Leaf Fan:
working on it, wait untill i have more info. i have sent emails to the locals and the specialty networks in regards of what format they are sending their signal to BEV.
there is difference of course otherwise the 2 standars would have not being developed. 720p is more suitable for sports and fast moving kind of programming. 1080i on the contrary better for still pictures , documentaries , nature views , dramas and things alike.
resolution wise if seated more than 3 times the height of the screen (not the diagonal distance but the actual vertical height) you will not tell any difference. but if you watch closely you will notice that fast moving objects or sections of the screen will macroblock in sporting events when broadcast at 1080i (even at 720p at some point they will too but it is more obvious at 1080i). for instance the legs of a ballerina, the football itself, any backgrounds when camera pans (most noticeable on dark backgrounds). After all ATSC broadcasters (OTA UHF) only have 6 Mhz bandwith available. That is basically why US networks like FOX and ABC decided to go 720p because their programming is more sports oriented. PBS, CBS and NBC on the contrary decided to go 1080i due to their documentary and dramas and primetime shows programming. Some local stations like PBS Buffalo, for instance, after starting in 1080i changed to 720p more than a year ago in their OTA broadcast due to severe compression artifacts that started to appear mainly also because the multicast with 2 more digital channels. It also boils down to your set up , TV set in this case for PQ, as I remember back in the summer of 2006 when the before mentioned PBS Buffalo station problems started I did not noticed half of the problems that OTA users were reporting on the www.remotecentral.com/hdtv website. I was only using a CRT-based 1080i 29 inch TV at the time. Bigger screens give you a better picture of the problems. It is also important to differentiate compression artifacts due to bandwith constrictions to other local problems related to your TV and its scaler and display technology and so on.
It is apparently broad consensus among forums members that as of today only the CBC HD is broadcast by BEV in 1080i , the rest of the channles i repeat apparently are all 720p. CBC HD , TSN HD enjoy 1 TP each for them self.
local OTA UHF format wise this is the configuration as of today. All Canadian Networks broadcast 1080i , the only exception i beleive is the new Global HD (channel 65 UHF)which is testing 720p but I can not say for sure as I have not being able to receive it yet. will have to play more with the UHF antenna for that.
Buffalo stations like PBS, FOX and ABC affiliates also use 720p and all of them multicast up to 2 additional channels. PBS HD national feed is actually 1080i so maybe PBS Boston that BEV carries still uses 1080i. The rest major US networks Buffalo affiliates use 1080i with NBC multicasting a 480i weather channel. for obvious resons due to no multicasting at all , CBS Buffalo , has the better PQ most of the time for any kind of programming. full 19.4 Mb/s or if you prefer 6 Mhz bandwith is dedicated by WIBV for their 1080i programming. A good opportunity to test PQ for all major networks is when there is elections or the address to the nation programming. All networks are broadcasting the same content and program but the only difference is their own equipment (cameras included) and thei broadcasting facilities and technologies. To really view the diferrences you have to view your tv very close , not at your usual location, probably for most users beyond the 2.5 to 3 times the screen height.
this a response of PBS HD national feed about the 720p Buffalo affiliate.
Mr. Fdez:
Glad to hear you are enjoying PBS programming, especially in HD. The
decision of which HD format a local PBS station uses, 720p or 1080i is
that station's decision. But there are other factors that can affect
picture quality and I would be surprised if it was simply the difference
between 720p and 1080i. Also at viewing distances of 3 picture heights
or more (3 times the measured height of your screen) you should not be
able to distinguish a difference in resolution between 720p and 1080i.
So if you are noticing this at what would be normal viewing distances I
would suspect something other than the format difference. I will pass
along your concerns to the station but I would also encourage you to
also contact them directly with your observations.
Thanks for supporting public television
Best regards,
PBS Station Relations
Granduncle quoted a link that directs to the BEV technical forum that has very usefull info on this matter. apparently BEV is upgrading their facilities to allow local stations and networks (like CBC, CTV and maybe who knows specialty channels like TSN) to send their full HD signal via fiber optic cables therefore BEV encoders and stat mux equipment will do a better job than when receiving the same channel at even 1080i with 19.4 Mb/s available for them. I say this because some BDU's apparently relay on others providers signals or even satellite communications that already are multicasting several channels to pipe their programming to BEV facilities.
As consumers we should report this PQ to BEV but also I would encourage people to report this to the stations and networks it self.
The decision of a BDU to wether they use 720p or 1080i is based on technical reasons of course and broadcast engineers most of the time they have their hands tied with not too much room to improve. everybody wants more HD channles but no one is willing to give their BDU's more bandwith to acomplish that. My gripe is that their CSR and Store people tell you one thing and the reality is another but that is out of the scope of this post or thread.
CRTC rules allow BDU's to braodcast their programming at at least the same quality they receive it , so therefore gives them some room to agree with the stations or networks to send them the programming in 720p instead of 1080i. an example could be CBC HD broadcast 1080i and more importantly produce the signal at 1080i but then send it at 720p for Rogers cable for instance. Global HD produces a 1080i signal but sends a 720p version to BEV. Therefore complaining to the CRTC is not an option.
post too long already , i better stop now and do something else, lol lol lol lol
Hugh , I have not forgot about your question , but I am still debating myself on an answer. Because apparently I have no idea what i was talking about, lol lol lol. is it because the canadian in me , if any, or the cuban one, lol lol lol.
Thanks for reading, and have a great day
Juan J. Fernandez
