Re: [ecasound] eci / ecamonitor / -ev

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Subject: Re: [ecasound] eci / ecamonitor / -ev
From: Mario Lang (mlang_AT_delysid.org)
Date: Wed Nov 06 2002 - 16:56:54 EET

Adam Linson <adam_AT_semioweb.com> writes:

[...]

> is it possible to "harvest" the values from "-ev" for use in an ECI
> implementation?
Yes, of course.

> concretely: in the ECI example at
> http://www.wakkanet.fi/~kaiv/ecasound/Documentation/programmers_guide/html_ecidoc/eci_doc.htmlthe sample position is checked, and a conditional command is issued,
> depending on the sample position. is it possible, with ECI, to check
> various amplitude statistics (as with "-ev"/ecamonitor) and use (the
> many aspects of) that information in conditions for issuing commands as
> well?
>
> my guess is that it's a bit tricky, since the normal EIAM "-ev" waits
> for the sample to finish ("wait_for_stop ok"), and only with ecamonitor
> am i able to check the "-ev" values on a quasi-real-time basis.

Use cop-status instead of copp-get.
cop-status will include a line like this:
           Status info:
(audiofx) -- Amplitude statistics -------
.......

So you only need to parse that out there.

ecasound.el implements that.

(defvar eci-cop-status-header
  "### Chain operator status (chainsetup '\\([^']+\\)') ###\n")

(defun eci-process-cop-status (string)
  (with-temp-buffer
    (insert string) (goto-char (point-min))
    (when (re-search-forward eci-cop-status-header nil t)
      (let (result)
        (while (re-search-forward "Chain \"\\([^\"]+\\)\":\n" nil t)
          (let ((c (match-string-no-properties 1)) chain)
            (while (re-search-forward
                    "\t\\([0-9]+\\)\\. \\(.+\\): \\(.*\\)\n?" nil t)
              (let ((n (string-to-number (match-string 1)))
                    (name (match-string-no-properties 2))
                    (args
                     (mapcar
                      (lambda (elt)
                        (when (string-match
                               "\\[\\([0-9]+\\)\\] \\(.*\\) \\([0-9.-]+\\)$"
                               elt)
                          (list (match-string-no-properties 2 elt)
                                (string-to-number (match-string 1 elt))
                                (string-to-number (match-string 3 elt)))))
                      (split-string
                       (match-string-no-properties 3) ", "))))
                (if (looking-at "\tStatus info:\n")
                    (setq args
                          (append
                           args
                           (list
                            (list
                             "Status info" nil
                             (buffer-substring
                              (progn (forward-line 1) (point))
                              (or (re-search-forward "\n\n" nil t)
                                  (point-max))))))))
                (setq chain (cons (append (list name n) args) chain))))
            (setq result (cons (reverse (append chain (list c))) result))))
        result))))

So to access the status info in elisp, do:

(nth 2 (nth 2 (nthcdr 2 (assoc "Volume analysis"
                               (assoc (car (eci-c-selected))
                                      (eci-cop-status))))))

or something like that. 

-- 
CYa,
  Mario | Debian Developer <URL:http://debian.org/>
        | Get my public key via finger mlang_AT_db.debian.org
        | 1024D/7FC1A0854909BCCDBE6C102DDFFC022A6B113E44

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