seth_petry_john

Display resolution of digital cable?

Can someone tell me the native display resolution of digital cable, Time Warner's to be exact?

I am considering switching to DirecTV over cable, and the last DirecTV salesperson I spoke with claimed that the satelite signal is transmitted at 480 but that cable is only 200-something. Can anyone confirm/refute that?

AFAIK my TV upconverts all incoming signals to at least 480i but that really doesn't help me identify the native resolution of cable.

Thanks in advance,
Seth

Allan Jayne

The native vertical resolution is always 480 scan lines for NTSC channels, analog and digital. There are still the 480 scan lines per pair of interlaced fields (= 1 frame) but how much detail is preserved on each scan line (horizontal resolution) may vary from one channel to another even on the same cable system. I don't know what Time Warner does.

Most cable TV systems use compression to fit more channels on the cable. Compression often shows up as the inability to preserve the narrowest details on each scan line.

Numbers for comparison: For VHS tape, typically the smallest detail as preserved can be about 1/300'th the screen width; for standard NTSC broadcasts, 1/400'th; for DVD, 1/700'th (1/720'th for some).

Video hints:
http://members.aol.com/ajaynejr/video.htm