Open VLC and Click Media > Convert/Save.
Then click Add and select your video file (you can also select multiple files to convert them as a batch).
Click Convert/Save to bring up conversion options. In the Profile dropdown, you’ll need to select the type of conversion that you want.
Because VLC doesn’t display estimated file sizes, you’ll need to guess at which level of conversion to apply. Fortunately, VLC has recommendations for different types of videos.
For example, if you’re uploading to YouTube, you probably want to retain high quality. Just select Video for YouTube HD. Think people will be watching your video on a TV? Use Video for MPEG4 1080p TV/device. Want something smaller? Try Video for MPEG4 720p TV/device. Optimizing for Android, iPod, or iPhone will also get you smaller files.
To further reduce your video file size, you can change the resolution of the video. Click the Settings button (it looks like a wrench and a screwdriver) to the right of the Profile dropdown, then select the Resolution tab.
From there, you can adjust the scale to retain your current proportion, or manually adjust the size of the video.
When you’re done, click Save. You’ll need to enter a destination location and filename—click Browse to specify them.
Once you’ve done that, just hit Start.
If you’re compressing a large video, it might take some time. But when it’s done, you’ll have a new video file that should take up a lot less space