"We value quality above all else, blah blah," the announcer warmly drones, his voice dripping like a honey-glazed ham. "But don't take our word for it - why not ask old J.M.?"
The scene switches to an ancient piece of footage with grandfatherly old J.M. Schneider leaning on a chair, preaching the uncompromising virtue of his packaged meat. The film is grainy and sepia toned, and the audio is full of clicks and glitches. And as anyone with any knowledge of video instantly sees, it's fake. "Old J.M." is an actor, and the footage has been doctored.
The sepia tone is way over the top. The vertical glitching looks contrived. The audio could easily be cleaned up from its abyssmal state, indicating that it has actually been put in that state to begin with.
Furthermore, anything that looks this ancient would predate the mainstream use of sound in film. Take a look at "The Jazz Singer," the first talkie - the visual quality is actually quite sharp. The Schneider footage looks more like something produced by the Lumiere brothers.
Maybe in the post-modern age we're not supposed to care whether what we're seeing is "Old J.M." or a reasonable facsimile.