Converting AVI MP3 audio to AC3 recommended?

[BlueWeasel]

I'm in the process of converting several AVI files to DVD using DIKO and TMPG. I've seen several guides recommending to convert the audio seperately and use DVD authoring software to rejoin the audio and video.

With TMPG, it's simple enough to do the video only (ES). However, with DIKO there is no option to disable the audio.

I've used FFmpeg (GUI) to extract the MP3 audio from the AVIs to AC3.

I'm confused, though. Since all the AVIs are 23.97FPS, they are converted to the NTSC DVD standard of 29.97 during the encoding. However, FFmpeg doesn't appear to adjust the audio for this. Yet, the audio and video appear to be in sync during playback.

Am I missing something here?

[Abond]

Am I missing something here?

Generaly no.
But it is not bad to go to top left part of the page and to read in the GLOSSARY what is pulldown.

[BlueWeasel]

Am I missing something here?

Generaly no.
But it is not bad to go to top left part of the page and to read in the GLOSSARY what is pulldown.

I just read the pulldown entry in the Glossary, but I'm still confused. If the playback is converted from 23.97 to 29.97 FPS, then the audio must be converted else there will be sync. issues, right?

[Abond]

Well, let say so - the video is sped up, but new frames are added so the duration is the same as audio duration - this is the key word "duration". Audio has no framerate