Full conversion done

2026-06-25 21:52:17 +02:00
parent f175ac69b6
commit 7a742fcda9
8 changed files with 637 additions and 331 deletions
@@ -0,0 +1,50 @@
+#lang racket/base
+(require racket-audio/flac-decoder
+         racket-audio/audio-encoder
+         "log.rkt"
+         )
+
+(provide determine-flac-khz-and-bits
+         convert-flac-to-rate)
+
+
+(define (determine-flac-khz-and-bits path)
+  (with-handlers ((exn? (λ args
+                          (error (format "Cannot process ~a" path)))))
+    (let* ((meta #f)
+           (flac-handle (flac-open path
+                                   (λ (info) (set! meta info))
+                                   (λ data #t)))
+           )
+      (flac-read-meta flac-handle)
+      (flac-stop flac-handle)
+      (if (eq? meta #f)
+          (values #f #f)
+          (values (hash-ref meta 'sample-rate)
+                  (hash-ref meta 'audio-bits-per-sample))
+          )
+      )
+    )
+  )
+
+
+(define (convert-flac-to-rate path rate)
+  (let* ((tmp-file (build-path (string-append (path->string path) ".tmp.flac")))
+         (encoder-settings (hash 'target-sample-rate rate
+                                 'compression-level 8))
+         )
+    (with-handlers ([exn? (λ (e)
+                            (err-am (format "~a" e))
+                            (when (file-exists? tmp-file)
+                              (delete-file tmp-file))
+                            #f)])
+      (let ((result (audio-encode path tmp-file
+                                  encoder-settings
+                                  #:encoder 'flac
+                                  #:copy-tags? #t
+                                  )))
+        (rename-file-or-directory tmp-file path #t)
+        #t)
+      )
+    )
+  )