Does UPC HD Transmit in 720p or 1080i?

guv999

Hi
Can anyone confirm if the HD channels transmit in 720p or 1080i on UPC?
I am getting 720p but know that BBCHD does send out a 1080i signal
Thanks

200motels

guv999 wrote: »

Hi
Can anyone confirm if the HD channels transmit in 720p or 1080i on UPC?
I am getting 720p but know that BBCHD does send out a 1080i signal
Thanks

I'm not sure. But theirs not much difference between 720p and 1080i.

GrumPy

1080i is arguably worse then 720p anyway.

Mikey23

There's a setting on UPC's HD box where you can select 720p, 1080i, or automatic. The last was a bit irritating the first few days I had it, as my TV would switch mode fairly often as I browsed channels, so I've left it at 1080i.

guv999

Mikey23 wrote: »

There's a setting on UPC's HD box where you can select 720p, 1080i, or automatic. The last was a bit irritating the first few days I had it, as my TV would switch mode fairly often as I browsed channels, so I've left it at 1080i.

i hadn't noticed that myself. I will take a look. Thanks

who_me

I've a 720p TV, but some time ago I tried setting the cable box to 1080i to see what would happen (I know... I know..).

The picture disappeared, would appear for a fraction of a second, then go again. Unlike similar settings on PCs, there's no "This setting will revert in 30 seconds if you don't click OK". Only be remembering the menu layout and selecting 720p "blind" was I able to revert back.

To summarise: before switching resolution, be certain your TV can support it!!

Bob_Latchford

To summarise: before switching resolution, be certain your TV can support it!!

I've just done this tv should be able to do 1080i though.

Can any kind soul give me directions to the settup screen to get it back, all i have is blank screen.

So far i can get menu -> settings -> tv settings. But cant get further. Need something like menu -> down 2 -> press ok etc etc

Much appreciated! :cool:

Bob_Latchford

went for factory reset instead, sorted:)

highdef

If this happens, simply connect to the TV via scart so you can change the settings back on the STB.

Bob_Latchford

couldnt get scart to work, got sound but no pics

celticbest

Bob_Latchford wrote: »

couldnt get scart to work, got sound but no pics

Remove the HDMI cable from the back of the UPC box.

celticbest

I have my box set to 1080 and have never had any problem, just make sure your TV is capable of receiving this input.

Bob_Latchford

Remove the HDMI cable from the back of the UPC box.

ah ok, will do next time. Pretty sure tv (kdl40w400) should have been capable of 1080i, not sure what went on, chose 1080 and blank screen straight away.

might try it again later if i am feeling bravethanks everyone for suggestions

djimi

I have the 40v4000 (the model below yours) and I have no problem selecting 720p or 1080i.

I usually leave mine in 720p as changing it to 1080i makes absolutely no difference whatsoever as far as I can tell.

Kensington

djimi wrote: »

I have the 40v4000 (the model below yours) and I have no problem selecting 720p or 1080i.

I usually leave mine in 720p as changing it to 1080i makes absolutely no difference whatsoever as far as I can tell.

Leave it at 1080i. The channels are all broadcast at 1080i, AFAIK, so setting the box output to 720p will just mean you are making the box unnecessarily fiddle with the picture to scale it down from the 1080i broadcast to the 720p output. You may not notice the difference, but when you shell out all that money for equipment and service, you may as well get the most out of it :P

watty

It's likely ALL HD content is 1080i. Any other setting involves de-interlacing and re-sampling, both of those blur the image.

dunworth1

just a quick question my tv is 720p which setting would be best.


Edit: i suppose it depends on weather my tv has a better descaler then the hd box

what would be the best way to test this any ideas

watty

Pick best quality channel during a program with scrolling ticker tape.

Compare. Ask others who do not know which you have selected.

djimi

You mean like Sky News or the likes which has a scrolling info bar? What will that show?

Mountjoy Mugger

Maybe something like ESPN HD with scores running along the bottom - you can get it during baseball etc.

watty

djimi wrote: »

You mean like Sky News or the likes which has a scrolling info bar? What will that show?

yes.

Poor De-interlacing will make it shudder. Any de-interlacing blurs it.

Sharp detail is blurred and can get artefacts (like excessive JPEG compression) around high contrast small objects.

It's also a reasonable quality of bitrate. The shopping channels are useless to test as some are only 384 x 288 scaled up!

I'd not use any US originated content as it could be standards converted from 30fps. So not ESPN.

djimi

Cool, Ill check that out later! Sky News SD on my TV at home looks awful, as do most of the SD channels, but Id be interested to see if there is a noticable difference between 720p and 1080i.

highdef

AFAIK, the HD Disney Cinemagic and ESPN HD are broadcast in 720P....as in the broadcasters themselves send out 720P, rather than 1080i. I'm not positive on the other channels. 1080i is still an option on the STB for these channels but not sure if it makes a difference....perhaps UPC upscales everything to 1080i

watty

AFAIK NO cable or Satellite is actually carried in 720p in Europe.

What Cinemagic and ESPN do in USA is not relevent. If it's 30fps source rather than 24fps film it will be standard converted to 25 fps anyway, so useless for comparson.

24FPS content is simply encoded at 25fps and audio pitch change of 25/24 corrected by resampling.

zilog_jones

GrumPy wrote: »

1080i is arguably worse then 720p anyway.

For film content (24 or 25 fps), 1080i is essentially progressive scan anyway so is undoubtedly superior. For video content with lots of motion (sports etc.) 720p is probably better. But if the channel is 1080i, setting your STB's output to 720p will only make it worse.

Mikey23 wrote: »

There's a setting on UPC's HD box where you can select 720p, 1080i, or automatic. The last was a bit irritating the first few days I had it, as my TV would switch mode fairly often as I browsed channels, so I've left it at 1080i.

I found setting it to 1080i makes SD channels too blurry - horizontal resolution certainly looked worse to me when viewing SD channels with the 1080i output versus Auto. However on Auto mode AFAIK it still de-interlaces SD channels itself and outputs 576p, and its de-interlacer doesn't seem as good my TV's (horizontal lines look more jaggedy, etc.).

Bob_Latchford wrote: »

Pretty sure tv (kdl40w400) should have been capable of 1080i, not sure what went on, chose 1080 and blank screen straight away.

It might not like changing resolutions like that, did you try turning the TV off and on again after doing this, or change to a different AV input and back?

dunworth1 wrote: »

just a quick question my tv is 720p which setting would be best.

Edit: i suppose it depends on weather my tv has a better descaler then the hd box

what would be the best way to test this any ideas

Your TV probably isn't really 720p, if it's an LCD the native resolution is probably something like 1366x768, I'd be almost certain the vertical res. is 768 anyway. So if you use the 720p output the TV has to upscale 720p to 768p, and if you output 1080i it has to deinterlace and downscale to 1080i. From my experience (my TV is 1366x768) 1080i always looks better if the source is HD. But as I said above I just leave it on auto as the SD channels look better, but the downside to this (as Mikey23 said) is that it takes a few seconds to switch between SD and HD channels. I only watch two of them anyway (BBC HD and Eurosport) so it's not a very common occurrence for me.

djimi

zilog_jones wrote: »

For film content (24 or 25 fps), 1080i is essentially progressive scan anyway so is undoubtedly superior. For video content with lots of motion (sports etc.) 720p is probably better. But if the channel is 1080i, setting your STB's output to 720p will only make it worse.

Would you mind elaborating on this a little? Im not disagreeing with you, but Im curious to know how 1080 interlaced can be effectively the same as progressive.

djimi

zilog_jones wrote: »

Mikey23 wrote:

There's a setting on UPC's HD box where you can select 720p, 1080i, or automatic. The last was a bit irritating the first few days I had it, as my TV would switch mode fairly often as I browsed channels, so I've left it at 1080i.

I found setting it to 1080i makes SD channels too blurry - horizontal resolution certainly looked worse to me when viewing SD channels with the 1080i output versus Auto. However on Auto mode AFAIK it still de-interlaces SD channels itself and outputs 576p, and its de-interlacer doesn't seem as good my TV's (horizontal lines look more jaggedy, etc.).

I had a play around with this after reading this thread, and while before I used to have my UPC box set to 1080i, I set it to Auto meaning that the SD channels switch to 576p, and I think the picture quality is a little better. Its still pretty poor but its very slightly less blurry.

I also found that setting my tv to Full Pixel mode made a little difference (although I could be imagining this), but it will introduce a tiny black bar at the edge of SD channels.

zilog_jones

djimi wrote: »

Would you mind elaborating on this a little? Im not disagreeing with you, but Im curious to know how 1080 interlaced can be effectively the same as progressive.

1080i (over here) is 50 interlaced fields per second (1080i50 or 1080i/25). Anything shot on film or video shot at film-like framerates (24p or 25p, a lot of TV shows are done like this these days) is shown on this at 25 frames per second. Each field in an interlaced picture only refreshes half of the picture, changing between even and odd lines (horizontal) in each field. But if the source is 25 progressive fps (25p), you've got 2 fields to reproduce the whole frames in their entirety, and your TV should be able detect this (cadence detection) and show the progressive frames without loss (i.e. as 1080p25).

The same happens with film content on PAL SD (576i). It's called 2:2 pulldown.

It's only when the source is proper full speed progressive video (50 or 60 fps) that 720p can be better than 1080i.

watty

zilog_jones wrote: »

It's only when the source is proper full speed progressive video (50 or 60 fps) that 720p can be better than 1080i.

And only for moving content. As 1080p has twice Temporal resolution (movement) of 1080i, but identical static resolution.

So it depends on the actual moving scene content if 720p is better than 1080i, or not. They actually have almost identical data rate content, as the 720p is half the total pixel resolution (X x Y) but twice the temporal resolution. This means there is moving scene content where they are equal, and with less movement 1080i is better and with more movement 720p is better.

But LCDs have lag (apart from the alleged 8ms response) and people can see less sharpness (detail) the faster the objects move even if no lag. So the main advantage of 720p is for screens that have to de-interlace interlaced sources as de-interlacing a source that is not Interlaced originally Progressive source will blur it (depending how good your de-interlacing is).

It's all moot anyway, as AFAIK no-one in Europe broadcasts 720p.