Video Asylum

Posted by Tom Dawson (A) on July 30, 2002 at 13:36:13

In Reply to: Lossy compression - how much is really "lost"? posted by John C. - Aussie on July 25, 2002 at 18:57:37:

My experience is that AC3 is not even close in reproducing the original soundtrack to uncompressed analog or digital (based on mono movie soundtrack comparisons on LD vs DVD). Not close at all.

There's an immediately noticeable and consistent loss of high end ambient and transient energy (not sine wave response) with AC3 and modification of timbres throughout the audio band (worse at higher frequencies). The excerpt you quoted has huge, huge problems with veracity, claiming time and again as givens that what is discarded is 'inaudible' when, even under controlled test conditions with limited audio reference material, many subjects found the losses audible in some tests with such severe compression as AC3 has, and with the acoustical response variationsand much wider available range of material in typical playback at home, many of the sonic lacunae of AC3 are perceptually magnified in terms of lack of similitude.

That's what I hear with identical soundtracks compressed with AC3 on DVD vs uncompressed LD audio. End of story.