D1 and 1/2 D1....?

[wayoutthere]

I have read a few threads about file sizes and conversion types but am a bit foggy about the whole resolution/ file size bit.
I understand that D1 is 720x480 and 1/2 D1 is 352x 480, but what would it look like on the screen, I mean does it affect the aspect ratio or picture size?...Quality?... what differences would i see between the two if i where to watch them side by side on 2 tv.
thanks

[mats.hogberg]

affect the aspect ratio or picture size?

No.

Quality?

Yes.
The up side of 1/2 D1 is that you get by with lower bit rate, (half compared to D1), the down side is lower resolution.
Let's say full D1 at 8000 kbps on one telly and half D1 at 4000 kbps on one, you'd notice the lower resolution (more "jaggies", less detail). If you use the same bit rate for both, you'll notice more macro blocks in full D1 as the encoder compresses the image. The same effect can be seen when saving a photo with high jpeg compression - large areas of similar color are compressed to large areas of exactly the same color.

/Mats