If your movie is in uncompressed format, then a 1920 x 1080 size file can be a huge burden for your computer or hard drive to playback.  I have an 8-core, NVidia 8800, and fast SATA drives  and it won't even handle that kind of animation file!   You'd need SATA RAID drives at least.

Try compressing it to H.264 with Quicktime, then it should playback fine.