Read video with different fps

I use to read a video, and the number of frames is based on the intrinsic fps of the video.
I wonder if there is easier way to use this api, but one can feed a specific fps value?

VideoClips class has a frame_rate argument, but the size is fixed by clip_length_in_frames and frames_between_clips.
I want videos with variant duration have their corresponding frames based on the specified fps.