iDVD to BluRay player problem

OK, I'm hoping someone's kind enough to a newbie to answer what I hope is an easy one:

I upload HD movies from my Canon HF M31 camcorder using iMovies on my IMac (2.5 GHz Intel Core i5, 8GB memory, latest versions of all S/W).
I create a project and choose the 1080 format.
Project runs for 9-10 hours but completes successfully (1080p/720p).
I then use iDVD to burn to a DVD+R DL disc.
Chunks along and spits out the disc in ~ 30 minutes.
Walk across the room, pop it in my Panasonic DMP-BD85 BluRay player and...
Disc can't be "read" error...BluRay player is connect to the internet so firmware is the latest.
What am I missing? Do I need software like Toast or Final Cut Express? Am I creating a DVD with a format the BluRay player doesn't read (MP4)? Does any (aforementioned) software allow a different format burn to DVD? (I'm just trying to burn HD family movies to DL DVDs). Thanks in advance for any help...

If you want an HD DVD, you will have to use something like Roxio's Toast:
Roxio Toast 11 Titanium - CD & DVD Burning for Mac
and to produce a BluRay dvd you will also need an external BluRay burner. There is no support for BluRay with Macs.

iDVD produces dvds to these specs:

To record moving pictures, DVD-Video uses either MPEG-2 compression at up to 9.8 Mbit/s (9,800 kbit/s) or MPEG-1 compression at up to 1.856 Mbit/s (1,856 kbit/s).
The following formats are allowed for MPEG-2 video:
At 25 frame/s, interlaced (commonly used in regions with 50 Hz image scanning frequency - PAL):
720 × 576 pixels (same resolution as D-1)
704 × 576 pixels
352 × 576 pixels (same as the China Video Disc standard)
At 29.97, interlaced (commonly used in regions with 60 Hz image scanning frequency - NTSC):
720 × 480 pixels (same resolution as D-1)
704 × 480 pixels
352 × 480 pixels (same as the China Video Disc standard)

Click to expand...