DVD played w/ Surround proc. - Mutes the VoiceOver

Don Sweger wrote on 2/28/2008, 1:33 PM
OK. I'm having a problem with a DVD project edited in Vegas7 and authored in DVDA4. Whenever I play the DVD, with any of the Dolby surround modes on my receiver enabled, the Voiceover is muted. The music sounds fine, it is as if the Voiceover track is muted, which should not be possible at this point. If I disable Dolby processing, everything is fine. The Voiceover is very clear and the music bed plays along just like it is supposed to. I have been able to re-create this on several different audio systems with different manufacturers etc. and the common failure mode is Dolby processing.

In the Vegas project I have a track of stereo music and several tracks of voiceover under the video tracks. The voiceover was recorded as two channels of mono voice, ( not stereo ) and laid into an audio track with two channels. I used multiple tracks because I applied some different effects (EQ, reverb, etc.) to various parts of the video and it was easier to apply the effects to a track rather than to each audio event.
I then rendered (or encoded depending on who you ask) to mpg2 using the NTSC DVD template with the audio included using the template settings in the audio tab.

Then in DVDA, I "prepared" the project using AC3Stereo (NOT 5.1) for the audio setting. Of course DVDA re-encoded the audio because it said the audio stream provided by Vegas was non-compliant.

I am at a loss. I have done dozens of projects this way and have never had this effect show up before. This project is a Promo video for a local non-profit and the way I found out about the problem is that the client called and said " Hey, I went to show the video to a group and there was no narration. The music played, but there was no voice." I said, "Impossible, it is all on one track."

I stumbled onto the Dolby processing issue by accident at home trying to find out what was wrong with the client DVD....... I hooked 7 different DVD players to my system and never got it to fail. Then by accident I changed sound modes on my receiver and bingo - music with no voice. I cycled through all of the "psuedo" modes and all the Dolby moeds failed. DTS and NEO all worked fine.

Any ideas what may be happening?

Any ideas how to prevent this?

P.S. The client is being very nice about this and I am working on another project for them, of which I did a quick render to test things and guess what, the voiceover is clearly audible in that project in all modes including the Dolby modes. ( all using the same templates and settings as the failing project............

Any and all help is greatly appreciated.
Don Sweger
High Driver Video Productions


Chienworks wrote on 2/28/2008, 3:06 PM
Wild guess, but maybe you accidentally inverted the phase on one of the mono voice tracks. The dolby processing might be combining those two channels together. If they're out of phase they would cancel.
newhope wrote on 2/29/2008, 5:23 AM
"The voiceover was recorded as two channels of mono voice, ( not stereo ) and laid into an audio track with two channels. I used multiple tracks because I applied some different effects (EQ, reverb, etc.) to various parts of the video and it was easier to apply the effects to a track rather than to each audio event."

This explanation is a little confusing. I understand that the VO is mono but am I correct in my interpretation that you put it on an audio track as dual channel mono, possibly across more than one track to allow for differing processing?

As it is mono in the first place you are better off dealing with it in that mode, no matter how many tracks it occupies in your session it's better off being mono wherever it exists in your tracklay.

To do this I'd try right clicking the track and selecting the Channel menu in the dropdown. Choose any one of the following:-

Combine will sum the two mono tracks... if they are out of phase they'll cancel each other.
Left will select the left channel of the two giving a mono track made up only of that one channel.
Right will select the right channel giving you a mono track of only the 'right' signal.

Having done this try rendering (encoding) your AC3 file again but before rendering enter the Dolby Digital set up by clicking on Custom and set the surround mode selection to NOT Surround. This will make sure that the Dolby Decoder in the DVD player does not try to output a surround signal from your mix.

My reasoning is that, it is possible that the re-encode in DVDA, which shouldn't be happening if the encode from Vegas was correct, DVDA is flagging the AC3 as surround encoded and the DVD player when trying to decode it is sending the mono component of your mix, in this case your VO, to a non-existent centre speaker. Hence you hear the stereo music but the VO is being sent nowhere.

New Hope Media

A final hint. I have had the odd track in Vegas display very weird behaviour that I could not explain or stop. On the couple of occasions this has happened, out of hundreds of edits, I created a new track and copied the contents of the old track to the new one. This fixed the problem and I then deleted the original.

In future try recording your VO as amono signal only it makes life simpler
Don Sweger wrote on 2/29/2008, 5:23 AM
OK. A little update.

First, I failed to mention that this project was a compilation of two veg files. The beginning sequence had 5 tracks moving in 3d space so I kept this more complicated segment as one project and then nested the rest of the project (from a seperate veg file) at the end. The Dolby sound problem was throughout the entire piece encompassing both veg files.

Last night I took the end piece which was the simpler of the two, and renamed the veg file, so I could experiment without messing up the original project. Then I started looking for "problems" like phase inversion, or whatever. So after poking around for 10 or 15 minutes looking at effects chains, media properties, etc. I could find nothing out of the ordinary. At this point I had not changed anything other the the name of the veg file. I decided to render just this project file again, using my same old templates and workflow, and verify that I could in fact duplicate the problem at will. I pulled the mpg2 file into DVDA and created a single file disc with no menus or other files. After preparing and burning, I popped it into my DVD player and much to my suprise the whole thing played perfectly in every sound processing mode. At this point the only difference between the working DVD and the "failing" DVD are: the names of the files, no disc menu, and a new fresh render/encode.

Now I have renamed the original total project into a new veg file and am rendering/encoding that onto another disc for testing to see if I can narrow this down. I'll post back when more information is available.
Don Sweger wrote on 2/29/2008, 11:50 AM
OK. I found the problem. Thanks guys for the suggestions, as indeed everyone was on the right track.

I said it was recorded in mono, well that was almost true......... I used a mono microphone, (an MXL desktop recording mic with XLR output) and using the supplied XLR to 1/8 mini-stereo adapter I recorded the Voiceover with my Olympus DS-40 digital recorder, using the HQ stereo mode. It never entered my mind that the XLR to Stereo adapter would give me two channels with INVERTED phase. I feel sooooooo stupid now looking back....

So, at least now I know what is going on, and how to fix it, and how to prevent it in the future..

Thanks again to everyone for your help and suggestions.

Don Sweger