Hello, I need to write an application that captures two video streams simultaneously. I'm using two consumer camcorders and bttv cards on v4l. I'm using a two thread model (each thread captures one stream) and I time stamp each frame. My goad is to track a few points in the video streams which are then used for 3d trajectory reconstruction. Since I cannot use genlocks I have to resort to other "tricks" to minimize synchronization errors. (frequency drifts between the two cameras (I'm using PAL so the nominal freq. is 50Hz)) Since I'm only analyzing trajectories, I thought the easies thing to do would be to timestamp the frames and interpolate coordinates linearly (based on current x,y previous frame's x,y and time stamp). What I was wondering if someone of you has an idea what kind of drifts consumer cameras experience in the real world (eg +/-1% of 50Hz ?) and if these drifts are pretty constant or vary due to temperature changes etc. Anyway common sense would tell me that the drift would be pretty small and constant so I guess linear interpolation is more than adequate. thanks for infos, cheers, Benno http://www.linuxaudiodev.org The Home Of Linux Audio Development
