263 lines
9.5 KiB
Racket
263 lines
9.5 KiB
Racket
(module audio-decoder racket/base
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(require "flac-decoder.rkt"
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"mp3-decoder.rkt"
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"ffmpeg-decoder.rkt"
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"audio-sniffer.rkt"
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"private/utils.rkt"
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racket/contract
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racket/string
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racket/path
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)
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(provide audio-open
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audio-read
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audio-stop
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audio-seek
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audio-kind
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audio-valid-ext?
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audio-file-valid?
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audio-known-exts?
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audio-register-reader!
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make-audio-reader
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audio-handle?
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audio-supported-extensions
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)
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; Audio readers
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(define-struct audio-reader
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(exts valid? open reader seeker stopper ao-type))
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;; audiotype, audio-reader
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(define audio-readers (make-hash))
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;; FLAC
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(hash-set! audio-readers
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'flac
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(make-audio-reader '("flac")
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flac-valid?
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flac-open
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flac-read
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flac-seek
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flac-stop
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'ao))
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;; MP3
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(hash-set! audio-readers
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'mp3
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(make-audio-reader '("mp3")
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mp3-valid?
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mp3-open
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mp3-read
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mp3-seek
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mp3-stop
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'ao))
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;; FFmpeg decodere
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(hash-set! audio-readers
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'ffmpeg
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(make-audio-reader '("ogg" "oga" "opus"
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"m4a" "mp4" "m4b"
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"aac"
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"wav"
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"aiff" "aif" "aifc"
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"wma"
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"webm" "mkv" "mka")
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ffmpeg-valid?
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ffmpeg-open
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ffmpeg-read
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ffmpeg-seek
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ffmpeg-stop
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'ao))
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; Known extensions
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(define known-extensions
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'("flac" ; FLAC decoder
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"mp3" ; mp3 decoder
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"ogg" "oga" "opus"
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"m4a" "mp4" "m4b"
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"aac"
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"wav"
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"aiff" "aif" "aifc"
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"wma"
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"webm" "mkv" "mka" ; FFMPEG decoder
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))
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(define (audio-supported-extensions)
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known-extensions)
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; Register audio reader
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(define/contract (audio-register-reader! type reader)
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(-> symbol? audio-reader? void?)
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(set! known-extensions (append known-extensions (audio-reader-exts reader)))
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(hash-set! audio-readers type reader))
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; Generic audio reader
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(define-struct audio-handle
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((kind #:mutable)
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(cb-stream-info #:mutable)
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(cb-audio #:mutable)
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(driver #:mutable)
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(driver-handle #:mutable)
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)
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)
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(define (audio-known-exts?)
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known-extensions)
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(define/contract (audio-kind handle)
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(-> audio-handle? symbol?)
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(audio-handle-kind handle))
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(define (audio-valid-ext? ext)
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(set! ext (format "~a" ext))
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(when (string-prefix? ext ".")
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(set! ext (substring ext 1)))
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(if (not (null? (filter (λ (e) (string-ci=? ext e)) known-extensions)))
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#t
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(begin
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(warn-sound "extension '~a' not in known-extensions '~a'" ext known-extensions)
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#f))
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)
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(define/contract (audio-file-valid? file)
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(-> (or/c string? path?) boolean?)
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(let ((f (build-path file)))
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(let ((e (format "~a" (path-get-extension f))))
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(if (audio-valid-ext? e)
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(let ((reader (find-reader file)))
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(if (eq? reader #f)
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#f
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((audio-reader-valid? (cadr reader)) file)))
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#f))))
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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; cb-stream-info will be called with
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; - audio-type: symbol? (e.g. 'flac, 'mp3)
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; - ao-type: symbol? - e.g. 'flac, 'ao (ao means the buffer can be used directly by aolib).
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; - handle: audio-handle?
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; - meta: hash?
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; Meta information must at least contain:
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; ('duration . seconds) - duration of the audio in seconds (or fractions): double
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; ('bits-per-sample . integer) - number of audio bits per sample
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; ('channels . integer) - number of audio channels
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; ('sample-rate . integer) - number of samples per second per channel
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; ('total-samples . integer) - total number of samples of the audio
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;
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; cb-audio will be called with
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; - audio-type: symbol?
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; - ao-type: symbol? - e.g. 'flac, 'ao (ao means the buffer can be used directly by aolib).
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; - handle: audio-handle?
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; - buf-info: hash?
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; - buffer: cpointer? - contains data to be fed to ao - must be owned / released by the driver
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; the ao-async backend will copy the data
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; - buf-size: integer? - contains the size of the data
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; buf-info must at least contain:
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; ('duration . seconds) - duration of the audio in seconds (or fractions): double
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; ('bits-per-sample . integer) - number of audio bits per sample
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; ('channels . integer) - number of audio channels
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; ('sample-rate . integer) - number of samples per second per channel
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; ('total-samples . integer) - total number of samples of the audio
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; (sample . integer) - the current sample the audio buffer applies to.
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(define/contract (audio-open audio-file cb-stream-info cb-audio)
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(-> (or/c string? path?) procedure? procedure? audio-handle?)
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(let ((file (if (path? audio-file)
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(path->string audio-file)
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audio-file)))
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(unless (audio-file-valid? audio-file)
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(error (format "Not a valid audio file '~a'" audio-file)))
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(unless (file-exists? audio-file)
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(error (format "File '~a' does not exist" audio-file)))
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(let ((reader* (find-reader audio-file)))
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(when (eq? reader* #f)
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(error (format "Cannot find reader for '~a'" audio-file)))
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(let* ((reader-type (car reader*))
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(reader (cadr reader*))
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(ao-type (audio-reader-ao-type reader))
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(handle (make-audio-handle reader-type cb-stream-info cb-audio reader #f))
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)
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(set-audio-handle-driver-handle!
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handle
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((audio-reader-open reader)
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file
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(λ (meta)
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(cb-stream-info reader-type ao-type handle meta))
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(λ (buf-info audio-buffer buf-len)
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(cb-audio reader-type ao-type handle buf-info audio-buffer buf-len)))
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)
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handle)
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)
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)
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)
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(define/contract (audio-read handle)
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(-> audio-handle? void?)
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(let ((reader (audio-reader-reader (audio-handle-driver handle))))
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(void (reader (audio-handle-driver-handle handle)))))
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(define/contract (audio-seek handle percentage)
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(-> audio-handle? number? void?)
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(let ((seeker (audio-reader-seeker (audio-handle-driver handle))))
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(void (seeker (audio-handle-driver-handle handle) percentage))))
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(define/contract (audio-stop handle)
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(-> audio-handle? void?)
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(let ((stopper (audio-reader-stopper (audio-handle-driver handle))))
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(void (stopper (audio-handle-driver-handle handle)))))
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; Utils
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(define (right-reader? reader ext)
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(not (null? (filter (λ (e) (string-ci=? ext e)) (audio-reader-exts reader)))))
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(define reader-for-kind
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(make-hash '((mp3 . ffmpeg) ; ffmpeg does a better job on gapless playback...
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(flac . flac)
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(ogg . ffmpeg)
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(vorbis . ffmpeg)
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(opus . ffmpeg)
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(wav . ffmpeg)
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(aiff . ffmpeg)
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(mp4 . ffmpeg)
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(aac . ffmpeg)
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(alac . ffmpeg)
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(ac3 . ffmpeg)
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(ape . ffmpeg)
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(wavpack . ffmpeg)
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(wma . ffmpeg)
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(matroska . ffmpeg))))
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(define (find-reader audio-file)
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; First try to sniff the format
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(let ((format (audio-sniff-format/extension audio-file)))
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(let ((reader-kind (hash-ref reader-for-kind format #f)))
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(if (eq? reader-kind #f)
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#f
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(let ((reader (hash-ref audio-readers reader-kind)))
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(list reader-kind reader))
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)
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)
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)
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)
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) ; end of module
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