Info about US tv

[daWsOn_s]

This thread are for US people :)

Hi,
I'm very interested in knowing the best the US transmission.
These are the questions, please be very patient.

For what I know free networks like ABC, NBC, CBS, The CW, FOX etc do SD and HD multicast. Visiting the related sites I read "find your station" or something like that so I would suppose that these channels are transmitted via ATSC, your national digital terrestrial standard.
ATSC supports from 19Mbit to 38Mbits (cable Tv), so how could you possible have so many HDTV (on ATSC 19Mbits) channels on this limited bandwidth? I mean a good mpeg-2 720p require at least 15mbits right?
How many frequencies can you have? ATSC is also used for SD channels for people who don't have HD receiver? Do different networks share the transponder size? Do they use mpeg-2 or h264 for SD and HDTV, what are the resolution?

I'm really really curious so please tell me everything about your digital system.

Hope a lot of people will consider join this thread.

PS: I'm Italian, the digital terrestrial TV (DVB-t) is really really boring and so out of quality. At the moment the government is not investing on the technology and we're currently stocked at the point that no one is trying to offer something new because the channels are all full with digital and analog TV. NO ONE has a great SD quality, no one uses full pal (720x576i) with enough quality, no one uses AC3 for at least stereo sound (still MP2), the widescreen is STILL unknown in ANY network.

Thanks

[Guest]

Hope a lot of people will consider join this thread.
If I could make any sense out of your posting I would try to answer it. Try asking one clear, concise question.

[JohnnyMalaria]

US television sucks.

The video quality and the programs.

I'd prefer to watch European programming in PAL any day.

My equipment is analog. My programming is via satellite so it's digital - and it's crap. All kinds of artifacts as they cram more and more pointless channels into the satellite bandwidth.

I much prefered my analog cable. The picture quality was better and I never lost it. I lose satellite during heavy rain.

Well, that's what I have to say on the matter :p

[d1g1ta7]

Each channel gets 19mbit, rather than all channels sharing the same bandwidth. So you can have ABC @ 19mbit, CBS @ 19mbit, NBC @ 19mbit, etc.. all running on different frequencies independent of each other.

[JohnnyMalaria]

I'm not refering to channel allocations.

The satellite has a finite bandwidth into which all the TV channels and other communications have to be squeezed.

On nearly every channel, I see severe motion artifacts due to over-compressed MPEG2. And it's getting worse.

[Guest]

Johnny, ATSC refers to terrestrial broadcast, not satellite broadcast.

[daWsOn_s]

Hello everyone, I'm sorry if I wrote in bad English but I'm italian as I said :)

So...I would like to know: if every network gets all bandwidth where do they broadcast the SD channel?
Maybe I misunderstood the mechanics of ATSC but don't you have single limited channels? For example DVB-t uses the same stations and same technology of analog tv in fact there are at least 50 channels-transponder which can provide 24mbit each one.

Please tell me:
- how do you receive the SD channel
- how do you receive HDTV channel
- what is the quality and what is the compression?
- if they are completely free and if there is some other option to receive them, like cable or satellite for free

:thanks:

[Guest]

Terrestrial ATSC is broadcast using radio waves from antennas. The bandwidth that used to hold an analog channel now is used to transmit a digital transport stream containing MPEG2 video and AC3 audio. That transport stream can contain multiple progams. For example, here in Chicago, WTTW 11 digital sends 4 programs in their stream. One is 720P HDTV, and three are SD. If I remember correctly, the HD channel is about 11Mbps, so the SDs take the other 8Mbps. The SD channels are pretty poor and the HD is passable. The programming is free. Local channels can sometimes be received on DirecTV if you have the local channels option. You can also get the local HD feeds if you have the HD package.

[JohnnyMalaria]

if they are completely free and if there is some other option to receive them, like cable or satellite for free

Right now, you can get local broadcast (free) channels via satellite but you have to pay extra - at least that's the case with my DirecTV satellite service. (I can get the New York and Los Angeles local channels for free which is stupid.)

When I used to have cable, all the local stations were part of the basic package - no need to pay extra.

I hate satellite :mad:

[daWsOn_s]

ok :) for example WTTW 11 has one 720p program, what is it? And the other 3 SD channels are from the same network? (only mpeg-2 is possibile? no h264?)

So the analog channels don't exist anymore from antenna?

Another example: ABC transmits HD via ATSC ok, but if a person does not have a digital receiver or a HD receiver what does this person do? The SD/HD simulcast is one the same transponder?

[daWsOn_s]

Right now, you can get local broadcast (free) channels via satellite but you have to pay extra - at least that's the case with my DirecTV satellite service. (I can get the New York and Los Angeles local channels for free which is stupid.)

When I used to have cable, all the local stations were part of the basic package - no need to pay extra.

I hate satellite :mad:

So if direct TV service offers the local broadcast channels this means that not everybody can receive via antenna these channels, what about the coverage?


I have another question.
If I see "Hereos at 9/8 central" what does it mean? USA has 4 time zones so when do New York and Los Angeles see Heroes?

[JohnnyMalaria]

Yes, not everyone can receive via antenna. I live about 8 miles from some of the transmitters and can't get anything without lots of noise except one. I'm not using an external attenna, though. I suspect if I installed one then my local channels would be a lot better! And, frankly, television doesn't rule my life in the way it did 20 years ago. But they are ugly (so are the satellite dishes). I used to live in a house that had a very large, motorized rotating one.

9/8 central means: 9 Eastern, 8 Central. It can imply 7 Mountain, 6 Pacific but not always. Sometimes a program will be broadcast at 9/8 Central only in those regions. It will be broadcast by West Coast providers at 9/8 Pacific. Usually, if it is broadcast across the country, you may see 9e/6p.

[daWsOn_s]

Yes, not everyone can receive via antenna. I live about 8 miles from some of the transmitters and can't get anything without lots of noise except one. I'm not using an external attenna, though. I suspect if I installed one then my local channels would be a lot better! And, frankly, television doesn't rule my life in the way it did 20 years ago. But they are ugly (so are the satellite dishes). I used to live in a house that had a very large, motorized rotating one.

9/8 central means: 9 Eastern, 8 Central. It can imply 7 Mountain, 6 Pacific but not always. Sometimes a program will be broadcast at 9/8 Central only in those regions. It will be broadcast by West Coast providers at 9/8 Pacific. Usually, if it is broadcast across the country, you may see 9e/6p.

Thank you I finally understand!:thanks: