Ralfs
Video Formats
Formats

DVDs are always encoded at 720x576 (5:4) although the picture will be scaled at playback. Common video formats are 4:3 = 1.33 for TV, 16:9 = 1.78 for normal cinema movies and 2.35:1 for Cinemascope.

Here is a list of common scenarios:

SVCD
Creating DVD menus
MPEG1
MPEG1 use mpeg layer 2 Audio and mpeg1 video. A subset of MPEG1 movies are VCD's. You can use VBR for the Video (although VCDs are almost always use CBR video) but the Audio has to be CBR (Constant BitRate). MPEG1 is recommended for picture sizes up to 352x288 for PAL and 352x240 for NTSC MPEG1 can't handle interlaced sources. If you video is interlaced you need MPEG2 to get it proper encoded.
MPEG2
MPEG2 can also handle interlaced sources like recording from TV at full resolution. MPEG2 allows the usage of mpeg layer 3 (mp3) sound. MP3 audio is not valid for DVDs. It is best to use MP2 (Layer 2) audio. The audio can also be a VBR Stream. MPEG2 is usually a VBR Stream.
ffmpeg
Video Options:
-s size
	`sqcif'	128x96
	`qcif'	176x144
	`cif'	352x288
	`4cif'	704x576