As documents say an HDTV channel requires at least 13mbit.Many HDTV chans on satellite/cable go as low as 7 (eg ExpressVu & DishNet with own experience) which looks simply horrible!
Question to wise technicians out there: would love to know bitrates of Rogers Cable and OTH HDTV channels in Ontario because of deciding where to go first after sat. flopped for me.Hope to find out this here as nobody was able to tell me this before.Thank you in advance!

ATSC bitrates are variable, up to 19.8Mb/s.

Thanx automan1, it's pleasant to know but what's the minimum also?How many out of Ontario ones are actually 20mbit?

There is no official "minimum"... as far as I know all major network feeds use the full available bandwidth. If the local station wants to also run a subchannel or two, they'll compress the main channel down further to make room. Sometimes this is quite noticable.

Fox is a somewhat special case... if I remember correctly they've got new advanced variable bitrate encoders and can actually squeeze their video further, down to about 15mbit, apparantly leaving room for at least one "free" subchannel.

I've done side-by-side comparisons between OTA HDTV and Rogers Cable HDTV and OTA is quite noticably sharper.

If you have a DTV video card or USB DTV interface for your PC you can download a lite version of TSReader from www.coolstf.com.

Here is a short discription taken from the web site.
TSReader is a transport stream analyzer, decoder, recorder and stream manipulator for MPEG-2 systems. It supports DVB, ATSC and Digicipher® II extensions to the base MPEG-2 specification.

I have seen "DTV" used as an informal abbreviation for DirecTV, but I did not know that they make video cards or USB computer interfaces. Are you referring to another brand?

Then again, it took me three or four times seeing "RS" on this site before I figured out they meant Radio Shack....

I think he just means Digital TV, or ATSC digital transmission. DTV meaning DirecTV has mostly faded because it is such a generic term, too many people used it for too many things. That's why most forums now use D* as shorthand for DirecTV.

I wish someone could compare TWC in the Raleigh, NC area on the PBS channel to the OTA HD signal. I have noticed for along time how close ups on the HD OTA channel become pixelated momentarily than they go away. First noticed it in a running water close up.
I wonder if the TWC HD version does the same thing.

I have talked about this before on this Forum.

I assume that PBS is compressing the HD bitrate in order to simulcast their other subchannels.

I was putting up with it but... the better half noticed it for the first time last night.

-Don B

PBS is a perfect example of over-compressing their HD bandwidth. The Buffalo station has two subchannels and their HD is still mostly watchable, but a while ago I pullen in Rochester PBS with THREE subchannels and their HD was visibly more compressed.

Wait, wait...this is going in other direction.
I would like to know which is average or min+max bitrates of, at least, main OTH HD channels because that matters the most actually.If it's 15mbit then it's not too amazing and 20 is another thing where under 15 is pretty poor, pixelated picture.
Daniel Tonks: "feeds use the full available bandwidth" <<==so that's exactly what i'm asking: those full available ones are...(For each station)?Carriers vary from 10 to 35mbit which makes SO MUCH difference!
Example of answer: PBS Buffalo 20mbit 1080i two sub channels/3mbit each.Thank you.

Here's an interesting site: [Link: widemovies.com]

Not near Buffalo, but the idea could help someone.

DJG,

I guess a straight calculation of "PBS Buffalo 20mbit 1080i two sub channels/3mbit each" works as long as the stations don't use variable bitrate encoders.

I still have not figured out how you guys are coming up with mbit numbers. Sounds like it is PC based.

-Don B

Barlow, i just wonder why nobody is interested in posting actual bitrate information around because quality depends on it and is nice for comparising with cable, sat. ones.
There's two ways: using stable or VBR (variable) bitrates and both are easy to find out.Difference is only in that stable is around one number and VBR can change from min to max or have average bitrate.I'm not using receivers so there might be other case (which i doubt) but with DVB cards it's very simple as every PC media player is showing you resolution, sound and picture standard/bitrates in real time.I bet receiver is supposed to have an option to find that out.
If it's not such a big of a deal between 5+mbit of difference that happens then i donno what to say.

Spiky, thanx a lot!At least gives general idea.Looks like DishNet & co. are finally started to add more bitrates but 9mbit average on Showtime, for example, is still ridiculous.

DJG,

Thanks for patience with my ignorance. I agree 100 percent that the more info we have in front of us the easier it will be to understand HD.

I asked some of my coworkers who use Tivos and the like and they were not familiar with bit rate. I will introduce the TSReader software to them.

So I guess we are all learning.


Spikey ,

That site you posted helped a lot in my understanding of this.


-Don B