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trying to overcome gapless problems with mpg123 (very small tick left) and facilitate output to wav

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Hans Dijkema
2026-04-23 11:03:47 +02:00
parent 4bbfa43501
commit 3fd5fdbdd5
5 changed files with 120 additions and 77 deletions
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libmpg123-ffi.rkt
+24 -16
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@@ -329,6 +329,7 @@ int main(int argc, char *argv[])
(define pcm-length -1)
(define encoding -1)
(define mp3-file "")
(define current-pcm-pos 0)
(define (new)
(if (eq? mh #f)
@@ -386,11 +387,8 @@ int main(int argc, char *argv[])
(define (set-param p val)
(mpg123_param2 mh p val (exact->inexact val)))
(define (init file)
(let ((r (mpg123_open mh file)))
(unless (eq? r 'MPG123_OK)
(error (format "mpg123_open: ~a" (mpg123_plain_strerror r))))
)
(define (do-format)
(dbg-sound "do-format called, got an MPG123_NEW_FORMAT message")
(let-values ([(fr rate* channels* encoding*) (mpg123_getformat mh)])
(unless (eq? fr 'MPG123_OK)
(error (format "mpg123_format: ~a" (mpg123_plain_strerror fr))))
@@ -404,11 +402,19 @@ int main(int argc, char *argv[])
(unless (eq? sr 'MPG123_OK)
(error (format "mpg123_scan: ~a" (mpg123_plain_strerror sr))))
(set! pcm-length (mpg123_length64 mh)))
)
(define (init file)
(let ((r (mpg123_open mh file)))
(unless (eq? r 'MPG123_OK)
(error (format "mpg123_open: ~a" (mpg123_plain_strerror r))))
)
(set! mp3-file (format "~a" file))
(set! current-pcm-pos 0)
#t)
(define (mp3-format cb)
(cb rate channels sample-bits sample-bytes pcm-length))
(cb current-pcm-pos rate channels sample-bits sample-bytes pcm-length))
(define (close)
(let ((r (mpg123_close mh)))
@@ -423,16 +429,18 @@ int main(int argc, char *argv[])
(set! mp3-file "")
#t))
(define (read cb)
(define (read cb format-cb)
(let-values ([(r done) (mpg123_read mh buffer buf-size)])
(if (eq? r 'MPG123_DONE)
(cb 'done -1 buffer done)
(if (eq? r 'MPG123_OK)
(let ((pcm-pos (mpg123_tell64 mh)))
(cb 'data pcm-pos buffer done))
(error (format "mpg123_read: ~a" (mpg123_plain_strerror r)))
)
)
(cond
((eq? r 'MPG123_DONE) (cb 'done -1 buffer done))
((eq? r 'MPG123_NEW_FORMAT) (do-format)
(mp3-format format-cb)
(read cb format-cb))
((eq? r 'MPG123_OK) (let ((pcm-pos (mpg123_tell64 mh)))
(set! current-pcm-pos pcm-pos)
(cb 'data pcm-pos buffer done)))
(else (error (format "mpg123_read: ~a" (mpg123_plain_strerror r))))
)
)
#t)
@@ -453,7 +461,7 @@ int main(int argc, char *argv[])
[(eq? cmd 'close) (close)]
[(eq? cmd 'format) (mp3-format (car args))]
[(eq? cmd 'info) (info)]
[(eq? cmd 'read) (read (car args))]
[(eq? cmd 'read) (read (car args) (cadr args))]
[(eq? cmd 'seek) (seek (car args))]
[(eq? cmd 'tell) (tell)]
[(eq? cmd 'file) mp3-file]