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generic audio decoder framework implemented

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This commit is contained in:
Hans Dijkema
2026-04-21 18:01:33 +02:00
parent fd124f594a
commit 630a0423a0
3 changed files with 182 additions and 14 deletions
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audio-decoder.rkt
+159
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@@ -0,0 +1,159 @@
(module audio-decoder racket/base
(require "flac-decoder.rkt"
racket/contract
racket/string
racket/path
)
(provide audio-open
audio-read
audio-stop
audio-seek
audio-kind
audio-valid-ext?
audio-file-valid?
audio-known-exts?
audio-register-reader!
make-audio-reader
audio-handle?
)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Audio readers
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define-struct audio-reader
(exts open reader seeker stopper))
;; audiotype, audio-reader
(define audio-readers (make-hash))
(hash-set! audio-readers
'flac
(make-audio-reader '("flac")
flac-open
flac-read
flac-seek
flac-stop))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Known extensions
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define known-extensions
'("flac"))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Register audio reader
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define/contract (audio-register-reader! type reader)
(-> symbol? audio-reader? void?)
(set! known-extensions (append known-extensions (audio-reader-exts reader)))
(hash-set! audio-readers type reader))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Generic audio reader
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define-struct audio-handle
((kind #:mutable)
(cb-stream-info #:mutable)
(cb-audio #:mutable)
(driver #:mutable)
(driver-handle #:mutable)
)
)
(define (audio-known-exts?)
known-extensions)
(define/contract (audio-kind handle)
(-> audio-handle? symbol?)
(audio-handle-kind handle))
(define (audio-valid-ext? ext)
(set! ext (format "~a" ext))
(when (string-prefix? ext ".")
(set! ext (substring ext 1)))
(not (null? (filter (λ (e) (string-ci=? ext e)) known-extensions)))
)
(define/contract (audio-file-valid? file)
(-> (or/c string? path?) boolean?)
(let ((f (build-path file)))
(let ((e (format "~a" (path-get-extension f))))
(audio-valid-ext? e))))
(define/contract (audio-open audio-file cb-stream-info cb-audio)
(-> (or/c string? path?) procedure? procedure? audio-handle?)
(let ((file (if (path? audio-file)
(path->string audio-file)
audio-file)))
(unless (audio-file-valid? audio-file)
(error (format "Not a valid audio file '~a'" audio-file)))
(unless (file-exists? audio-file)
(error (format "File '~a' does not exist" audio-file)))
(let ((reader* (find-reader audio-file)))
(when (eq? reader* #f)
(error (format "Cannot find reader for '~a'" audio-file)))
(let* ((reader-type (car reader*))
(reader (cadr reader*))
(handle (make-audio-handle reader-type cb-stream-info cb-audio reader #f))
)
(set-audio-handle-driver-handle!
handle
((audio-reader-open reader)
file
(λ (meta)
(cb-stream-info reader-type handle meta))
(λ (buf-info audio-buffer buf-len)
(cb-audio reader-type handle buf-info audio-buffer buf-len)))
)
handle)
)
)
)
(define/contract (audio-read handle)
(-> audio-handle? void?)
(let ((reader (audio-reader-reader (audio-handle-driver handle))))
(void? (reader (audio-handle-driver-handle handle)))))
(define/contract (audio-seek handle percentage)
(-> audio-handle? number? void?)
(let ((seeker (audio-reader-seeker (audio-handle-driver handle))))
(void (seeker (audio-handle-driver-handle handle) percentage))))
(define/contract (audio-stop handle)
(-> audio-handle? void?)
(let ((stopper (audio-reader-stopper (audio-handle-driver handle))))
(void (stopper (audio-handle-driver-handle handle)))))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Utils
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define (right-reader? reader ext)
(not (null? (filter (λ (e) (string-ci=? ext e)) (audio-reader-exts reader)))))
(define (find-reader audio-file)
(let* ((f (build-path audio-file))
(ext (substring (format "~a" (path-get-extension audio-file)) 1)))
(letrec ((f (λ (keys)
(if (null? keys)
#f
(let ((reader (hash-ref audio-readers (car keys))))
(if (right-reader? reader ext)
(list (car keys) reader)
(f (cdr keys))))))))
(f (hash-keys audio-readers))
)
)
)
) ; end of module
flac-decoder.rkt
+9 -2
View File
@@ -48,6 +48,8 @@
(channels (hash-ref h 'channels))
(block-size (hash-ref h 'blocksize)))
(hash-set! h 'duration (flac-duration handle))
(let ((sample (hash-ref h 'number)))
(hash-set! h 'sample sample))
(set! last-buffer buffer)
(set! last-buf-len block-size)
(hash-set! kinds type #t)
@@ -70,12 +72,17 @@
(hash-ref mh 'channels)
(hash-ref mh 'bits-per-sample)
(hash-ref mh 'total-samples))))
(let ((duration (exact->inexact
(/ (hash-ref mh 'total-samples)
(hash-ref mh 'sample-rate)))))
(hash-set! mh 'duration duration))
(set-flac-handle-stream-info! handle si)
(let ((cb (flac-handle-cb-stream-info handle)))
(when (procedure? cb)
(cb si))))))
(cb mh))))))
)
))
)
)
(define (flac-read handle)
(let* ((ffi-handler (flac-handle-ffi-decoder-handler handle))
play-test.rkt
+14 -12
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@@ -1,7 +1,8 @@
#lang racket/base
(require "libao.rkt"
"flac-decoder.rkt"
"audio-decoder.rkt"
simple-log
"private/utils.rkt"
;data/queue
;racket-sound
)
@@ -25,20 +26,20 @@
(sl-log-to-display)
(define (flac-play frame buffer buf-len)
(let* ((sample (hash-ref frame 'number))
(rate (hash-ref frame 'sample-rate))
(define (audio-play type handle buf-info buffer buf-len)
(let* ((sample (hash-ref buf-info 'sample))
(rate (hash-ref buf-info 'sample-rate))
(second (/ (* sample 1.0) (* rate 1.0)))
(bits-per-sample (hash-ref frame 'bits-per-sample))
(bits-per-sample (hash-ref buf-info 'bits-per-sample))
(bytes-per-sample (/ bits-per-sample 8))
(channels (hash-ref frame 'channels))
(channels (hash-ref buf-info 'channels))
(bytes-per-sample-all-channels (* channels bytes-per-sample))
(duration (hash-ref frame 'duration))
(duration (hash-ref buf-info 'duration))
)
(when (eq? ao-h #f)
(set! ao-h (ao-open-live bits-per-sample rate channels 'big-endian)))
;(displayln 'ao-play)
(ao-play ao-h test-file3-id second duration buffer buf-len 'flac)
(ao-play ao-h test-file3-id second duration buffer buf-len type)
;(displayln 'done)
(let ((second-printer (λ (buf-seconds)
(let ((s (inexact->exact (round (ao-at-second ao-h)))))
@@ -87,13 +88,14 @@
)
)
(define (flac-meta meta)
(displayln meta))
(define (audio-meta type handle meta)
(dbg-sound "type: ~a" type)
(dbg-sound "meta: ~a" meta))
(define (play)
(set! ao-h #f)
(let ((flac-h (flac-open test-file3 flac-meta flac-play)))
(flac-read flac-h)
(let ((audio-h (audio-open test-file3 audio-meta audio-play)))
(audio-read audio-h)
(ao-close ao-h)
(set! ao-h #f)))
;(sleep 1.0)