Microsoft KB Archive/944732

= Audio may be much louder when you play an alternative audio source than when you play a DVD movie in Windows Vista =

Article ID: 944732

Article Last Modified on 11/9/2007

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APPLIES TO


 * Windows Vista Home Premium
 * Windows Vista Ultimate

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Symptoms of the problem
Consider the following scenario. You play a DVD movie by using Windows Media Center in Windows Vista or by using Windows Media Player 11. You eject or stop the DVD, and then you play audio from an alternative source, such as a music CD or a multimedia audio format. (WMA and MP3 are examples of multimedia audio format files.) In this scenario, the audio may be much louder when you play the alternative audio source than when you play the DVD movie.



Methods to resolve the problem
By modifying the audio output configuration for your Windows Vista-based computer, run some tests in Media Player 11 to determine the optimal volume level when you play a DVD movie. Repeat these tests when you play an alternative audio source, such as a music CD. Then, every time that you switch from playing a DVD movie to playing an audio CD, or vice versa, adjust your volume level to the optimal setting.



MORE INFORMATION
DVDs that use Dolby Digital or DTS audio are mastered by using a higher dynamic range than other audio formats. Therefore, if you play back both a DVD and an alternative audio source without changing the volume in Windows Vista, the alternative audio source's output may be louder to a varying degree.

Most consumer electronic hardware and most software playback applications that play both DVDs and CDs provide dynamic range compression for audio. If the volume level exceeds a certain threshold in an application that uses dynamic range compression, the volume level is reduced. Therefore, you do not notice much difference in audio volume when you switch between a DVD and an audio CD. Currently, Windows Vista does not support dynamic range compression for audio. Therefore, if you play audio from another source immediately after you play a DVD movie in Windows Vista and if you do not adjust the volume level, the alternative source audio may be much louder than the DVD audio.

The following multimedia file types are examples of common alternative audio sources:
 * WMA
 * WMV
 * MP3
 * AVI
 * MPEG
 * DVR-MS
 * QT

Keywords: kbtshoot kbprb kbceip KB944732

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