Cable vs On-Air resolution

MH_Stevens wrote on 2/4/2006, 1:05 PM
I thought I had seen my answer somewhere here before but my searches came up blank. So here is the question:-

Watching TV at home on a standard 1366x768 HDTV that should display 1080i my cable pictures look quite poor and the TV info screen says the resolution being received is 480i. It says this for ALL channels both HD and SD. When watching PBS on Air (which I thought was 1080i but correct me if I'm wrong) the picture is much better so I'm thinking poor cable wiring is loosing resolution or maybe the cable box is configured wrong. If my TV gets a 480i signal will it upscale it to 1080i for display and hence it looks poor? And if I buy a 10480P TV will that upscale a 1080i signal to play at 1080P and maybe still look poor?

Mike S

Comments

Steve Mann wrote on 2/4/2006, 2:26 PM
Your cable company is proably sending you 480i (SD). What makes you think that they are sending 1080i down the wire? Because you're paying for it?

If the original program is in SD, does the cable company is probably sending it to you in SD. They have bandwidth limits just like the OTA TV, so if they don't have to upres or send HD video, they won't.

But you get to pay for it.......
fldave wrote on 2/4/2006, 2:28 PM
Are you sure you are on the correct cable tv channel for HD? Here's my setup:
-full 1080i resolution Sony HDTV (rear proj) with built-in tuner
-large Channel Master antenna in attic with Channel Master signal booster (behind the TV) between antenna and TV.
-el cheapo cable service (ultra basic $11/mo) I don't use cable hardly at all as I have Dish Network satellite. No cable box.

Now, over the air PBS an NBC look fantastic, they are 1080i broadcasts. CBS just powered up and they are not retransmitting much in HD (CBS I think uses 720p). I also get ABC, Fox and UPN over the air.

I switched TV to cable input, and did a digital and analog channel scan. Cox Cable is gradually adding HD, and I keep getting more digital channels. Keep in mind I don't have a cable set-top box. These digital channels are broadcast in the range of about 106.0 to 111.9, so if I am looking at cable channel 3, I use the "down" channel button to go past channel 2 and into the upper channel ranges and keep track of what network is on what channel. Keep in mind that since I don't have a cable box, I don't get the pay HD movie channels. The TV shows me whether it is HD 16x9 or SD, though it doesn't distinguish between 1080x and 720p.

The other day, I found ABC HD on cable channel 111.2. Getting ready for the Super Bowl, in case my over-the air ABC signal is weak and drops out. Two HD channels for Super Bowl!

So I would make sure you are on the correct channel, and if you have a tuner in your TV, try the direct connect like I describe.

Upscaling is dependent on the TV, I would think that all upscale, but I'm sure not all do it well. My brother just got a 50+" 1080p Sony, and it looked fantastic, just like my 1080i. I'm sure if they were side by side you could tell the difference.

480i up to 1080i is a stretch, and if your cable is as bad as my regular SD cable, it's worse. Also, my over-the-air channels look slightly better than my cable HD channels, so I would think there is some extra compression somewhere before it gets to your house.

Edited:
Oh yeah, my local cable provider has a mandate to provide free HD for every over-the-air SD station. Not sure if it is a federal requirement, so I'm not "stealing" the HD signal from the cable company.
Steve Mann wrote on 2/4/2006, 3:48 PM
"... my local cable provider has a mandate to provide free HD for every over-the-air SD station. Not sure if it is a federal requirement, so I'm not "stealing" the HD signal from the cable company."

That's the "must carry" provision that the Cable comapny must carry the local channels as broadcast. There has been an ongoing argument between the broadcasters and the cable industry about the sub-channels when the main channel isn't carrying HD. There was a court ruling recently but I didn't read the details yet.

Steve Mann
TheHappyFriar wrote on 2/4/2006, 5:28 PM
actuatly, they don't HAVE to carry all local stations. They find ways around it. :) (in my old station's case it was the "we have no more room on our lineup" excuse. They only want POPULAR stations, not all stations. :) )

also, FYI... HD doesn't mean better picture. like you've seen it's only better if the source is better.

Also, don't worry about your cables with digital. no dropouts = good connection. Unlike analog, digital doesn't degrade with crappy cables: it just disapears! :) (and 60mph winds on 12 foot solid dish's don't help digital signal eigther.. uhhgg...)
Steve Mann wrote on 2/4/2006, 5:37 PM
I don't know what the timeframe is that you're referring to, but the "must carry" rule says, basically, that the cable company must carry any OTA broadcast station in their Designated Marketing Area.


Steve Mann

jaegersing wrote on 2/4/2006, 5:41 PM
I've been wondering about the quality of cable TV in other countries. In Singapore, the free-to-air TV (via cable) is quite decent, but the commercial cable channels are basically varying degrees of garbage. There are obvious compression artifacts that show they are really squeezing the bandwidth.

And this is all SD. HD trials don't start until later this year, on the free-to-air channels only. Not surprisingly, the cable company is not very keen to talk about HD.

Richard Hunter
fldave wrote on 2/4/2006, 6:10 PM
And the reason that the cable company is so slow in adding HD around here is that they have to negotiate monitarily with each station for the HD feed. Some of the stations are asking exhorbant fees for the feeds, thus the delay as the cable company is apparently being asked to pay for all of the HD upgrades at the station.
MH_Stevens wrote on 2/4/2006, 8:23 PM
fldave:
I am talking here ONLY about HDTV. I'm referring to the HD channels like Discovery HD Theater, PBS etc. My provider in Time Warner and they use a upgrade HDTV tuner/descrambler box. No TV tuner is required except for of air. So for off-air PBS (great picture) I use the TV tuner, for cable HD the Time Warner box gives the signal.

The TV I'm using this week, Samsung LN329R has a resolution of 1366x766 or thereabouts and I'm sure that as LCDs have a native resolution they must convert any signal they receive to that. For off-air reception the TV does not give the resolution being received but with signals from the cable box it does and it says the Time Warner HD signal is 480i. Now I notice it says ALL Time Warner channels were 480i so maybe the TV has a problem correctly interpreting the signal.

While I'm back here I will ask what is the point of 1080P? Is it just the doubling of the frame-rate done by the TV to convert i to p to give a better picture? Does anyone plan to broadcast in 1080P?

Michael
Coursedesign wrote on 2/4/2006, 8:40 PM
what is the point of 1080P? Is it just the doubling of the frame-rate done by the TV to convert i to p to give a better picture?

LCD, plasma, DLP, etc. technologies are all progressive by nature, so any incoming interlaced signals must be converted.

1080p/i contains twice as many pixels as 720p, so you do get a sharper picture, not just in theory but also as can be seen in most bigbox stores when looking at different displays (assuming a competent HD setup which may not always be the case).

fldave wrote on 2/4/2006, 8:52 PM
MH_Stevens:
My PBS coming in from cable is nearly as good as my PBS over the air. Incredible. Saturday Night Live right now in HD is great, as was Harry Potter ABC HD earlier (I have a six year old). Both through cable. No box, and free.

If your Time Warner cable box is telling you that you are getting 480i on the HD channels, then I would call them and have them fix it or refund all of your money if you are paying extra. If there is a difference between your over the air PBS HD and cable PBS HD (simple verification) then have them fix it.

Sounds like something is definitely wrong with your broadcast delivery.
JJKizak wrote on 2/5/2006, 5:59 AM
You have entered the "pandora's box" of HDTV. From what the zillions of users have said on the AVS forum and by the way these comments are comunity related as the problems vary, the OTA is considerably better and more reliable. The cable companies recode the hd stuff and use their boxes to decode it. Their boxes sometimes screw up and I see comments that they are frequently replaced. There is also a problem with the cable signal strength as when it gets down to about -16db they have to add a booster amplifier and they don't like to do that. They try to keep the signal strength at least -12 db. OTA has problems like signal strength and dumb engineers forgetting to flip the switch from SD tyo HD. I use an LG 3510-A tuner with a Sony TV and also the MY-HD 120 card in the computer. I have also seen the new Mitsubishi 1080P DLP's and they are outstanding compared to the 720p's. The 1080P sets have 2 million pixels instead of 960 thousand. The big argument going on now is the first Sony 1080P sets will not let the upconvert pass through the HDMI jack, but the newer ones have corrected this. So you can get burned. Much more info on the AVS forum related to your community and cable company and the models of the cable boxes.

JJK