HDTV: Picture quality based on imaging science

[HDTV Forum]

... I am incensed by banding, macro blocking and other artifacts caused by what is, in fact, greed. This is the broadcasters' dirty little secret as consumers get ready to spend billions on what is, in many cases, a poor substitute for real HD. It seems to me that no one is talking about it. I don't know if it is because we are all afraid the equipment in which we have invested so much cash and emotion may be somehow at fault, or out of fear that HD won't "catch on" if we expose problems. It is actually the case that, if we don't complain now, we are likely to be short changed in the long run. Qui tacet consentire videtur (He who is silent seems to consent).

regards, billb

[HDTV Forum]

Bill,

You have my vote! And your concerns are mine as well and I have the same reaction of disgust and disappointment. HD-DVD anybody?

From Shane Sturgeon on the TIPS List...

"Beware the lollipop of mediocrity. Lick once and you suck forever."
-- Anonymous

I am currently using cable HD and it sucks. Why? They are obviously shaving bits on the OTA channels and it is enough to make a grown videophile cry.

I have posted this in local forums and of course there is no response because of that damn lollipop of mediocrity. They think it looks just fine.

[HDTV Forum]

From the TIPS List

Per James Snyder - industry insider for HDTV and also PBS engineer

DirecTV transmits all of its HD channels with the resolution decreased to 1440 x 1080. The bitrate is dynamically allocated.

Dish's HD tends to compress their HD more, but they transmit at 1920 x 1080. The data rates are dynamically allocated, depending on the compression rate needed and the satellite transponder's available total data rate.

CBS transmits and encodes at 1920 x 1080 at 45 Mbps for transmission to stations, and their VTRs are HD-D5s, so they can reproduce full resolution 1920 x 1080 using only 4:1 compression with a recording data rate of 360 Mbps.

NBC transmits and encodes 1920 x 1080 at 45 Mbps for transmission to stations, but the equipment in Burbank they use for the Tonight Show is Sony. Sony's HDCAM VTRs (which many stations and post-production facilities use) only records 1440 x 1080, and has a much lower data rate of about 145 Mbps.

PBS transmits and encodes at 1920 x 1080 at 19.39 for transmission to stations, uses HD-D5s for on-air play, but many member stations produce using Sony HDCAM's which only reproduce 1440 x 1080.

ABC transmits and encodes at 1280 x 720 @ 60fps with 45 Mbps for transmission to stations. They use mostly HD-D5s for production and play-to-air.

James Snyder

>>But James, What about cable service?<<

I stayed away from describing cable because there are so many permutations spread between so many different cable systems around the country that it would have made the email three times longer and I probably wouldn't haven't gotten everything correct even then.

As a rule, I think you are probably right that OTA HD is best, cable second and DirecTV third.

However, given the very wide range of how cable systems carry HD, whose HD they carry, and at what bitrate non-OTA cable channels are encoded I would say the best way to find out is to contact your local cable provider and hope they can give you a straight answer.

I contacted my local cable provider (Comcast in Alexandria, VA) to ask them about their digital cable service and what HD I could get over it. The operator did not even know what "hi-def" was ("is that as good as DVD?") and could not figure out anybody to refer me to to answer the question. This was after I watched a Comcast ad on my analog Comcast cable tier subscription specifically touting "High Definition" as being a part of the Comcast digital cable package.

**sigh**

In my experience with Comcast Digital Cable in Alexandria, VA (which I tried for three months at a special rate before returning to just the analog tier) I experienced horrendous amounts of digital artifacting (constant blockiness, horrendous mosquito noise, etc.) that indicated to me that Comcast was heavily compressing ALL of the channels it was transmitting over its digital tier. Even the pay-per-view movies, which one would expect they would devote the most bits to since it is a major revenue producing service, were of equally poor quality as the rest of the digital tier's channels.

Clearly these folks still believe the old saw that "digital equals perfect". And the check is in the mail. And unicorns are alive and well in Atlantis.

I would not be surprised, therefore, if Comcast of Alexandria has added HD to its tier (even if they have not bothered to tell any of their order takers) that it would probably suffer similarly low bitrates and make the HD a chore to watch compared to the off-air HD I get from my CBS, ABC, NBC and two PBS affiliates in the Washington, DC area. The question then becomes, "do I really want to pay an extra $60 a month plus equipment rental to get a whole bunch of digitally encoded SD channels of poor quality and a couple of HD channels of unknown quality?"

At this point, for me as a consumer, the answer is no. I am quite happy with my off-air and DirecTV channels. That will change over time, but for now I am satisfied. Not content, just satisfied. For the rest of you, do your own homework and make your own decisions. It is quite likely most of you will find cable HD good if it available to you.

But caveat emptor.

James Snyder

[Doug K]

I just waded through three pages of absolutely wonderful stuff.

Somewhere though, we are missing the point.

HDTV is so good that the intent of the artist can be fully realized

( Richard Fisher )

We all paid more for unleaded gas when they stopped putting lead in.
Point #1 Why do we pay more for something with less?

Consumers paid more for VHS than Beta when beta was a superior format and cost less.
See Point #1

HDTV has resolutional capabilities to render exactly the authors intent, yet we settle for mush pandered by moguls.
See Point #1

Point #2. Unless we as a group act responsively and reject inferior products, albeit with great advertizing, we deserve exactly what we are getting....dumbed down crap!

So... Point #3. When inferior products come along, stop buying them.

Doug k.