In some applications, the R200 freezes up or crashes if it is running at a speed of 60 frames per second (FPS). A workaround for this - if it is indeed the cause of your depth camera problem - that has been listed in the RealSense SDK's release notes is to reduce the camera's speed to 30 FPS.
I could not find an option in Vuforia to set a maximum FPS. My research suggested that if you set the frame rate in the scripting of whatever platform you are using with Vuforia (e.g Unity) then the camera FPS in Vuforia changes. In Unity, for example, the setTargetFrameRate instruction is used.
Thank you for the reply and suggest.
I tried your suggest then it still can not be initialize too.
I think the setTargetFrame is not the stream setting of the input camera (R200). It is about the frame rate of the output application.
It was the belief of the Vuforia users that provided that information that changing the frame rate of the output application would cause the RealSense camera's FPS to reduce.
It looks as though 'item_unavailable' is an error generated by Vuforia, as other people have got that error when using Vuforia with various applications. This makes it difficult to diagnose, since there is not widespread experience of Vuforia on this forum.
I did find on here a post from a couple of months ago where another user wanted to use Vuforia with Unity. This might be of use to you if you have not seen it already.
Thanks your reply, but I wonder that why SR300 streams can be initialized individually in such situation.
Is there something different about DCM working principle between SR300 and R200 ?