in Windows DirectShow camera driver:
1. Single-frame capture bug - streaming stopped after first frame
2. No virtual camera support - OBS Virtual Camera didn't work
3. Unfriendly device names - showed DirectShow paths instead of camera names
Changes:
- Remove Null Renderer connection to enable continuous frame delivery
- Auto-detect NV12 and YUY2 formats based on buffer size
- Convert both formats to I420 (4:2:0) for consistency
- Use IPropertyBag FriendlyName property for readable camera names
(e.g., "OBS Virtual Camera" instead of "@device_sw_{...}\{...}")
- Fix memory leak in Open() if listResolution fails
- Optimize NV12 conversion with loop unrolling
- Add channel buffer to reduce frame drops
- Add oleaut32 library dependency for VARIANT functions
Tested on:
- Windows 10/11
- OBS Virtual Camera (NV12 format) - now works
- Physical webcams (YUY2 format) - continue working
- Device enumeration shows friendly names
- Sustained 30+ FPS streaming
Files modified:
- pkg/driver/camera/camera_windows.cpp
- pkg/driver/camera/camera_windows.go
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## master #657 +/- ##
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Coverage 42.52% 42.52%
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Files 84 84
Lines 5703 5703
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Hits 2425 2425
Misses 3130 3130
Partials 148 148 ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
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at-wat
reviewed
Oct 21, 2025
| memset(&mediaType, 0, sizeof(mediaType)); | ||
| mediaType.majortype = MEDIATYPE_Video; | ||
| mediaType.subtype = MEDIASUBTYPE_YUY2; | ||
| // Accept any format by leaving subtype as zeros (equivalent to GUID_NULL) |
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Is it possible that an incompatible format is chosen?
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| // FIX: Don't connect to null renderer | ||
| // Null renderer causes DirectShow to pause after one frame |
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I thought output pins should be terminated by connecting to null renderer when I wrote this long ago. (I'm not familiar with windows API)
If it's not necessary, please remove the code instead of commenting out.
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| fprintf(stderr, "Unexpected buffer size: %d (expected NV12=%d or YUY2=%d)\n", | ||
| len, expectedNV12, expectedYUY2); | ||
| return S_OK; |
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I think the whole program should fail instead of ignoring the data if an incompatible format is selected.
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Partially addresses #95 - Adds NV12 format support and fixes continuous frame delivery
Problem
The current Windows DirectShow implementation has three critical issues:
Solution
This PR fixes all three issues:
Testing
Tested on Windows 10/11 with:
Before/After
Device names:
Streaming:
Files Modified
pkg/driver/camera/camera_windows.cpp(~90 lines changed)pkg/driver/camera/camera_windows.go(~25 lines changed)Breaking Changes
None - 100% backward compatible
Notes
This patch was developed with Claude AI assistance through extensive testing and iteration. I'm not a C programmer, so please review carefully. Happy to address any feedback!
Co-authored-by: Claude AI https://claude.ai