P  Windows Media Player 6.4

Decoder Source: Microsoft http://www.microsoft.com/
Version: © 1992-1999 Microsoft Corp.
Price: free
Settings: none
Similar products: this version built into some releases of Windows (98 and 2000).
Verdict: Very Good
VBR: All
Full file: Always
Major Flaws: none
Minor Flaws: 128kbps files have slight 16kHz+ error on one channel, output level.
Output level: slightly too low on left channel
1-bit relative accuracy: Fair
1-bit absolute accuracy: Fair

Windows Media player 6.4 from Microsoft is the default player for mp3s in Windows 98 and 2000. It is sometimes packaged with Internet Explorer 5 too. It will play lots of audio and video files, and is expandable by adding new codecs. WMP 6.4 does not decode mp3 files, only play them. The output was captured via Total Recorder for analysis. This program intercepts the bitstream on the way to the sound card and diverts it to a wavefile.

WMP 6.4 seems to use the same decoder as Audio Active, and yields the same subtle high frequency errors on the left channel only. Unlike audio active, it copes well with all VBR files (though it displays the incorrect time).

There are settings for volume and balance within Windows Media Player. Some players link these to the analogue controls on your sound card, but WMP changes the actual digital data it sends to the sound card, via DirectSound. Unfortunately there isn't a centre position on the balance control! The position that looks like centre, actually pushes the audio slightly right (by lowering the level of left channel). If you move it one notch to the left to compensate, the it just lowers the right channel instead. There is no middle! Also, the maximum volume on the volume control isn't quite maximum. These issues affect the low level accuracy of the player somewhat, as shown by the results of the Least Significant bit test.

Windows Media Player has been superseded (see WMP 7). The DirectSound level issues remain, but the slight high frequency errors have been fixed in the newer version. If you require bit-perfect playback of mp3 files, then you must look elsewhere. However, as Windows Media Player 6.4 has no serious problems, and will be pre-installed on many systems, most users may continue using it to listen to mp3 files without concern.


  1. The previous review of Windows Media Player 6.4 on this site was incorrect. An Xing DVD application's mp3 audio decoder had replaced the default WMP 6.4 mp3 decoder on my system, and gave the poor results published previously. Thanks to Reinhardt Mueller for spotting this.
  2. Windows Media Player 6.4 is the last Microsoft Media Player compatible with Windows 95. The version tested here was actually released in early 2000, despite the copyright date.


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