AC-3 Normalization ?

[Spc01]

Hi,
I've downloaded full version of David Gilmour: Remember That Night and i want to convert AC-3 5.1 (448kbit/s 6ch) to 6 ch wave file for further audio processing.. and testing

But when i check ac-3 audio i noticed that when something loud happens audio volume drops for about 6dB and then slowly rises again to normal level.. why is this happening ?
Maybe because of program that decrypted DVD to disk normalized the high dynamic range AC-3 track ? or am i doing something wrong.
I am using iviaudio.ax and standard mpeg-2 splitter then wave dest and file writer..

Example:
http://www.youtube.com/watch?v=CsvCZFSzxFY

at 1:12 this happens.

Did anyone experience priblems like that ? because i've seen this alot lately.

[Spc01]

is it possible that iviaduio.ax lowers the high dynamic sound that exceeds certan dB levels ??

:confused:

[tebasuna51]

To decode an AC3 to test and processing, you must recover the original signal with the full dynamic range, then you need set off the Dynamic Range Compression and the Dialog Normalization.

The DirectShow filters have defaults (for listen) with these options activated and maybe with Dynamic Normalization also. I don't know iviaudio but ffdshow or Ac3Filter can be configured to obtain the original signal.

[Spc01]

Yeah just figured it out myself ... i can't use iviaudio.ax because it doesn't offer that setting.. so i used ac3filter.ax and it works like a charm.

:)