The PeakValue attribute contains contains a 16-bit amplitude value designating the peak volume level of audio content. With AverageLevel, this attribute is used for normalization. Normalization is the process of adjusting the playback volume level of audio files so that the loudest parts of files playback at the same level and the average volume for each is the same..
This attribute is set by the writer object based on information from the codec. Only streams compressed with one of the Windows Media Audio codecs have an automatically set value.
PeakValue is not read-only. However, if the file will be played by the Windows Media Player, you should not alter this value. The Windows Media Player uses this for normalizing the levels of files in a playlist.