AVI is often misleading. There are non-compressed AVI files and highly compressed AVI file from, for example XVID or DivX.
What kind do you have? You may have both types. They all have to be converted to VOB files (which are mpg2 files under a different name) to be put on a DVD that will play on a standard DVD player.
Remember the rule of thumb is no more than 2 hours of mpg 2 files at best quality to a double sided DVD. Are you exceeding that?
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BoilerPlate: To posters who ask for help -- it is nice to thank the volunteers who try to answer your questions !
Anything I post unless stated with a reference is my personal opinion.