[vdr] Low volume on Pro7 ?

Prakash Punnoor prakashp at arcor.de
Sat Jun 11 12:21:26 CEST 2005

Rainer Zocholl schrieb:
> hm at seneca.muc.de(Harald Milz)  10.06.05 22:24
> Once upon a time "Harald Milz " shaped the electrons to say...
>>Dr. Werner Fink <werner at suse.de> wrote:
>>>Most AC3 channels do have a lower volume due to the fact that
>>>the dynanic range of AC3 is much more than 100dB. This is much
>>>more than you can do with Mpeg Audio and raw PCM at 16bit[1].
>>Hmmm - I'm missing the logic here. If the average level of an AC3
>>channel is below the other (PCM) channels, I turn the receiver up
>>anyway. The next explosion - well, you get the idea.
> The trick must be not to increase the volume of ac3 but to reduce
> the volume of other channels.

Nope, in fact the correct way to do it, would be if a *correct* value for
dialog normalization in the ac3 header would be sent and then the receiver
amplifies the whole track relative to this and the volume setting you chose so
that it matches "non-ac3" streams. Unfortunately no broadcaster really does
this. Otherwise eg commercial breaks in movies with 5.1 wouldn't be this
horrible load. So you have to complain to the broadcasting station to learn to
transmit correctly filled ac3 headers...

If dynamics are too much for you, simply enable DRC, which every receiver
should be able to handle. Then your ac3 5.1 sounds like every other compressed
source, if you select heavy DRC. (Yes, every standard 2ch downmix is heavily

I like to have dynamics. I agree that even 100db would probably enough for
giving that, but I don't mind that at least 5.1 ac3 does actually provide
dynamics in sound.

> 1. Marketing, bigger number looks better (see PPMO)

I guess you are refering to PMPO? ;-)

> We already had this disussion with "CD" and the "giant" 90dB
> they claimed to give.

IIRC, CD gives something like 114db with dithering...and 96db without.


Prakash Punnoor
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