Vidcap A/V Synchronization Boggle

[flvrec0r3r]

I have a wierd problem that evades solution. Regardless the window size, frametrate, quality, codec, etc. I always experience A/V de-synchronization when using video capture software.

The source is Flash in a browser. It is seemingly without fail that a 21 minute video will have an audio stream 8 seconds shorter than the video. I can't reproduce this with RVC as any corresponding issue in a one minute eval video is sort of imperceptible.

Continuous audio recording with Audacity in the background during a capture also results in the same issue. A crop before the first sound and after the last sound for a 21 minute video episode and the resulting audio is about 8 seconds shorter than the video captured during the same period.

What could this be and how to fix it?

The dirty fix now is "change video framerate so audio and video durations match." This does result in A/V synchronization throughout the length of the video.