Dolby Surround - Question

Cunhambebe wrote on 8/16/2004, 8:53 PM
As soon as you set your project, I know you can right click on the first audio track and choose FX Automation Evelopes and then at the end of the list, FX Automation to open a screen called FX Automation Chooser. Well, on the second guide there, or better yet, Plug-in, which is Track EQ, there's a list. If you choose Select All, 6 of them remain unchecked:
Left Enable;
Right Enable;
Center Enable;
Left Surround Enable;
Right Surround Enable;
LFE Enable.
That means, you have to check them manually.
Question: I've encoded my project (without checking those 6 mentioned above) as Dolby Surround 5.1 and my DVD player recognizes the audio as Dolby Surround, but I've noticed something. When I encode as AC-3, I open <Custom> and on the guide < Preprocessing> I try to ckeck some boxes which are 3dB attenuation and RF overmodulation protection, hitting OK at the end. As soon as I return to the main AC-3 Screen, if I try to get back to that same guide <Preprocessing> the box RF overmodulation protection is definitely unchecked. If I Check those 6 boxes described above, once you check RF overmodulation protection, it remans this way (checked). That makes me wonder if not checking those 6 boxes, will make Vegas render a real AC-3 Dolby Surround file.
Questions:
1. If I do not check those 6 boxes (described above), I'm gonna have a real AC-3 Dolby Surround File?
2.Will Vegas render a real AC-3 Dolby Surround File if only those aren't checked? If so, why my DVD player recognizes my audio as Dolby Surround?
...what a mess...
Can anyone help me out with this?
Thanks in advance.

Comments

Spot|DSE wrote on 8/16/2004, 9:09 PM
Yes, you'll have a real Dolby AC3, 5.1 file if you don't check those. Those are for auto control for the EQ, or rather, I assume that's what you're looking at. To my knowledge, that's the only automatable 5.1 plug in. Dither and Wavehammer don't support automation.
Your system is correct in detecting Dolby surround if that's how you encoded the file.
If you want to really figure out how this works, create a short video file that's maybe 3 mins in length, add 5.1 surround to it. Make sure you've got some dialog in the Center channel, some extreme low actions in the LFE channel like gunfire, helicopters, bombs. Now make several copies of this same project with slightly different names. They should all have the exact same mix.
Render them all out, using various parameters of the AC3 encoder. Burn all of these projects to one DVD, each with it's own menu button, each with the unique 5.1 file muxed with it, you probably want to label either the button, or put a text header on each video file so you know which one you're listening to. You'll VERY quickly hear what all the AC3 parameters do. And, it might help you fine tune your 5.1 mixing skills. This is the only way I know of to quickly learn how each parameter functions, and to get a fast grip on what you're doing with 5.1.
5.1 ain't no easy picnic, not to do it right.
Cunhambebe wrote on 8/16/2004, 9:17 PM
Thank you very much for your help, Spot....
you wrote....
Yes, you'll have a real Dolby AC3, 5.1 file if you don't check those.

Question: What If I just check those 6 boxes....without touching anything else. Will that mean a better AC-3 Dolby Surround file? I've also noticed if you check all those 6 boxes...audio volume will be slightly increased if compared to a file encoded without choosing those 6 boxes.

Thanks in advance, as always...
;)
Spot|DSE wrote on 8/16/2004, 9:32 PM
You're likely noticing the difference because you are routing each of the EQ channels to those buses.
No, you won't get a "better" encode, these check boxes have nothing to do with the quality or lack thereof of the encode. They are related to how the EQ is automated/routed. Play with it, you'll quickly hear it, if you are authoring with a 5.1 system.
Cunhambebe wrote on 8/16/2004, 10:08 PM
Ok, thanks again, but finally, what do you recommend me do? Check or uncheck'em all?
One more thing: you wrote...
Play with it, you'll quickly hear it, if you are authoring with a 5.1 system.
-Yes I do have a 5.1 system. Can you pls tell me HOW to play with that?????
;)
Spot|DSE wrote on 8/16/2004, 10:21 PM
Well...if you want automated EQ to feed different channels differently in your mix, by all means check em.' If you don't want to shift the EQ in the channel mixes, don't check em.'

Route your audio to the varioius locations via your sound card with your sound card preferably in either Classic or ASIO driver mode. Move audio around with the placement target or with a joystick, which ever turns your fancy, and listen to the audio fly around the room. Obviously, you'll need to have your project in 5.1 format.
Cunhambebe wrote on 8/16/2004, 10:32 PM
Thank you very much Spot. I'm sure a lot of people now know a little bit more about rendering a Surround project. Thanks, really.
Now I've just got to find out what ASIO driver mode means......lol....sorry for being a newbie.
;)
JUST IN TIME: I've just found it out....
Choose a driver type from the drop-down list. The Microsoft Sound Mapper is the default setting. If you want to activate specific sound cards, choose Windows Classic Wave Driver or ASIO and choose a device from the Default Stereo and Front playback device drop-down list.

Click the Advanced button to change settings for the selected device.


ASIO support is available only in the full version of Vegas software.