Vedio record for a certain time long

[王福海]

Hello，I'm a new Bonsai user and i want to record a video for a certain length such as 1 or 5 minutes, but I have to set the framerate in the "VideoWriter". In this case, the video I get is not exactly  1 or 5 minutes, because the frame rate of my camera is changing at all times. So, I wonder if there is a better work flow or any suggestions. Thank you so much!