Files
audio-library-manager/private/opus-convert-place.rkt
T
2026-06-09 08:41:01 +02:00

112 lines
4.8 KiB
Racket

#lang racket/base
(require racket/file
racket/list
racket/path
racket/place
racket/string
"util.rkt")
(provide convert-flac-to-opus)
(define conversion-note "Converted from FLAC to Opus by flac2opus-manager")
(define (temp-output-path output-path)
(define-values (base name dir?) (split-path output-path))
(define name-str (if (path? name) (path->string name) "output.opus"))
(build-path base (format ".~a.tmp-~a.opus" name-str (current-inexact-milliseconds))))
(define (list-of-strings? v)
(and (list? v) (andmap string? v)))
(define (property-key-symbol k)
(cond [(symbol? k) k]
[(string? k) (string->symbol (string-downcase k))]
[else (string->symbol (string-downcase (format "~a" k)))]))
(define (first-comment-value v)
(cond [(and (pair? v) (string? (car v))) (car v)]
[(string? v) v]
[else #f]))
(define (source-tags-data input-file)
(define call-with-id3-tags (dynamic-require 'racket-audio/taglib 'call-with-id3-tags))
(define tags-valid? (dynamic-require 'racket-audio/taglib 'tags-valid?))
(define tags-keys (dynamic-require 'racket-audio/taglib 'tags-keys))
(define tags-ref (dynamic-require 'racket-audio/taglib 'tags-ref))
(define tags-picture (dynamic-require 'racket-audio/taglib 'tags-picture))
(call-with-id3-tags
input-file
(lambda (tags)
(if (not (tags-valid? tags))
(list (cons 'properties '()) (cons 'picture #f))
(let* ((keys (sort (tags-keys tags) string<? #:key (lambda (x) (format "~a" x))))
(properties (for/list ([k (in-list keys)])
(cons (property-key-symbol k) (tags-ref tags k)))))
(list (cons 'properties properties)
(cons 'picture (tags-picture tags))))))
#:mode 'read))
(define (source-tags->settings input-file kbps)
(define data (source-tags-data input-file))
(define properties (alist-ref/default data 'properties '()))
(define picture (alist-ref/default data 'picture #f))
(define comments (make-hash))
(for ([kv (in-list properties)])
(define v (first-comment-value (cdr kv)))
(when v (hash-set! comments (car kv) v)))
(hash-set! comments 'flac2opus conversion-note)
(define settings (make-hash))
(hash-set! settings 'bitrate (* kbps 1000))
(hash-set! settings 'vbr? #t)
(hash-set! settings 'comments comments)
(unless (eq? picture #f) (hash-set! settings 'picture picture))
(values settings properties picture))
(define (copy-all-tag-properties! output-file properties picture)
(define call-with-id3-tags (dynamic-require 'racket-audio/taglib 'call-with-id3-tags))
(define tags-valid? (dynamic-require 'racket-audio/taglib 'tags-valid?))
(define tags-set-values! (dynamic-require 'racket-audio/taglib 'tags-set-values!))
(define tags-set! (dynamic-require 'racket-audio/taglib 'tags-set!))
(define tags-picture! (dynamic-require 'racket-audio/taglib 'tags-picture!))
(define tags-save! (dynamic-require 'racket-audio/taglib 'tags-save!))
(call-with-id3-tags
output-file
(lambda (tags)
(when (tags-valid? tags)
(for ([kv (in-list properties)])
(define v (cdr kv))
(cond [(list-of-strings? v) (tags-set-values! tags (car kv) v)]
[(string? v) (tags-set! tags (car kv) v)]
[else (void)]))
(tags-set! tags 'flac2opus conversion-note)
(unless (eq? picture #f) (tags-picture! tags picture))
(tags-save! tags)))
#:mode 'read-write))
(define (convert-flac-to-opus input-path output-path kbps)
(define tmp-path (temp-output-path output-path))
(ensure-parent-directory! tmp-path)
(define worker
(place ch
(define msg (place-channel-get ch))
(define in-file (list-ref msg 0))
(define out-file (list-ref msg 1))
(define kbps (list-ref msg 2))
(with-handlers ([exn:fail? (lambda (e) (place-channel-put ch (list 'error (exn-message e))))])
(define-values (settings properties picture) (source-tags->settings in-file kbps))
(define audio-encode (dynamic-require 'racket-audio/audio-encoder 'audio-encode))
(define result (audio-encode in-file out-file settings #:encoder 'opus #:copy-tags? #f))
(copy-all-tag-properties! out-file properties picture)
(place-channel-put ch (list 'ok result)))))
(place-channel-put worker (list (path->string input-path) (path->string tmp-path) kbps))
(define response (place-channel-get worker))
(cond [(and (pair? response) (eq? (car response) 'ok))
(ensure-parent-directory! output-path)
(rename-file-or-directory tmp-path output-path #t)
(cadr response)]
[else
(when (file-exists? tmp-path) (delete-file tmp-path))
(error 'convert-flac-to-opus "conversion failed for ~a: ~a" input-path
(if (and (pair? response) (pair? (cdr response))) (cadr response) response))]))