MPEG Artifacts on Regular Cable???

[mikewg]

I'm pretty new to Digital Cable... at least I think I have digital cable. Anyways, I notice that when I'm watching normal TV (no computers, no capture cards, no DVD players... just a cable feed from the wall to the TV), I'll see MPEG artifacts on the screen, especially when the picture on the screen has a lot of motion. I've never ever seen them from regular cable before... is this a byproduct of having digital cable? Should this be happening, or should I call my cable company and complain?

[AntnyMD]

On Comcast digital cable service here in Montgomery County, Maryland, a rather large number of channels are compressed MPEG-2 feeds, even channels that aren't compressed on their analog cable services. I've had digital cable about a year now, and I've seen marked improvements in the quality of the compressions. I'm assuming these programs are 352x480 at 4000 CBR compressions -- before I think they used some sort of variable bit rate compressions and the quality was horrid.

Just about the only channels that arent compressed are the news channels, locally broadcasted channels and MTV. Some of the worst compressions I've seen have been cablecast on the SoapNet channel. Some of the best compressions I've seen have been cablecast on the Sundance channel.

[N0SoopForU]

The Digital Comcast here in Baltimore County, MD is the same way. It is normal too see artifacts with digital cable. I've seen them in digital satellite also.

[Anonymous65]

You still might have analog cable (unless you have a digital converter box) BUT the source of the channel is digital, which means the signal is digital to the headend of the cable company and analog to your home. If the signal is digital any place between you and the place the program is broadcasted from, you might see digital artifacts. Since many channels are didital now via satellite, you will see digital artifatcs on your regular analog cable...

[mikewg]

Okay this is a total newbie question... but what is the benefit of cable companies offering digital cable as opposed to analog cable? I mean, if analog cable looks better (or does digital look better with the exception of the artifacts)... why does everyone want to move to digital? Because my "digital" cable company offers the same amount of channels as my last cable company did, nothing special.

[ngnr]

At least part of the reason is bandwidth. A digital, compressed video channel will require much less bandwidth than the same channel in analogue so more channels in the same spectrum space. The difference in bandwidth (and quality) will depend on how highly compressed the signal is but I would suspect that you could squeeze maybe 15 times as many compressed digital channels into the same spectrum space as one analogue channel. I could be corrected on this...

Another reason is the ability to transmit the digital signals a lot further than the analogue signals without adding noise or causing signal attenuation, thereby allowing the elimination of some head ends and cutting costs for the cable company. One head end and a fibre feeder network can be much more efficient than multiple head ends to serve multiple locations. There are probably other reasons as well that other posters can add.

[Anonymous65]

It is mostly to add channels. Cable is competing with satellite, who can deliver hundreds of channels. Cable is stuck with a max. number of analog channels, some place around 80 channels. When people demand 10 HBO channels, 10 Cinemax channels and 10 different versions of Discovery channel, analog cable TV gets into trouble! The only way for cable to compete with direct satellite is to convert the space of a single analog channel into a digital carrier, that can do 4 channels of "good" quality mpeg-2. So, when the cable company go digital, they can deliver up to 4 times as many channels. Also, you get the "high" quality label that is slapped on everyhting that is digital today!

[Greg12]

how do people watch 10 HBO channels?

[FiEND]

good question dood, i was gonna ask this myself since i recently got a cable box.

fortunately I dont see this poor compression on movie channels - but still sucks bad, watching MenTV Benny Hill was on and my god was it horrible, it looked like a 300kbit asf file from a year ago.

not only that but ever since i got a nice large screen TV, i see jpeg lossy around text on many commercials and such, like logos and crap.

but the very worst annoying thing, and i blame this on my years of video capping and editing and encoding. when alot of action happens on these channels, the frames get artifacts, then ghosts. when the action slows, the ghost catches up much like poor noise reduction. I HATE THAT

welp thanks for the info guys, i was really wondering, even wondering if my digital to analog converter in my tv was bad. if it truely is alot better now, i would hate to have seen it before.