Due to the unique characteristics of video, traditional surrogates and control/browsing mechanisms that facilitate text-based information retrieval may not work sufficiently for video. In this paper, a video browsing interface prototype with key frames and fast play-back mechanisms was built and tested. Subjects performed two kinds of browsing-related tasks: object identification and video comprehension under different display speeds (1 fps, 4 fps, 8 fps, 12 fps and 16 fps). It was found that browsing the key frames between 8 to 12 fps could potentially define a functional limit in object identificationaccuracy. There was no significant performance difference found across display speeds tested. The results also showed that lower speeds were required for object identification than for video comprehension. How user performance was affected by individual characteristics such as age, gender, academic background and TV- or movie-watching habits, was investigated, but no significant difference was found due to the limit of sample size and other constraints. (Also cross-referenced as UMIACS-TR-97-40) (Also cross-referenced as CLIS-TR-97-06)