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SupaCoopa
28th January 2002, 08:02
Hi all.
I have this problem and can't do anything about it. Maybe someone can help me out? Well, first you'll have to understand what I mean below...

When I capture with Virtual Dub the sound is strangely corrupted. When someone talks I can hear a brief cracking sound just before I hear their words. Then the sound is normal until there is a pause and the other person starts to talk and then I hear again this cracking sound and so on. This is really strange, as I can't hear this cracking sound while listening to real-time line-in, it's only produced on the captured recording. Also if I record line-in using Sound Recorder or whatever, there is no such corruption.

I'm capturing 480x288 with no lost frames, the sound I grab is PCM 44khz, 16 bit, mono. I check "lock video stream to audio" and "dynamically adjust video clock" as I get de-synch if I don't.
I have a Celeron 900, 512K Ram, NVidia MX 400 VIVO and SB Live and run Windows XP Pro and VDub 1.4.5 and 1.4.8.

What is wrong? What can I do about it?
Cheers

Cart
28th January 2002, 18:33
First of all, make sure that line-in and only line-in is selected as the recording source in both Windows' mixer and your SB mixer. Also make sure that your recording properties are set to "best quality" in the Sounds & Multimedia control panel.

Try capturing with 48 KHz to see if it helps any.

-Cart
http://www.geocities.com/lukesvideo/index.html

SupaCoopa
29th January 2002, 08:23
Cart, ta for your reply. Yes, only line-in is selected as recording input, and everything else is muted at playback properties.

I have tried every available sound format, from 11khz, 4 bit, mono to 48khz, 16 bit, stereo but the results are identical.
I have done some testing with other capturing programs like AVI_IO and freeVCR. Same thing happens. If I record line-in from a non-video-capture program (WinRec, Cool Edit etc) the sound is perfect!

I have been listening more careful to the "corrupted" recordings through my hi-fi speakers. It seems that the recording is actually vibrating, both in tone and volume (couldn't make that out using lame PC speakers). Maybe a case of VFW messing with timing then?

I haven't installed Creative's XP drivers, so no SB Mixer. I'm just going with XP's native SB Live Drivers, will update them to see if it makes any difference.

Cheers

SupaCoopa
31st January 2002, 12:01
Problem solved!

I had a look in BIOS settings and found out that AGP WS Read and AGP WS Write were disabled. I enabled both of them and now the sound of captured video is loud and clear.

Just thought you might wanted to know!