AC-3 Preprocessing dynamic range compression question

[sdsumike619]

Ok, so I read that threat on Doom9 all about dolby digital sound. Now in the preprocessing tab under dynamic range compression, there is Line and RF mode profile. Can someone explain what the RF and Line is all about and the choices under each, i.e. None, Film: Standard, Film: Light, Music:Standard, Music:Light and Speech.

I'm producing guitar instructional DVDs and I noticed this setting, and of course the "Music" setting jumped out at me, but I'd like to know what these should be set to.

And, is there ANY way to avoid the sharp decrease in volume in the encoded AC-3. I read about using the RMS level to determine the dialog normalization level, but that doesn't do much to help the volume it seems....

MiKe

[sdsumike619]

oh yeah, not to mention all the choices under "bitstream mode" (main audio service, associated service, etc)

Here there is also a "music and effects setting" should I be using this? is there a guid anywhere that goes into detail about each individual setting?

[hrlslcbr]

If you have Dynamic Range Compression set to "none", the volume shouldn't be decreased, because the dynamic range of the audio file wouldn't be altered. Try encoding a short audio file with Dynamic Range Compression set to NONE to see if it works (NOT in the bitstream mode setting, that's another thing)

[sdsumike619]

you mean in the preprocessing section right? set line mode and rf mode to none? I think I tried that - what about the dialog normalization level, doesn't that effect it? I would think so with the word normalize in it?

mike

[hrlslcbr]

Yes, it's in preprocessing mode (at least in the encoder I'm using). But what you need to change is the "Compression Characteristic" (which is set to "film: standard" as the default mode in most encoders) to none. This way the Dynamic Range of the audio you are encoding will not be compressed.