Can anyone tell me if Quicktime Pro retains aspect ratio once a video is rotated?

Every video format is always wider than it is tall. When you shoot in portrait mode (not landscape) the video will playback "on its side" when viewed.

QuickTime Player Pro can rotate the video orientation so the video plays "tall and narrow". Any exported file will maintain this orientation but many playback devices (DVD's for example) can't display these dimensions without "forcing" the normal landscape view expected causing the distortion.

The trick for these files is to add a landscape image file to the portrait mode video. A 640X480 image (all black) is added to the duration of the 480X640 video track. The video track is then "scaled" (and centered) so the height is 480. This will add black bars on both sides of the playback video.

AVI is just another container. In nearly every use there is no need for a conversion to AVI.

I took some videos with my iPhone (the long way), and need to be able to rotate them and convert them to avi files. I understand that Quicktime Pro can do the rotation and conversion, but I saw one review that said the aspect ratio is not retained, i.e. the video comes out flattend (wider).

This may or may not depend on your specific work flow. Many "settings' saved to the original file by QT 7 Pro are merely "playback instructions" which may or may not play correctly in other media players while these same settings do work properly when saved/converted to a new file container. In addition, not being a Windows user, I don't know if there are are any significant differences between the Mac and Windows versions of QT 7. In any case, I just took a short sample clip, stored it on my hard drive via Aperture 3, opened the file in QT 7 Pro, rotated the clip in QT 7 Pro, and used the "Save As..." command to store the modified file. This modified file now plays correctly in current versions of the QT 7, MPEG Streamclip, and VLC media players. Have uploaded a copy of this file so you can download it, test playback in various players you normally use, and/or test convert it to your specific AVI audio and video compression formats.

SAMPLE ROTATED FILE

Can anyone tell me if this is still true with QT Pro, or if there are other solutions for resolving this outside of QT Pro?? I have tried a number of other converters, and found one that rotates, but aspect ratio not retained.

As indicated above, the file plays correctly for me in various media players and all media "Inspector" windows, including other third party media information utilities, confirm the correct dimensions and aspect ratio as displayed. As to AVI conversion, I test converted the uploaded file to AVI (DivX5/MP3) at original dimensions using VisualHub. (Also tried the VideoMonkey AVI encode but it limited the source 720p file to a 720x480 output and I did not know if you were agreeable to such a restriction.) Suggest you run similar tests with your preferred Windows converters to confirm/refute results on your system.