Dropping frames when capturing audio

[roh]

hello,

I am using MIRO PCTV to capture video (Composite video in) . It works perfect when I am not capturning audio. But with Audio capture, it starts dropping frames.

I am using VirtualDub and am capturing audio thru the Line In of my sound card. I have PIII 800, 512 MB, 15 GB UDMA 66. I have tuned my system quite well but still the problem persists.
I have checked and the sound card (C-media) is not in interrupt conflict.

I have spent quite a lot of time to figure out the problem but am not able to solve. Need your help.

Thanks and Regards,
Roh

[Cloud]

I was having the same problems under XP, until I tried the WDM drivers.
http://btwincap.sourceforge.net/download.html.

[Anonymous65]

When you capture audio, the sample rate cannot be changed. Your sound card's frequency accuracy will influence how many frames you drop or repeat when you capture audio and video, and you want the two streams to stay in sync. VirtualDub does not have any feature to change the sampling frequency of you sound card. So, if you sound card is off-frequency, Vdub compensates by dropping or repeating frames so the video stream stays in sync with the audio stream. It would be much better if the video stream was the reference stream, and the audio sample rate would change. However, there is no easy way to do this unless you resample the captured audio before you save it. So, only a audio capture card with high frequency stability and accuracy will lower the number of dropped/repeated frames in Vdub.

Hopefully, the maker of Vdub will include this real-time audio resample feature in the future.

[roh]

Thank you very much for your comments. Actually, I tried again to capture from svideo input instead of composite Video and I am not dropping any frames now.

Therefore, I will use the SVIDEO input.

Thanks and Regards,
Rohit