In order to play an MP4 file with Windows Media Player, a codec is required. One of the best codecs for Windows Media Player is the K-Lite Codec Pack. To download the K-Lite Codec Pack, navigate to the Codec Guide website and click "Download." Select a mirror from which to download the software. Once it has downloaded, install the software. Restart the computer and then play the MP4 file.
The K-Lite Codec Pack lets Windows Media Player play many file formats, including MKV, OGG and FLAC. The codec pack is available in different-sized packages: basic, standard, full and mega. Even the basic pack lets Windows Media Player open MP4 files. The larger packs contain more codecs and include a lightweight media player called Media Player Classic.
The different formats of video files represent different levels of compression. The codec lets the media player read files that are compressed heavily or in different ways. Different compression rates result in different video quality. For example, WMV is less compressed than MP4, and this results in better video quality. The MP4 format allows for large video files to be much smaller; therefore, it is a highly sought after and popular format of video. Many mobile phones record video in the MP4 format to cut down on file size.