Problems mixing AVI with AC3 audio file

[the ripper]

Hi.
I've a question anout Virtual Dub. I download a last version of Virtual Dub that support an AC3 audio file. When I mix AVI with AC3 files of "The Mummy returns", and then I watch the AVI mixated, audio go up and down when a peak of audio were generated. If I mix AVI with an audio mp3 this problem doesn't exist. I think that Virtual Dub normalize the AC3 file in real time. If it scans an AC3 file and than normalize the audio file before mix, it's better. There is a option to disable the "normalize" functon in mixing of AC3 audio file?
I'm sorry of my english, but I'm italian.
Tanks.
^-^ @*Arzan*@ ^-^

[UncasMS]

if that version might do so ( i cant judge) use nandub for muxing audio + video

[the ripper]

Problem exist

Thank you for reply my problem. I downloaded NunDub, mix AVI with AC3 file, but the problem exist. I think: the central channel is -24 db, the surround channel and front channel are 0 db. I think that here is the problem, but if I listen only AC3 file, audio is ok. Virtual and NunDub normalize all channel in real time. I want only disable the real time normalization or download software that mixing AVI with AC3 file without normalization.
Thanks for all.