;+
; NAME:
;    IS_VIDEOSTREAM
;
; PURPOSE:
;    Check whether a variable is a video stream returned by
;    OPEN_VIDEOFILE.
;
; CATEGORY:
;    Image acquisition, Image analysis
;
; CALLING SEQUENCE:
;    ret = is_videostream(s)
;
; INPUTS:
;    s: variable to be checked.
;
; OUTPUTS:
;    ret: TRUE if s is a video stream.  FALSE otherwise.
;
; PROCEDURE:
;    Checks if s is a named VIDEOSTREAM structure.
;
; EXAMPLE:
;    IDL> s = open_videofile("myfile.avi")
;    IDL> print, is_videostream(s)
;
; MODIFICATION HISTORY:
; 01/25/2010: Written by David G. Grier, New York University
; 06/10/2010: DGG. Eliminated QUIET keyword.  Added COMPILE_OPT.
;
; Copyright (c) 2010 David G. Grier
;
; UPDATES:
;    The most recent version of this program may be obtained from
;    http://physics.nyu.edu/grierlab/software.html
; 
; LICENSE:
;    This program is free software; you can redistribute it and/or
;    modify it under the terms of the GNU General Public License as
;    published by the Free Software Foundation; either version 2 of the
;    License, or (at your option) any later version.
;
;    This program is distributed in the hope that it will be useful,
;    but WITHOUT ANY WARRANTY; without even the implied warranty of
;    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;    General Public License for more details.
;
;    You should have received a copy of the GNU General Public License
;    along with this program; if not, write to the Free Software
;    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
;    02111-1307 USA
;
;    If the Internet and WWW are still functional when you are using
;    this, you should be able to access the GPL here: 
;    http://www.gnu.org/copyleft/gpl.html
;-

function is_videostream, s, quiet=quiet

COMPILE_OPT IDL2

is_vs = strcmp(size(s, /sname), "videostream", /fold_case)

return, is_vs

end