There is a familiar audio effect in old films where the music (especially if a note is held a bit longer) bends in pitch and sounds damaged or slightly worn out. The only example I could find is someone recreating the effect:
Although this sounds similar to a normal Doppler effect where the soundwaves are being stretched/compressed as an object moves away/toward you, the sound in this case is coming out of something stationary (e.g. the VCR), so it can't be the Doppler effect. It is my understanding that pitch is also not directly equivalent to wave frequency, but is a collective result of loudness, timbre, and duration.
From Wikipedia: "Pitch may be quantified as a frequency, but pitch is not a purely objective physical property; it is a subjective psychoacoustical attribute of sound."
So what causes this pitch bending effect? Is it a physical property or perceptual/sensory property?