In tests, I had to make a switch from MP4 to MKV format to get my test video to download in 4K. 4KVD snagged the 579.4MB file in about 43 seconds. It defaults back to 1080p HD, so I made the same switch when downloading an Ultra High Definition (8K) playlist. If you enable the Smart Mode and its pre-sets, 4K Video Downloader can then do one-click downloads to your favorite format. If you want to download more than 25 videos at a time or subscribe to YouTube channels to instantly download the latest, that requires the $15 paid version. Playback of the MKV file via VLC Media Player was flawless.