D Richard Felker III wrote:
II.2. Constraints of DVD, SVCD, and VCD
Unfortunately, the DVD, SVCD, and VCD formats are subject to heavy constraints. Only a small selection of encoded picture sizes & aspect ratios are available. If your movie does not meet one of these, you must scale and crop or add black borders (which are bad for quality!) to make it compliant.
Format Resolution V.Codec A.Codec FPS Aspect NTSC DVD 720x480 * MPEG-2 MP2,MP3,AC3,PCM 24,30 4:3,16:9 NTSC SVCD 480x480 MPEG-2 MP2 30 4:3 NTSC VCD 352x240 MPEG-1 MP2 24,30 4:3 PAL DVD 720x576 * MPEG-2 MP2,MP3,AC3,PCM 25 4:3,16:9 PAL SVCD 480x576 MPEG-2 MP2 25 4:3 PAL VCD 352x288 MPEG-1 MP2 25 4:3
* DVD also offers other resolutions but they are usually not desirable.
mp3 is neither permitted nor frequently supported by players; for dvd x=704 is standard and very useful, because it often permits to crop without rescaling