Cooley-Tukey FFT: You don't have to zeropad to a power of 2?

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The discussion centers on the Cooley-Tukey FFT algorithm, highlighting its applicability to any composite length, not just powers of 2. It emphasizes that while the algorithm performs best with highly composite lengths, particularly powers of 2, it is a misconception that signals must be zero-padded to these lengths for the algorithm to work. The example of processing a 1920x1080 image illustrates that zero-padding to a size like 2048x2048 is not necessary when using the Cooley-Tukey FFT. The conversation also references a Wikipedia page that discusses generalized factors beyond powers of 2, prompting questions about the classification of certain FFTs.
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Someone wrote "The algorithm that Cooley and Tukey presented in their classic paper (Math. Comp. 19 (1965), 297-301. http://dx.doi.org/10.1090/S0025-5718-1965-0178586-1) can be applied to any composite length. The performance advantages are greatest for highly composite lengths, of which powers-of-2 are one example, and lengths of powers-of-2 result in other advantages on binary computers, so **it has become a common misconception that the algorithm is only applicable to signals whose length is a power of 2**."

Does that mean that when you **DO use the Cooley-Tukey FFT** You don't have to zeropad to a power of 2?
Take for example an image of 1920x1080. So, if you want to use the Cooley-Tukey FFT, you don't need to zeropad the 1920x1080 image to 2048*2048?
 
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@Bill Simpson: Are you sure that those are all Cooley-Tukey FFTs?
 
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