Go to FVC Free Online Video Converter, you can click the Add Files to Convert button to add the MP4 file into the program. Provide an easy interface to convert MP4 to MKV files within 3 steps. The conversion is straightforward without watermark, or other restriction. Tweak the video codec, frame rate, video format, as well as video format. Convert MP4 to MKV, AVI, FLV and more other media formats/presets. Moreover, it supports batch conversion that you can convert a bunch of videos or audio with ease. It also enables you to tweak the video and audio settings for the output. When you want to convert MP4 files to MKV online, FVC Free Online Video Converter is a versatile video converter to convert most of the video formats, such as MP4, MKV and more for free. Part 1: 3 Best Methods to Convert MP4 to MKV Top 1: How to Convert MP4 to MKV Online for Free Moreover, here is an ultimate method to add the subtitles and edit the video with ease you should know. You can learn more details about the 4 best methods from the article. It is not difficult to convert MP4 to MKV files. MKV is a Matroska video file that supports an unlimited number of audio, pictures and subtitle tracks. If you want to add subtitles to a MP4 video, you’d better convert MP4 to MKV instead. 4 Best Free MP4 to MKV Converters to Turn MP4 Files into MKV within Clicks