Video representation through key frames has been addressed frequently as an efficient way of preserving the whole temporal information of sequence with a considerably smaller amount of data. Such compact video representation is suitable for the purpose of video browsing in limited storage or transmission bandwidth environments. In this-case, the controllability of the total key frame number (i.e. key frame rate) depending on the storage or bandwidth capacity is an important requirement for the key frame selection method. In this paper, we present a sequential key frame selection method when the number of key frames is given as a constraint. It first selects the pre-determined number of initial key frames and time-intervals. Then, it adjusts the positions of key frames and time-intervals by iteration, which reduces the distortion step by step. Experimental results demonstrate the improved performance of our algorithm over the existing approaches. (C) 2002 Elsevier Science B.V. All rights reserved.