Add hooks.

ffmpeg-player.el

@@ -80,7 +80,7 @@
   :group 'ffmpeg-player)
 
 (defcustom ffmpeg-player-mode-hook nil
-  "*Hook called by `ffmpeg-player-mode'."
+  "Hook called by `ffmpeg-player-mode'."
   :type 'hook
   :group 'ffmpeg-player)
 
@@ -89,6 +89,26 @@
   :type 'boolean
   :group 'ffmpeg-player)
 
+(defcustom ffmpeg-player-before-insert-image-hook nil
+  "Hook called before inserting image."
+  :type 'hook
+  :group 'ffmpeg-player)
+
+(defcustom ffmpeg-player-after-insert-image-hook nil
+  "Hook called after inserting image."
+  :type 'hook
+  :group 'ffmpeg-player)
+
+(defcustom ffmpeg-player-before-insert-string-hook nil
+  "Hook called before inserting string."
+  :type 'hook
+  :group 'ffmpeg-player)
+
+(defcustom ffmpeg-player-after-insert-string-hook nil
+  "Hook called after inserting string."
+  :type 'hook
+  :group 'ffmpeg-player)
+
 (defconst ffmpeg-player--command-video-to-images
   "ffmpeg -i \"%s\" %s \"%s%s%s.%s\""
   "Command that convert video to image source.")
@@ -442,15 +462,19 @@ Information about first frame timer please see variable `ffmpeg-player--first-fr
       (ffmpeg-player--clean-up)
     (with-current-buffer ffmpeg-player--buffer
       (erase-buffer)
-      (insert-image-file path))))
+      (run-hooks 'ffmpeg-player-before-insert-image-hook)
+      (insert-image-file path)
+      (run-hooks 'ffmpeg-player-after-insert-image-hook))))
 
 (defun ffmpeg-player--update-frame-by-string (str)
   "Update the frame by STR."
   (if (not (ffmpeg-player--buffer-alive-p))
       (ffmpeg-player--clean-up)
     (with-current-buffer ffmpeg-player--buffer
       (erase-buffer)
-      (insert str))))
+      (run-hooks 'ffmpeg-player-before-insert-string-hook)
+      (insert str)
+      (run-hooks 'ffmpeg-player-after-insert-string-hook))))
 
 (defun ffmpeg-player--update-frame-index ()
   "Calculate then update the frame index by time."