iDVD and iMovie address different needs:
- iDVD is necessary to create a video DVD; it will also create chapter titles and a menu for navigation on the DVD,
- iMovie lets you add a more advanced audio track and cut the final video to add transitions, effects, animated titles, credits and video effects, like blue (green) screen matting.
So it will depend on what you want to do. If youhave iDVD, you could also skip Aperture altogether and simply import a folder with images into iDVD, iDVD will render a basic slideshow and even include the image files as a data dvd.
I usually create my slideshows directly in iMovie and share them from iMovie to iDVD,
To get started with DVD making see this:
I hope others will chime in with more info on the different video formats.
To add to what leonieDF has said.
I don't use Aperture for slide shows very often, but I make hundres of DVD's with iDVD and Toast.
All DVD's are standard definition, unless you use aa application like Toast and create a AVCHD Bluray disk. It doesn't mater what type of TV you play it on, it's SD. Some TV's do a good job of upscaling and the SD looks very good on them.
If you were to send a folder of full resolution 20 MP ( or whatever your camera is) images to iDVD there may be problems. I don't think iDVD is a very good at rescaling images. Sending 1920 x 1080 images or movies to iDVD has worked very well for me. I expect 720p would do well also.
I would recomend you do a test of a slide show of 1 min or less and trry a few different settings. I would try to export with a preset of Apple TV,iPad for a starter. Note that using Apple TV iPad 720p will give you a frame rate of 24, where as the other Apple TV is 30 fps. I have never tried feeding iDVD a movie that was 24fps, I not sure how that would go. I may give that a try and see what happens.
I use FCPX not iMovie, but I think that iMove works the same way. In the moive editing software you can just drag your Aperture stills into the timeline from the photo browser to creat your slide show/movie. But realize that the movie editing sofatware will actually use your Aperture previews for this. So your preview preference will determine the resolution of the images going into your movie. If your previews are set real low the results may not be very good. A setting that is closer to your monitor resoulton would work very well.
Do a test and let us know hoiw you make out. If I get a chance tomorrow I'll drop a quick slide show into iDVD. I'll export the same slide show with a few differnt settings and then put them all on one DVD to play back.