Just a couple of question before I start the process of converting AVIs to MP4s: 1. Is there a difference between using the iTunes tab and the MP4 tab? 2. I'm going to select "copy original audio track (passthrough)" which I suspect would save time, but what would happen if I also choose "copy original video track (passthrough)." Would it just convert the AVI to MP4 and not re encode the video? Since the video is already compressed I suspect this would be the best option, assuming I've understood it right. 3. Would changing the bitrate to a higher level than the original file increase the quality, or just unnecessarily increase the file size. 4. Is it wise to covert a batch of files rather than doing them one at a time. If the original source video is different for each file then wouldn't they all be converted with the same settings (which may not always be appropriate for each file.) 5. I would like to keep the file as close to the original file size (or lower without loosing quality), but not higher if possible. What are the best settings to achieve this? Thanks.