HD movies on Sky

[fayeanddavid]

What or how do Sky use as their source for the HD movie brodacasts, would that be from a 1080p BluRay source that is "down scaled" to 1080i?
I got to thinking that it wouldn't (??) be standard movie source (as in what you pay to see at the movies) as the PQ does seem quite poor in a movie house, hence the question.
Ant thoughts on this?

 

[Anonymous]

sky only broadcast in 720p fella they dont broadcast in 1080i

 

[fayeanddavid]

hmmm...............I was under the impression that they broadcast in either according to the source material?

Are you saying then that 720p is then "upscaled" to 1080i as per the selction you make in the Picture options screen, begs another question, is it better to leave as 720p?

Shouldn't deflect from the original question though re HD source though?

 

[daveh75]

arnott73: sky only broadcast in 720p fella they dont broadcast in 1080i

No they dont.

They may have done in the early/testing days,but thats certainly not the case now. All UK HD broadcasts are 1080i.

The horizontal resolution can vary though, BBC HD, ITV HD and LUXE HD for example are all broadcast at 1440 x 1080i

 

[robjcooper]

fayeanddavid:What or how do Sky use as their source for the HD movie brodacasts, would that be from a 1080p BluRay source that is "down scaled" to 1080i?I got to thinking that it wouldn't (??) be standard movie source (as in what you pay to see at the movies) as the PQ does seem quite poor in a movie house, hence the question.Ant thoughts on this?

It'll be delivered to them on an HDCamSR tape as a 1080 24psf master (if it's a movie) and can possibly be 4:4:4 although Sky's preferred deliverable HD spec is 4:2:2. However, HDCamSR machines are capable of playing those tapes at 1080 50i and converting from 4:4:4 to 4:2:2, so the content can then be uploaded into the transmission servers. It could also be at this ingest point that the full HD signal is compressed into the H.263/Mpeg-4 AVC format which is used for transmission.This may not be the exact route Sky use, but it gives you some idea what the broadcasters do to the lovely masters that they are supplied with ! That master will have either been transferred to tape from 35mm film on an HD telecine or more likely with modern movies, downresed to tape from a 4K or 2K datafile of the DI master.

1080i is not a downscaled version of 1080p. Intrinsically they are both the same. 1080 50i consists of 50 separate and individual fields of information per second, each field consisting of half the resolution contained in a frame. 1080 25p consists of 25 full resolution frames per second. It takes far less bandwidth to transmit 50 smaller pieces of information in a second than 25 full frames.

In a properly lined up digital cinema the picture quality should be excellent (at work we have 2 Digital Intermediate grading and effects suites (which are mini cinemas) which are meticulously aligned constantly so that what you see in a digital cinema (and when they appear on BluRay) will be as near to the director's vision as possible) and will be far less compressed than anything Sky or any other broadcaster is transmitting. As to film based cinema, depends how experienced the projectionist is, which as a lot of them these days seem to be just out of school possibly explains a lot !

Oh and all Sky's HD broadcasts are 1080i - the Sky box has the option to convert to 720p, but they are not transmitted that way.

Rob

 

[fayeanddavid]

robjcooper

Exellent reply and tutorial.

Thanks very much for the technical aspect as well as making it simple enough to follow.

Top man

 

[Anonymous]

robjcooper:HDCamSR machines are capable of playing those tapes at 1080 50i and converting from 4:4:4 to 4:2:2, so the content can then be uploaded into the transmission servers.

Always preferred 4:4:2 meself!