Ram Render mayhem

TeeJay wrote on 8/31/2005, 4:53 AM
I'm currently working on a training video for a retail chain and when I did my location shoot, I simultaneously captured sound to my Laptop and External Drive.

Now, my problem is that when I am syncing the audio to the video stream, I am having an aweful time trying to marry it up together.
When I get a piece close, I Pre Render (Shift B) to ensure that is is locked tight, only to find that it is very out of sync in my final render.
I never had this problem in Version 5.

I use a MOTU 828MK2 soundcard with the latest drivers in a P4, 3.2 Ghz system with a RAID striping config with 2Gig of DDR Ram, although i certainly don't think that there is a problem with my system.
It definately seems to be a Version 6 thing to me.
Anyone have any thoughts on this?

Cheers,

TJ

Comments

Grazie wrote on 8/31/2005, 6:56 AM
TJ? If you still have V5, try a short piece to confirm.

"When I get a piece close, I Pre Render (Shift B) to ensure that is is locked tight, only to find that it is very out of sync in my final render."

What you are seeing as "in-synched" maybe your observation of it being synced BUT delayed through f/w, and you go on synch and synch away an UN synched event. . . . How are you previewing the "synch"? External monitor? But this shouldn't matter as Vegas will or SHOULD synch back up. What method do you use to synch? Visual clues? Clpper board?

Interesting ..

Grazie
TeeJay wrote on 8/31/2005, 8:17 AM
This particular project is predominately a presenter in fairly tight shots so i am syncing my audio to the mouth movement. I tried an experiment tonight by nudging the audio event in time without pre rendering to view the result. I rendered out to MPEG and it was very very close, in fact quite liveable.

I guess that I am just perplexed as to why the pre render is so out of whack, when it should give me a reasonably true representation of the final render........
FrigidNDEditing wrote on 8/31/2005, 8:23 AM
What are you previewing on?

Ext. monitor via firewire? On screen? BMD? Secondary monitor?

little help here would help here.

Dave
TeeJay wrote on 8/31/2005, 8:48 AM
I am monitoring to an external Sony 51cm CRT TV, via Canopus ADVC 100 (firewire).
FrigidNDEditing wrote on 8/31/2005, 10:01 AM
That's your problem - probably.

To sync - just try using your internal preview and then if you still have problems let us know.

Not sure why exactly you would have problems but it does things differently sometimes because it delays video and audio sebarately via output over firewire.

Give it a shot syncing on you computer monitor and then see how it goes

(you may have you audio sync messed up too, this could also cause a problem as to why it would be messed up looking when you render, but not when you preview)

Both potential problems - the audio delay is changed in your tools -> options (you may know this already but it never hurts to say it again).

Dave
JackW wrote on 8/31/2005, 11:45 AM
If I understand the problem correctly, I believe the "sync audio to its video" utility in Excalibur 2.0 will do this for you very nicely. I've been using it successfully for the past several days.

The script corrects any situation in which the video (or audio) has been slid along the timeline without reference to the accompanying audio (or video).

Jack
Grazie wrote on 8/31/2005, 12:29 PM
Hold on! This was 2 bits of media: Video + Audio .. neither of them sycnch to start with? How could Excalibur synch something that wasn't synced to start with?

Grazie

Liam_Vegas wrote on 8/31/2005, 12:43 PM
Can I ask a silly question? You say you are syncing on "lip movements".... but don't you have the audio that was captured from the camera anyway?

The way I normally do these types of syncs is to at least temporarily enable the audio that came with the video. Then I monitor both audio tracks simultaneously and when you get it close you can hear very clearly one or the other tracks is leading/lagging the other (you get a sort of "echo"). With further small adjustments the "echo" disappears then you pretty much know the audio is synched... and at that point you can disable the track you no longer need.

At least doing it this way will remove any issues of video / preview delay.
Grazie wrote on 8/31/2005, 2:15 PM
I'm with you Liam .. but I think the Audio was captured separate .. read the whole post. AND yes capture film AND capture audio. Not a silly Q!

Grazie . .. I'm off to bed . . nite!
Liam_Vegas wrote on 8/31/2005, 3:10 PM
but I think the Audio was captured separate

Yeah... I got that... buit nowhere did TJ say he did not capture audio also with his video. (I'm assuming of course that he is not working Film - as he would have said something to that effect I would think). If he was using a Video camera... then I can't imagine a reason why the audio for that would not have also been captured.

In situations where I have done this... that is the way I do it. Run audio on everything - as that makes the syncing much easier.

It's a good backup... as you never know when or if something might happen with your master audio - and at least then you have options of using the "backup" audio from the camera.
JackW wrote on 8/31/2005, 3:31 PM
Right on, Grazie: Excalibur won't sync if the the audio and video are not associated in the same clip. However, it is difficult to understand from the original posting exactly what the relationship of audio and video.

Jack

TeeJay wrote on 8/31/2005, 3:50 PM
Yes, I did capture audio on the camera and inititially set my audio sync to the primary audio stream, then once set, removed that stream from the timeline to clear up a little clutter. In hindsight, I should have moved the track down to the bottom out of the way instead.

However, that's not really the point of the original post. It is easy enough for me to get it back and sync to the original audio stream.

What I am trying to determine, is why my Pre Render (Shift B) doesn't give me a true representation of the final render.
I will redo it whilst monitoring from the comp screen and see how it turns out.

Cheers for all of your replies,

T
Liam_Vegas wrote on 8/31/2005, 4:26 PM
I should have moved the track down to the bottom out of the way instead.

Yep.... that would have helped.

What I am trying to determine, is why my Pre Render (Shift B) doesn't give me a true representation of the final render.

That certainly needs to be figured out - however I think currently you don't have a way to truly verify if your audio is now <really> out of sync or not. If you had the original audio in the Veg then it would be very simple to do that test.

There is a "restore orphan audio" feature in Excalibur .. and that will bring back the original audio for a video event.
TeeJay wrote on 9/4/2005, 11:42 PM
Just a quick update,

I still haven't been able to ascertain the Pre Render Latency issue, but I wound up using the Create SubClip function to bring the original back with sound and have successfully synced all of my audio.

Thanks to all of you for taking the time to respond to my initial post.

T
Grazie wrote on 9/5/2005, 2:29 AM
Ok, so, in terms of synch-ing, what is SUB-clip doing that RAM Preview doesn't? Now that I'd really like to know. - G
TeeJay wrote on 9/5/2005, 4:21 AM
Well, by bringing the original clip back that has the DV tape audio already synced, I simply marry both audio streams together.

So, to do this, i simply double click the event first, then right click>create subclip. Then, drag the subclip from the project media window to a track below the event that is already on the looped timeline. I have programmed a left and right "event nudge" button on my Shuttle Pro2 so I first highlight the audio that i want to sync up and start nudging it until there is no phasing.