Gdiplus and directshow video renderer

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C++

GDI

directshow

Hi,
I developped an application capable of playing video with DirectShow and scrolling text with layered windows. Text is drawn using GDIPlus.

I remarked text was sometimes stuttering when using EVR renderer.
I could point out that stuttering occurs exactly during the RenderFile method call.
In fact, I finally did noticed it's also stuttering with VMR9, but almost not perceptible.

So it looks like RenderFile is locking GDIPlus access, particularly noticeable when in EVR mode.
My application is fully multi-threaded.

Any idea of what can happen, and how to fix it ?

Thanks in advance.

What I have tried:

I did not try anything special so far.
The application was VMR9 based and I just implemented EVR and discovered the issue.
Any idea of things I can try would be appreciated, provided that it does not reconsider use of GDIPlus for text scrolling and DirectShow for video playback.