mpgread.doc

Motion detection in matlab

MPGREAD

Purpose

	Translate a movie file in MPEG format into a Matlab movie matrix.

Synopsis

	[movie, map] = mpgread('filename', frames)
		Matrix movie;
		Matrix map;
		String filename;
		Vector frames;

	[R, G, B] = mpgread('filename', frames);
		Matrix R;
		Matrix G;
		Matrix B;
		String filename;
		Vector frames;

Arguments

	movie 		a matrix containing a Matlab movie.
	map 		(optional) matrix containing a Matlab colormap.
	'filename' 	string containing the name of the MPEG
				file to be translated.
	frames 		(optional) a vector of frame numbers.
	R		a matrix containing the red image component.
	G		a matrix containing the green image component.
	B		a matrix containing the blue image component.

Description

	The mpgread routine translates a movie file from the International
	Standards Organization MPEG format into the Matlab movie format
	and places the results into the matrices "movie" and "map".  
	Alternatively, the output may be requested in RGB format.  The
	matrix movie contains the Matlab movie and map is filled with a
	corresponding Matlab colormap.  For example, the first 20 frames of an
	MPEG movie can be shown with following sequence of commands:

	[movie, map] = mpgread('movie.mpg', [1:20]);
	figure;
	colormap(map);
	movie(movie);

	The frames vector can contain frame numbers in any order and 
	frames numbers may be repeated.  For example, the following
	command will create a movie which plays the first 20 frames
	forward and then in reverse:

	movie = mpgread('movie.mpg', [1:20,20:-1:1]);

	If frame numbers are requested which exceed the total number of
	frames in the MPEG movie an error message will be printed with the
	number of MPEG frames in parentheses.  For example:

	??? Frame(s) requested beyond last frame (25).

	indicates that the MPEG movie actually has only 25 frames, but
	frame numbers greater than 25 had been requested.
	
	If the frames vector is ommitted, all frames in the MPEG file
	will be translated and returned in movie.

See Also

	mpgwrite


Copyright (c) 1994 The MathWorks Inc.