John, not being the sharpest tool in the shed when it comes to audio, I need to ask... Why would he want to adjust the normalization to "minus 31"? That's awfully low, isn't it?

Jay

http://www.hometheaterhifi.com/volume_7_2/feature-article-dialog-normalization-6-2000.html

-31 is a magic number, it's the level at which no volume adjustment is applied by the decoder.

Thanks, Scott. Very informative article!

[Edit] Is this done in Vegas on somewhere in the home theatre equipment?

Jay

It's a setting on the audio tab when you do the AC3 render from Vegas.

Thanks, Scott!

Jay

Thanks Scott. I'll give that a try.

Tom,
Sorry I didn't explain further. I was in a rush that day. Let me explain further:
From Dolby Labs:
"To prevent these apparent loudness differences from becoming bothersome when switching between programs—thus causing the listener to readjust the volume control—Dolby Digital has incorporated a "dialog normalization" feature to allow the producers to set the appropriate reproduction level to a known average level reference. This feature is implemented in Dolby Digital encoders and consumer decoders."


Since the quietest sounds amidst the grenade launchers and Jurrasic growls are the movie dialog, Dolby Labs have set the encoding standards to a dialog normalization level of -31db. The Dolby Digital encoder sends a control word called a dialnorm to the decoder to adjust playback level. It acts like an automatic volume control but only through attenuation (lowering). For full volume with no attenuation the dialog normalization value is -31db (in other words an "average" of -31db) which the dialnorm in the encoder leaves alone when it encodes AC-3. This allows the other levels in the program to be adjusted appropriately relative to the dialog, but striclty through attenuation. Thus the default setting of -27db is already telling the encoder that the average dialog is 4db higher than the -31db reference and as a result the dialnorm will reduce the levels across the board by 4 db. Set it to -20db and it will reduce it by 11db. That's why lowering the number will do the reverse of what one would think would happen at first glance.
So If you want to raise the overall volume of the encode set dialog norm to -31db.
You should also set the line mode profile under dynamic range control to none so that the dynamic range isn't compressed especially if there is music.

John

Also, setting the Film Mode to none, and same with the LMP, you'll remove some of the decoder's control over your sound as well.

Great. Thanks for your help, all. I can check this off my list of all that is going wrong with my project - many parents of 3 year olds waiting to see their little ones.

Thomas

If one is not worried about size would it be advisable to just use .wav with say 3/1 compression?
TIA,
Randy

Doug,
Was any of this covered in the V5 book?

I guess I never looked at the AC3 templates...at what point with data rates selection is there a diminished return...or should you select 640kbps if you have the available space on the DVD?

If you set your bitrate too high, some systems may not be able to accomodate the decode.
Some of this is covered in the Vegas book, it was one of the places we choose to cut due to page count. It's covered in some of the extra media, and on the VASST site. The publisher kept a lock on page count due to shipping weight issues.

It would be nice to have checklists that I can look at before I complete steps in the process that is Vegas/DVD. Like "Did you do this?"; "Did you do that?".

This would be a time saver.

g randybrown:

If capacity is not a concern, then sure, you can use wav audio on a DVD. Keep in mind that the maximum bitrate is 9.8, and since wav is about 1.5, your video bitrate will have to be under 8.3. As already mentioned, it would help to be even lower than 8.3, since running right at the legal limit can tax some DVD players.

I'm not sure what you mean by wav with 3:1 compression. Wav is wav, or else you can do a bitrate compression with something like AC-3, but then it's not wav anymore. If you're refering to "audio compression" then that's an entirely different matter--it means that the average audio level can be increased because the peaks are gently rounded off: the audio sounds "louder", in the same way that AM radio sounds louder than FM. This sort of compression has nothing to do with the bitrate.

Mark Foley:
You can use any bitrate for Dolby encoding you want. In theory, 2/0 audio (stereo) would sound better at a bitrate higher than the default 192Kb/sec, but I can't hear any difference. You might be able to.

Why is the default not set at -31? I took your advice - worked perfectly. So nice to have something corrected without having to jump through hoops. Thanks.