Part 2. How to Convert M4V to MP4 Online Without Spending a Dime
Besides the downloaded program we introduced above, there are many free online converters such as FileZigZag, Zamzar, etc. You don't need to download or install the tools. Just make sure you have Internet connection, and you can go to the websites and be able to use them on the browser. The downside is that the converting and uploading speed is slow.
Take the FileZigZag as an example. It is a free M4V to MP4 converter, but it can only convert one file at a time and you are limited to convert only one file over 180MB(up to 2GB) one day for free. Now let's go to the FileZigZag website and start to convert a video with it.

Step 1. Drag & drop your M4V movie file to the importing area or click 'Select' to browse a file from your computer. It may take a few minutes to upload.
Step 2. Click the 'Convert to' droplist and select the output format as 'MP4'.
Step 3. On the 'Email address' box, please input your email address. Make sure to input your right email.
Step 4. Click 'Convert' button to start converting. The converting time is a little long, so please wait patiently. When it is done, you will get the video download link by email.