Adobe Premiere Elements 10 on Mac OS 10.7.2 - Hanging and Freezing

Question

Hello there,
While I'm not very knowlegable about video editing software, I do use Premiere Elements 10 to edit videos for YouTube. I recently have been able to record using a device which records in 1080i, 29.97fps and saves as an mp4 file format. I've been trying to edit these files (which can be up to an hour long) in Premiere Elements; however, as soon as a video file from this recorder is imported and dragged into the project, it hangs and freezes. Sometimes, the hang happens when "conforming" the video file; other times it happens when trying to preview the video.
My theory is that it is due to the file format, or because of the sheer size of the file. The files can be several GBs.
I have tried to reinstall the program, but this hasn't worked.
Is there any advice you could give me?
Thanks,
LiamWatson28.

Answer 1

Hey Bill, thanks for the quick response.
It does use the H.264 CODEC. The project preset I'm using is NTSC-AVCHD-Full HD 1080i 30, although when I import the video to the project, I sometimes get a dialog box telling me that the project settings can be matched to the imported video, which I allow it to do. I have around 250GB of free space on my HDD. I allow the video and audio to conform and such on importing, I do not try to edit the video/audio while it is conforming. I'd also like to add that all files are transferred onto the HDD before the edit.
My specs:
MacBook Pro 13" (Late 2011) running Mac OS 10.7.4 (Lion) I apologise, I had this wrong in the title and the original post.
Intel Core i5 2.4GHz Dual-Core
8GB RAM
500GB SATA HDD
Intel HD3000 Integrated Graphics (if that's any help)
If there's anything else I need to provide, please let me know.
EDIT: I just tested editing a 10 minute video with the same file format and project preset, and, while it was hanging as frequently, it would only be for up to 5 seconds. Compared to the 50 minute video I was trying to edit, the hangs were much longer, sometimes becoming freezes.  I know that if there aren't any immediate fixes and using the same video settings, I'll have to reduce the file size by reducing the length of the video, so cutting more frequently rather than recording long stretches.
Thanks,
LiamWatson28.