Auto Play in general will slow down load times for a site.
Think about it your loading a 110mb file or around there for the ATA video, it still has to load that file auto-play gives people no choice wheather they'd like to load it or not. its the same on every site, it actually works better with flash, but still keeps things loading slowly.
if you want to keep videos auto playing make the video size under 10mb. Dont try to force load a full length ski movie.
Auto-Play in general is annoying, especially when you have the choice to pick the video you want to watch, its not neccescary to load a video right away for people.
its not gonna change site to site, player to player cuz all flash players are built OFF of Adobes/Macromedia's SWF Flash Player they built to support their codec.