What extension does the input file need to be?

[Shinehah-Gnolaum]

In the README.md, at Decoder, it says that the input file needs to be unheadered. I think that means it needs to be a file of type raw, with the ".raw" extension.

However, at Q: How can I decode audio encoded with a codec (mp3, mu-law, mp4, g729), it shows that the input file needs to be a wav file.

The example at Processing an Audio File doesn't specify the type of file.

Can the input file be unheadered if it's a wav file?

I attached the file in mp3, raw, and wav formats in a zip file.
audio.zip