基本GPUImage iOS7应用视频冻结/无法正常工作

I am new to GPUImage and I added GPUImage to a Default Single-View template Xcode 5.1.1 app. I successfully the static GPUImage library and I am trying the example from Readme file. I have iO S7.1 as base SDK. The app compiles and loads and the video just freezes. It freezes with or without the Filter. How do I fix this? I want to display live camera preview with a filter applied to itI am new to GPUImage and I added GPUImage to a