Flash video

Hi

I’ve been set the task of editting a video, want an flv version and a mp4.

Although from looking at it, its people talking over a powerpoint presentation.

I’m thinking sticking in the slides with audio, then wheverver there is a actually a person it cuts to video to save file size.

Would that work?

I guess the simple question is how do I ensure best quality, my experience with FLVs greatly reduce the quality.

Thanks