Sound glitches at start of every event

johnmeyer wrote on 6/18/2003, 9:13 AM

I installed Vegas 4.0 on my laptop so I could use it while on vacation (Compaq 1800T Presario, 700 MHz). I'm on vacation now. I put the captured footage on the timeline. As I play the footage, I get audio dropouts at each scene change The DV footage was captured using Vegas' capture utility and was captured using a DV PCMCIA card. It was captured with each new scene in a different file.

If I put the cursor at the beginning of a scene, there is no audio dropout. It only occurs when the cursor crosses from one scene (file) to the next. Thus the capture has occurred correctly; the problem is in the playback.

I deleted all the SFK file and let Vegas re-create them. Same problem. I tried changing to the direct sound and ESS drivers (the laptop has an ESS sound card built in). That didn't change anything.

I still have Videofactory on this laptop, so I put the same video files on the timeline in VideoFactory, and they play just fine.

Any ideas?

Comments

cacher wrote on 6/18/2003, 9:20 AM

Same thing happens to me even though I have a fairly fast PC (2.4 ghz). Final encoding to mpeg-2 and burning to SVCD came out Ok though (no dropouts or stuttering).

TheHappyFriar wrote on 6/18/2003, 9:21 AM

how much memory do you have? it sound like there may be a lack of memory, along with the "weak" power of your CPU (100mhz bus speed?). I have a p3-667 and ocationatly get audio dropouts when playing back. But NOT after I render the file (i render out to NTSC DV). Try that to see if you ge tthe dropouts.

johnmeyer wrote on 6/18/2003, 10:17 AM

Interesting that others are having this problem. Believe me, you should not be having these problems at all. Also, if the problem were strictly a weak CPU, then the video would glitch as well, and it doesn't: The video plays fine.

This has got to have something to do with how sound is being buffered, and I'm guessing that it is probably a sound driver issue of some sort. It is supposed to rain this afternoon (I'm on vacation, after all) and if it does, I'll see if there is a better sound driver for my laptop.

I still think that the fact that Videofactory 2.0 plays the files perfectly, and Vegas 4.0 doesn't, holds a clue to what is going on.

CrazyRussian wrote on 6/18/2003, 10:57 AM

How are you arranging files on the timeline? back to back, or overlaying one onother? If back to back then look into default transition that vegas put on audio and video tracks, it is set to 0.1 sec by default i think. So everything you drop on the time line, even if files dont everlay each other for a transition, they still have default fade in for 0.1 sec.
Try doing this, drop a video/audio file onto the timeline not overlaying any ohter files, noo look at the beging or end of the file, the upper corner will have yellow triangle indicating that there is a fade in effect. You can drag it towards begining or end of the fle (depends which transition you're dragging) to set it to 0

mikkie wrote on 6/18/2003, 11:48 AM

FWIW, I'd start with what CrazyRussian wrote, that you're creating a fade in and out perhaps, that's only noticable visually when you really zoom in. Simple to duplicate, just split an existing avi on the timeline where there's continuous audio & there is a dropout on playback - until you eliminate the fades or for the future set Vegas to not create them in the 1st place.

Videofactory wouldn't/doesn't include this feature, and also FWIW, the severity of dropout could possibly vary with horsepower because Vegas has to calculate the fades on playback, plus any audio filters engaged (I think by default VV4c adds 3 of them).

The sfk files are kind of a record of peaks so you don't have the lag building them you might get in prem. on zooming into the timeline.

johnmeyer wrote on 6/18/2003, 5:37 PM

There are no fades or transitions -- I zoomed all the way in to make sure. Also, the glitches continue for almost two seconds into each scene.

Again, as I said before, I don't think it is a horsepower issue because the video plays fine and everything works fine in VideoFactory. I believe it has to have something to do with the way Vegas interacts with the sound subsystem.

Any other thoughts?

RedEyeRob wrote on 6/18/2003, 9:28 PM

This is a known glitch. It does not affect all users. There is little you can do about it. If you change playback buffering to 0.07 you can minimize the problem but not eliminate it completely. Note the 3rd link and the post from SonicMattL which shows they found and confirmed the issue, although I'm not sure his description about there not being a problem if there is a non uniform offset is correct. It doesnt happen with earlier versions ov Vegas.

http://www.sonicfoundry.com/forums/ShowMessage.asp?MessageID=190314&Page=0

http://www.sonicfoundry.com/forums/ShowMessage.asp?MessageID=182184&Page=0

http://www.sonicfoundry.com/forums/ShowMessage.asp?MessageID=183054&Page=0

johnmeyer wrote on 6/19/2003, 8:09 AM

RedEyeRob,

This is very useful. It saved me from unecessarily installing new drivers on my computer and screwing everything up.

Based on the information you provided, I found that if I create two audio tracks and then put every other event's audio on the lower track, the problem goes away. Of course, I shouldn't have to do this. It is obviously a bug in Vegas. I sure hope they fix this because it makes the program very difficult to use on this machine.