There's always a time you need to compress the large video file to the smaller size to save your device storage space. I know that some camera will record some 4k videos but 4k resolution video are too large to keep on a mobile phone or other devices. And there are so many 4K movies or HD movies. To save more high-definition videos, you can reduce them to a smaller size: 

http://www.videoconverterfactory.com/tips/reduce-video-size-file.html

https://www.cnet.com/how-to/save-storage-space-by-compressing-your-media-files-in-windows/

Video encoder and bit rate are essential for the video size, so you change the video size by adjusting them. The above review has listed four quick methods on how to deal with lossless compression.