I use 4 Sensors by Asus Xtion， but if i record More than two Sensors video files，ipiMocap does not appear in the “project calibration” option。

Help me please！

Thanks！！！！！！！

More than two Sensors did't has "Calibration project" option 。 Only “Action project”。 How to Calibration？？？

Hi
Please ensure that iPiVideo file indeed contains a video footage from 4 depths sensors. You can open iPiVideo file in iPi Recorder to check this.

But xtion recorded video frame rate is very low, even with 320 * 240 resolution, and only less than 10 frames

iPi Recorder warns you about low frame rate when about to start recording. You should not ignore this warning but solve a problem causing it.
Usually, low frame rate problems are caused with USB bandwidth problems. Either you connect too many cameras to a single USB controller, or there is a compatibility issue with specific USB controller model.
Each Xtion depth sensor should be connected to a separate USB controller to get full frame rate. Thus, you need 4 USB controllers in a single PC or use distributed recording.
For known compatibility issues see our online docs.