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Non usb8 buffers #3

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Non usb8 buffers #3

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784042d
also-alsa: Minor indentation fixes.
aartaka Mar 31, 2022
18032b7
also-alsa: Allow non-usb8 buffer contents.
aartaka Mar 31, 2022
83fa716
also-alsa: Optimize for the usb8-typed buffers.
aartaka Apr 9, 2022
9897619
README: Update the example to comply with the non-usb8 shift.
aartaka Jun 19, 2022
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17 changes: 7 additions & 10 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -12,15 +12,12 @@ To play random noise on one channel of default stereo device:
(defconstant +channels+ 2)

(also-alsa:with-alsa-device (pcm "sysdefault" +buffer-size+ '(signed-byte 16) :direction :output
:channels-count +channels+ :sample-rate +sample-rate+)
:channels-count +channels+ :sample-rate +sample-rate+)
(also-alsa:alsa-start pcm)
(loop repeat 2 do
(loop with buffer = (also-alsa:buffer pcm)
for pos from 0 below (* +channels+ (also-alsa:buffer-size pcm)) by (* 2 +channels+)
for sample = (coerce (- (random 65535) 32767) '(signed-byte 16)) do
(setf (aref buffer pos) (logand sample #xff))
(setf (aref buffer (1+ pos)) (logand (ash sample -8) #xff))
(multiple-value-bind (avail delay) (also-alsa:get-avail-delay pcm)
(also-alsa:alsa-write pcm)))))

(loop with buffer = (also-alsa:buffer pcm)
for pos from 0 below (also-alsa:buffer-size pcm)
for sample = (coerce (- (random 65535) 32767) '(signed-byte 16)) do
(setf (aref buffer pos) sample)
(multiple-value-bind (avail delay) (also-alsa:get-avail-delay pcm)
(also-alsa:alsa-write pcm))))
```
104 changes: 60 additions & 44 deletions also-alsa.lisp
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Original file line number Diff line number Diff line change
Expand Up @@ -167,7 +167,7 @@

(defun alsa-element-type (type)
(cond ((equalp type '(signed-byte 16)) :int16)
((eql type 'single-float) :float)
((eql type 'single-float) :float)
((eql type 'double-float) :double)
((equalp type '(unsigned-byte 8)) :uint8)
((equalp type '(signed-byte 8)) :int8)
Expand Down Expand Up @@ -210,20 +210,22 @@
pcs)

(defun make-alsa-buffer (&key element-type size channels)
(cffi:make-shareable-byte-vector (* (cffi:foreign-type-size (alsa-element-type element-type)) size channels)))
(if (equalp element-type '(unsigned-byte 8))
(cffi:make-shareable-byte-vector (* size channels))
(make-array (* size channels) :element-type element-type)))

(defun alsa-open (device buffer-size element-type &key direction (sample-rate 44100) (channels-count 2) buffer)
(when buffer
(assert (and (subtypep (type-of buffer) 'simple-array)
(subtypep (array-element-type buffer) element-type))))
(subtypep (array-element-type buffer) element-type))))
(let ((pcs (make-instance 'pcm-stream
:direction (case direction
(:input :snd-pcm-stream-capture)
(:output :snd-pcm-stream-playback))
:device device
:element-type element-type
:buffer (or buffer
(make-alsa-buffer :element-type element-type :size buffer-size :channels channels-count))
(make-alsa-buffer :element-type element-type :size buffer-size :channels channels-count))
:buffer-size (* buffer-size channels-count) ;number of samples really
:channels-count channels-count
:sample-rate sample-rate
Expand All @@ -234,33 +236,35 @@
(:documentation "Reopens the stream. If all parameters are the same, just keeps the exiting one."))

(defmethod alsa-reopen ((pcs pcm-stream) device buffer-size element-type &key direction (sample-rate 44100) (channels-count 2))
(if (or (eql (status pcs) :initial)
(not (and (equal device (device pcs))
(= (* buffer-size channels-count) (buffer-size pcs))
(equal element-type (element-type pcs))
(eql direction (case (direction pcs)
(:snd-pcm-stream-capture :input)
(:snd-pcm-stream-playback :output)))
(= sample-rate (sample-rate pcs))
(= channels-count (channels-count pcs)))))
(progn
(when (eql (status pcs) :open)
(alsa-close pcs))
(alsa-open-2 (reinitialize-instance pcs
:direction (case direction
(:input :snd-pcm-stream-capture)
(:output :snd-pcm-stream-playback))
:device device
:element-type element-type
:buffer (cffi:make-shareable-byte-vector
(* (cffi:foreign-type-size (alsa-element-type element-type)) buffer-size channels-count))
#+nil(foreign-alloc (alsa-element-type element-type)
:count (* (cffi:foreign-type-size (alsa-element-type element-type)) buffer-size channels-count))
:buffer-size (* buffer-size channels-count) ;number of samples really
:channels-count channels-count
:sample-rate sample-rate
:pcm-format (to-alsa-format element-type))))
(snd-pcm-drop (deref (handle pcs))))
(if (or (eql (status pcs) :initial)
(not (and (equal device (device pcs))
(= (* buffer-size channels-count) (buffer-size pcs))
(equal element-type (element-type pcs))
(eql direction (case (direction pcs)
(:snd-pcm-stream-capture :input)
(:snd-pcm-stream-playback :output)))
(= sample-rate (sample-rate pcs))
(= channels-count (channels-count pcs)))))
(progn
(when (eql (status pcs) :open)
(alsa-close pcs))
(alsa-open-2 (reinitialize-instance
pcs
:direction (case direction
(:input :snd-pcm-stream-capture)
(:output :snd-pcm-stream-playback))
:device device
:element-type element-type
:buffer (make-alsa-buffer :element-type element-type
:size buffer-size
:channels channels-count)
#+nil(foreign-alloc (alsa-element-type element-type)
:count (* (cffi:foreign-type-size (alsa-element-type element-type)) buffer-size channels-count))
:buffer-size (* buffer-size channels-count) ;number of samples really
:channels-count channels-count
:sample-rate sample-rate
:pcm-format (to-alsa-format element-type))))
(snd-pcm-drop (deref (handle pcs))))
pcs)

(defmethod ref ((pcm pcm-stream) position)
Expand Down Expand Up @@ -307,32 +311,44 @@
(defmethod alsa-write ((pcm pcm-stream))
(assert (eql (direction pcm) :snd-pcm-stream-playback))
(let* ((expected (/ (buffer-size pcm) (channels-count pcm)))
(result (with-pointer-to-vector-data (ptr (buffer pcm))
(snd-pcm-writei (deref (handle pcm)) ptr expected))))
(element-type (array-element-type (buffer pcm)))
(result (if (equalp element-type '(unsigned-byte 8))
(with-pointer-to-vector-data (ptr (buffer pcm))
(snd-pcm-writei (deref (handle pcm)) ptr expected))
(with-foreign-array
(ptr (buffer pcm)
(cffi::ensure-parsed-base-type
(list :array (alsa-element-type element-type) expected)))
(snd-pcm-writei (deref (handle pcm)) ptr expected)))))
(cond ((= result (- +epipe+))
;; Under run, so prepare and retry
(alsa-warn "Underrun!")
(alsa-warn "Underrun!")
(snd-pcm-prepare (deref (handle pcm)))
(alsa-write pcm))
((/= result expected)
(error "ALSA error: ~A" result)))))

(defmethod alsa-read ((pcm pcm-stream))
(assert (eql (direction pcm) :snd-pcm-stream-capture))
(let ((result (with-pointer-to-vector-data (ptr (buffer pcm))
(snd-pcm-readi (deref (handle pcm)) ptr (/ (buffer-size pcm) (channels-count pcm))))))
(let* ((expected (/ (buffer-size pcm) (channels-count pcm)))
(element-type (array-element-type (buffer pcm)))
(result (if (equalp element-type '(unsigned-byte 8))
(with-pointer-to-vector-data (ptr (buffer pcm))
(snd-pcm-readi (deref (handle pcm)) ptr expected))
(with-foreign-array
(ptr (buffer pcm)
(cffi::ensure-parsed-base-type
(list :array (alsa-element-type element-type) expected)))
(prog1
(snd-pcm-readi (deref (handle pcm)) ptr expected)
(setf (slot-value pcm 'buffer)
(foreign-array-to-lisp ptr cffi-type :element-type element-type)))))))
(unless (= result (/ (buffer-size pcm) (channels-count pcm)))
(if (eql result (- +epipe+))
(progn (alsa-warn "Underrun!") (snd-pcm-prepare (deref (handle pcm))))
(error "ALSA error: ~A" result)))
(progn (alsa-warn "Underrun!") (snd-pcm-prepare (deref (handle pcm))))
(error "ALSA error: ~A" result)))
pcm))

(defmethod contents-to-lisp ((pcm pcm-stream))
(let ((result (make-array (buffer-size pcm) :element-type (element-type pcm))))
(loop for i from 0 below (buffer-size pcm) do
(setf (aref result i) (ref pcm i)))
result))

(defmacro with-alsa-device ((stream device buffer-size element-type &key direction (sample-rate 44100) (channels-count 2) buffer) &body body)
(assert direction)
`(let ((,stream (also-alsa:alsa-open ,device ,buffer-size ,element-type
Expand Down