Video files purchased or rented from iTunes Store are usually in M4V format with DRM protection which can only be played on Apple players such as iPad, iPhone, iPod Touch etc. Due to Apple DRM protection, you can not play your purchased or rented videos on non-apple devices. That is to say, you don't have right to use them even you pay the fee.
And if you want to convert Apple DRM protected M4V to AVI, the professional third-party M4V Converter software which supports removing Apple DRM from M4V and converting M4V to AVI is required.
M4V Converter Plus is what you are looking for to convert DRM protected M4V to AVI. With M4V Converter Plus, you can remove DRM protection from iTunes videos easily and convert them to plain AVI at lossless quality.
The following tutorial is mainly tell you how to convert Apple DRM protected M4V to AVI on Windows.
1.Download, install and run the DRM protected M4V to AVI software on your computer.
2.Click Add Movies button on the top left corner to import DRM protected M4V files.
3.Choose Customized AVI Videos as output format.
4.Click Convert button to start convert DRM M4V to AVI.
More info you can find at
M4V Converter Plus for Win