problem of writing device camera app

Question

Sorry for my english!!

I have some question on camera device app developing.

1.       Can multiple camera driver MFTs be loaded together?

When use MediaCapture class, we can use AddEffectAsync function to add multiple MFT effects.

Can we use multiple camera driver MFTs on one device together?

2.       How to draw a transparent image on CameraCaptureUI preview Window?

I have a camera Metro style device app attached to my camera device. When call CameraOptionsUI.show function,

My own setting can be loaded.

My question is, I want to draw a transparent(50%) frame on the preview window, how to do this?

I guess the following two ways may work:

1)       Get the camera preview data in my driver MFT, and then compose the frame and image.

2)       Can I use overlay to draw the transparent frame on top of preview window? How to use overlay?

thanks.

Answer 1

Hi Kyo Wang,

We're looking into this and will get back to you soon.

--Rob

Answer 2

Hello Kyo,

Here are the answers to your questions:

Q. Can multiple camera driver MFTs be loaded together?
A. If an MFT can be wrapped as a media extension plugin it can be inserted into the pipeline using AddEffectAsync. There is no upper limit on the number of MFTs that can be inserted. If you want to use a driver MFT (mft0), only one can be registered. That said, we do allow multiple instance of MFT0 to be loaded for different pins of the camera.

Q. How to draw a transparent image on CameraCaptureUI preview Window?
A.  You should not use CameraCaptureUI to draw a transparent image. I would recommend that you use MediaCapture, call AddEffectASync. You can then use the effect to draw a transparent image. Keep in mind that your effect is responsible for overlaying any images. The final rendered effect is then passed on to the preview window.

I hope this helps,

James

Windows Media SDK Technologies
Microsoft Developer Services
http://blogs.msdn.com/mediasdkstuff/

Answer 3

Hello Kyo,

Here are the answers to your questions:

Q. Can multiple camera driver MFTs be loaded together?
A. If an MFT can be wrapped as a media extension plugin it can be inserted into the pipeline using AddEffectAsync. There is no upper limit on the number of MFTs that can be inserted. If you want to use a driver MFT (mft0), only one can be registered. That said, we do allow multiple instance of MFT0 to be loaded for different pins of the camera.

Q. How to draw a transparent image on CameraCaptureUI preview Window?
A.  You should not use CameraCaptureUI to draw a transparent image. I would recommend that you use MediaCapture, call AddEffectASync. You can then use the effect to draw a transparent image. Keep in mind that your effect is responsible for overlaying any images. The final rendered effect is then passed on to the preview window.

I hope this helps,

James

Windows Media SDK Technologies
Microsoft Developer Services
http://blogs.msdn.com/mediasdkstuff/

Hi James,

I am writing a Mft0 for my camera in Windows 8.1 Preview. I've followed the Driver MFT Sample and i am able to see my effects applied to the camera preview, but when i take pictures or record videos using CameraCaptureUI Sample, the filter is not applied to the picture/video.

What i would like to know is how can i load multiple instance of my MFT0 to the different pins of the camera? Where, in the driver implementation, do i do that?

Any help would be highly appreciated.

Thanks.