How am I to open an avi file for motion tracking?

this is what happens when I enter it

>> avi = mmreader('samplevideo4.avi');
??? Initialization failed. (No combination of intermediate filters could be found to
make the connection.)

Error in ==> mmreader.mmreader>mmreader.init at 423
            obj.MMReaderImpl = audiovideo.mmreader(fullName);

Error in ==> mmreader.mmreader>mmreader.mmreader at 133
            obj.init(fileName);

as for aviread

>> avi = aviread('samplevideo4.avi');
Warning: AVIREAD will be removed in a future release. Use MMREADER instead. 
> In aviread at 29
??? Error using ==> aviread at 84
Unable to open file.

Answer 1

[Walter Roberson]

Use aviinfo() or mmfileinfo() or VideoReader.get() to examine the properties of the AVI file.

It could be that the AVI file uses a codec that you do not have installed. That happens especially for the Indeo5 codec, which is not installed by default in Windows 7, and it is not possible to get a version of the Indeo5 codec that works with a 64 bit version of MATLAB.