ImageJ/FIJI cannot read Cinepak codec video files. There are two plugins that attempt to address this for ImageJ:
But I found neither of them to work for me on the particular AVI Cinepak video I was given.
FFmpeg video format conversion
These snippets show to how to convert from any FFmpeg-readable video format to particular video formats.
Motion JPEG is widely-compatible with video players.
ffmpeg -i video1990s.avi -vcodec mjpeg -qscale 1 test.avi
Uncompressed AVI output file size could be a factor of 10 larger than the Cinepak version. By definition, every video player should be able to play uncompressed AVI–including ImageJ.
ffmpeg -i video1990s.avi -vcodec rawvideo out.avi
FFV1 preserves the original video quality with lossless compression. Many video players can handle FFV1 AVI video.
ffmpeg -i video1990s.avi -vcodec ffv1 out.avi
PNG image stack
Convert video to PNG image stack. The advantage of using a PNG image stack comes in frame-by-frame analysis of the video.
You could also consider converting video to HDF5 for analysis purposes.