Some questions about MPEG4

[richard_chen]

Dears
I have couple of questions about MPEG4 which had been confounded me for such a long time. I hope some body could give me some guides.
1.As far as I know, the resolution of standard DVD(MPEG2) is 720*480 for NTSC and 720*576 for PAL. If we rip DVD and covert ripped data to MPEG4, why does the resolution of MPEG4 file become smaller than those unripped, such as ??
2.Is the scan type of MPEG4 video interlaced or progressive??
Thanx for answering.

[Batman]

Using an mpeg-4 codec such as XVID or DIVX for encoding, you can select any resolution/framerate of your choice. When converting to XVID or DIVX the resolution is often reduced to compensate for a low bitrate (Encoding at full DVD resolution would produce artifacts/macroblocks).