Audio Sync Problems

RangerMax wrote on 3/18/2005, 11:55 AM
Hello all,
I use an ati all in wonder to capture the latest battlestar galactica on the scifi channel. I capture it in a mpeg-2 720x480 48khz 16bit.
Every time I open up any of the files (I have several ep.) the audio will go out of sync with the video about 10 minutes in. This happens when previewing and also on rendered files. The master files play fine in windows media player, real player, and the ati player. Not so in vegas.
Any help will ba appreciated
RangerMax

Comments

RangerMax wrote on 3/20/2005, 9:45 AM
Hmmmm
Any suggestions?
RangerMax wrote on 3/21/2005, 7:58 AM
Ok
I have tried options/prefs and selected thid party codex and microsoft codex----no joy
Here are the settings
mpeg2 dvd ntsc 720x480
de-interlacing option - encode interlaced
48khz 16 bit
p frames 4
b frames 2
Video Encoding parameters
variable bit rate
max bit rat - 8.0 target bit rate - 6.0
motion estimation - 84
audio - 224kb/s
videosoap - light
There are several other formats you can select of tailor yourself.
So which ATI all in wonder recording settings work best in Vegas>?
RangerMax wrote on 3/29/2005, 9:40 AM
Seems when I de-interlace the audio it works ok.
Is there a way to de-interlace the footage I already have that was encoded interlaced?
Throw the newbie a bone here!
Rednroll wrote on 3/29/2005, 11:39 AM
Have you tried posting your message in the Vegas Video forum? They'll probably be able to assist you a little more over there, since a lot of users have more experience with this type of thing. You'll probably get criticized for using an "all-in-wonder" card, because they're known to have problems from what I've gotten over there.

I'ld be interested in hearing if there is a solution. I've downloaded Mpeg Videos off the net, trying to get more into the video editing aspects of Vegas, and have opened them in Vegas, and notice the audio is not in sync for some reason also, but then I open them in WMP or Nero and it seems fine.
PipelineAudio wrote on 3/29/2005, 5:50 PM
I was goi9ng to ask those same things red! WMP plays stuff fine, and vegas plays all out of sync
Rednroll wrote on 3/30/2005, 1:39 AM
Yeah, I opened a Mpeg I downloaded, and I mean it was really out of sync when I played it back in Vegas. I think it was like a 10 minute video and the audio was like 2 minutes behind the video. So I burned a VCD, thinking maybe it was my system that couldn't keep up or something. The VCD again was still like 2 minutes out of sync. So I then opened the same Mpeg in WMP and played it, and everything was ok. I then opened it in Nero and played it, and again it was ok. I then burned a VCD from Nero, and this time I got a VCD that the audio was actually in sync with the video. Maybe it was something I was doing wrong in Vegas? Maybe there's a preference I forgot to check or something like, "Keep audio in sync with Video."? I guess Vegas is what it does, what more could I want?
farss wrote on 3/30/2005, 4:26 AM
The problem with the ATI card is that the video is encoded in the ATI card but the audio is encoded through your sound card. In many systems the clocks aren't exactly correct so over time they drift in sync. If it was just a sync offset that'd be a piece of cake to correct in Vegas but in this case you need to change the speed of the audio and perhaps resync it. So get the start of the video in sync by ungrouping the audio and video tracks and sliding one of them until the start is in sync. Then go to the end and ctl drag the end until an event near the end is also in sync. Gunshots or doors closing are good thing to use for judung sync.
But if you use a proper analogue capture card that encodes to DV you'll not have the issues to deal with and you'll find you get better image quality.

As to the sync issue in mpeg files I msut say I've not noticed this although I rarely have to deal with mpeg program streams in Vegas. I suspect given the way mpeg muxes audio and video it's possible Vegas isn't reading some offset value in the streams hearder. Still so long as it's a fixed offset it's easy enough to fix in Vegas. Oddly enough WMV files which are more complex to decode don't seem to have this issue. Bear in mind that Vegas uses 3rd parrty code to encode and decode mpeg so the problem may well lie there.
Bob.
Rednroll wrote on 3/30/2005, 8:04 AM
Farss, regarding your response to the first question, I fully understand your response. The only thing I can't understand is as me and Pipeline noted in our examples that is similar to Ranger"s experience. If it was the card, then why would it play fine in WMP and not in Vegas? If it was just the ati CARD , then why would it not play out of sync in WMP also?

"Bear in mind that Vegas uses 3rd parrty code to encode and decode mpeg so the problem may well lie there."

Now this makes sense to me
PipelineAudio wrote on 3/30/2005, 3:15 PM
well rednroll, remember, vegas isnt a video editor, but an NLE, so things like keeping audio in sync with the video may not be in keeping with vegas being what it is what it is or how ever they like to put it :)
PipelineAudio wrote on 3/30/2005, 3:17 PM
another thing, many times vegas cant see audio streams in some videos. I check them in gspot codec information appliance and they say the audio stream is wmv what gives?
RangerMax wrote on 3/30/2005, 6:45 PM
Thank you all for responding
I was not able to find a fix in Vegas but I was able to find a fix in the ATI software.
When using the "library" you can get listings of what video, picture, and audio files that are on you computer. There is an option to "export" the file. You can then tailor the new settings under the custom tab to modify the audio stream to be "de-interlaced". It exports the file about 2.5x speed. Then I could import them into Vegas without problem. It seems when the audio stream is "interlaced" with the video (for smaller file size) it goes out of sync.
As for not seeing the audio track when using some formats, I have had this problem as well when I tried to use the vcr extension settings on my ATI card. Make sure that under tools/preferences that you have selected "use microsoft DV codex" and also select "use third party codexs". That might help you with the WMV audio stream.
I will try and make a list of settings in ATI that will work in Vegas
PipelineAudio wrote on 3/31/2005, 6:17 PM
Ok I got a ton of videos that play fine in wmp, but if I burn em my dvd player has no audio, and vegas shows no audio stream. Is there a de-interleave tool somewhere?
SonyEPM wrote on 4/1/2005, 7:45 AM
The ATI card isn't bad per se but the files it captures are not by any measure editing-friendly and should be converted to an edit-friendly format if you want to edit. So, render your MPEG-2 captured clips, the entire MPEG file from start to finish, to DV .avi before editing. The sync problem should go away, performance will be much better.