YouTube Decreases Audio Quality

Posted Jul 27, 2008

Google Inc. (NASDAQ:GOOG) subsidiary, YouTube  is tampering with the audio quality of newly upload videos.  This was pointed out by guitar player and YouTube user, ccalam.  The changes began to reflect this past June. 

“The main problem is too much compression and peak level is set to exceed max value of 0db in their current settings probably by an error by inexperienced engineer in audio field, in turn it results clipping sound in loud passages and produces unacceptable breathing sound/noise in quiet passages which I checked the wave forms on encoded audio track by [YouTube],” stated Sopranoguitar.

After conducting several tests, Sopranoguitar discovered that if audio is kept under -3 decibels, YouTube avoids loud passages from being clipped.  Another idea “is to turn down the audio and mix in a high frequency sine wave (I used 19kHz). The sine wave fools YouTube’s compressor into thinking that the file is at a uniform level (and does not need the volume changing at all) but is filtered out by the encoding process (so, no need to worry about deafening any dogs),” wrote ccalam on SlashDot.

YouTube’s bandwidth is estimated to cost about $1 million per day.  In January 2008, YouTube’s 79 million users viewed over 3 billion videos.  Decreasing audio quality on YouTube videos save costs.

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