Let's suppose that, when you try to join two AVI files, VirtualDub gives you this error: 'the video streams have different sampling rates (29.97003 vs. 29.97000)' .
The error lies is in the fact that the audio of those AVIs, was compressed MP3 VBR instead of MP3 CBR.
To correct this error you have to:
1) Load CD1.AVI wth VirtualDub
2) Set audio__full processing mode. File__Save WAV.
3) Use HeadAC3he, load the WAV, compress to MP3, [options >>] twice, choose MP3 'alt preset CBR' . Click [start] and it will create the new MP3 CBR 128 kbps.
If HeadAC3he gives errors, use FFMPEG GUI. Parameters: AC3, 192 kbps, 48000 Hz and 2 channels. You'll create an AC3 instead of a MP3. 4) Load CD1.AVI with VirtualDubMod. Set Video__direct stream copy (make a 1:1 copy of the video, which won't be modified). Fix the audio: do Stream___Stream List, Disable the old one, Add the MP3[AC3] CBR 128 kbps you just made. Save (F7) --> CD1_new.avi.
5) Repeat with CD2.AVI.
6) Now the error should have disappaered and VirtualDub will be able to join the AVI files you made.
In the case you used AC3, when you want to create a DVD simply 'demux' it from the final AVI to create a DVD using 'elementary streams' (read the 'sticky' post http://forums.afterdawn.com/thread_view.cfm/351013 ).
You'll just have to create a 'mute MPEG-2' (M2V), since you already have the audio stream, now.
