The flipped classroom is an instructional model in which students viewed the learning content before class through instructor-provided video lectures or other pre-class learning materials, and in-class time is used for student-centered active learning. Video is widely utilized as a typical pre-class learning material in the flipped classroom. This paper reports the findings from a survey about students' attitudes and preferences regarding the pre-class learning experiences in an undergraduate science course that utilized a flipped classroom model. Findings demonstrate that students had positive attitudes towards using pre-class videos in the flipped classroom. Students had different perceptions towards the four types of pre-class learning materials used in this course, including three types of videos and text-formatted materials. Students' attitudes and preferences on pre-class learning materials did not differ across class levels, major fields, or previous experience of learning via videos. Students suggested that pre-class videos should be kept short and engaging.