Hi, I'm facing a hard problem, I'm developing an app to capture video from both front and rear camera simultaneously on IPhone 4 without jail-break and save it to one video with AVI format. I'm facing 2 problems: 1. Capture videos simultaneously from both camera (front and rear). 2. Save captured videos to only 1 file with AVI format. I have worked arround with multimedia lib in IPhone SDK and know that UIImagePicker class support me capture video on IPhone, but it only support one camera device by setting cameraDevice property of UIImagePicker . Seem UIImagePicker can't help me more.... I want to display 2 captured videos from both camera in screen, one is background video (full screen) and one foreground video, like PIP effect (picture in picture video effect on Television program), then I wanna save them (captured videos) to only 1 video file with video format, properly AVI format. For those purpose, I did search around on google, and know that FFMPEG seem support merge 2 video with PIP effect but I don't see any tutorial about it. I don't have any exp on FFMPEG before.... I'm very sad now, because the problem (1) & (2) are still there. I don't know how to capture videos simultaneously on IPhone, then merge and save them in only 1 video file like PIP effect. Anyone have idea about my those problems ? please help me !