Plugin for seqIo and videoIO to allow reading of seq files.

 Do not call directly, use as plugin for seqIo or videoIO instead.
 The following is a list of commands available (srp=seqReaderPlugin):
  h = srp('open',h,fName)    % Open a seq file for reading (h ignored).
  h = srp('close',h);        % Close seq file (output h is -1).
  [I,ts] =srp('getframe',h)  % Get current frame (returns [] if invalid).
  [I,ts] =srp('getframeb',h) % Get current frame with no decoding.
  ts = srp('getts',h)        % Return timestamps for all frames.
  info = srp('getinfo',h)    % Return struct with info about video.
  [I,ts] =srp('getnext',h)   % Shortcut for 'next' followed by 'getframe'.
  out = srp('next',h)        % Go to next frame (out=0 on fail).
  out = srp('seek',h,frame)  % Go to specified frame (out=0 on fail).
  out = srp('step',h,delta)  % Go to current frame+delta (out=0 on fail).

 USAGE
  varargout = seqReaderPlugin( cmd, h, varargin )

 INPUTS
  cmd        - string indicating operation to perform
  h          - unique identifier for open seq file
  varargin   - additional options (vary according to cmd)

 OUTPUTS
  varargout  - output (varies according to cmd)

 EXAMPLE

 See also SEQIO, SEQWRITERPLUGIN

 Piotr's Computer Vision Matlab Toolbox      Version 3.10
 Copyright 2014 Piotr Dollar.  [pdollar-at-gmail.com]
 Licensed under the Simplified BSD License [see external/bsd.txt]