Vista Codec Package software (version 7.1.0) is a collection of audio and video codecs that allow playing various media formats on Windows. It includes codecs for popular media formats such as AVI, MKV, MP4, FLV, and more. The software also includes a media player that supports playback of many file types and allows users to adjust settings such as subtitles and aspect ratio. Additionally, it includes tools for tweaking codec settings and configuring audio and video output.