audio riddle

Maxter wrote on 12/4/2003, 7:36 PM
I want a portion of my movie to play and switch sound formats as it plays. This is to demonstrate recording studio footage where the video will have graphics that say "Live Sound"....then " Stereo Mix" ...then "5.1"

The live sound and stereo mix are easy. but since i cant bring an ac3 file to VV how will i get the "5.1" sound to suddenly happen.

will I have to leave that section in VV without audio and then slide the ac3 in my timeline in my DVD authoring program?

Comments

Spot|DSE wrote on 12/4/2003, 9:04 PM
You can't do this. No matter what. An MPEG or DV file cannot have multiple audio format streams in one file.
You could render the video as a stereo stream, then the section that is to be 5.1 becomes another. You could stitch these together in some DVD apps where it's a 'seamless' transition from one to the other, but that's it.
the correct way to do this is to have a 5.1 project, and nothing happening in the rear/center speaks, until you want it to be there. That's the only way to do this and have it be correct.
You could also use a DVD authoring tool that allows multiple audio streams, such as Encore, DVD Workshop 2.0, or DVD Studio Pro, and let the user select, but sounds like you are trying to do more/show more than just selectable streams.
A 5.1 project will sound in stereo, the same as a stereo project so long as you pan nothing to the rear or center, and don't create an LFE track.
Maxter wrote on 12/5/2003, 1:54 AM
So you are saying the easiest way in VV would be to make the project a 5.1 project- and just have stereo playing untill I get to the 5.1 part of the movie.

then if i add the surround and lfe channels at the 5.1 point and render the project as ac3- and just flash a 5.1 graphic at that one point- any 5.1 eqiped listeners will be able to hear the 5.1 of the ac3?
Spot|DSE wrote on 12/5/2003, 6:39 AM
Yes. That's the only effect, non-jarring or program interrupting method of doing this.
You'd want to render to AC3 anyway. Whether it was 5.1 or stereo. AC3 and 5.1 have little to do with each other. It's like MP3 vs wav.
vitalforces wrote on 12/5/2003, 12:45 PM
Ah yes, DVD Workshop 2.0 rears its pretty head...
Maxter wrote on 12/5/2003, 4:01 PM
Why do you say dont create an lfe track?
cant you create one and just use it or not use it like all other tracks?
Spot|DSE wrote on 12/5/2003, 6:20 PM
Read carefully:

A stereo mix in a 5.1 project will sound just like a standard stereo mix, as long as you don't pan anything to the rear, center, or create an LFE track.
You CAN create an LFE track, but it's not used for the stereo audio.
So:
When you want the video to be stereo only, there is nothing in the
Rear
Center
LFE

When you want it to be 5.1 then there is audio in
Front R/L
Rear R/L
Center
LFE
Be sure you know what you are doing with LFE regardless. This is where most folks screw up surround.
Maxter wrote on 12/5/2003, 6:39 PM
Since this is just a quick 5.1 demo would it be safe to send a low level kick signal to LFE in the 5.1 section? Any precautions?
Spot|DSE wrote on 12/5/2003, 9:26 PM
It's always SAFE to send an LFE channel. I'm interpreting that you want strong definition between the 5.1 areas and the 2 channel sections. Therefore, in the stereo sections, you don't have LFE, and in the 5.1 sections, you do.
The 5.1 project settings will auto-create an LFE track. You can't change that. But you can determine whether you want to send a kick drum, bass guitar, synth to the LFE channel or not. You need a separate, rendered channel to do this with if you want specific lows. Just running a kick to the LFE will probably sound strange, but it may not. I've never tried just a kick and nothing else.