[dhs12345]

Good. Most monitors should convert the source to whatever their native mode is, 720p, etc. if they are not capable of 1080p.

And a 1080p monitor had better be able to play 1080p.

The distorted stations were live. Usually sports.

"No change to the original bit rate and source" --- makes sense since the cable company would have to re-encode at a slower bit rate which will take time and resources.

Suspect that the cable companies, etc. are playing with the bit rate, etc. since audio digital distortion is pretty bad on some shows. May be multiple conversion steps, too -- show was on an analog station and could have been a digital source that was originally an analog movie, etc. The movie was The Water Boy. Video was okay.

Just suspicious of the cable company because they have a limited bandwidth on their cable and if they can cut a few Mb here and there without the customer noticing...

A lot easier to notice now with HD monitors.

[-YYZ-]

The cable companies only allocate so much bandwidth to each of the HD channels. With MPEG2 compression that bandwidth may not be enough to transmit all the detail in the original source as they receive it. In my experience this only becomes noticeable in relatively extreme cases with lots of detail that is moving.

Other times the compression artifacts have clearly originated upstream of the cable company. For example, the "Star Trek - The Next Generation" episodes aired on "Spike" have horrible compression artifacts that were noticeable even with analog cable on my old 20" 4:3 CRT. Mostly noticeable as motion glitches, where character's movements appeared a little strange.

There's another thing to consider. When you're watching a DVD, that's also MPEG2 compressed. But in high-quality DVDs, considerable time can be spent optimizing the MPEG compression parameters for each scene. For live broadcasts, or for digital cable, the re-encoding to MPEG2 is done on the fly and is not optimized for the type of scene on the screen.

Have you noticed the quality of live HD broadcasts vary greatly? Lighting may be a big part of it. Some sports broadcasts appear very muddy and murky and lack the crisp detail you expect with HD. Others are very good. The late-night shows with David Letterman and Jay Leno in HD look absolutely fantastic (but aren't generally of interest to me).