If you want to upload your MKV files to the YouTube to share them with your friends or your family, but the website does not support the MKV format video, now what you have to do is to convert MKV to WebM, good news, here the article provide a powerful MKV to WebM Converter - AVS Video Converter, with which you can convert MKV to WebM with super fast speed. What's more, the Video Converter can keep the original quality of your MKV format files.
Tips about WebM
YouTube now offers WebM videos as part of its HTML5 player experiment. All uploaded files with resolutions from 720p and above are encoded to WebM in 480p and 720p, and other resolutions will follow. YouTube has committed to encode their entire portfolio of videos to WebM. Android is also officially planned to be WebM-enabled.
Tips: If your computer is running the Mac OS now, please have a try Mac Video Converter!
Preparation: Click the above "Browse..." button to download the MKV to WebM Converter, follow the "Next >" wizard to install it, and then launch it.
Step 1: Add MKV files as the input
Click the "Browse..." circled to import MKV files into the software.

Step 2: Output format setting
Press the "To WebM" button to choose the WebM format as the output format.

Step 3: Set the root directory
Click the other "Browse..." button to specify a destination folder for the converted files.
Step 4: Convert MKV to WebM
At last, click the "Convert Now!" button to start the MKV to WebM Conversion.
Not only can convert MKV to WebM, the unmatchable MKV to WebM can also convert MKV to FLV, convert MKV to GIF, and to almost other video formats, it also can convert WebM to AVI, MP4, etc. Have interest in it, just download it and have a try!