mp3HD is a format for lossless compression of audio signals. mp3HD is compatible to the ubiquitous MP3 format. Therefore mp3HD is both a lossless format and a standard MP3 file. By default, the mp3HD Winamp Decoder plug-in decodes mp3HD files in highest quality. You may configure the plug-in to play mp3 quality instead of mp3HD quality by default. In addition, you can activate in the settings dialog to display a window in which you can switch between mp3 quality and mp3HD quality in real time while decoding an mp3HD file. Sample tracks are available at http://www.all4mp3.com/Listen_mp3HD.aspx. We recommend to use Winamp version 5.5 or above.
This input plugin will allow you to get the most out of new mp3HD format. There is a link for where to get some sample files in the author's comment.