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VMIX trouble with capture NDI with Alpha channel
Rank: Newbie
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Joined: 4/22/2025(UTC) Posts: 3
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I’m facing an issue where vMix is blurring the edges of titles specifically when using an alpha channel. I’m sending titles from one machine to another via NDI—when I disable the alpha channel, the capture in vMix works perfectly. However, with the alpha channel enabled, the problem reappears only at the boundaries between transparent and opaque areas, or on elements with semi-transparent backgrounds.
The first photo shows the output from NDI Studio Monitor, and the second shows the input in vMix. This is happening entirely within a single vMix instance—both sending and receiving are handled by the same vMix setup.
Both systems are running the latest vMix versions, with progressive settings everywhere. Attached are screenshots of my output settings and the incoming signal.
Has anyone encountered this? How to fix it?
The graphics are animated and appear in different areas, sent via a single NDI stream. I even downloaded OBS, applied the same scenes/inputs for comparison, and added the NDI source there—it works fine, no blurriness. The issue seems isolated to vMix’s NDI capture when alpha channels are involved.
I’ve tried resetting vMix settings, reinstalling it, but no luck. Settings are shown in the screenshots attached to the post.
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Rank: Newbie
Groups: Registered
Joined: 4/22/2025(UTC) Posts: 3
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Rank: Administration
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Joined: 1/13/2010(UTC) Posts: 5,201  Location: Gold Coast, Australia Was thanked: 4465 time(s) in 1558 post(s)
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I would suggest contacting support and sending a Support Report in vMix with your setup. https://www.vmix.com/contact-us.aspxMy guess is there is multiple layers or some other settings enabled that are messing things up. See the shortcut below of vMix NDI out to vMix NDI in with alpha, on top of a grey input, you can see the edges look fine:  Colour 22 April 2025 20-34-21.png (63kb) downloaded 41 time(s).P.S image uploads should be fixed now
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Rank: Newbie
Groups: Registered
Joined: 4/22/2025(UTC) Posts: 3
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Issue Resolved - Windows Reinstall Fixed NDI Alpha Problem
Hi everyone,
Just wanted to follow up and let you know the issue has been resolved. After extensive troubleshooting, a clean Windows reinstall finally fixed the NDI alpha channel blurring problem.
Key details:
Problem: Blurred edges on alpha channels in vMix NDI (while OBS worked fine)
Solution: Fresh Windows installation
Still unclear what exactly caused it - possibly some deep system-level codec or GPU compositing issue
Since the thread might help others facing similar problems, here's what we tried before the reinstall:
Complete vMix reinstall (multiple versions)
NDI runtime reinstallation
GPU driver rollback/update
Various alpha channel & NDI setting combinations
Big thanks to everyone who offered suggestions! Moderators, please feel free to close this topic.
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VMIX trouble with capture NDI with Alpha channel
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