;; This file:
;;   http://anggtwu.net/elisp/waveform.el.html
;;   http://anggtwu.net/elisp/waveform.el
;;          (find-angg "elisp/waveform.el")
;; Author: Eduardo Ochs <eduardoochs@gmail.com>
;;
;; (defun e () (interactive) (find-angg "elisp/waveform.el"))



(defun subed-waveform--ffmpeg-args (filename from to width height)
  "An internal function used by `subed-waveform--from-file'."
  (append
   (list "-accurate_seek"
         "-ss" (format "%s" from)
         "-to" (format "%s" to))
   (list "-i" filename)
   (list
    "-loglevel"
    "0"
    "-filter_complex"
    (format "volume=%s,showwavespic=s=%dx%d%s"
            subed-waveform-volume
            width height
            (cond
             ((functionp subed-waveform-ffmpeg-filter-args)
              (funcall subed-waveform-ffmpeg-filter-args width height))
             ((stringp subed-waveform-ffmpeg-filter-args)
              subed-waveform-ffmpeg-filter-args)
             (t "")))
    "-frames:v" "1"
    "-c:v" "png"
    "-f" "image2" "-")))

(defun subed-waveform--from-file (filename from to width height)
  "Returns a string representing the image data in PNG format.
FILENAME is the input file, FROM and TO are time positions, WIDTH
and HEIGHT are dimensions in pixels."
  (let* ((args (subed-waveform--ffmpeg-args filename from to width height)))
    (with-temp-buffer
      (apply 'call-process subed-waveform-ffmpeg-executable nil t nil args)
      (encode-coding-string (buffer-string) 'binary))))


;; (find-hvariable 'subed-waveform-svg-map)
;; (find-hvariable 'subed-waveform-minor-mode-map)




;; Local Variables:
;; coding:  utf-8-unix
;; End: