Picture Quality Question

Discussion in 'Over the Air TV By RabbitEars.Info' started by andy_horton, May 22, 2017.

  1. Last night I was watching the Billboard Music Awards on ABC on my antenna. If I remember right, they broadcast in 720p. I noticed more "little pixels" than normal, even when they broadcast events that have a lot of motion and colors it seems to have looked better than the awards. Could this be caused by my local affiliate also using .2 in HD and .3 in SD? Fox is on .2 and Weathernation is on .3 (don't figure much motion would've eaten up much bandwidth on that.) Just curious. or maybe just the feed? Thanks. But it really overall looked vivid, and sharp!! Just more little pixels when a lot of motion was going on. My tv has a refresh rate of 60 if that helps. Only a 32 inch. Andy
  3. Your theory is correct. With only a limited amount of bandwidth, something needs to be compressed to fit multiple channels on a single channel allocation. To broadcast two channels in HD, they have to reduce the bitrate on both channels. A lower bit rate will look fine on pictures with little motion, but depicting motion requires more data, and the lower bit rate can't keep up, so data packets are dropped and that results in the pixelation you see.
    Tampa8 and andy_horton like this.
  4. The days of OTA being superior to everything are long gone. WIth the right broadcast equipment, you may be able to wring two 720p channels out of a RF channel. Any less than the best multiplexers or additional channels will likely cause noticeable degradation. My DMA's PBS station, KOPB, has two 1080i live feeds (OPB and OPB Plus), an SD live feed of PBS Kids and three stereo audio feeds (with a slide show) and the damage can be quite apparent. My ABC channel that has ABC HD (720p), MeTV HD (720p) and Comet (SD) and ABC looks horrible during confetti drops and shows with lots of flashing lights (like awards shows and DWTS). Confetti drops can kill just about any HD feed.

    As the repack progresses, some may get a little better as new equipment may be installed. If an ATSC 3.0 push comes, things will likely deteriorate as some stations will likely share channels and there will be multiple HD feeds on many DTV multiplexed RF channels.

    Yes, ATSC 3.0 can handle more channels, but that doesn't help the stations that must still broadcast DTV until it is no longer the standard. The theory people can talk until they're blue in the face, but the reality never seems to get particularly close to the theoretical ideals.
    andy_horton likes this.
  5. The Georgia PBS main feed is HD, and then they have Create, Knowledge/World, and PBS kids. I don't know what setup they have, but all channels look absolutely incredible, even all the ones just in SD. I look at those channels and originally I thought they were being broadcast in HD!! I had to hit the info button on the remote to verify the .2, .3, and .4 were in SD only!!
  6. There's some pretty amazing equipment out there but many stations haven't kept up.

    As for not being able to tell the difference between SD and HD, perhaps you're vision correction is not up-to-date or your display is too small to take full advantage of HD.

    Of course many thoughtful posters (and most all C-band weenies) have long held that a great SD stream trumps a poor HD one.
    boba likes this.
  7. All the other channels that are in SD I can tell. But WNGH compared to WTCI with the same shows on, main PBS both in HD, WNGH is deeper, more rich HD. Create on WNGH looks incredible for an SD channel compared to WTCI because I notice a lot more pixelation on the WTCI Create. WTCI PBS Kids utilizes full screen SD and so does WNGH, but there is a definite difference in PQ. I have a 32" HD TV, and just got new glasses last August....
  8. Years ago Ct PBS was broadcasting on three sub channels and finally had to drop to two because it was so affecting PQ.
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