Capture the audio of VCD using audio-out and record the same using audio-in. Hope this makes sense. Share with us if you have any luck. Or Google for 'demux' or demultiplexer tool.

Also, I found this in another website:

Use TMPGEnc as follows:

File>>MPEGTools>>Simple DeMultiplex
Save separate video and audio tracks

To merge the video and audio tracks and again create the VCD formatted file:

File>>MPEGTools>> Simple Multiplex - IMPORTANT! AFTER loading in audio and video files, set mode to "MPEG1-VideoCD" (NOT just "MPEG1")
Save as a VCD-formatted MPEG1 file, ready to burn as VCD.

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Unlike celluloid films, both audio and video is encoded together in VCD as one datastream.

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