I have an AVI file which I converted to DVD using above program which I use very often for this type of operation.

While the sound was okay in AVI format, it was difficult to follow in DVD mode due to scratch-like noises coming from the audio stream. Output sample rate is 48000 Hz by default and Ouput Volume is increased by 1 time. I always use those parameters.

Using GSpot on the AVI file, I found the following in the Audio Section:
Codec 0x0055(MP3, ISO) MPEG-2 Layer 3
Stat "Codec installed"
Info : "22050Hz 48 kb/s total (2 chnls)"

Is the problem due to the difference between 22050 Hz and 48000 Hz?