OTA channel not 1080

January 21, 2022 1:43 PM

I recently purchased a new TV and installed a small/med sized attic antenna. I am getting great reception on a large number of channels. However, only one major network channel only comes in at 720 instead of 1080. Is it an antenna reception issue or some other issue? (That channel's tower is at the same distance and direction as the other network channels where the antenna is pointed.)
posted by roaring beast to Technology (6 answers total)

Best answer: Some networks are 720p.
posted by GCU Sweet and Full of Grace at 1:47 PM on January 21, 2022 [5 favorites]

Best answer: If there's a signal quality issue you'll see pixellation, drop outs, etc. The resolution is completely unrelated to the signal quality- it's not like internet streaming where a slow or poor connection will force the resolution lower to attempt to compensate- the resolution the station transmits in is the resolution you'll receive.
posted by Larry David Syndrome at 1:56 PM on January 21, 2022 [4 favorites]

Best answer: Broadcast TV isn't like streaming - it doesn't "buffer down" to lower resolutions if your signal is bad, it stutters or breaks up. If you're getting 720p, your local affiliate is simply broadcasting in 720p.

I have a pretty new 4K ATSC 3.0 tuner and good signal strength from my antenna, I'm picking up HEVC feeds from my local stations, and while things look great, I can assure you that I haven't actually seen *any* of my local affiliates broadcasting in true 4K yet. One day.
posted by eschatfische at 2:22 PM on January 21, 2022 [1 favorite]

Best answer: Seconding the above answers. Of the "big four" major networks that broadcast over the air, for ATSC 1.0, CBS and NBC use 1080i, and Fox and ABC use 720p. They've been like that since they started broadcasting in digital, and I just double checked with my antenna here in the Denver metro and that's still the case. With the new ATSC 3.0 standard that is super brand new, everyone should theoretically be all on 4K eventually, but it's early days and besides, there are few TVs or tuners that can receive those broadcasts currently.
posted by zsazsa at 2:34 PM on January 21, 2022 [1 favorite]

Response by poster: Ok, that makes sense! Thanks everyone!
posted by roaring beast at 2:59 PM on January 21, 2022

Just some background on this ... About 20 years ago when this digital TV revolution was finally getting going, 720p and 1080i were the two major formats to choose from. Each network (ABC, CBS, etc.) could choose whichever one they wanted, because both fit well into the over-the-air bandwidth that had been allotted by the FCC.

You might think 1080 is better than 720 because it's a bigger number (higher resolution), but that's not necessarily the case, thanks to that pesky p vs i. Progressive frames give you an entire still frame of video in one go, but interlaced frames require two frames to give you the entire picture, because each frame actually only gives you half the picture. It's like two combs, and only when you have both (with the teeth interlaced) do you get the whole picture.

Where interlacing really sucks is sports. When you have high motion (e.g. fast panning shots of action), or want to do slow-motion or stop frame analysis (e.g. is the ball in or out?), interlaced video is a disaster. Progressive crushes it. (and by the way, badly deinterlaced video is a surefire way to detect amateurs working with video)

ABC and Fox had / have sports-heavy programming. They decided to go with 720p. NBC and CBS had more non-sports programming (e.g. dramas, comedies) and went with 1080i.

(now don't get me started on 3:2 pulldown)
posted by intermod at 8:19 PM on January 22, 2022