NTSC - 720 x 405 (letterbox - black bars at top + bottom)
720P - 1280 x 720 (HD - we could burn a Blueray DVD)
Both formats use a PIXEL ASPECT RATIO = 1.0 (SQUARE)
720P would be more flexible - you can downsample it to create a standard NTSC version - but obviously this comes at the cost of render time and file size.
