Note in the quoted line in your post I was using the standard NTSC mpeg A/V file (it has both the audio and video in a single mpeg file) not the separate streams. When loaded into DVDA this version of the mpeg file displays the correct audio level as a waveform graphic and plays back the audio correctly when I preview the DVD. It's when DVDA recompresses the audio stream when making the DVD itself that the level gets lowered quite a lot.

I did use the AC3 Pro encoder when I creating two streams from Vegas and, as you say, DVDA didn't need to recompress the audio stream. The audio loaded into DVDA at a very low level. It not only sounded low, but it was almost non-existent on the audio track waveform.

Maybe I'm not explaining this very well...

Jim

your problem started with your original mix.

Dolby has been told (in the custom settings of the Pro encoder) to expect an average level of -27dB (default) in your mix.

Dolby has very strict standards for the way a mix sounds.

It expects Dialogue to be at a certain level
and it expects explosions and gunshots to be at a much higher level

In the Pro AC3 encoder in the custom settings you will see a box that says Dialog normalization.

The number you see there is what you're telling Dolby at which level your dialog levels were mixed at.

It defaults to -27dB. This means that Dolby engineers have decided that the dialog of a movie should average about -27dB below 0dB. And by leaving the setting at -27dB you're telling the encoder that you have followed Dolby standards.

This means you have 27dB of headroom above the dialog for Explosions / Gunshots etc.....

If your mix is averaging closer to 0dB in normal dialog portions, because you have used a plugin like Wave Hammer, then the -27dB setting is lying to the Dolby encoder, so it ends up re-positioning your mix at a much lower level because it is anticipating +27dB of explosions / gunshots to be louder than your average dialog. But these loud gunshots / explosions never come and your whole mix has been lowered dramatically for no reason.

There are 2 ways to fix this.

The hard way... (pro)

Remix your project so that it follows what Dolby thinks it should be. (Average levels for the movie will be around -27dB) but it has peaks going up to 0dB

or the easy way... (trying to become pro)

Tell Dolby that you made an unconventional mix, and you expect it to follow your rules because you know better ;)

to do this, you will need to raise the level of -27dB for Dialog Normalization in the Dolby encoder settings to something like -5dB or something like that. It will take some experimenting to get the right value. Too high and your mix will be overly compressed. Too low and it will sound quiet.

Dolby is essentially trying to prevent mix engineers / producers / marketing types from making the movies as loud as possible for as long as possible. For example new Pop music CDs and commercials on television. Dolby is essentially anti Wave Hammer. They expect your mixes to be pleasant to listen to, with lots of dynamics.... not as loud as digitally possible.

If your mix is constantly as loud as digitally possible, the gunshots / explosions will completely disappear into your mix. You won't get a bang. You'll get a fizzle.

Hope this helps

Chris

Or if this is all too complicated, and you only have a stereo mix...

Just render out your audio as a *.wav file and change the properties in DVD architect to burn PCM audio.

PCM audio is uncompressed it is much higher quality than AC3.

AC3 is more like an MP3 file, it has been compressed so that within the same bandwidth of a PCM *wav file it can hold 6 channels of audio.

Using AC3 for a stereo file is close to pointless. The only benefit is that you will have slightly higher bandwidth available for the video portion.

gwailo,

Thanks for the information. No, it's not too complicated, but when I change the AC3 template to anything other than -27db, all I get is a null audio track in DVDA (zero db). I did discover that rendering to a 48KHz, 24bit, Stereo PCM works great without causing DVDA to recompress. All is now good ;-)

Thanks again!

Jim

Go to the Preprocessing Tab. Change Line Mode Profile and RF Mode Profile to None.
Change Dialog Normal to -31dB.

You should get out of the encoder the same levels that you put into it.

Bob.

farss -- that works perfectly! I get AC3 and I don't have to turn the volume up to ten on my clients monitor!

Thanks!

wow I thought I understood this dolby stuff :) I did some more reading.

sorry I had my dialog normal adjustment directions backwards. If you shift the dialog norm up to -5dB it will force your overall level down by 26dB. So this probably sent your levels to close to nothing.

the setting of -31dB in the dialog norm tells Dolby to leave the volume alone. So farss is correct in saying you should use -31dB to avoid any of Dolby's rigid mix enforcement.


In the pre-processing tab
with the Line Mode Profile and RF Mode do not affect your AC3 mix that goes into DVD Architect.

But it will make your mix sound differently depending on what hardware you're playing your DVD audio through. There are 2 scenarios.

1. if your set-top box is outputting 5.1surround and has a setting for "midnight listening" it will use lots of dynamic compression (RF mode) / If it is set to (line mode) it will have a lighter compression - that's why the encoder defaults to Film Standard for line mode and Speech for RF mode. It's telling your set-top box how to adjust your mix, so these features will still work. If you set them to none as Farss suggests the RF / Line settings on your playback device / decoder will do nothing.

2. If your set-top box is outputting a stereo line through RCA connectors. It may automatically put itself into Line mode with no option to change it. This option prevents the sound from distorting the consumer line inputs of your tv on the high peaks. If your set-top box is outputting through an RF cable to the tv it will default to RF mode which has lots of compression because the RF input on your tv has an even lower tolerance for peaks.

So if you set the Line mode and RF mode to none, it's possible that your mix will distort when it plays out to the TV.

But it also means that your mix will be dynamically adjusted according to Dolby's rules, which means you may not like the results if you're not following Dolby's specifications for mixing.

After all this....

If you're doing a stereo mix don't use AC3 it's lower quality than the PCM.

If you're doing 5.1 make sure you know what you're getting into.

Bob gave the right settings.
This may help:
http://www.sonycreativesoftware.com/forums/ShowMessage.asp?ForumID=22&MessageID=655195