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The MPEG3 is a thin wrapper around the libmpeg3 C library.
The official documentation for the C library is available here:
Show information of an MPEG3 audio file
(use mpeg3) (define *path* "/tmp/file.mp3") ; Verify that the file has the right signature: (unless (mpeg3-check-sig *path*) (error "Invalid file type")) ; Open the file: (define *file* (mpeg3-open *path*)) ; Make sure the file has audio: (unless (mpeg3-has-audio *file*) (error "File doesn't have audio")) ; Get the total number of audio streams in the file: (define *total-streams* (mpeg3-total-astreams *file*)) ; Print information for each audio stream in the file: (let loop ((stream 0)) (unless (= stream *total-streams*) (format #t "Stream: ~A~% Channels: ~A~% Sample rate: ~A~% Samples: ~A~%" stream (mpeg3-audio-channels *file* stream) (mpeg3-sample-rate *file* stream) (mpeg3-audio-samples *file* stream)) (loop (+ stream 1)))) ; Close the file. This step is optional: if you don't do it, Chicken ; will close it when it no longer is required. However, if you open ; a lot of files you will want to close them as soon as you know you'll ; no longer require them. (mpeg3-close *file*)