Abstract: A motion analyzer in which full frames of video information from two video imagers are recorded in interleaved fashion on magnetic tape. The motion analyzer records at multiple frame rates in a block sequential format in which blocks of parallel lines of video information are recorded sequentially on magnetic tape. Frames of video in block format from one imager are alternately recorded on magnetic tape with frames of video in block format from the other imager. Although the effective recorded frame rate for each imager is one-half of the analyzer frame rate, each recorded frame has been exposed at the analyzer frame speed.