Check out this Apple document: iDVD '09 (7.x): Preparing images for iDVD slideshows.
Follow this workflow to help ensure the best quality final product:
Once you have the project as you want it save it as a disk image via the File ➙ Save as Disk Image menu option. This will separate the encoding process from the burn process.
To check the encoding mount the disk image and launch DVD Player and play it. If it plays OK with DVD Player the encoding was good.
Then burn to disk with Disk Utility or Toast at the slowest speed available (2x-4x) to assure the best burn quality. Always use top quality media: Verbatim, Maxell or Taiyo Yuden DVD-R are the most recommended in these forums.
When I burn that slide show on a DVD and I put the DVD in my DVD reader, conected to the television, the quality of the images become very poor.
What's appens ??
As I see it - it falls back on that DVD is as STANDARD only Interlaced SD-Video at it's best (even commercial made ones)
The Quality You see on Your Mac is prior to this down-scaling process.
If You need higher quality (and this includes several problems)
• DVDs can not be used
• You can try Blu-Ray (short one on DVD disks) - BUT You also need a Blu-Ray Player as a PlayStation 3 (you also need a program that can author BD-Disks as Roxio Toast™)
• You can try to Export as HD and to an USB-Memory stick - if You have any device that can take this
• You can connect a Mac to a big sized flat-screen TV - and playback this way
End of ideas.
Yours Bengt W