A video can be seen as comprising a series of still images called frames. In celloloid filmograohy, these were literally sepaarte transparencie son the real, but now are stored digitally and often compressed so that eaxh still frame has to be decoded from the file format. If you view a single frame it can often look blurred or indistinct, but our eyes interpret the moving image so that the qualiy when played may be better than each still on theor own -- compression algorithms exploit these visual properties to enable higher compression without loss of pereceived quality.
Used on Chap. 9: page 189; Chap. 12: pages 285, 286
Filmstrip of Butterfly Dance (ca. 1895), an early Kinetoscope film produced by Thomas Edison. (Source: Annabelle Whitford, Public domain, via Wikimedia Commons)
