[X4U] Does size matter?

[Kevin Willis]

I have been recording my favorite TV shows on my Mac and turning them  
into DVD's for a couple of years now. I would always add episodes to  
iMovie until I got about 2 hours worth of shows. Then, I would use  
iDVD to burn them. The iMovie files were over 20 GB, but the running  
time was less than 2 hours. I have never had a problem getting them  
to burn on regular 4.7 GB DVD's. Now when I try, I get a message from  
iDVD saying the file is too big, and I need double layer disks.

What has changed, or what am I doing wrong?

Thanks,

Kevin