videoread

VIDEOREAD Read an video file in a mannter compatible with Matlab's
          built-in AVIREAD function, but using a videoReader object to do
          the work instead. 

   MOV=VIDEOREAD(FNAME)
     Read the video file FNAME into the Matlab movie structure MOV.  MOV
     has two fields, "cdata" and "colormap".  Since all videoReader
     plugins currently output 24-bit images in all cases, colormap will
     always be blank.    

   MOV=VIDEOREAD(FNAME,VRARGS)
     The same as MOV=VIDEOREAD(FNAME), but VRARGS are passed to the 
     videoReader constructor.  VRARGS should be a cell array of arguments.
     E.g. 
         mov = videoread('tests/numbers.wmv3.avi', {'DirectShow'});

   MOV=VIDEOREAD(FNAME,INDEX)
     Reads only the frame(s) specified by INDEX.  INDEX can be a single
     index or an array of indices into the video stream, where the first
     frame is  number one.  IMPORTANT NOTES: If you use videoReader
     directly, it assumes  frames start at 0, not 1.  We use 1-indexing
     here in VIDEOREAD to maximize  compatibility with MathWork's AVIREAD.  
     Also, if you find yourself making several calls to VIDEOREAD to 
     extract different portions of the file and/or if the number of 
     frames is large, consider using videoReader directly instead of this 
     wrapper function.

   MOV=VIDEOREAD(FNAME,VRARGS,INDEX)
     The same as MOV=VIDEOREAD(FNAME,INDEX), but VRARGS are passed to the 
     videoReader constructor.  VRARGS should be a cell array of arguments.  

Copyright (c) 2006 Gerald Dalley
See "MIT.txt" in the installation directory for licensing details (especially 
when using this library on GNU/Linux).

0001 function mov=videoread(fname,varargin)
0002 %VIDEOREAD Read an video file in a mannter compatible with Matlab's
0003 %          built-in AVIREAD function, but using a videoReader object to do
0004 %          the work instead.
0005 %
0006 %   MOV=VIDEOREAD(FNAME)
0007 %     Read the video file FNAME into the Matlab movie structure MOV.  MOV
0008 %     has two fields, "cdata" and "colormap".  Since all videoReader
0009 %     plugins currently output 24-bit images in all cases, colormap will
0010 %     always be blank.
0011 %
0012 %   MOV=VIDEOREAD(FNAME,VRARGS)
0013 %     The same as MOV=VIDEOREAD(FNAME), but VRARGS are passed to the
0014 %     videoReader constructor.  VRARGS should be a cell array of arguments.
0015 %     E.g.
0016 %         mov = videoread('tests/numbers.wmv3.avi', {'DirectShow'});
0017 %
0018 %   MOV=VIDEOREAD(FNAME,INDEX)
0019 %     Reads only the frame(s) specified by INDEX.  INDEX can be a single
0020 %     index or an array of indices into the video stream, where the first
0021 %     frame is  number one.  IMPORTANT NOTES: If you use videoReader
0022 %     directly, it assumes  frames start at 0, not 1.  We use 1-indexing
0023 %     here in VIDEOREAD to maximize  compatibility with MathWork's AVIREAD.
0024 %     Also, if you find yourself making several calls to VIDEOREAD to
0025 %     extract different portions of the file and/or if the number of
0026 %     frames is large, consider using videoReader directly instead of this
0027 %     wrapper function.
0028 %
0029 %   MOV=VIDEOREAD(FNAME,VRARGS,INDEX)
0030 %     The same as MOV=VIDEOREAD(FNAME,INDEX), but VRARGS are passed to the
0031 %     videoReader constructor.  VRARGS should be a cell array of arguments.
0032 %
0033 %Copyright (c) 2006 Gerald Dalley
0034 %See "MIT.txt" in the installation directory for licensing details (especially
0035 %when using this library on GNU/Linux).
0036 
0037 if nargin==1,
0038   vrargs = {};
0039 elseif nargin==2,
0040   if (iscell(varargin{1})),
0041     vrargs = varargin{1};
0042   else
0043     vrargs = {};
0044     index  = varargin{1};
0045   end
0046 elseif nargin==3,
0047   vrargs = varargin{1};
0048   index  = varargin{2};
0049 end
0050 
0051 vr = videoReader(fname, vrargs{:});
0052 if ~(exist('index','var')),
0053   info = getinfo(vr);
0054   index = (0:info.numFrames-1); % 0-indexed
0055 else
0056   index = index - 1; % 0-indexed
0057 end
0058 
0059 mov = struct;
0060 currFrame = -1;
0061 if (size(index)>0)
0062   % index supplied or deduced from file
0063   for i=1:length(index)
0064     f = index(i);
0065     if (f == currFrame+1)
0066       if ~next(vr), error('Could not advance to frame %d\n', f+1); end
0067     else
0068       if ~seek(vr, f), error('Could not seek to frame %d\n', f+1); end
0069     end
0070     currFrame = f;
0071     mov(i).cdata = getframe(vr);
0072     mov(i).colormap = [];
0073   end
0074 else
0075   % no index was supplied and we could not deduce the number of frames
0076   % in the video.
0077   i=1;
0078   while next(vr)
0079     mov(i).cdata = getframe(vr);
0080     mov(i).colormap = [];
0081     i = i+1;
0082   end
0083 end
0084 
0085 vr = close(vr);
0086