Working with digital video files provides convenience over discs and other storage media. For one thing, the length of a digital video file is not limited by the capacity of a CD or DVD disc. A long movie that was split into multiple parts for storage on two or more discs, can be reassembled into a single, complete movie on your hard drive. A number of programs are available for this purpose, but the free QuickTime player from Apple is one of the easiest and cheapest options. This process will work for a number of file formats, including .M4V files.
Open the QuickTime player by clicking "Start", "Programs" and "QuickTime Player", or by clicking the "QuickTime" icon on your desktop.
Click the "Computer" link on the desktop to view your files, and navigate to the folder where your .M4V files are located.
Click on the first video file and hold the mouse button as you drag it into the QuickTime window, then release the mouse button. The beginning of the video file should appear in the viewer.
Click and hold the "Scrub" icon, which looks like a small triangle. Drag the "Scrub" icon all the way to the right edge of the timeline. This marks the location where you would like the next file to be inserted.
Click on the next video and hold the mouse button as you drag it onto the QuickTime window. This will insert the second video directly after the first. Repeat steps 4 and 5 for any other videos you would like to add to the merged file.
Click "File" in the title bar and choose "Save As..." once all files have been added to the timeline. Choose a location for your saved file and rename the file if necessary. Also make sure the option for "Save as a self-contained movie" is checked.
Click the "Save" button at the bottom right of the window. The program will now take some time to process the video file. When it is complete, you will have a merged copy of your video files.
Video files can be very large. If you are running out of hard drive space, you may need to move or delete some files before starting the merge process.