M4V

The M4V file format is a video container format developed by Apple and is very similar to the MP4 format. The primary difference is that M4V files may optionally be protected by DRM copy protection.Apple uses M4V to encode video files in its iTunes Store. Unauthorized reproduction of M4V files may be prevented using Apple's FairPlay copy protection. A FairPlay-protected M4V file can only be played on a computer authorized (using iTunes) with the account that was used to purchase the video.

- - Wikimedia

AVI

Audio Video Interleave , known by its initials AVI, is a multimedia container format introduced by Microsoft in November 1992 as part of its Video for Windows software. AVI files can contain both audio and video data in a file container that allows synchronous audio-with-video playback. Like the DVD video format, AVI files support multiple streaming audio and video, although these features are seldom used. Most AVI files also use the file format extensions developed by the Matrox OpenDML group in February 1996.

- - Wikimedia

Step-By-Step to Convert M4V to AVI

Interface

Step 1. Download and install the program, then double click it to run it, and then you'll see the main interface of the program.

Load Files

Step 2. Click "Add File(s)" button. Here you can select "Add Video" or "Add Folder" button to add files as you like.

Profile

Step 3. Click the drop-down arrow right beside the "Profile" column and select your desired video format from the drop-down list.

Edit

Step 4. Click "Edit" button to customize the output video like Effect, Trim, Crop, 3D Settings and Watermark.

More Reading