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Do Detailed HDTV Listings Exist?

Posted by Cliff on from the tv-guide-needs-an-update dept.

nick_davison asks: "Having finally made the move to HDTV, I've been getting up to speed on the usual debates about HDTV (is 720 rows/frame better than 1080 served every other frame, 540 at a time? Is 1080i meaningless if all your signals are 720, and thus 1080 is just having to resample your image? Is 1080i and 720p meaningless if the digital signals bitrate is so low it's garbage anyway? etc). Trying to form my own opinions, I went looking for TV listings that would at least show the resolution of the signal (1080i or 720p) and, ideally, though I guess less likely, the bit rate. What I ended up with was, if I was lucky, TV listings that differentiated HD and non HD shows on HD channels but nothing more. Do such listings exist? Is this something the TV companies deliberately hide? Is there any way to even piece together this information?"

4 of 31 comments (clear)

  1. Here in Austin... by caperry · · Score: 3, Interesting

    I don't know about where you are, but here in Austin TX the resolutions are fixed by channel. For example, ABC, NBC, PBS, and WB all broadcast at either 480i or 1080i. The FOX affiliate broadcasts at 480i or 720p. These are OTA only. On the local cable company, everything except FOX and ESPN are upconverted to 1080i - why I don't know. I believe the reason is 1080 is a bigger number than 720 and thus must be better. Finally, everything HD on DirecTV is 720p. Bitrates vary (IMHO PBS usually having the best starting in the evening when they turn off the three other feeds they provide OTA) all the time. The best resource I've found has been the AV Science Forum which has a rather large listing of HDTV information for various cities.

    Finally, to add some fuel to the 720p vs 1080i debate - IMHO: it's all about your output device. If your output device is any type of projection (including rear projection TVs) then p is always better than i simply because that's how your device draws the screen anyway. I could be wrong, but at least it seems that way to me.

    --
    -Carl "No, we already thought of that one. 'Why?' '42' - It doesn't fit." -Hitchhiker'
  2. Bitrates? by Trip+Ericson · · Score: 3, Interesting

    There's really no way to deal with listing of bitrates, since the amount of bandwidth given to the stream varies by station.

    For example, NBC29 (WVIR in Charlottesville, VA) dedicates the entire 19.393 MBPS to their NBC-1080i broadcast, while my local NBC station (WSLS in Roanoke, VA) reserves a small amount for a radar feed and serves the rest (in the neighborhood of 16.5 MBPS) to HDTV.

    Further, some stations that broadcast more than one stream do what's called stat-muxing, short for Statistical Multiplexing. This means that when the HDTV feed needs the bandwidth, it is given to it and the other streams are cut down, then when it's not needed anymore, it is given to the subchannel, so there is NO set bitrate. This is done dynamically as it is transmitted, so in a high-motion scene it may draw 18 MBPS, but then change to a scene of someone sitting in a chair talking and drop to 12 or 13 MBPS.

    1. Re:Bitrates? by Trip+Ericson · · Score: 2, Interesting

      Well, the rule is NORMALLY this:

      1080i:
      Everyone except ABC and Fox stations and other properties, such as ESPN.

      720p:
      ABC, Fox, ESPN. Dunno for sure about DirecTV, but it would make sense as they're owned by Fox.

      Now there are exceptions, such as WVEC-13 (ABC) in Norfolk and WFAA-8 (ABC) in Dallas doing 1080i instead of 720p. All Belo stations are doing 1080i, even if they're ABC (they're upconverting it).

      On the other hand, WHRO-15 (PBS) in Norfolk and WCBI-4 (CBS) in Tupelo, MS doing 720p instead of 1080i.

      Most stations maximize the HD at the expense of the SD, so if you realize that an SD stream will survive with about 3MBPS, you should be able to figure the bitrates.

      Now if you want to know what subchannels you have, if you're lucky enough to be near myself or a fellow in Minnesota I have helping me, I've set up a site ( http://www.rabbitears.info/ ) that I've been working on in my spare time. Otherwise, check http://www.avsforum.com/ and look for your market in the Local HDTV forum. Also, you could webmaster email at me rabbitears and dot I info could try to help you out, if you'll give me the city the stations you watch come from.

      I honestly can't say I've seen a big difference between 720p and 1080i, though 720p is less likely to "pixelate" in high motion. I have a front-projector that has been well-calibrated and it does 720p, and that's the only thing I've noticed different about the two.

      If you have any more questions, feel free.

  3. HD Sports Guide by angle_slam · · Score: 2, Interesting

    If you're interested in sports, check out HD Sports Guide, which shows what sports are available in HD and in what resolution they will be aired.