There isn't a way to determine with absolute certainty the codec used to compress a file, but the following are your best options: This lets you return to your original system configuration, if necessary. Before installing any digital media components, set up a system restore point. Even then, use caution: some codec providers offer minimal customer support. Install codecs, filters, and plug-ins only from trusted sources, such as the provider's official website. Therefore, we strongly discourage you from installing these codec packs and recommend that you remove them if you have installed them and are having problems with the Player. Use caution when installing codecs that you find on the internet, particularly some of the free codec packs that claim to include codecs from a wide variety of companies or organizations. There are known compatibility issues with some of the components in these codec packs, and these can trigger serious playback problems in Windows Media Player and other players, cause system corruption, and make it difficult for Microsoft Support to diagnose and troubleshoot playback issues.

Media player classic codec