While the 1878 experiments were groundbreaking, they are often distinguished from the "first true motion picture": What Was The First Ever Film Made? | EverPresent
The "mp4" version of these 19th-century sequences is a digital reconstruction. Modern archivists take the original still frames from Muybridge’s plates and sequence them at a standard frame rate (usually 12–24 fps) to create a smooth video file. Clarifying "The First Film"
In 1878, "film" as we know it did not exist. Instead, photographers used , a method of capturing sequential still images to study movement.
: His work included famous sequences like "Sallie Gardner at a Gallop" (1878) and various human movements such as "Woman Kicking" (1887) or "Annabelle’s Serpentine Dance" (1895, by the Lumière brothers). Why the MP4 Exists Today