Merging Audio and Video Problems

[Nefarion]

Ok, Ive got the Ripping (smart ripper) and Extracting the Video(flaskmpeg) as well as the Audio(Chiller's ac3 tool) from the DVD down. But when i try and use Nandub or Virtualdub to combine the audio with the video...the audio comes out all jittery. Although, when I play the audio file (either wav. or mp3.) it is perfectly clear. I am not sure why combining the two would cause the other (in this case, the audio) to malfunction. There has to be something i missed. Thanks in advance to anyone who can give me any kind of help on this.

[Nefarion]

I downloaded TMPGEnc to merge the audio with the video and it worked fine. So i guess i got this problem fixed, now i have another problem. I made my first video using the divx low motion codec, later to find out that the divx 4.11 codec is much better, especially since im on a pentium 4. Anyhow, ive had the codec for a while, just didnt realize that it was newer/better. So anyway, i tried to make the video (flaskmpeg) with the divx 4.11 codec but when its done and i try and play it (on any media player) it says format is not supported. Its weird that Flaskmpeg would reconize that i have the codec but not windows mediaplayer or a few others that i tried to play it with. My operating system is windows XP, im on a 1.8ghz P4, 512k RAM, 80 gigs of HD space. Ive had trouble playing many DIVX movies in the past (i cant remember a specific one that i got to play), so im guessing all those were ripped using the 4.11 codec therfor, me not being able to play them. Anyone got any ideas??