Some video files which you record from analog sources like Analog TV, or other video sources may have horizontal lines which show up when you play them back on your TV.
The lines are very annoying since they make your video looks distorted, fuzzy, and less clear. However, they are very easy to filter out with Media Player software which support video playback, and supports deinterlacing to get rid of the horizontal lines during video playback.
Some video online also have annoying interlace lines, so you can download the video and playback on your local computer hard drive with a media player which supports deinterlacing video which will get rid of those annoying horizontal clear lines, and make your video look smooth, and sharp when playing them back on your PC.
The simplest way to hide the horizontal clear lines during Playback is to use GOM Player which is a very feature rich media player which is set to deinterlace your video when it detects your video files are interlaced with horizontal lines. I have been using GOM Player for a few years as my primary video player in Windows because it seems to play video better then Windows Media Player, and it is more feature rich then VLC player, and seems faster then SMPlayer in Windows. It is also very easy to use, and has a nice theme.
Check out GOM player at http://player.gomlab.com/eng/download/
If you use Linux, you need to download and install VLC media player, or SMplayer which has a deinterlace video feature. You can usually find VLC player in the Software Center like Ubuntu Software Center in Ubuntu. Just search for it, and you can find and install it.
VLC and SMplayer are also available for Windows, but in my experience GOM player works better in Windows then VLC and SMplayer for playing back video. You can find VLC and SMplayer at Download.com and other download sites like SourceForge.
To get rid of interlace clear horizontal lines in video, you just right mouse click the video with your mouse. Go to Video then Deinterlace sub-menu, and click on “ON”. You can also change the Deinterlace Mode in the Deinterlace Mode Menu to Discard, Blend, etc. You can also go into the preferences/settings of VLC’s Video to permanently turn Deinterlace on.
For stopping interlace for SMplayer, it is also similar to VLC Deinterlace. You right click the video, and go to the video menu where you can find the Deinterlace submenu where you can turn it on by picking lowpass and other options. If you want interlace to be permanently turned on you can go into the Preferences/settings’s video tab to permanently turn on Deinterlace by picking Lowpass, or the other available options..
If your TV tuner card came with a Media player, you can use the media player like WinTV to get rid of those annoying horizontal clear interlace lines, and also use WinTV to watch TV without seeing those interlace video lines since WinTV is optimized for watching analog and digital TV signals which may be interlaced with clear lines.
Some more advance video editors like Adobe Premier, Final Cut Pro, iMovie, etc may also have a deinterlace option to deinterlace your video to get rid of horizontal clear lines in the newly encoded video files.