View Full Version : Audio Causing Frame Drops???

4th February 2002, 07:41
I'm having a strange problem...capturing audio is causing frame drops - on the level of 1 frame every 10-15 seconds or so. The video still ends up looking decent, but I would like to get this eliminated.

It's definitely the audio, as I've tested w/out it capturing audio and confirmed that the frame drops stop w/out it (this was with the video being captures at 80x60 resolution, so it def. wasn't a cpu/bandwidth problem).

Also, the jitter seems to be jumping up- and down (it's in the thousands of ms's) - when I attempt it in compat. mode it doesnt do this at all. (but the resolutions I can use go to crap)

I've been trying to find a solution to this but haven't really seen anything on Usenet or any of these forums. Thanks for any help.

4th February 2002, 08:23
AFter searching and clicking almost every option on and off in Vdub I found that turning off the Audio/Video sync timing completely stopped the frame drops.

So, it seems the jitter/desp (not that I know what they are) were jumping over 10000ms and causing a frame drop.

Now, will a new sound card fix this? (sound blaster) or would just changing the audio connections from the external jumper cable to an internal one do it?

4th February 2002, 14:47
A different sound card may be better or not. Depends on how lucky you are with timing difference between sound and tv card.

Switching off Audio/Video synch will cause audio to be off the video more and more the longer the capture continues. But you can correct this by remuxing using VDub's "change frame rate so that video and audio durations match" (or similar).


4th February 2002, 18:25
So, would a better option be to just take the frame drops or to redo the syncing after the fact? (I only have like 15-20gb to work with so not having to resave the file would be a great help).

5th February 2002, 06:37
If you ask me, don't worry about the few dropped frames. I don't think you'll notice that when playing the film.
The remux option changes the video frame rate, which will not be noticable either. It might be a better choice for idealists, but these guys probably capture DVB nowadays.


5th February 2002, 15:54
I'vebeen talking to a few people, and I THINK that I may have found another reason this could be occuring - the WDM wrapped VFW driver for my PCTV pro. I'm installing Win98 on my secondary partition to test it out.

Reason I've come to this is that I'm getting the frames dropped when I tried a SB16 ISA sound card as well...which should have cleared up the problem (and not resulted in the EXACT SAME freq. of drops, etc.)