Sky to transmit all its own HD channels in 1080i

[blun]

The whole HD thing still seems to be so up in the air.. I think I'll stick with my good 'ol CRT for a bit longer and wait to see how it develops.

Anyone know what the plans are for HD terrestrial?

[Rave]

Are they even going to have sky sports in 1080i? Because that would suck ass.

[Nick F]

Originally Posted by Rave

Are they even going to have sky sports in 1080i? Because that would suck ass.

Yeah they will but you can get the transmission converted to 720p which is much better for sport

[Alex]

I think that the Sky HD box will output on either 1080i or 720p depending on the signal it receives, or you can force it to one or the other regardless of source if you'd prefer. We shall see soon enough

[Rave]

Originally Posted by Nick Flood

Yeah they will but you can get the transmission converted to 720p which is much better for sport

Yes, but if the original transmission only contains (effectively) 25 frames per second of picture, the motion is simply not going to me as smooth as if it contained 50. Clever algorithms might be able to put some otf the smoothness back but it would be better if it was there to start with. You might be able to see the blades of grass clearer with a static camera, but the pans etc. are going to look worse. It's total daftness, there's no technological reason why they can't broadcast a mixture of 720p and 1080i material, and ATM you can count the number of true 1920x1080 resolution TV screens on the market in this country on the fingers of one hand. 99% of the installed HD base here is 1366x768 or lower, so is incapable of displaying all the pixels in a 1080i signal anyway.

Put simply, they're choosing to transmit extra pixels which most people can't use, instead of extra smoothness which most people can.

For films, of course, 1080i is fine. There's no point using 1080p when your source material only contains 24 full frames of picture per second, and you can get more detail for a similar use of bandwidth than if you used 720p.

[TheAnimus]

what?! there's no technical reason why they can't broadcast a mixture of 720p 1080i.

yes there damn well is. It costs bandwidth, and money in transmission. The source data has to be in that format (why do conversion for the transmission, when it could be done at the end box). Myself i'd prefer 1080p, but thats just that.

besides the only time you'd really notice 1080i is on objects like the football, crass you wouldn't because of how the human eye tends to view textures in motion, its only when its a known form that is moving the eye can detect the "interlacing" at the edges.

[Rave]

Originally Posted by TheAnimus

yes there damn well is. It costs bandwidth, and money in transmission.

Erm...no? As already stated, 720p is slightly lower bandwidth than 1080i, so there's no problem transmitting sky sports in 720p and the rest of them in 1080i. They don't have to duplicate the transmission in both formats.

The source data has to be in that format

Again- no? There's no reason why they can't film it in 720p.

besides the only time you'd really notice 1080i is on objects like the football, crass you wouldn't because of how the human eye tends to view textures in motion, its only when its a known form that is moving the eye can detect the "interlacing" at the edges.

Erm yes, the ball and the players will show interlace effects. Not like they're important in football is it.

[Bob Crabtree]

I really don't mean to take the Mickey but what I'd be really keen to hear is people's first-hand experiences of problems they've seen with their own eyes of 1080i footage of sport or action.

We all know the theory but it's amazing what the TV-set makers can do with electronics and my guess is that they'll be trying very hard to use electronic trickery, possibly including interpolation and 100Hz, to prevent the viewer seeing the artefacts that untreated 1080i might show.

Anyone able to comment from experience?

Bob

[TheAnimus]

Rave mate, its not that simple at all.

You can save a lot of money just broadcasting in one constant format.

if you've got 1080i camera's covering the sport, then how can you just film it in 720p without extra cost. Then hardware constantly picking n choosing between the two, mixing between the two, its expensive.

Now, interlacing, with football, will only matter when something is panning against a form you know well. A football player will not look hideously stupid on 1080i.

I've seen a demo by Samsung of F1, which generally moves a bit faster, and just as tediously as football, and i couldnt tell the difference between 1080i/1080p But i had been drinking the free drink. Its worth noting this was only a 40" screen.

Also i don't know what the interpolation rate was. As bob's said they might use double our frequency. (thou now adays this makes little sense).

My guess is, if we're lucky will see that magic 76hz, aka enough to shut us up.

you have to remeber that with a lot of these highdef camera's they're using clever trickery to reduce the cost, now apparently they can do something with a cheap layer over the sensor to provide interlacing at about 3/4 the cost of progressive scans. Thats quite neat.

[browri]

okay....here's the thing.......my friend is convinced that it is impossible technically, physically and in all other aspects to transmit a 1080i signal from the satellite down to the dish on the ground......and that essentially the signal that the satellite providers are giving is only about 520p

can anyone supply some proof for me that transmitting in 1080i is now possible? i'm waiting on an email back from directv in USA and Sky here in New Zealand for proof because both have claimed that they are now transmitting their channels in 1080i and that the boxes that they supply their customers can downgrade the signals to 720p for the TVs to handle them....

[Skinleech]

Sky's broadcasts are sent out at 1080i50, so if you can find a way to play them back on your PC, and set your decoder to not use any deinterlacing, you'll get playback at 1080i25, which equals 1080p, so it's certainly not impossible.

[directhex]

ehm..... your friend is clueless

some sample stream grabs from around europe give the following resolutions:
1920x1080 anixe.hd.ts
1920x1080 arte.hd.ts
1920x1080 astra.hd.ts
1920x1080 premiere.hd.ts
1920x1080 prosieben.hd.ts
1920x1080 sky.movies.9.hd.ts
1440x1080 bbc.hd.ts
1440x1080 euro1080.hd5.ts
1440x1080 hd.forum.tf1.hd.ts
1280x1088 luxe.hd.ts
1280x1080 luxe.hd.ateme.ts

we're talking DIGITAL satellite/cable here. the resolution is encoded into the video files which are sent around - what matters is the bitrate. Some carriers are pushing up to about 22 MBit, some as low as 6 (DVD, for comparison, is up to 10; freeview is up to 8)

[shaithis]

Originally Posted by directhex

we're talking DIGITAL satellite/cable here. the resolution is encoded into the video files which are sent around - what matters is the bitrate. Some carriers are pushing up to about 22 MBit, some as low as 6 (DVD, for comparison, is up to 10; freeview is up to 8)

Comparing bitrates across compression schemes can be very misleading.

MPEG4 is a lot more efficient then MPEG2 and therefore would require a lesser bitrate to deliver the same image as MPEG2.

[directhex]

Originally Posted by shaithis

Comparing bitrates across compression schemes can be very misleading.

MPEG4 is a lot more efficient then MPEG2 and therefore would require a lesser bitrate to deliver the same image as MPEG2.

which is why you can get away with double the bitrate with six times the resolution

and why US HD sucks (since it's dvd bitrate at best, mpeg2)

[Skinleech]

Originally Posted by directhex

which is why you can get away with double the bitrate with six times the resolution

and why US HD sucks (since it's dvd bitrate at best, mpeg2)

US HD does have it's flaws certainly, but not all bitrates are that low. Several stations/channels send out 15mbit plus feeds.

Some episodes of Lost were aired with 40mbit average, 640k Dolby Digital sound tracks, and clocked in about 12gb without the ads.