Snd Customization and Extension Part 2


related documentation: snd.html extsnd.html sndscm.html sndclm.html fm.html sndlib.html libxm.html s7.html index.html
this file:extsnd.html:

Snd Startup


Snd invocation flags

Snd recognizes the following switches in its command line (leaving aside all the usual Xt/X-related flags like -xrm).

-h -horizontallayout sounds as horizontal panes
-v -vertical layout sounds vertically (the default)
-notebook layout sounds in a notebook widget (Motif 2.0 or later)
-separate layout sounds each in a separate window (listener is in main window)
--help print some help, version info, and exit
--version print version info
-noglob don't read /etc/snd.conf
-noinit don't read ~/.snd
-nostdin don't watch for possible input from stdin
-p -preload <dir> add sound files in directory <dir> to the View:Files list (snd -p .)
-l -load <file> load Scheme, Ruby, or Forth code in <file> (snd -l test.scm)
-e -eval expr evaluate expr
-b -batch <file> load Scheme, Ruby, or Forth code in <file> as a batch (no GUI) job
-I <dir> add <dir> to the load search list
-nogtkrc don't read ~/Snd.gtkrc or any of its friends (Gtk only)
notebook
snd -notebook oboe.snd pistol.snd
(set! (graph-style) graph-lollipops)
(set! (dot-size) 8)

The -e switch evaluates its argument. The initialization file, if any, is loaded first, then the arguments are processed in order:

    snd -e "(set! (data-color) (make-color 1 0 0))" oboe.snd

reads ~/.snd, if any, then sets the (unselected) data color to red, then opens oboe.snd.

    snd -eval '(begin (display (+ 1 2)) (exit))'

prints "3" and exits. The "-title" argument works in both versions of Snd. The following adds "WAV" to the sound file extension table before adding all the sound files in the directory to the View:Files dialog's list:

    snd -e '(add-sound-file-extension "WAV")' -p /home/bil/sounds
black background
snd oboe.snd
(set! (selected-data-color) (make-color 1 1 1))
(set! (selected-graph-color) (make-color 0 0 0))
(set! (graphs-horizontal) #f)
(set! (transform-graph?) #t)
(set! (show-transform-peaks) #t)


The initialization file

When Snd starts, it looks for an initialization file, normally named "~/.snd". This optional file is supposed to be similar to Emacs' .emacs file, containing any customizations or extensions that you want loaded whenever Snd starts. Say we want the Snd window to start out 800x500, want to predefine an envelope named "env1", and want the file selection box to show just sound files. We make ~/.snd and put in it:

Scheme:
    (set! (window-width) 800)
    (set! (window-height) 500)
    (set! (just-sounds) #t)
    (define-envelope env1 '(0 0 1 1 2 0))

Ruby:
    set_window_width(800)
    set_window_height(500)
    set_just_sounds(true)
    define_envelope("env1", [0, 0, 1, 1, 2, 0])

Forth:
    800 set-window-width drop
    500 set-window-height drop
    #t set-just-sounds drop
    $" env1" '( 0.0 0.0 1.0 1.0 2.0 0.0 ) 1.0 define-envelope drop

In more complex situations, you may want an initialization file particular to a given extension language, machine, or global across users; the name of this optional global initialization file is "/etc/snd.conf". It is read before your local file; both can, of course, be absent. To override reading the global init file when Snd is invoked, include the switch -noglob. To override the local init file, use -noinit.

The initialization files particular to a given extension language have names such as ~/.snd_s7 and ~/.snd_prefs_ruby. Currently the possibilities are: ~/.snd_prefs_ruby|forth|s7, /etc/snd_ruby|forth|s7.conf, ~/.snd_ruby|forth|s7 (the notation "ruby|forth" means either "ruby" or "forth", so the file names spelled out completely are "/etc/snd_ruby.conf", etc; which one is loaded obviously depends on which language you chose during configuration). The save-options (preferences dialog) process writes to .snd_prefs_* which is loaded first, if it exists; then Snd looks for .snd_* (s7, ruby, or forth); then .snd. If you're always using just one version of Snd, it's simplest to stick with .snd. The actual load sequence is:

    /etc/snd_ruby|forth|s7.conf    (these two canceled by -noglob)
    /etc/snd.conf               
    ~/.snd_prefs_ruby|forth|s7     (the rest canceled by -noinit)
    ~/.snd_ruby|forth|s7
    ~/.snd                         (also SND_INIT_FILE_ENVRIONMENT_NAME)

Here's a more elaborate initialization file (~/.snd_s7):

(set! (window-width) 800)           ;these set the initial window size
(set! (window-height) 500)

(if (provided? 'snd-motif)          ;Motif and Gtk use different font naming conventions
    (begin
      (set! (listener-font) "9x15")
      (set! (axis-label-font) "-*-times-medium-r-normal-*-18-*-*-*-*-*-*-*")
      (set! (axis-numbers-font) "9x15"))
    (begin
      (set! (listener-font) "Sans 10")
      (set! (axis-label-font) "Times Medium 14")
      (set! (axis-numbers-font) "Sans 10")))

(set! (listener-prompt) ":")        ;change listener prompt from the default ">" to ":"
(set! (show-listener) #t)           ;include the listener window initially

(define beige (make-color 0.96 0.96 0.86))
(define blue (make-color 0 0 1))
(set! (selected-graph-color) beige) ;selected graph background is beige
(set! (selected-data-color) blue)   ;selected graph data is blue

(set! (save-dir) "/zap/snd")        ;save-state files are placed in /zap/snd
(set! (temp-dir) "/zap/tmp")        ;temp files are placed in /zap/tmp
(set! (peak-env-dir) "~/peaks")

(load "hooks.scm")
(load "extensions.scm")

(set! (with-inset-graph) #t)        ;display an overview of the current window in the upper right
(set! (with-pointer-focus) #t)      ;automatically focus on (activate) the widget under the mouse

(if (provided? 'snd-motif)          
    (load "popup.scm")              ;context-sensitive popup menus
    (if (provided? 'snd-gtk)
        (load "/home/bil/cl/gtk-popup.scm")))

(add-hook! after-open-hook          ;if sound has many chans, use just one pane for all
  (lambda (snd)
    (if (> (channels snd) 4)
        (set! (channel-style snd) channels-combined))))

(set! (selection-creates-region) #f) ;turn off automatic region creation

A similar Ruby initialization file (~/.snd_ruby):

require "draw"
require "popup"

set_window_width 800
set_window_height 500

set_listener_font "9x15"
set_axis_numbers_font "9x15"

set_show_mix_waveforms true
set_trap_segfault false
set_listener_prompt ":"
set_show_listener true

beige = make_color 0.96, 0.96, 0.86
blue = make_color 0, 0, 1
set_selected_graph_color beige
set_selected_data_color blue
make_current_window_display

$mouse_enter_graph_hook.add_hook!("focus") do |snd, chn|
  focus_widget(channel_widgets(snd, chn)[0])
end
$mouse_enter_listener_hook.add_hook!("focus") do |widget| focus_widget(widget) end
$mouse_enter_text_hook.add_hook!("focus") do |widget| focus_widget(widget) end

And Forth (~/.snd_forth):

\ .snd_forth -- start up file for Snd/Forth -*- snd-forth -*-

\ You can install the *.fs scripts with:
\ 
\   cd ${top_srcdir}/examples/site-lib
\   ./install.fth
\ 
\ or even better
\
\   cd ${top_builddir}
\   make install
\
\ If you have installed *.fs scripts with one of the above mentioned
\ commands, you don't need to add a path to *load-path*.
\ ${prefix}/share/fth/site-fth is already included.  Otherwise you can
\ add a path with e.g.:
\ 
\   "/home/mike/snd" add-load-path

\ A special *SND-HOME* path points here to ~/.snd.d (similar to ~/.emacs.d):
\ 
\ ~/.snd.d            directory for save-state-file
\ ~/.snd.d/sound      directory for *clm-file-name*
\                                   add-directory-to-view-files-list
\                                   set-open-file-dialog-director
\ ~/.snd.d/zap        directory for set-temp-dir
\                                   set-save-dir
\ ~/.snd.d/peaks      directory for set-peak-env-dir
\
\ "HOME" getenv       value *home*
\ *home* "/.snd.d" $+ value *snd-home*
\
\ Change these paths to fit your needs!
\

#t to *fth-verbose*
#f to *fth-debug*

#f value *init-with-peaks*		\ with peak-env support
#f value *init-graph-extra-hooks*	\ with display-correlate, zoom-spectrum, superimpose-ffts
#f value *init-lisp-graph-extra-hooks*	\ with display-energy, display-db

: print-loading-file { fname -- }
  *fth-verbose* if $" \\ loading %s\n" '( fname ) clm-print then
;

*filename* print-loading-file

"HOME" getenv                     value *home*
*home* "/.snd.d"               $+ value *snd-home*
hostname                          value *hostname*
*hostname* /\\./ string-split car value *short-hostname*
*argv* length 0> [if] *argv* car undef file-basename [else] "snd" [then] value *program-name*

before-load-hook lambda: <{ fname -- f }>
  fname print-loading-file
  #t
; add-hook!

\ if configured --with-shared-sndlib
dl-load sndlib Init_sndlib

\ Set them before loading clm.fs.
2                      set-default-output-chans   drop
48000    	       set-default-output-srate   drop
512                    set-dac-size               drop
mus-clipping           set-clipping               drop
1024 1024 *            set-mus-file-buffer-size   drop
24                     set-mus-array-print-length drop
mus-array-print-length set-print-length           drop
128                    set-object-print-length

require clm
require clm-ins

\ Environment variable CLM_SEARCH_PATH
\ Path variable where sound files reside.
\ csh: setenv CLM_SEARCH_PATH /usr/gnu/sound/SFiles:${HOME}/.snd.d/sound
\  sh: CLM_SEARCH_PATH=/usr/gnu/sound/SFiles:${HOME}/.snd.d/sound; export CLM_SEARCH_PATH

"CLM_SEARCH_PATH" getenv dup [if]
  ":" string-split [each] *clm-search-list* swap array-push to *clm-search-list* [end-each]
[else]
  drop
  *clm-search-list* *snd-home* "/sound" $+ array-push to *clm-search-list*
[then]
#t                                     to *clm-play*
#t                                     to *clm-statistics*
#t                                     to *clm-verbose*
#f                                     to *clm-debug*
*snd-home* "/sound/fth-test.snd"    $+ to *clm-file-name*
*snd-home* "/sound/fth-test.reverb" $+ to *clm-reverb-file-name*
#t                                     to *clm-delete-reverb*
lambda: <{ ins beg dur -- }> $" %14s: %5.2f %5.2f" '( ins beg dur ) clm-message ; to *clm-notehook*

'snd-nogui provided? [if]
  \ snd-nogui repl and prompt hooks
  before-repl-hook reset-hook!		\ remove default hook
  before-repl-hook lambda: <{ -- }>
    "" #f clm-message
    $" Starting session on %s." '( $" %Ev %Er" current-time strftime ) clm-message
    "" #f clm-message
  ; add-hook!
  after-repl-hook lambda: <{ history -- }>
    "" #f clm-message
    $" Thank you for using %s!" #( *program-name* string-upcase ) clm-message
    "" #f clm-message
    1 sleep
  ; add-hook!
  
  \ A more elaborated prompt for fth and snd-forth-nogui.
  before-prompt-hook lambda: <{ prompt pos -- new-prompt }>
    "%EI:%EM%p" current-time strftime string-downcase! { tm }
    "(/usr)?" *home* $+ make-regexp file-pwd "~" regexp-replace { path }
    $" (%s:%s)\n[%s %s] (%d)> " #( *short-hostname* path *program-name* tm pos ) string-format
  ; add-hook!
[then]

*snd-home* add-load-path
*init-with-peaks* [if]
  *snd-home* "/peaks"      $+ set-peak-env-dir               drop
[then]
*snd-home* "/snd-saved.fs" $+ set-save-state-file            drop
*snd-home* "/zap"          $+ set-temp-dir                   drop
*snd-home* "/zap"          $+ set-save-dir                   drop
*snd-home* "/sound"        $+ set-open-file-dialog-directory drop
"/usr/gnu/cvs/snd"            set-html-dir                   drop
"BROWSER" getenv "firefox" || set-html-program               drop
#t                	      set-trap-segfault              drop
#t                            set-show-listener              drop
0.0               	      set-auto-update-interval       drop
"rev"           	      add-sound-file-extension       drop
"reverb"        	      add-sound-file-extension       drop
"wave"          	      add-sound-file-extension       drop
*clm-search-list* [each] ( dir ) undef add-directory-to-view-files-list drop [end-each]

before-save-state-hook lambda: <{ fname -- f }>
  $" \\ -*- snd-forth -*-\n" :filename fname with-output-port
  #t				      \ #t --> append mode
; add-hook!

\ make-default-comment from clm.fs
output-comment-hook lambda: <{ str -- s }>
  str empty? if make-default-comment else str then
; add-hook!

'snd-nogui provided? [unless]
  'snd-motif provided? [if]
    \ if not configured --with-static-xm
    'xm provided? not [if] dl-load libxm Init_libxm [then]
    require snd-xm
    add-mark-pane
    #t show-smpte-label
    after-open-hook <'> show-disk-space add-hook!

    require effects
    #f to use-combo-box-for-fft-size	\ boolean (default #f)

    require popup
    edhist-save-hook lambda: <{ prc -- }> "%S" #( prc ) clm-message ; add-hook!
  [then]

  'snd-gtk provided? [if]
    \ if not configured --with-static-xg
    'xg provided? not [if] dl-load libxg Init_libxg [then]
    $" Serif 10" set-axis-label-font drop
  [then]

  require extensions
  #t set-emacs-style-save-as
  #t check-for-unsaved-edits
  *snd-home* "/snd-remember-sound.fs" $+ to remember-sound-filename
  3 remember-sound-state
  0.00 0.10 #t prefs-activate-initial-bounds
  with-reopen-menu
  with-buffers-menu
  2 set-global-sync

  require examp
  *init-graph-extra-hooks* [if]
    graph-hook         <'> display-correlate  add-hook!
    graph-hook         <'> zoom-spectrum      add-hook!
    graph-hook         <'> superimpose-ffts   add-hook!
  [then]
  *init-lisp-graph-extra-hooks* [if]
    lisp-graph-hook    <'> display-energy     add-hook!
    lisp-graph-hook    <'> display-db         add-hook!
  [then]
  after-transform-hook <'> fft-peak           add-hook!

  require mix
  mix-click-hook       <'> mix-click-sets-amp add-hook!
  mix-click-hook       <'> mix-click-info     add-hook!

  require marks
  save-mark-properties
  mark-click-hook      <'> mark-click-info    add-hook!

  require dsp
  graph-hook lambda: <{ snd chn y0 y1 -- #f }>
    $" freq: %.3f" #( snd chn left-sample  snd chn spot-freq ) string-format
    snd #f report-in-minibuffer drop
    #f
  ; add-hook!

  mouse-click-hook lambda: <{ snd chn button state x y axis -- a }>
    axis time-graph = if
      $" freq: %.3f" #( snd chn #f cursor  snd chn spot-freq ) string-format
      snd #f report-in-minibuffer
    else
      #f
    then
  ; add-hook!

  require env
  enved-hook lambda: <{ en pt x y reason -- en'|#f }>
    reason enved-move-point = if
      x en 0 array-ref f> x en -2 array-ref f< && if
	en en pt 2* array-ref x #f #f stretch-envelope ( new-en ) dup pt 2* 1+ y array-set!
      else
	#f
      then
    else
      #f
    then
  ; add-hook!

  require rgb
  lightsteelblue2 	 set-help-button-color       drop
  lightsalmon2    	 set-reset-button-color      drop
  light-salmon    	 set-quit-button-color       drop
  wheat           	 set-doit-button-color       drop
  burlywood       	 set-doit-again-button-color drop
  lightsteelblue1 	 set-pushed-button-color     drop
  beige                  set-selected-graph-color    drop
  blue                   set-selected-data-color     drop

  #t           	         set-show-indices            drop
  #f		         set-verbose-cursor          drop
  #t                     set-with-inset-graph        drop
  #t                     set-with-pointer-focus      drop
  #t  			 set-just-sounds             drop
  #t  			 set-enved-wave?             drop
  #t  			 set-show-y-zero             drop
  #t                     set-show-transform-peaks    drop
  speed-control-as-ratio set-speed-control-style     drop
  graph-as-spectrogram   set-transform-graph-type    drop \ graph-once graph-as-sonogram
  rainbow-colormap	 set-colormap                drop
  $" snd> "              set-listener-prompt         drop
  160 		         set-window-x                drop
  0 			 set-window-y                drop
  800 		         set-window-width            drop
  600 		         set-window-height           drop

  exit-hook lambda: <{ -- f }>
    save-state-file save-state drop
    sounds each close-sound drop end-each
    #t
  ; add-hook! 

  window-property-changed-hook lambda: <{ cmd -- }>
    $" remote command received: %S" #( cmd ) clm-message
    #f
  ; add-hook!

  after-open-hook lambda: <{ snd -- }>
    snd channels 0 ?do snd short-file-name snd i time-graph set-x-axis-label drop loop
    #t snd set-with-tracking-cursor drop
    channels-combined snd set-channel-style
  ; add-hook!

  : snd-set-cursor-style { snd kind -- #f }
    snd sound? if kind snd #t set-cursor-style drop then
    #f
  ;
  start-playing-hook lambda: <{ snd -- f }> snd cursor-line  snd-set-cursor-style ; add-hook!
  stop-playing-hook  lambda: <{ snd -- f }> snd cursor-cross snd-set-cursor-style ; add-hook!

  \ bind-key ( key modifiers func :optional extended=#f origin="" prefs-info="" -- val )
  \ 
  \ modifiers:
  \   0 normal
  \   1 shift
  \   4 control
  \   8 meta
  \ 
  \ extended (prefix key):
  \   #t  C-x
  \   #f  none
  \
  \ func ( -- val )
  \
  \ val should be:
  \   cursor-in-view
  \   cursor-on-left
  \   cursor-on-right
  \   cursor-in-middle
  \   keyboard-no-action
  \ 
  \ C-x C-c terminate Snd
  <char> c 4 lambda: <{ -- val }>
    0 snd-exit drop
    cursor-in-view
  ; #t $" terminate Snd" "terminate-snd" bind-key drop
  \ C-x k close selected sound
  <char> k 0 lambda: <{ -- val }>
    selected-sound close-sound-extend
    cursor-in-view
  ; #t $" close sound and jump to next open" "close-current-sound" bind-key drop
  \ C-x C-k show listener
  <char> k 4 lambda: <{ -- val }>
    #t set-show-listener drop
    cursor-in-view
  ; #t $" show listener" "show-listener" bind-key drop
  \ C-x C-n hide listener
  <char> n 4 lambda: <{ -- val }>
    #f set-show-listener drop
    cursor-in-view
  ; #t $" hide listener" "hide-listener" bind-key drop
  \ C-x C-x play
  <char> x 4 lambda: <{ -- val }>
    #t play drop
    cursor-in-view
  ; #t $" play current sound" "play-current-sound" bind-key drop
  \ C-x C-t play from cursor
  <char> t 4 lambda: <{ -- val }>
    selected-sound :start undef undef undef cursor play drop
    cursor-in-view
  ; #t $" play from cursor" "play-from-cursor" bind-key drop
  \ C-x x eval over selection
  <char> x 0 lambda: <{ -- val }>
    undef selection? if
      $" selection-eval:" <'> eval-over-selection #f #f prompt-in-minibuffer
    else
      $" no selection" #f #f report-in-minibuffer
    then drop
    cursor-in-view
  ; #t $" eval over selection" "eval-over-selection" bind-key drop
[then]					\ not snd-nogui

'snd-nogui provided? [unless]
  save-state-file file-exists? [if] require snd-saved [then]
[then]

\ find-file searchs in *clm-search-list*
sounds empty? [if]
  *clm-file-name* find-file dup [if] open-sound [then] drop cr
[then]

$" Snd of %s (Fth %s)" #( snd-version fth-version ) clm-message

\ .snd_forth ends here

If you loaded Snd with GSL, and have set the GSL_IEEE_MODE environment variable, it will override Snd's default arithmetic mode settings. GSL recommends the setting:

    GSL_IEEE_MODE=double-precision,mask-underflow,mask-denormalized

For more complex initialization files, see snd_conffile.scm, snd_frg.scm, and edit123.scm.

Normally, the initialization file also adds the Snd sources directory to the load path. For more temporary situations, you can use the environment variable SND_PATH. It is a colon-separated list of directories that will be added to the load path when Snd starts.


Snd resources

Motif

In the Motif version, there are a few X-style resources (for use in your ~/.Xdefaults file) that Snd looks for (see Snd.ad); each has a built-in default value, so you can ignore this entirely, and use the extension language initialization file to choose new values. I may remove all this stuff eventually (it was always a bad idea).

Resource NameDefault Value
Purpose
Scheme Name


autoResize1should Snd window resize automaticallyauto-resize
horizontalPanes0basic paned window layout


peaksFonttimes 14fft peaks fontpeaks-font
boldpeaksFonttimes bold 14main fft peaks fontbold-peaks-font
axisLabelFonttimes 20axis label ("Time")axis-label-font
axisNumbersFontcourier 14axis tick numbersaxis-numbers-font
listenerFontfixed 7x13listener textlistener-font


basiccolorivory2default background color everywherebasic-color
cursorcolorred color of the cursor cursor-color
datacolorblackunselected data color data-color
graphcolorwhite unselected channels' graph background graph-color
highlightcolorivory1 highlighting here and there highlight-color
listenercoloraliceblue background color of the listener listener-color
listenertextcolorblack text color in the listener listener-text-color
markcolorred color of the mark indicator mark-color
mixcolordarkgray used for mix waveforms mix-color
positioncolorivory3 color of position sliders position-color
pushedbuttoncolorivory1 color of pushed button pushed-button-color
sashcolorlightgreen color of paned window sash handles sash-color
selecteddatacolorblack color of the data in selected channel selected-data-color
selectedgraphcolorwhite background of selected channel's graphselected-graph-color
selectioncolorlightsteelblue1 color of an active selection selection-color
textfocuscolorwhite color of text field with focus text-focus-color
zoomcolorivory4 color of zoom sliders zoom-color

In the extension language, colors are defined by make-color with the three red/green/blue values, each a float between 0.0 and 1.0.

    (set! (basic-color) (make-color 1.0 0.0 0.0))

sets the overall background color of Snd to red. rgb.scm defines all the standard X11 color names.

help-button-color and friends only work in a few cases (Motif, 2.n where n < 3), so I may deprecate them someday.

There are several other resources that set widget sizes: zoomSliderWidth, positionSliderWidth, toggleSize, sashSize, sashIndent, channelSashSize, and channelSashIndent. And several more color resources: whitecolor (list background), blackcolor, redcolor (buttons, VU clipping, etc), greencolor (a few buttons), yellowcolor (a few envelope editor buttons), lightbluecolor, and lighterbluecolor (the fft option panel).

You can experiment with other choices by using the -xrm switch:

    snd -xrm '*Highlightcolor: Red' oboe.snd
    snd -xrm '*AxisNumbersFont: 6x10' oboe.snd
    snd -xrm '*fontList: 9x15' oboe.snd
    snd -xrm '*listenerFont: 6x10' oboe.snd
    snd -xrm '*mixwaveformcolor: red' oboe.snd -notebook
    snd oboe.snd pistol.snd -xrm '*selectedgraphcolor: black' -xrm '*selecteddatacolor: white'
    snd -xrm '*fontList: -*-times-medium-r-*-*-14-*-*-*-*-*-*-*'
    snd -xrm '*fontList: -*-symbol-*-*-*-*-18-*-*-*-*-*-*-*'
    snd oboe.snd -title hiho -display fatty.hiho:0.0 -xrm '*chn-graph*backgroundPixmap: text.xpm'

Perhaps this is most useful when your window manager assumes white text for labels (menus); since Snd defaults to an off-white background, this makes everything unreadable. You can get the black text back with:

    snd -xrm '*foreground: Black'

or put the equivalent line in your .Xdefaults file. The listener text color can be set via (set! (listener-text-color) (make-color 0 0 0)) in ~/.snd.

The last example above sets the window title to "hiho", rather than "snd", displays the window on the machine fatty.hiho (presumably accessible over the net), and tiles the graph backgrounds with the contents of text.xpm. To get the -geometry argument to work, set the autoResize resource to 0:

    snd oboe.snd -geometry 800x200 -xrm '*autoResize: 0'

These resources can be set in Snd.ad or in your ~/.Xdefaults file:

    snd*axisLabelFont:      -*-times-medium-r-normal-*-18-*-*-*-*-*-*-*
    snd*axisNumbersFont:    9x15
    snd*fontList:           -*-times-bold-r-*-*-14-*-*-*-*-*-*-*

To find what fonts are available, and what they look like, I use xfontsel. I think other toolkits use helvetica where Motif defaults to a small fixed font — it looks like 7x13 on my machine.

The autoResize resource determines how Snd acts when files are added to or removed from its overall display. The default (1) causes Snd to expand or contract the main window's size to accommodate the sounds; many people find this distracting. If 'autoResize' is 0, the outer window size remains the same, and the sounds try to fit as best they can (to some extent the window manager controls this stuff). See also the variable auto-resize. The horizontalPanes resource is equivalent to the -h flag; if 1, sounds are layed out horizontally rather than vertically; if 2, you get a notebook widget holding the sounds.

Gtk

In Gtk, the various default colors and fonts are set via the "gtkrc" file(s). If you are using some global "theme", you probably have ~/.gtkrc-2.0. Snd looks for this file first. If it isn't found, Snd looks on the current directory for Snd.gtkrc. If that isn't found, it looks for ~/Snd.gtkrc. If that isn't found, it uses a built-in default equivalent to the Snd.gtkrc file in the Snd tarball. If you want to change the overall appearance of Snd, you can edit any of these rc files. Currently, the simplest way to change the menu label fonts is to change the "default" or "default_menu" styles in Snd.gtkrc:

    style "default"
    {
      font_name = "Sans Serif 11"
      ....
    }

To get the "brushed metal" look, for example, put the line:

pixmap_path "/usr/share/themes/BrushedMetalClean/gtk"

at the start of Snd.gtkrc, then add these lines:

  bg_pixmap[NORMAL]      = "bc.xpm"
  bg_pixmap[PRELIGHT]    = "bc-light.xpm"
  bg_pixmap[ACTIVE]      = "bc-dark.xpm"
  bg_pixmap[INSENSITIVE] = "bc.xpm"

to the "default" section (the first style). Frank Barknecht made a more elaborate example using the Xfce-b5 theme:

Snd with Xfce-b5 theme

To get the default theme (set by Gnome or whatever), use the -nogtkrc startup switch. This is especially useful if you're using an inverse video theme.




Configuration choices

The configuration process is controlled by a set of switches, some specific to Snd. The latter are (configure --help):

Audio choices(normally this is decided automatically)
--with-esduse ESD (enlightened sound daemon)
--with-alsause ALSA (the default in Linux)
--with-ossuse OSS
--with-static-alsause ALSA statically loaded
--with-jackuse JACK (Linux audio stream sharing support, can be used with ALSA)
--with-pulseaudiouse pulseaudio (may not work yet)
--with-portaudiouse portaudio (may not work yet)
Graphics choices
--with-gtkuse Gtk+ to build Snd (Gtk+ version 2.0 or later)
--with-motifuse Motif (version 2.0 or later) to build Snd (the default), Lesstif is not supported
--with-static-motifuse libXm.a to build Snd
--with-motif-prefix=PFXwhere Motif is installed (--with-motif-prefix=/usr/X11R6)
--with-no-guimake Snd without any graphics support
--with-static-xminclude the xm module at build time; this is easier than trying to dynamically load xm.so
--with-static-xginclude the xg module at build time; this is easier than trying to dynamically load xg.so
--with-glinclude OpenGL support (spectrogram, etc, Motif only)
--with-just-glinclude OpenGL support, but omit the GL/s7/Ruby/Forth bindings (Motif only)
--with-gl2psinclude gl2ps (GL to Postscript code, Motif only)
--with-editresinclude editres in xm (default: no)
--with-xpmuse xpm, default: yes
--with-builtin-gtkrcinclude built-in gtkrc fallbacks (default: yes)
--with-cairouse cairo for Gtk graphics if possible (work in progress)
Language choices
--with-forthuse Forth as the extension language
--with-rubyuse Ruby as the extension language; version 1.6.4 or later
--with-s7use S7 as the extension language (default = yes)
--with-ruby-prefix=PFXwhere Ruby is installed
Numerical choices
--with-doublesuse doubles throughout (default: no)
--with-float-samplesuse floats or doubles as the internal sample representation (default: yes)
--with-sample-width=Nif not float samples, use N bits for ints (default: 24, must be between 16 and 31)
Library choices
--with-gsluse GSL (for Chebyshev window), default: yes if local C does not support complex trig
--with-static-gsluse libgsl.a (only for obsolete RPM stuff)
--with-fftwuse fftw, default: yes; fallback fft is built-in
--with-gmpuse gmp, mpfr, and mpc to implement multiprecision arithmetic (default: no)
--with-famuse libfam (Gamin), default: yes; fallback is polling via auto-update-interval
--with-ladspainclude support for LADSPA plugins (in Linux default: yes)
--with-shared-sndlibtry to load libsndlib.so, rather than building it into Snd (default: no)
--disable-deprecateddo not include any deprecated stuff from gtk, s7, sndlib, xen, clm, etc
--enable-threadsinclude pthreads to take advantage of multiprocessor machines
--with-threadsinclude pthreads, same as --enable-threads
Directory choices
--with-temp-dirdirectory to use for temp files (default: ".")
--with-save-dirdirectory to use for saved-state files (default: ".")
--with-doc-dirdirectory to search for documentation (html-dir, elaborate set of defaults)
Debugging etc
--with-snd-as-widgetmake Snd a loadable widget, not a standalone program
--with-profilinginclude profiling (branch counting) machinery, default: no (only for s7)
--enable-snd-debuginclude internal Snd debugging functions, default: no (not useful if not actually debugging!)
--disable-largefileomit support for large (64-bit byte address) files
  ./configure
  make
  make install

tries to use s7, Motif, ALSA (if Linux), and a float sample representation, then installs the snd executable in /usr/local/bin, with a brief blurb in /usr/local/man/man1. Here at CCRMA, we normally use:

  ./configure --with-alsa --with-temp-dir=/zap --with-static-xm --with-gl

There are many more examples in tools/compsnd. Don't use the --enable-snd-debug switch unless you know what you are asking for! Depending on how Snd is configured, any of the following symbols may be "provided" (on the *features* list in Scheme):

clmclm module (always included — once upon a time it was optional)
glOpenGL callable from Scheme/Ruby/Forth (--with-gl switch)
snd-ladspaLADSPA loaded (--with-ladspa, but also the default in Linux if ladspa.h can be found)
sndlibsndlib module (always included)
snd-motifMotif used as GUI toolkit (--with-motif, usually the default if Motif can be found)
snd-gtkGtk+ used as GUI toolkit (--with-gtk)
snd-noguiNo GUI built-in (--with-no-gui, or neither Motif nor Gtk+ found)
snd-rubyRuby as extension language (--with-ruby)
snd-forthForth as extension language (--with-forth)
snd-s7S7 as extension language (--with-s7)
snd-debuginternal debugging hooks included (--enable-snd-debug)
sndIt's Snd, ferchrissake... (always included)
xgGtk module (xg.c) included (--with-static-xg, or loaded dynamically)
xmMotif module (xm.c) included (--with-static-xm, or loaded dynamically)
alsaALSA is in use, rather than OSS (--with-alsa)
gslGSL is loaded (--with-gsl)
gl2psgl2ps is included (--with-gl2ps)
cairocairo used for graphics (--with-cairo)
snd-threadsmultithreading support is included (--enable-threads)

To check whether something is available in the current Snd, use:

    Scheme:  (provided? 'snd-gtk)
    Ruby:    provided? :snd-gtk
    Forth:   "snd-gtk" defined?

Environment variables

There are several environment variables specific to Snd:

SND_PATHSnd source load path list (a colon separated directory list)
SND_INIT_FILE_ENVIRONMENT_NAMEinit file name
LADSPA_PATHLadspa modules directory
MUS_ALSA_PLAYBACK_DEVICEname of playback device (Alsa only)
MUS_ALSA_CAPTURE_DEVICEname of capture device (Alsa only)
MUS_ALSA_DEVICEname of the playback and capture device (Alsa only)
MUS_ALSA_BUFFERSnumber of "periods" used (Alsa only)
MUS_ALSA_BUFFER_SIZEnumber of samples per channel per buffer (Alsa only)
AUDIODEVaudio device name (Sun and related drivers)

Runtime modules and external programs


Snd as an Emacs subjob

Snd watches stdin; any input received is evaluated as if typed in Snd's listener; any subsequent output is sent to stdout. Presumably any process could communicate with Snd in this manner, but the real reason for this is to make it possible to run Snd as a subjob of Emacs. The simplest way to enable that is to use inf-snd.el by Michael Scholz. It starts with a long and detailed commentary.


Dynamically loaded modules

You can import shared object files into Snd at any time.

  (define lib (dynamic-link "/home/bil/cl/cscm.so"))
  (dynamic-call "init_hiho" lib)

External Programs

Any external program that knows about sound files can be used to perform editing operations in Snd. You get Snd's display, analysis, header and format conversion, and edit-tree support, and can concentrate on the actual sound effect you're developing. The original impetus for Snd came from CLM, a large lisp-listener based program which normally runs without a graphical user interface, and without any simple way to move around in what Snd calls the edit history. Since interprocess communication proved problematic in this case, the communication path was simplified to consist of little more than shared files, with CLM treated as a batch program.

Say we have a sound processing CLM instrument we like; it takes two sound file names as its arguments, reading the first and writing the second. In Snd we write the current edited state to a temporary file (save-sound-as), start CLM, call the instrument passing it the input filename (just written by Snd), then pass CLM's output back to Snd. Snd replaces (via set-samples) the current data with the data our instrument wrote, as if it had incorporated that instrument as an editing operation from the beginning. We then delete the Snd output (the input to CLM).


Snd as a Widget

To include the entire Snd editor as a widget in some other program, first compile it with -DSND_AS_WIDGET. Then load it into your program, using the procedure snd_as_widget to fire it up. See saw.c included with Snd.

  void snd_as_widget(int argc, char **argv, XtAppContext app, Widget parent, Arg *caller_args, int caller_argn)

starts up the Snd editor in the widget 'parent', passing the outer Snd form widget the arguments 'caller_args' and 'caller_argn'. The enclosing application context is 'app'. 'parent' needs to be realized at the time of the call, since Snd uses it to set up graphics contexts and so on. 'argc' and 'argv' can be passed to simulate a shell invocation of Snd. Remember that in this case, the first string argument is expected to be the application name, and is ignored by Snd. In Gtk, the arguments are different, but the basic idea is the same:

  GtkWidget *snd_as_widget(int argc, char **argv, GtkWidget *parent, void (*error_func)(const char *msg))

Snd and CLM

The files clm.c, clm.h, and clm2xen.c implement CLM (a Music V implementation), always included in Snd. You can see what a generator does, or a group of generators, by running them in the listener, and using the graph and spectrum functions. Say we have these declarations in ~/.snd:

(define data-size 1024)
(define data (make-vct data-size))

(define (run-gen func)        ; func is a function of no arguments (a "thunk")
  (do ((i 0 (+ 1 i))) 
      ((= i data-size))
    (set! (data i) (func))) ; fill data vct with output of 'func'
  (graph data))               ; display data as a graph

(define (run-fft func)
  (do ((i 0 (+ 1 i))) 
      ((= i data-size))
    (set! (data i) (func)))
  (graph (snd-spectrum data blackman2-window data-size #t)))

Now we can open the listener, and type:

    (define hi (make-oscil))
    (run-gen (lambda () (oscil hi)))
    (define ho (make-oscil))
    (run-fft (lambda () (oscil hi (* .5 (oscil ho)))))

Any CLM instrument or function can be used in this way to edit sounds. Say we want an echo effect:

(define echo 
  (lambda (scaler secs)
    (let ((del (make-delay (round (* secs (srate))))))
      (lambda (inval)
        (+ inval (delay del (* scaler (+ (tap del) inval))))))))

Here 'scaler' sets how loud subsequent echos are, and 'secs' sets how far apart they are in seconds. 'echo' uses the 'secs' argument to create a delay line (make-delay) using the current sound's sampling rate to turn the 'secs' parameter into samples. echo then returns a closure, that is, a function with associated variables (in this case 'del' and 'scaler'); the returned function (the second lambda) takes one argument ('inval') and returns the result of passing that value to the delay with scaling. The upshot of all this is that we can use:

    (map-channel (echo .5 .75) 0 44100)

to take the current active channel and return 44100 samples of echos, each echo half the amplitude of the previous, and spaced by .75 seconds. map-channel's first argument is a function of one argument, the current sample; when we pass it (echo ...), it evaluates the echo call, which returns the function that actually runs the delay line, producing the echo.

If we want "pre-echoes" instead (echoes of the future):

    (reverse-sound)
    (map-channel (echo .5 .75) 0 44100)
    (reverse-sound)

Generators are "applicable" in most versions of Snd: the generator knows its type, so the explicit "oscil" function (for example) isn't needed.

    >(define hi (make-oscil 440.0))
    #<unspecified>
    >(hi)
    0.0
    >(oscil hi)
    0.125050634145737

We can make a generator that is either an oscil or a sawtooth-wave:

    >(define sine-or-sawtooth
       (lambda (sine)
         (let ((gen ((if sine make-oscil make-sawtooth-wave) 440.0)))
           (lambda (fm)
             (gen fm)))))
    #<unspecified>
    >(define osc (sine-or-sawtooth #t))
    #<unspecified>
    >(osc 0.0)
    0.0
    >(osc 0.0)
    0.125050634145737

Here are a few more examples, taken from examp.scm.

(define comb-filter 
  (lambda (scaler size)
    (let ((cmb (make-comb scaler size)))
      (lambda (x) (comb cmb x)))))

; (map-channel (comb-filter .8 32))

;;; by using filters at harmonically related sizes, we can get chords:

(define comb-chord
  (lambda (scaler size amp)
    (let ((c1 (make-comb scaler size))
	  (c2 (make-comb scaler (* size .75)))
	  (c3 (make-comb scaler (* size 1.2))))
      (lambda (x)
        (* amp (+ (comb c1 x) (comb c2 x) (comb c3 x)))))))

; (map-channel (comb-chord .95 60 .3))

;;; or change the comb length via an envelope:

(define max-envelope
  (lambda (e mx)
    (if (null? e)
	mx
      (max-envelope (cddr e) (max mx (abs (cadr e)))))))

(define zcomb
  (lambda (scaler size pm)
    (let ((cmb (make-comb scaler size :max-size (+ size 1 (max-envelope pm 0))))
	  (penv (make-env pm :length (frames))))
      (lambda (x) (comb cmb x (env penv))))))

; (map-channel (zcomb .8 32 '(0 0 1 10)))

;;; to impose several formants, just add them in parallel:

(define formants
  (lambda (r1 f1 r2 f2 r3 f3)
    (let ((fr1 (make-formant f1 r1))
	  (fr2 (make-formant f2 r2))
	  (fr3 (make-formant f3 r3)))
      (lambda (x)
	(+ (formant fr1 x)
	   (formant fr2 x)
	   (formant fr3 x))))))

; (map-channel (formants .01 900 .02 1800 .01 2700))

;;; to get a moving formant:

(define moving-formant
  (lambda (radius move)
    (let ((frm (make-formant (cadr move) radius))
	  (menv (make-env move :length (frames))))
      (lambda (x)
        (let ((val (formant frm x)))
	  (set! (mus-frequency frm) (env menv))
	  val)))))

; (map-channel (moving-formant .01 '(0 1200 1 2400)))

;;; various "Forbidden Planet" sound effects:

(define fp
  (lambda (sr osamp osfrq)
    (let* ((os (make-oscil osfrq))
	   (sr (make-src :srate sr))
	   (len (frames))
	   (sf (make-sampler))
	   (out-data (make-vct len)))
      (vct-map! out-data
		  (lambda () 
		    (src sr (* osamp (oscil os))
			 (lambda (dir)
			   (if (> dir 0)
			       (next-sample sf)
			       (previous-sample sf))))))
      (free-sampler sf)
      (vct->channel out-data 0 len))))

; (fp 1.0 .3 20)


;;; -------- shift pitch keeping duration constant
;;;
;;; both src and granulate take a function argument to get input whenever it is needed.
;;; in this case, src calls granulate which reads the currently selected file.

(define expsrc
  (lambda (rate)
    (let* ((gr (make-granulate :expansion rate))
	   (sr (make-src :srate rate))
	   (vsize 1024)
	   (vbeg 0)
	   (v (channel->vct 0 vsize))
	   (inctr 0))
      (lambda (inval)
        (src sr 0.0
	  (lambda (dir)
	    (granulate gr
	      (lambda (dir)
		(let ((val (v inctr)))
		  (set! inctr (+ inctr dir))
		  (if (>= inctr vsize)
		      (begin
			(set! vbeg (+ vbeg inctr))
			(set! inctr 0)
			(channel->vct vbeg vsize 0 0 v)))
		  val)))))))))

Geez, I haven't had this much fun in a long time! Check out examp.scm and snd-test.scm for more. You can load Rick Taube's CM into Snd as Scheme code:

    snd -l /home/bil/test/cm-2.8.0/src/cm.scm

and all of CM is at your disposal! See also Snd and Common Music.

In most CLM instruments, including all those in clm-ins.scm, the assumption is that you're reading and writing a temp file, calling the instruments within with-sound. The special generator snd->sample provides a way to redirect the CLM input handlers (in-any in particular) to a Snd sound (via its index).



Snd and Common Music

You can load Common Music into Snd. The only real "gotcha" is that Snd's ws.scm has to be loaded before cm's clm2.scm. I load ws.scm in my init file, but in the following example, I'll start -noinit, and load it explicitly.

> (load "ws.scm")
#<unspecified>
> (load "/home/bil/test/cm/src/cm.scm")
#<unspecified>
> (definstrument (simp beg dur freq amp)
   (let* ((o (make-oscil freq))
          (st (seconds->samples beg))
          (nd (+ st (seconds->samples dur))))
     (run
       (do ((i st (+ 1 i)))
           ((= i nd))
         (outa i (* amp (oscil o)))))))
#<values ()>

If the result of the definstrument call is #<unspecified> then cm's definstrument-hook isn't loaded into Snd's definstrument; if you go on anyway, you'll get some complaint that there is no class named "simp".

> (define (random-fn n) 
    (process repeat n output (new simp :beg (now) :dur .1 :freq (between 220 880) :amp .1) wait .25))
#<unspecified>
> (events (random-fn 10) "test.clm" 0 :output "test.snd")
"test.clm"

and the result ("test.snd") is opened in Snd. It's also possible to load sndlib into cm. Here's a note from Rick:

    a tarball of clm+cm in s7 scheme is available at 
    
        http://camil.music.uiuc.edu/Software/grace/downloads/cm3.tar.gz 
    
    the clm+cm app is fully relocatable and requires no runtime sources.   
    to use the app in emacs do 
    
    (setq scheme-program-name "/path/to/cm3/bin/cm") 
    M-x run-scheme 
    
    building is a snap: 
    
    wget ftp://ccrma-ftp.stanford.edu/pub/Lisp/sndlib.tar.gz 
    tar -zxf sndlib.tar.gz 
    cd sndlib 
    ./configure CC=g++ 
    make 
    cd .. 
    
    wget http://camil.music.uiuc.edu/Software/grace/downloads/cm3.tar.gz 
    tar -zxf cm3.tar.gz 
    cd cm3 
    premake --verbose --target gnu --juce /path/to/juce --sndlib ../sndlib 
    make 
    bin/cm 
    
    S7 Scheme 1.2, (c) 2008 William Schottstaedt 
    SNDLIB 20.10, (c) 2008 William Schottstaedt 
     /\\\ 
    ---\\\--------- 
    ----\\\-------- 
    ----/\\\------- Common Music 3.2.0 
    ---/--\\\------ 
    --/----\\\----- 
     /      \\\/ 
    Type 'q' to quit. 
    cm> (list 1 2 3) 
    (1 2 3) 
    cm> (load "/Users/hkt/Software/snd-11/v.scm") 
    fm-violin 
    cm> (with-sound () (fm-violin 0 1 440 .1)) 
    "test.aiff" 
    cm> (define (foo n ) 
      (process for i below n 
           do (display (list i (elapsed))) 
           (newline) 
           (wait .5))) 
    
    foo 
    cm> (sprout (foo 10)) 
    (0 0.0) 
    (1 0.5000870000124) 
    (2 1.0009470000267) 
    (3 1.5018830000162) 
    (4 2.0025049999952) 
    (5 2.5038330000043) 
    (6 3.0042760000229) 
    (7 3.5051180000305) 
    (8 4.006182000041) 
    (9 4.5074370000362) 
    cm> q 
    Killing scheme thread...quitting Scheme 
    Bye! 



Snd and Motif

It is possible to add your own user-interface elements using the xm module included with Snd. 'make xm' should create a shared library named xm.so; you can load this at any time into Snd:

    > (define hxm (dlopen "/home/bil/snd-11/xm.so"))
    #<unspecified>
    > (dlinit hxm "Init_libxm")
    #t

and now we have access to all of X and Motif. Alternatively, use the configure switch --with-static-xm, and the xm module will be included in the base Snd image. Here's a dialog window with a slider:

(define scale-dialog #f)
(define current-scaler 1.0)

(define (create-scale-dialog parent)
  (if (not (Widget? scale-dialog))
      (let ((xdismiss (XmStringCreate "Dismiss" XmFONTLIST_DEFAULT_TAG))
	    (xhelp (XmStringCreate "Help" XmFONTLIST_DEFAULT_TAG))
	    (titlestr (XmStringCreate "Scaling" XmFONTLIST_DEFAULT_TAG)))
	(set! scale-dialog 
	      (XmCreateTemplateDialog parent "Scaling"
                (list XmNcancelLabelString   xdismiss
		      XmNhelpLabelString     xhelp
		      XmNautoUnmanage        #f
		      XmNdialogTitle         titlestr
		      XmNresizePolicy        XmRESIZE_GROW
	              XmNnoResize            #f
		      XmNtransient           #f)))
	(XtAddCallback scale-dialog 
		       XmNcancelCallback (lambda (w context info)
					   (XtUnmanageChild scale-dialog)))
	(XtAddCallback scale-dialog 
		       XmNhelpCallback (lambda (w context info)
					 (snd-print "move the slider to affect the volume")))
	(XmStringFree xhelp)
	(XmStringFree xdismiss)
	(XmStringFree titlestr)

	(let* ((mainform 
		(XtCreateManagedWidget "formd" xmFormWidgetClass scale-dialog
                  (list XmNleftAttachment    XmATTACH_FORM
		        XmNrightAttachment   XmATTACH_FORM
		        XmNtopAttachment     XmATTACH_FORM
		        XmNbottomAttachment  XmATTACH_WIDGET
		        XmNbottomWidget      (XmMessageBoxGetChild scale-dialog XmDIALOG_SEPARATOR))))
	       (scale
		(XtCreateManagedWidget "" xmScaleWidgetClass mainform
		  (list XmNorientation XmHORIZONTAL
			XmNshowValue   #t
			XmNvalue       100
			XmNmaximum     500
			XmNdecimalPoints 2))))

      (XtAddCallback scale XmNvalueChangedCallback (lambda (w context info)
					     (set! current-scaler (/ (.value info) 100.0))))
      (XtAddCallback scale XmNdragCallback (lambda (w context info)
					     (set! current-scaler (/ (.value info) 100.0)))))))
  (XtManageChild scale-dialog))

(create-scale-dialog (cadr (main-widgets)))

which creates a little dialog:

scale dialog

In Ruby, this is:

$scale_dialog = false
$current_scaler = 1.0

def create_scale_dialog(parent)
  if !RWidget?($scale_dialog) 
    then
      xdismiss = RXmStringCreate("Dismiss", RXmFONTLIST_DEFAULT_TAG)
      xhelp = RXmStringCreate("Help", RXmFONTLIST_DEFAULT_TAG)
      titlestr = RXmStringCreate("Scaling", RXmFONTLIST_DEFAULT_TAG)
      $scale_dialog = RXmCreateTemplateDialog(parent, "Scaling",
                   	[RXmNcancelLabelString,  xdismiss,
                      	 RXmNhelpLabelString,    xhelp,
                      	 RXmNautoUnmanage,       false,
                      	 RXmNdialogTitle,        titlestr,
                      	 RXmNresizePolicy,       RXmRESIZE_GROW,
                      	 RXmNnoResize,           false,
                       	 RXmNtransient,          false])
      RXtAddCallback($scale_dialog, RXmNcancelCallback, 
                     Proc.new { |w, context, info| RXtUnmanageChild($scale_dialog)})
      RXtAddCallback($scale_dialog, RXmNhelpCallback, 
                     Proc.new { |w, context, info| snd_print "move the slider to affect the volume"})
      RXmStringFree xhelp
      RXmStringFree xdismiss
      RXmStringFree titlestr
      mainform = RXtCreateManagedWidget("formd", RxmFormWidgetClass, $scale_dialog,
                  	[RXmNleftAttachment,      RXmATTACH_FORM,
                         RXmNrightAttachment,     RXmATTACH_FORM,
                         RXmNtopAttachment,       RXmATTACH_FORM,
                         RXmNbottomAttachment,    RXmATTACH_WIDGET,
                         RXmNbottomWidget,        RXmMessageBoxGetChild($scale_dialog, RXmDIALOG_SEPARATOR)])
      scale = RXtCreateManagedWidget("", RxmScaleWidgetClass, mainform,
                  	[RXmNorientation, RXmHORIZONTAL,
                         RXmNshowValue,   true,
                         RXmNvalue,       100,
                         RXmNmaximum,     500,
                         RXmNdecimalPoints, 2])
      RXtAddCallback(scale, RXmNvalueChangedCallback, 
                     Proc.new { |w, context, info| $current_scaler = Rvalue(info) / 100.0})
      RXtAddCallback(scale, RXmNdragCallback, 
                     Proc.new { |w, context, info| $current_scaler = Rvalue(info) / 100.0})
      RXtManageChild $scale_dialog
    end
end

$Snd_widgets = main_widgets()
create_scale_dialog $Snd_widgets[1]

All of Snd is at your disposal once this module is loaded. The next function installs our own file filtering procedure into the File:Open dialog (it uses match-sound-files from extensions.scm):

(define (install-searcher proc)
  (define (XmString->string str)
    (cadr (XmStringGetLtoR str XmFONTLIST_DEFAULT_TAG)))
  (define (XmStringTable->list st len)
    (XmStringTableUnparse st len #f XmCHARSET_TEXT XmCHARSET_TEXT #f 0 XmOUTPUT_ALL))
  (define (list->XmStringTable strs)
    (XmStringTableParseStringArray strs (length strs) #f XmCHARSET_TEXT #f 0 #f))
  (XtSetValues (let ((m (open-file-dialog #f)))
                         ; make sure the dialog exists
		  (list-ref (dialog-widgets) 6))
		(list XmNfileSearchProc                             ; set dialog file search procedure
		       (lambda (widget info)
			 (let* ((dir (XmString->string (dir info))) ; directory string
				(files (match-sound-files proc dir)) ; list of matching files
				(fileTable (list->XmStringTable      ; XmStringTable for XmNfileListItems
                                             (map (lambda (n)        ; every file needs prepended dir
                                                    (string-append dir n)) 
                                                  files))))
			   (XtSetValues widget                      ; change the list of files
					 (list XmNfileListItems fileTable
					       XmNfileListItemCount (length files)
					       XmNlistUpdated #t)))))))

;(install-searcher (lambda (file) (= (srate file) 44100)))
;(install-searcher (lambda (file) (= (channels file) 4)))

Now click the 'Filter' button to see only those files that fit the procedure in the dialog's files list. See snd-motif.scm and popup.scm.


Snd and Gtk+

There are tons of examples of using the gtk module. snd-gtk.scm and gtk-popup.scm might be places to start. All of gtk, gdk, and cairo, and much of pango and glib are accessible from the extension language if you loaded the xg module or built Snd with the configuration switch --with-static-xg. Here's the scale-dialog in xg/gtk:

(define scale-dialog #f)
(define current-scaler 1.0)

(define (create-scale-dialog parent)
  (if (not scale-dialog)
      (begin
	(set! scale-dialog (gtk_dialog_new))
	(g_signal_connect scale-dialog "delete-event"
			     (lambda (w ev info)
			       (gtk_widget_hide w)))
	(gtk_window_set_title (GTK_WINDOW scale-dialog) "Scale")
	(gtk_widget_realize scale-dialog)
	(let ((dismiss (gtk_button_new_with_label "Dismiss"))
	      (help (gtk_button_new_with_label "Help")))
	  (gtk_box_pack_start (GTK_BOX (.action_area (GTK_DIALOG scale-dialog))) dismiss #t #t 4)
	  (gtk_box_pack_end (GTK_BOX (.action_area (GTK_DIALOG scale-dialog))) help #t #t 4)	
	  (g_signal_connect dismiss "clicked"
			       (lambda (w info)
				 (gtk_widget_hide scale-dialog)))
	  (g_signal_connect help "clicked"
			       (lambda (w info)
				 (help-dialog "Scaler Dialog" "move the slider to affect the volume")))
	  (gtk_widget_show dismiss)
	  (gtk_widget_show help)
	  (let* ((adj (gtk_adjustment_new 0.0 0.0 1.01 0.01 0.01 .01))
		 (scale (gtk_hscale_new (GTK_ADJUSTMENT adj))))
	    (gtk_range_set_update_policy (GTK_RANGE (GTK_SCALE scale)) GTK_UPDATE_CONTINUOUS)
	    (gtk_scale_set_draw_value (GTK_SCALE scale) #t)
	    (gtk_scale_set_digits (GTK_SCALE scale) 2)
	    (g_signal_connect adj "value_changed"
				 (lambda (wadj info)
				   (set! current-scaler (.value (GTK_ADJUSTMENT wadj)))))
	    (gtk_box_pack_start (GTK_BOX (.vbox (GTK_DIALOG scale-dialog))) scale #f #f 6)
	    (gtk_widget_show scale)))))
  (gtk_widget_show scale-dialog))

(create-scale-dialog (cadr (main-widgets)))

The only change from the C code is the addition of GTK_ADJUSTMENT in the scale value_changed callback — currently the xg module assumes the first argument to the two-argument callback is a GtkWidget, so we have to cast a GtkAdjustment back to its original type.

Here are a couple other examples of things that aren't covered by the gtk code in snd-gtk.scm and friends:

;; report on mouse scroll wheel changes when in the channel graph
(g_signal_connect 
 (car (channel-widgets)) "scroll_event" 
 (lambda (w e i)
   (snd-print (format #f "~%state: ~A, x: ~A, y: ~A, direction: ~A" 
		      (.state (GDK_EVENT_SCROLL e))
		      (.x (GDK_EVENT_SCROLL e))
		      (.y (GDK_EVENT_SCROLL e))
		      (.direction (GDK_EVENT_SCROLL e))))
   #f))

;; report which kind of click was received in the channel graph
(g_signal_connect 
 (car (channel-widgets)) "button_press_event"
 (lambda (w e i)
   (snd-print (format #f "~%button: ~A, ~A click" 
		      (.type (GDK_EVENT_BUTTON e))
		      (if (= (.type (GDK_EVENT_BUTTON e)) GDK_BUTTON_PRESS)
			  "single"
			  (if (= (.type (GDK_EVENT_BUTTON e)) GDK_2BUTTON_PRESS)
			      "double"
			      (if (= (.type (GDK_EVENT_BUTTON e)) GDK_3BUTTON_PRESS)
				  "triple"
				  "unknown")))))
   #f))

;; a double click is reported as single/single/double

;; double-click time in milliseconds(?)
(define (double-click-time)
  (g_object_get (GPOINTER 
                  (gtk_settings_get_for_screen 
                    (gdk_display_get_default_screen 
                      (gdk_display_get_default)))) 
                "gtk-double-click-time" #f))

Snd with no GUI and as scripting engine

If Snd is built without a graphical user interface (by specifying --with-no-gui to configure), it runs the extension language's read-eval-print loop, with input from stdin. All the non-interface related functions are available, so you can do things like:

SchemeRubyForth
snd
:(new-sound "test.snd")
#<sound 0>
:(mix "oboe.snd")
(#<mix 0>)
:(frames)
50828
:(play)
#f
:(exit)
snd
> new_sound("test.snd")
0
> mix("oboe.snd")
[#<mix 0>]
> frames
50828
> play
false
> exit
snd
"test.snd" new-sound
0 ok
"oboe.snd" mix
-1 ok
frames
50828 ok
play
#f ok
snd-exit

Since there's no graphics toolkit event loop to get in your way, you can treat this version of Snd as a scripting engine. For example, if you have an executable file with:

#!/home/bil/test/snd-11/snd -l
!#
(define a-test 32)
(display "hiho")
(newline)

it can be executed just like any such script.

    /home/bil/test/snd-11/ script
    hiho
    :a-test
    32
    :(exit)
    /home/bil/test/snd-11/ 

As noted above, you can use the -e switch to use Snd as a pure command-line program, and, of course, (exit) to drop back to the shell. Here's a script that doubles every sample in "oboe.snd" and writes the result as "test.snd":

SchemeRubyForth
#!/home/bil/snd-11/snd -l
!#
(open-sound "oboe.snd")
(scale-by 2.0)
(save-sound-as "test.snd")
(exit)
#!/home/bil/snd-11/snd -batch
open_sound "oboe.snd"
scale_by 2.0
save_sound_as "test.snd"
exit
#! /usr/bin/env /home/bil/forth-snd/snd
"oboe.snd" open-sound drop
2.0 #f #f scale-by drop
"test.snd" save-sound-as
snd-exit

The functions script-args and script-arg can be used to access the script's arguments, and if necessary (if not exiting) tell Snd to ignore arguments. script-args returns a list of strings giving the arguments. The first two are always "-l" and the script file name. The current argument is (script-arg). If you set this to a higher value, Snd will subsequently ignore the intervening arguments as it scans the startup arguments (see snd-test.scm).

#!/home/bil/test/snd-11/snd -l
!#
(if (= (length (script-args)) 2) ;i.e. ("-l" "script")
  (display "usage: script file-name...")
  (begin
    (open-sound (list-ref (script-args) (+ (script-arg) 1)))
    (scale-by 2.0)
    (save-sound-as "test.snd")))
(exit)

This either grumbles if no argument is given, or scales its argument sound by 2.0:

    script pistol.snd

And we can run through the entire argument list, doubling all the sounds or whatever by using a do loop — the following displays all the comments it finds:

#!/home/bil/cl/snd -l
!#
(if (= (length (script-args)) 2) ;i.e. ("-l" "script")
  (display "usage: script file-name...")
  (do ((arg (+ (script-arg) 1) (+ 1 arg)))
      ((= arg (length (script-args))))
    (let ((name (list-ref (script-args) arg)))
      (display (format #f "~A: ~A~%" name (mus-sound-comment name))))))
(exit)

Say we save this as the file "comments".

    /home/bil/cl/comments *.snd

If you like, you can use env:

    #!/usr/bin/env snd
    !#

But if that works, so will:

    #!snd -l
    !#

This scripting mechanism actually will work in any version of Snd; to keep the Snd window from popping up, use the -b (-batch) switch in place of -l. Here's another script; it looks for any sounds that are longer than 40 seconds in duration, and truncates them to 40 seconds:

#!/usr/local/bin/snd -l
!#
(if (= (length (script-args)) 2)
  (display "usage: trunc.scm file-name...")
  (do ((arg (+ (script-arg) 1) (+ 1 arg)))
      ((= arg (length (script-args))))
    (let* ((name (list-ref (script-args) arg)))
      (if (> (mus-sound-duration name) 40.0)
	  (let* ((ind (open-sound name)))
	    (set! (frames ind) (* 40 (srate ind)))
	    (save-sound ind)
	    (close-sound ind))))))
(exit)

Here's a sndplay replacement script:

#!snd -b
!#
(play (list-ref (script-args) (+ (script-arg) 1)) :wait #t)
(exit)

And here's a script that splits a multichannel file into a bunch of mono files:

#!snd -b
!#
(if (= (length (script-args)) 2)
  (display "usage: split.scm filename")
  (let* ((name (list-ref (script-args) (+ 1 (script-arg))))
	 (chns (channels name)))
    (if (> chns 1)
	(let ((ind (open-sound name)))
	  (do ((i 0 (+ 1 i)))
	      ((= i chns))
	    (display (format #f "~A.~D " name i))
	    (save-sound-as (format #f "~A.~D" name i)
			   ind
			   (header-type ind)
			   (data-format ind)
			   (srate ind)
			   i))
	  (close-sound ind)))))
(exit)


Snd with Ruby

Ruby is an extension language described as an "object-oriented Perl". It provides a different syntax from that of Scheme; most of the *.scm (Scheme) files have corresponding *.rb (Ruby) files (written by Mike Scholz), so there's no penalty for using Ruby rather than Scheme. The only drawback is that the documentation uses Scheme. The differences between Scheme and Ruby, however, are not too severe. In Ruby, the following changes are made in the function names (as presented in Scheme): "-" becomes "_", "->" becomes "2", hooks and current_sound have "$" prepended (since they are global variables from Ruby's point of view), and all the constants are capitalized (e.g. Autocorrelation). The generalized set! functions are replaced by "set_" plus the base name (e.g. set_window_width), with arguments reordered in some cases to place the optional values after the new value. That is, (set! (sync snd) 1) becomes set_sync(1, snd). Hooks in Ruby (which have little or nothing to do with Ruby's "hookable variables") are just procedures or nil, not lists of procedures as in Scheme. Here's a Ruby version of the init file given above (named ~/.snd_ruby):

set_window_width 800
set_window_height 500

set_listener_font "9x15"
set_axis_numbers_font "9x15"

set_show_mix_waveforms true
set_trap_segfault false
set_show_indices true

set_listener_prompt ":"
show_listener

beige = make_color 0.96, 0.96, 0.86
blue = make_color 0, 0, 1
set_selected_graph_color beige
set_selected_data_color blue

Procedures are created via Proc.new, so to set the open-hook to print the file name,

    >$open_hook = Proc.new { |name| snd_print name }
    #<Proc:0x40221b84>
    >open_sound "oboe.snd"
    /home/bil/cl/oboe.snd
    0

(The trailing "0" is the result of open_sound). The Scheme hook list support procedures aren't included in Ruby — simply set the variable to the procedure you want, or false to clear it.

Vcts and sound-data objects mixin "Comparable" and "Enumerable", and respond to various array-like methods:

    >v1 = make_vct 4
    #<vct[len=4]: 0.000 0.000 0.000 0.000>
    >v1[3] = 1.0
    1.0
    >v1.sort
    0.00.00.01.0 # I don't know why it prints this way but ...
    >v1
    #<vct[len=4]: 0.000 0.000 0.000 1.000>
    >v1.max
    1.0

Keywords, CLM generic functions, and optional arguments work as in Scheme:

    >osc = make_oscil(:frequency, 440)
    oscil freq: 440.000Hz, phase: 0.000
    >oscil osc
    0.0
    >oscil osc
    0.1250506192
    >osc.frequency
    440.0

Lists (from the Scheme point of view) are arrays (vectors) in Ruby. Here's one more example, a translation of display-energy in draw.scm:

def display_energy(snd, chn)
  ls = left_sample
  rs = right_sample
  data1 = make_graph_data(snd, chn)
  data = data1
  if not vct? data
    data = data1[1]
  end
  len = vct_length data
  sr = srate snd
  y_max = y_zoom_slider(snd, chn)
  vct_multiply!(data, data)
  graph(data, "energy", ls / sr, rs / sr, 0.0, y_max * y_max, snd, chn, false)
  end

# $lisp_graph_hook = Proc.new {|snd, chn| display_energy(snd, chn)}

In Ruby you make a symbol by prepending ":", so Scheme's

    (list 'KeySym (char->integer #\F))

becomes

    [:KeySym, ?F]

In the listener, everything is line-oriented (that is, I'm not trying to catch incomplete expressions). And it appears that in Ruby, variables defined within a file are considered local to that file(?). For Ruby as an Emacs subjob, see inf-snd.el.


Snd with Forth

Snd can be built with Forth as its extension language. Forth is available at:

    http://sourceforge.net/projects/fth

An example initialization file (~/.snd_forth) is given in the initialization section. Mike Scholz (creator of the Forth library we use) has provided a bunch of Forth files along the lines of the Scheme and Ruby files described above — see *.fs. See also Mike's very fine documentation in the fth package. Here's an example from his fth.texi file showing how to define an instrument and use it in with-sound:

instrument: src-simp { start dur amp sr sr-env fname -- }
    :file fname make-readin { f }
    :input f input-fn :srate sr make-src { sr }
    :envelope sr-env :duration dur make-env { en }
    start dur run
        i                 \ sample position for outa
        sr en env #f src
        amp f*
        *output* outa drop
    loop
    f mus-close drop
;instrument
"/usr/gnu/sound/SFiles/fyow.snd" value fyow-snd
#( 0.0 0.0 50.0 1.0 100.0 0.0 ) value sr-env
0.0 1.5 0.5 0.2 sr-env array->list fyow-snd ' src-simp with-sound


Snd with s7

s7 is a Scheme implementation included in the Snd tarball and described in s7.html. It is now the Snd default extension language.

The s7 initialization file is ~/.snd_s7.



Snd and LADSPA Plugins

  init-ladspa
  list-ladspa
  analyse-ladspa library plugin [also analyze-ladspa]
  ladspa-descriptor library plugin
  apply-ladspa reader data duration origin snd chn

  ladspa-instantiate descriptor srate
  ladspa-activate descriptor handle
  ladspa-deactivate descriptor handle
  ladspa-cleanup descriptor handle
  ladspa-connect-port descriptor handle port vct
  ladspa-run descriptor handle count
  ladspa-run-adding descriptor handle count
  ladspa-set-run-adding-gain descriptor handle gain

Richard Furse has provided a module to support LADSPA plugins in Snd. Here is his documentation:

Supporting functions are:

	(init-ladspa)

	Performs a search of LADSPA_PATH for plugins, doesn't need to be called 
as LADSPA automatically initialises on first use however can be used to 
reinitialise if new plugins have arrived.

	(list-ladspa)

	Returns a list of lists where each inner list contains a string to 
identify the plugin library and a string to identify the plugin type within 
the library.

	(analyse-ladspa plugin-library plugin-type)

	Returns a list of assorted data about a particular plugin including a 
list of port descriptions. plugin-library and plugin-type are as provided 
by list-ladspa.

The main function is:

	(apply-ladspa reader (plugin-library plugin-type [param1 [param2 ...]]) samples origin snd chn)

	Applies a LADSPA plugin to a block of samples. 
An example call to apply the low-pass-filter in the CMT plugin library is 
(apply-ladspa (make-sampler 0) (list "cmt" "lpf" 1000) 10000 "origin").

Dave Phillips in Linux Audio Plug-Ins: A Look Into LADSPA adds this:

  (apply-ladspa (make-sampler 57264) (list "cmt" "delay_5s" .3 .5) 32556 "ibm.wav")

"This sequence tells Snd to read a block of 32556 samples from the ibm.wav file, starting at sample number 57264, and apply the delay_5s LADSPA plug-in (Richard Furse's delay plug-in, also found in cmt.so) with a delay time of .3 seconds and a 50/50 dry/wet balance."

To help Snd find the plugin library, set either the Snd variable ladspa-dir or the environment variable LADSPA_PATH to the directory. If, for example, cmt.so is in /usr/local/lib/ladspa, (and you're using tcsh), then

  setenv LADSPA_PATH /usr/local/lib/ladspa

or

  (set! (ladspa-dir) "/usr/local/lib/ladspa")

Snd plugins may have any number of inputs and outputs; if more than one input is required, the first argument to apply-ladspa should be a list of readers:

  (apply-ladspa (list (make-sampler 0 0 0)  ;chan 0
                      (make-sampler 0 0 1)) ;chan 1
                (list "cmt" "freeverb3" 0 .5 .5 .5 .5 .5) 
                100000 "freeverb")

The "regularized" version of apply-ladspa could be defined:

(define* (ladspa-channel ladspa-data (beg 0) ndur snd chn (edpos -1))
  (let* ((dur (or ndur (- (frames snd chn) beg)))
	 (reader (make-sampler beg snd chn 1 edpos)))
    (let ((result (apply-ladspa reader ladspa-data dur "apply-ladspa" snd chn)))
      (free-sampler reader)
      result)))

There are also functions to access the LADSPA descriptor directly:

    (define ptr (ladspa-descriptor "amp" "amp_mono"))
    (.Label ptr)
        "amp_mono"
    (.Name ptr)
        "Mono Amplifier"
    (.Copyright ptr)
        "None"
    (.Maker ptr)
        "Richard Furse (LADSPA example plugins)"
    (.Properties ptr)
        4
    (.UniqueID ptr)
        1048
    (.PortNames ptr)
        ("Gain" "Input" "Output")
    (.PortRangeHints ptr)
        ((593 0.0 0.0) (0 0.0 0.0) (0 0.0 0.0))
    (.PortCount ptr)
        3
    (.PortDescriptors ptr)
        (5 9 10)
    (logand (cadr (.PortDescriptors ptr)) LADSPA_PORT_INPUT)
        1

See ladspa.h for full details. We could replace analyse-ladspa using these functions:

(define (analyze-ladspa library label)
  (let* ((descriptor (ladspa-descriptor library label))
	 (data '())
	 (names (.PortNames descriptor))
	 (hints (.PortRangeHints descriptor))
	 (descriptors (.PortDescriptors descriptor))
	 (name (.Name descriptor))
	 (maker (.Maker descriptor))
	 (copy (.Copyright descriptor)))
    (for-each
     (lambda (port ranges port-name)
       (if (and (not (= (logand port LADSPA_PORT_CONTROL) 0))
		(not (= (logand port LADSPA_PORT_INPUT) 0)))
	   (let ((ldata '())
		 (hint (car ranges))
		 (lo (cadr ranges))
		 (hi (caddr ranges)))
	     (if (not (= (logand hint LADSPA_HINT_TOGGLED) 0)) (set! ldata (cons "toggle" ldata)))
	     (if (not (= (logand hint LADSPA_HINT_LOGARITHMIC) 0)) (set! ldata (cons "logarithmic" ldata)))
	     (if (not (= (logand hint LADSPA_HINT_INTEGER) 0)) (set! ldata (cons "integer" ldata)))
	     (if (not (= (logand hint LADSPA_HINT_SAMPLE_RATE) 0)) (set! ldata (cons "sample_rate" ldata)))
	     (if (not (= (logand hint LADSPA_HINT_BOUNDED_ABOVE) 0)) 
		 (begin
		   (set! ldata (cons hi ldata))
		   (set! ldata (cons "maximum" ldata))))
	     (if (not (= (logand hint LADSPA_HINT_BOUNDED_BELOW) 0) )
		 (begin
		   (set! ldata (cons lo ldata))
		   (set! ldata (cons "minimum" ldata))))
	     (set! ldata (cons port-name ldata))
	     (set! data (cons ldata data)))))
     descriptors hints names)
    (append (list name maker copy) data)))

Here's a function that processes a channel of data through a plugin, sending the data directly to the DAC:

(define* (ladspa-it library label :rest plugin-parameters)
  ;; (ladspa-it "cmt" "delay_5s" .3 .5)
  (init-ladspa)
  (let* ((descriptor (ladspa-descriptor library label))
	 (handle (ladspa-instantiate descriptor (srate)))
	 (block-size 256)
	 (in-block (make-vct block-size))
	 (out-block (make-vct block-size))
	 (len (frames))
	 (data (make-sound-data 1 block-size))
	 (audio-port (mus-audio-open-output mus-audio-default (srate) 1 mus-lshort (* block-size 2))))
  (dynamic-wind
   (lambda ()
     (let ((count 0))
       (for-each 
	(lambda (port)
	  (if (not (= (logand port LADSPA_PORT_CONTROL) 0))
	      (let ((parameter (make-vct 1 (car plugin-parameters))))
		(set! plugin-parameters (cdr plugin-parameters))
		(ladspa-connect-port descriptor handle count parameter))
	      (if (not (= (logand port LADSPA_PORT_INPUT) 0))
		  (ladspa-connect-port descriptor handle count in-block)
		  (ladspa-connect-port descriptor handle count out-block)))
	  (set! count (+ 1 count)))
	(.PortDescriptors descriptor))))
   (lambda ()
     (ladspa-activate descriptor handle)
     (do ((i 0 (+ i block-size)))
	 ((>= i len))
       (vct-subseq (channel->vct i block-size) 0 block-size in-block)
       (ladspa-run descriptor handle block-size)
       (vct->sound-data out-block data 0)
       (mus-audio-write audio-port data block-size)))
   (lambda ()
     (ladspa-deactivate descriptor handle)
     (mus-audio-close audio-port)
     (ladspa-cleanup descriptor handle)))))

One slight "gotcha" in this area: the Snd configuration switch --with-doubles causes "vcts" to be arrays of doubles, but Ladspa plugins expect to see arrays of floats. This is a problem only if you're calling ladpsa-connect-port yourself.


Snd and ALSA

(This section is a lightly edited copy of some notes Fernando sent me). The default ALSA device in Snd is "default". This virtual device tries to play sounds at any sampling rate, provide any number of input channels, handle data format conversions, and so on. Experts will probably want to use the "hw:0" device instead (this is the first hardware device; "hw:1" is the second, and so on), but in that case, ALSA provides only whatever sampling rates the hardware provides. To change the device, or the internal buffering amounts, you can either set up environment variables, or use the parallel Scheme/Ruby/Forth variables mus-alsa-*. The environment variables are:

MUS_ALSA_PLAYBACK_DEVICEname of playback device ("default")
MUS_ALSA_CAPTURE_DEVICEname of capture (recording) device ("default")
MUS_ALSA_DEVICEname of the playback and capture device ("sndlib")
MUS_ALSA_BUFFERSnumber of "periods" (buffers) used
MUS_ALSA_BUFFER_SIZEnumber of samples per channel per buffer

These can be set either in your shell initialization file (~/.cshrc for tcsh), or in the shell:

    setenv MUS_ALSA_DEVICE "hw:0"   ; tcsh
    MUS_ALSA_DEVICE="hw:0"          ; bash

or run Snd with a temporary setting:

    MUS_ALSA_DEVICE="plughw:0" snd somefile.wav

The parallel variables (for ~/.snd and friends, or at any time in the listener), are:

mus-alsa-playback-devicename of playback device ("default")
mus-alsa-capture-devicename of capture (recording) device ("default")
mus-alsa-devicename of the playback and capture device ("sndlib")
mus-alsa-buffersnumber of "periods" (buffers) used
mus-alsa-buffer-sizenumber of samples per channel per buffer

So, to use the "plughw" device, we could:

    (set! (mus-alsa-device) "plughw:0")

Similarly, if you know which device you want to record from (say your arecord command is "arecord -D hw:0.2"), you can tell Snd's recorder to use that device via:

    setenv MUS_ALSA_CAPTURE_DEVICE "hw:0.2"

or

    (set! (mus-alsa-capture-device) "hw:0.2")

It's also possible to define your own device, apparently, but that part of ALSA is beyond my ken.


Snd and Jack

(This section is from Kjetil Matheussen).

SNDLIB_JACK_DONT_AUTOCONNECTIf set, snd won't autoconnect jack ports
SNDLIB_NUM_JACK_CHANNELSNumber of in and out jack ports created by snd


Driving Snd remotely

It is possible to send to Snd arbitrary Scheme, Ruby, or Forth code from any other program; see the program sndctrl.c. Snd has two X window properties: "SND_VERSION" and "SND_COMMAND"; the former is the Snd version (a date), and the latter is the communication path for other programs. Any time such a program changes the SND_COMMAND property, Snd notices and evaluates the new value (as a string, as if typed in the Snd listener). To get a response from Snd, use (set! (window-property consat name) command) where 'consat' is the property name Snd should search for (to find the sending window), 'name' is the property to change (the X window property that Snd will change), and 'command' is the string that replaces the current property value (which Snd will evaluate).


Snd and OpenGL

Snd with Motif can be used in conjunction with OpenGL. If it is configured with the switch --with-gl or --with-just-gl, the top level Snd shell is setup to handle OpenGL graphics. These are used automatically by the spectrogram display; the colormap and viewing angle are set by either the View:Color/Orientation dialog or colormap, and the various spectro-* variables.

gl

The GL-to-Scheme bindings are in gl.c, and follow the same name and type conventions of the Motif bindings in xm.c. Any of the Snd drawing area widgets (or your own) can receive GL graphics commands. Here is a translation of the SGI/xjournal glxmotif program:

(define (draw-it)
  (glXMakeCurrent (XtDisplay (cadr (main-widgets))) 
		  (XtWindow (car (channel-widgets)))
		  (snd-glx-context)) ; the GL context
  (glEnable GL_DEPTH_TEST)
  (glDepthFunc GL_LEQUAL)
  (glClearDepth 1.0)
  (glClearColor 0.0 0.0 0.0 0.0)
  (glLoadIdentity)
  (gluPerspective 40.0 1.0 10.0 200.0)
  (glTranslatef 0.0 0.0 -50.0)
  (glRotatef -58.0 0.0 1.0 0.0)
  (let ((vals (XtVaGetValues (car (channel-widgets)) (list XmNwidth 0 XmNheight 0))))
    (glViewport 0 0 (list-ref vals 1) (list-ref vals 3)))
  (glClear (logior GL_COLOR_BUFFER_BIT GL_DEPTH_BUFFER_BIT))
  (glBegin GL_POLYGON)
  (glColor3f 0.0 0.0 0.0)   (glVertex3f -10.0 -10.0 0.0)
  (glColor3f 0.7 0.7 0.7)   (glVertex3f 10.0 -10.0 0.0)
  (glColor3f 1.0 1.0 1.0)   (glVertex3f -10.0 10.0 0.0)
  (glEnd)
  (glBegin GL_POLYGON)
  (glColor3f 1.0 1.0 0.0)   (glVertex3f 0.0 -10.0 -10.0)
  (glColor3f 0.0 1.0 0.7)   (glVertex3f 0.0 -10.0 10.0)
  (glColor3f 0.0 0.0 1.0)   (glVertex3f 0.0 5.0 -10.0)
  (glEnd)
  (glBegin GL_POLYGON)
  (glColor3f 1.0 1.0 0.0)   (glVertex3f -10.0 6.0 4.0)
  (glColor3f 1.0 0.0 1.0)   (glVertex3f -10.0 3.0 4.0)
  (glColor3f 0.0 0.0 1.0)   (glVertex3f 4.0 -9.0 -10.0)
  (glColor3f 1.0 0.0 1.0)   (glVertex3f 4.0 -6.0 -10.0)
  (glEnd)
  (glXSwapBuffers (XtDisplay (cadr (main-widgets))) 
		  (XtWindow (car (channel-widgets))))
  (glFlush))

See snd-gl.scm. To turn these graphs into Postscript files, include the --with-gl2ps switch at configuration time, and use the gl-graph->ps function.



Snd and GSL

If the GSL library is available, the following functions are imported into Snd:

gsl-dht size data nu xmax
gsl-dht performs the Hankel transform of "data", a vct. See add-transform for an example.
gsl-eigenvectors matrix
gsl-eigenvectors returns the eigenvalues and corresponding eigenvectors of "matrix", a mixer.
>(gsl-eigenvectors (make-mixer 4  -1.0 1.0 -1.0 1.0
                               -8.0 4.0 -2.0 1.0
                               27.0 9.0 3.0 1.0
                               64.0 16.0 4.0 1.0))
(#(-6.41391102627093 5.54555349890946 5.54555349890946 2.32280402845201) 
#(#(-0.0998821746683654 -0.111251309674367 0.292500673281302 0.94450518972065) 
  #(-0.0434869537653505 0.0642376994169207 -0.515252756143484 -0.840592191366022) 
  #(-0.0434869537653505 0.0642376994169207 -0.515252756143484 -0.840592191366022) 
  #(-0.144932944248023 0.356601443087312 0.91936884368837 0.0811836295983152)))
The value returned is a list of two elements. The first is a vector containing the eigenvalues, the second is a vector containing the corresponding eigenvectors (as vectors). See make-dpss-window in snd-test.scm (the corresponding C code is in clm.c).
gsl-ellipk k
gsl-ellipj j u m
These are calls on the functions gsl_sf_ellint_Kcomp and gsl_sf_elljac_e. See the elliptic filter code in analog-filter.scm for an example.
gsl-roots poly
This returns the roots of the polynomial "poly" via gsl_poly_complex_solve. See analog-filter.scm for an example.


Snd and multiprecision arithmetic

Multiprecision arithmetic for integer, ratio, real, and complex numbers is available in Snd via the gmp, mpfr, and mpc libraries and s7. Use the --with-gmp configuration switch. This version of s7 also supplies the functions:

bignum num

bignum converts its argument (a string) into a big number. This is the most convenient way to force a calculation to use big numbers.

    :(sqrt 2)
    1.4142135623731
    :(sqrt (bignum "2"))
    1.414213562373095048801688724209698078569E0

s7 uses normal C arithmetic unless something causes it to be suspicious. Since a number like 1.2345e-14 does not trigger an underflow in C, and is short (it's written with less than 20 characters), s7 trusts it even in a case such as:

    :(+ 1.2345e-15 1.0 -1.0)
    1.3322676295502e-15

In any case like this where C doubles are going to lose, you can force big float arithmetic by making one of the operands a bignum:

    :(+ (bignum "1.2345e-15") 1.0 -1.0)
    1.234500000000000042481989819014552503046E-15

There are lots of similar cases:

    :(* 2e-170 3e-170 4e+170 5e+170)
    0.0
    :(* (bignum "2e-170") 3e-170 4e+170 5e+170)
    1.200000000000000019643628722298292475697E2

but presumably you know when you're using these kinds of numbers.

bignum? num

bignum? returns #t if its argument is a big number.

bignum-fft rl im size sign
bignum-fft performs an FFT using big floats; rl and im are vectors of big floats.
bignum-precision

bignum-precision sets the number of bits used in floating-point big numbers (integer bignums have whatever size it takes to represent them). The default is 128 which gives about 40 decimal digits.

   :(* 2 pi)
   6.283185307179586476925286766559005768391E0
   :(set! (bignum-precision) 256)
   256
   :(* 2 pi)
   6.283185307179586476925286766559005768394338798750211641949889184615632812572396E0

If a big float is so large that the current bignum-precision has to approximate it, you can get confusing results:

    :(rationalize 385817946978768113605842402465609185854927496022065152.5)
    385817946978768113605842402465609185854927496022065152
    :(set! (bignum-precision) 512)
    512
    :(rationalize 385817946978768113605842402465609185854927496022065152.5)
    771635893957536227211684804931218371709854992044130305/2

Yet another source of confusion involves the conversion of the string representation of a bigfloat:

    :(bignum "0.1")
    1.000000000000000055511151231257827021182E-1
    :(/ (bignum "1.0") 10)
    1.000000000000000000000000000000000000001E-1

I think I'll eventually add bignum versions of all the CLM generators. Here, for example, is a bigfloat oscil:

(defgenerator (big-oscil 
  :make-wrapper 
    (lambda (g)
      (set! (big-oscil-frequency g) (/ (* (big-oscil-frequency g) 2.0 pi) (mus-srate)))
      g))
  (frequency *clm-default-frequency*) (angle 0.0))

(define* (big-oscil gen (fm 0.0) (pm 0.0))
  (let ((x (big-oscil-angle gen)))
    (set! (big-oscil-angle gen) (+ fm x (big-oscil-frequency gen)))
    (sin (+ x pm))))

Ideally, the run macro would know how to handle bignums (and complex numbers). But, one thing at a time...



related documentation: snd.html extsnd.html sndscm.html sndclm.html fm.html sndlib.html libxm.html s7.html index.html