Audio out of sync with video after render.

kirkdickinson wrote on 10/13/2003, 10:03 PM
I just updated a video that I did last winter. I added a couple of scenes, some new narriation and created a new audio track.

When I rendered out to MPEG-2, and pulled it into DVA to replace the old version. Burnt a DVD and all the audio is slightly out of sync.

I figured that I messed something up on the timeline, that is what is usually my problem with out of sync sound, but it is all ok.

I loaded the MPEG-2 into Windows media player and it is messed up there. I pulled the rendered file into the project and it doesn't line up. The entire project has slipped slightly shorter and the rendered audio is slightly ahead of the rendered video.

I checked to see if I was rendering with the same settings as the project and I am.

I am rendering with:
MainConcept MPEG-2
DVD NTSC template
All default settings left in place

Any ideas what might be going on??

Thanks,

Kirk

Comments

Jessariah67 wrote on 10/13/2003, 10:21 PM
If it's out of sync wherever you play it, then it's out of sync. Not a sexy deduction, but probably the one that cuts to the chase.

Did you render "loop region only" and have a few frames at the beginning that weren't included?

If you changed the edit in any way, then it would seem to be a good idea to render the video as well as the audio - just to make sure it all lines up. If I change the settings of a plugin or volume envelope, I might choose to just re-render the audio, but if I move ANYTHING at all, I generally re-render both audio & video.
kirkdickinson wrote on 10/14/2003, 12:25 AM
I had both audio and video changes so I rendered them both together.

It is in sync on the timeline, but not in the rendered file.

It takes about 7 hours to render and I started another render before I left work tonight.

If that one is screwed too, I will load the entire project onto the firewire drive and bring it home and try it on my home computer.

The computer at work is a dual P-III 1GHZ with 512 Ram and mine at home is a dual Xeon 2.4 Ghz with 1 gig of Ram.

Should render more than twice as fast on the Xeon machine and if the audio is still out of sync, it will tell me that it isn't the computer.

I have always rendered the video and audio together. Is there any advantage to rendering them separately? If I did that, how are they brought back into sync when I bring the separate files into DVA?

Thanks,

Kirk
Jay Gladwell wrote on 10/14/2003, 7:25 AM
Kirk, when you render, in Vegas, the video as a mpeg2 file and the audio as an ac3 file they must have the same name, i.e., horserace.mpg and horserace.ac3. Both must be in the same folder.

When opened by DVDA, I don't know how it does it, the two files, being the exact length, are automatically synced.
craftech wrote on 10/14/2003, 7:32 AM
Mpeg 2 audio is not part of the NTSC DVD specifications. Render video only by choosing Main Concept MPEG 2 file (DVD NTSC template). Then render the audio as AC 3. If you give them the same name DVDA will find the audio when you load the video into DVDA.

John
kirkdickinson wrote on 10/14/2003, 10:23 AM
Last time I did this project, I don't remember how I rendered it. But I did render the video and audio together and there wasn't a problem. The only other big project I did was pre-DVA and I rendered to AVI and used another program to put the DVD menus together.

Will try it this way and see what happens.

Thanks,

Kirk
pconti wrote on 10/14/2003, 11:21 AM
Actually, you want to choose the DVD Arhitect NTSC Video Stream template from the Main Concept selection drop down. There is another one for DVD NTSC and you don't want that, unless you are using someone else's authoring software. Render the video stream. Then , render the audio stream as an ac3 with the exact same name (as suggested by another post). In DVDA the default setup is to look for a matching audio stream when you bring in the video stream. So, unless you changed the defaults, it will use the audio without you having to specify it. That should end your "synch" problems.

Enjoy.
craftech wrote on 10/14/2003, 7:55 PM
Actually, you want to choose the DVD Arhitect NTSC template.
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Actually 'pconti' is right. My post was in error. It is actually the DVDA NTSC template that I use without a problem.
Sorry about that.

John