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View Full Version : Dinamic range compression (DRC) in AC3


pentaX
7th February 2005, 00:37
Hi, anyone knows if there's any software that tells you the "line mode profile" and "RF mode profile" parameters (film standard, film light,...) from an .ac3 file (or from a muxed .vob), i.e. the type of DRC in which the .ac3 was encoded.

Thx in advance

violao
7th February 2005, 11:03
AFAIK azid gives you that information.

pentaX
7th February 2005, 12:15
i think you're wrong.
i didn't find any way for azid to show me that info.

violao
9th February 2005, 15:52
You're right. If I understand this matter correctly there are no explicit profiles indicated in AC3 stream. Those profiles represent guidelines for encoder implementations. Encoder should indicate a certain "gain" in DRC, which is then used by decoder to amplify audio blocks accordingly. If you just run azid without compression flag (-c) then it should ignore DRC and output original audio as it has been encoded (without compression).