After Effects Robobrush edit 1 minute + project

After Effects Rotobrush Project I have approximately 1 minute and 10 seconds of video (one scene) that needs the subject matter (two mules and a wagon) isolated from the background. There is no requirement to preserve any shadows, as the png samples below will demonstrate. The camera was not mounted on a steadicam so there is movement in the subject matter and the camera. I do not expect any correction to the movement problems... only isolation of the subject matter from the background. I have AfterEffects CS3 and don’t want to upgrade to 64-bit, additional RAM and CS5 or CS6. I want the finished product rendered to a transparent background format that can be loaded into After Effects CS3. Avi. format (uncompressed) with alpha preferred. I’m not sure if the RotoBrush feature of AE5/6 produces a .aep file with a complicated bunch of Bezier masks. I don’t want to deal with the file and the masks. I want the final video file to be rendered , clean and contain a transparent alpha background because the background is being replaced. The video was shot in 720p, (1280 x 720 x 24), motion jpg. Please consult with me on the final format before proceeding. The final format must be compatible with AE CS3. My editing platform is PC based, using W7. There is no audio. There is no urgency to this project in terms of completion time. I will post a couple of still frames so you can see the subject matter and a sample of the objects to be isolated. Here are a couple of problems I foresee. 1. My guess is that Rotobrush can get messy if you have to stop every few frames and adjust the masking boundaries. Although I’ve never used Rotobrush, I’m guessing that isolating the legs of the mules from the shadows on the ground, and isolating the reins and all the tack leading from the mules back to the wagon might present a problem. I just don't know how good AE's algorithms are. If it is easier to eliminate the tack and reins, I will provide 1 minute and 10 seconds of footage similar to 3rd sample show below, which eliminates most of the legs/ground and some of the tack. 2. The fact that the frame rate was 24 fps instead of 30 fps creates some blur in the original footage, and my guess is that Rotobrush doesn’t like blurred edges. If you have any tests or suggestions on this matter, let me know before proceeding. In order to protect my client, I will ask that you sign an agreement acknowledging this is strictly work for hire and agreeing that no copy of the original video footage may be retained by you, offered for use by you or sold in any form or format by you.