Cutting/editing audio - Avisynth mangling it?

[wonkey_monkey]

Hi all,

I've just come across this oddity. I've cut a clip from a DVD rip in two using trim, then spliced the two clips back together with +. Using audiograph I can see the waveform of the audio, and on first stepping through the frames in VirtualDub (so not playing audio) it looks like this:



But after playing back any of the audio (before, during, or after the splice), it becomes this:



And the glitch is audible. Reloading the AVS file resets it again.

Can anyone shed some light as to what's going on, and tell me if there's any way to avoid this?

David