The Effects of Digital Video Quality on Learner Comprehension in an American Sign Language Assessment Environment

The effects of digital video frame rate and size on American Sign Language (ASL) learner comprehension were investigated. Fifty-one students were randomly assigned to one of three video-size treatment groups: 480×360, 320×240, and 240×180 pixels. Within each treatment, three 30-second videos of signed narratives at frame rates of 6, 12, and 18 frames per second were presented to students. Participants used ASL to retell each story, while a digital video camera captured their performances and archived them for evaluation. Three ASL experts evaluated the video performances and generated a fluency score for each student. The results indicate that frame rate and the interaction between frame rate and ASL level had significant effects on learner comprehension, but video size did not significantly affect comprehension. These results were used to generate frame rate and video-size recommendations for displaying and recording student performance and instructor feedback videos in an ASL performance assessment software environment.