VT Adjust in vdub

[EViLSouL]

When i capture in vdub, my vt adjust goes from +0 to +50 and causes me to lose frames. If anyone knows how to fix this please let me know, id appreciate it.

[Craig Tucker]

Virtualdub purposely drops the odd frame to keep the video and audio in sync, this is completely normal.

[EViLSouL]

well that always causes me to drop frames. so in 4 mins it makes me drop 10-15 frames.

[Craig Tucker]

That is a bit excessive, I lose the odd 1 or 2 in 4-5 mins. Are they all lost in 1 burst or do you lose 1 at a time.

[EViLSouL]

basically vt adjust shoots right to +9 then i drop a frame. then it goes to about +13 and another frame. etc etc etc

[Craig Tucker]

Are you using an onboard sound chip

Depending on your system, you will get some dropped frames simply because the clock on your video card and sound card are not perfectly syncronized.

VirtualDub will drop the occasional frame to maintain video and audio sync. This is a good thing (unless you want audio sync problems). It is also unavoidable unless you get another soundcard.

[Popsicle_Pete]

Craig Tucker, I get the same problem , I have onboard sound and I lose lots frames with vdub...Lots. If i CAPTURE 200 FRAmes, i lose about 75. But I have it set up NOT to capture audio...it still does drops crazy frames. I dont think it has anything with sound card , cuz when i use AVI IO and anything else, I dont drop any frames at all.

[Necromancer]

I don't know how VirtualDub thinks it's correcting the sync, but I have found that it doesn't do a very good job. Even though I select "lock audio to video", the only way virtual dub captures are 100% in sync is if I don't drop one single frame the entire capture. If I drop 1 or 2 frames, it is slightly off but still watchable. Any more than 2 frames dropped, and it's like watching a Bruce Lee movie dubbed to english.

[Popsicle_Pete]

1 or 2 frames shouldnt make a differnece..I wonder if you could edit that in premier ? you know what I mean??? Just copy the frame before the one that got dropped and paste it in? I guess that would be a lot of work..nevermind .

[Necromancer]

It would be a lot of work, even if I knew where in the stream the frame was dropped (which I wouldn't).

1 frame out of sync equals 0.033 seconds (at 30fps), which is at the limits of perception. 2 frames is .067 seconds, which is noticable if you're paying close attention. Once you get up to 0.1 seconds off sync, it begins to get objectionable.

[Craig Tucker]

I don't know how VirtualDub thinks it's correcting the sync, but I have found that it doesn't do a very good job. Even though I select "lock audio to video", the only way virtual dub captures are 100% in sync is if I don't drop one single frame the entire capture. If I drop 1 or 2 frames, it is slightly off but still watchable. Any more than 2 frames dropped, and it's like watching a Bruce Lee movie dubbed to english.

Do not select lock audio to video, and try again.

[Necromancer]

Won't that make it worse? Anyway, I will try that tonight.

[Popsicle_Pete]

dude, i figured out why i was losing frames in virtualdub....i guess the default capture is set at 15 frames per second... i changed it to 29.97 and now i dont lose anything. dunno if that hepls or not..

[Craig Tucker]

Won't that make it worse? Anyway, I will try that tonight.

Did it fix the problem

[Will Hay]

Do not select lock audio to video, and try again.

I'll be trying this myself too Craig, despite me thinking that 'do not select lock audio to video' sounds exactly the soloution to out of sync issues, right?
As you're in the UK too, what are your thoughts on dropping the frame rate from 25fps to 24.976fps to correct sound sync issues?
It's been kindly suggested to me by another forum user but I've yet to try it.
Will
--
www.milfordfc.com - maybe we should have a friendly, we both look as bad as each other

[Necromancer]

It did seem to work for me, but for various reasons I have not had the time to do a sure test.

[crahak]

VT isn't causing the problems, it's trying to make up for your lost frames. You're having a dropping frames issue. Try no sound/different card and lower resolutions (also different codecs prossibly) and see what happens.

[Craig Tucker]

Do not select lock audio to video, and try again.

I'll be trying this myself too Craig, despite me thinking that 'do not select lock audio to video' sounds exactly the soloution to out of sync issues, right?

Locking the audio to video will cause sync problems if your soundcard and video card clocks are not perfectly synchronized.

As you're in the UK too, what are your thoughts on dropping the frame rate from 25fps to 24.976fps to correct sound sync issues?
It's been kindly suggested to me by another forum user but I've yet to try it.

Never tried it, I always capture at 25 fps, do not lock audio to video and my captures are perfectly synced every time.
--

www.milfordfc.com - maybe we should have a friendly, we both look as bad as each other

Wheres Milford

[Will Hay]

Wheres Milford

Right in the heart of footballing country my friend, ten miles from from one of the greatest teams ever to grace a football team.
Home to some of the most beautiful landscapes in the world.....Yorkshire (Leeds to be specific).
Will

[Craig Tucker]

Bit of a trek from Swindon to Leeds :P

[Will Hay]

Bit of a trek from Swindon to Leeds :P

I was kidding
I'll try the 'don't lock audio to video' suggestion tonight and report back.
Thanks,
Will