Question re: HD lite on D* vs. OTA

[BuffaloDenny]

I've read here that D* is giving us what's being termed as "HD lite" on their HD channels via various compression techniques. I was wondering, if we are receiving HD broadcasts through our local channels via OTA antenna, is that compressed in any way as well? Or are we getting the true HD quality via OTA? Personally, I don't notice a difference when I watch the same broadcast on say channel 82 via satellite vs. my local NBC HD broadcast via OTA.

[Dssturbo1]

yes, it is compressed also but not near as much as dtv has to. and some dtv hd channels are worse than others.

[fatcat220]

Thanks for the question. I have the same set up and I don't notice a difference between OTA and DTV HD broadcasts.

[Dssturbo1]

yes, it is compressed also but not near as much as dtv has to. and some dtv hd channels are worse than others. and yes, alot of the time you will not see a difference.

[Sirshagg]

I've noticed OTA is usually significantly better than D*.

[djb61230]

My local NBC is multicasting three sub-channels. A weather loop, music video and a UPN feed. To my eyes it makes the main HD channel look like what I remember from D*. I have to go from memory because I dropped the D* networks when I was able to pick up all the big 4 nets OTA.

[TyroneShoes]

There are two distinct differences between DTV and OTA. One is the amount of compression, which is more on DTV than on OTA. There is also an implied second-gen re-encode tied to the second distinct difference, which is the rescaling of 1920x1080 to 1280x1080. This implies a lower ceiling on horizontal resolution for DTV compared to OTA 1080i, but not necessarily any difference in actual pr perceived resolution (the source material has to actually have H resolution greater than 1280 to make a visible difference, which is rare). And for 720p content it doesn't matter.

The visual differences in the compression are also typically not visible, because unless the signal is bit starved, lower compression has no more fidelity than higher compression (at least when the difference is not a marked one, as in this case). Since video from DTV is only bit starved during fast motion, transitions, rapidly-changing video during transitions or fade-outs, etc., the times when the difference is visible is limited to only a few frames out of every few hundred frames transmitted, which for the most part is invisible to most folks.

DTV has had to cut these corners due to limited bandwidth. The rescaling is actually done to improve (lessen) the amount of artifacts that would be visible at this compression level without rescaling. They are visible differences in some cases, but are well-chosen necessary technical compromises that are not noticeable for the most part, or at least that's what the DTV engineers keep telling themselves over and over.

[newsposter]

buffalo all you wanted to know and much much more

http://www.tivocommunity.com/tivo-vb/showthread.php?t=277955