The study aims to investigate the challenging situation that might be faced when using an existing video to interpret facial expressions within the context of a classroom situation. Facial expressions, as part of non-verbal communication, are a crucial means of sending messages between the teacher and students. Most studies assess facial expressions using static rather than moving images. One way to examine facial expressions deriving from the interactions between teacher and students, which are always represented as moving images, can be carried out using existing video. This study utilizes literature to investigate the challenges in assessing facial expression using existing video and will contribute to the scope of knowledge on this topic.