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SD on SkyHD with HDMI not as good as Sky+ with scart??

Slates71

Established Member
I had Sky HD fitted a few weeks back and find that the SD picture isn't very clear, infact its rather 'blurry'. When I watched SD on my Sky+ box via scart the picture was spot on. Is this an issue with my HD box?? The HD picture is superb its just that SD isn't very good. I was expecting SD to be even better through an HDMI cable than scart. I tried it with a scart but the picture was no different.
Any help would be appreciated and if it is an issue with the HD box I'll report it to Sky. The fact that the HD picture is perfect may mean there is no problem with the HD box so why is the SD picture worse than when I had Sky+ ?
:lease:
 

adrian3221

Established Member
I had Sky HD fitted a few weeks back and find that the SD picture isn't very clear, infact its rather 'blurry'. When I watched SD on my Sky+ box via scart the picture was spot on. Is this an issue with my HD box?? The HD picture is superb its just that SD isn't very good. I was expecting SD to be even better through an HDMI cable than scart. I tried it with a scart but the picture was no different.
Any help would be appreciated and if it is an issue with the HD box I'll report it to Sky. The fact that the HD picture is perfect may mean there is no problem with the HD box so why is the SD picture worse than when I had Sky+ ?
:lease:

I noticed this too when I upgraded. The SD movie channels are horrible on my plasma, like watching VHS. I only watch the HD channels so doesnt bother me too much.
 

Slates71

Established Member
The crazy thing is tho the majority of the channels are SD. I find ITV quite poor (and I don't just mean the football). But why is an old style scart on Sky+ better than HDMI on a new HD box, its wrong. I was expecting an excellent SD picture and amazing HD. HD is amazing but SD is average at best. If it was the same picture on Sky+ I wouldn't mind so much.
I might ring Sky and see what they do :confused:
 

mikelj

Prominent Member
I thought it could be down to the fact that the SKY HD box will not output 576i through the HDMI (but 576p instead).

But, since you state that the SD picture is no better through Scart...

Could ask for another HD box off SKY and see if that is the same?
 

adrian3221

Established Member
I should add that its only ITV/Sky Movies SD that I have issues with. The BBC channels are excellent.
 

tvdavid

Prominent Member
Most channels are very clear on my TV.
Even ITV is not that bad apart from when its sport.

I use both HDMI and RGB.
 

Slates71

Established Member
Most channels are very clear on my TV.
Even ITV is not that bad apart from when its sport.

I use both HDMI and RGB.

Do you find watching SD channels via RGB better than HDMI ? We shouldn't really have to accept that tho. HDMI should upscale SD and make it better not worse! I agree with the previous reply, ITV is generally the worst channel for SD. I also think that ITV2 and Virgin aren't that good.
 

mattclarkie

Distinguished Member
I've noticed that the SkyHD de-interlacer is pants, really pants.

I almost feel like connecting up the scart so I can use the superior one in my TV, but I can't be bothered with all that.
 

eiren

Distinguished Member
Do you find watching SD channels via RGB better than HDMI ? We shouldn't really have to accept that tho. HDMI should upscale SD and make it better not worse! I agree with the previous reply, ITV is generally the worst channel for SD. I also think that ITV2 and Virgin aren't that good.

ITV, ITV2, and Virgin are all broadcast at a very low quality/bitrate on Sky. They always look terrible.

I switch to my built in Freeview on my television and those channels look much better.
 

Optomotron

Established Member
I had sky hd installed today and i am amazed at the diffrence between scart connection and hdmi connection on my tv. SD sky looks so much cleaner and less blury. The hd channels look stunning well worth the purchase.
 

Slates71

Established Member
I had sky hd installed today and i am amazed at the diffrence between scart connection and hdmi connection on my tv. SD sky looks so much cleaner and less blury. The hd channels look stunning well worth the purchase.

Id be very interested to know what make and model your HD box is. Mine's a Thomson but need to check when I get home what model no it is. I'm going to try RGB scart again tonight and play with the picture settings on the TV and see what its like. I got this HD box not only for HD but to upscale SD into near quality HD..... how wrong I was !
 

tvdavid

Prominent Member
when I set my box to 1080i the SD picture is worse.
I have this set to auto.
 

thommcghome

Established Member
I've noticed that the SkyHD de-interlacer is pants, really pants.

I almost feel like connecting up the scart so I can use the superior one in my TV, but I can't be bothered with all that.
So why not use Component instead & set the Display Resolution to Auto? Best of both worlds, right ;)
 

StooMonster

Prominent Member
I had Sky HD fitted a few weeks back and find that the SD picture isn't very clear, infact its rather 'blurry'. When I watched SD on my Sky+ box via scart the picture was spot on. Is this an issue with my HD box?? The HD picture is superb its just that SD isn't very good. I was expecting SD to be even better through an HDMI cable than scart. I tried it with a scart but the picture was no different.
Any help would be appreciated and if it is an issue with the HD box I'll report it to Sky. The fact that the HD picture is perfect may mean there is no problem with the HD box so why is the SD picture worse than when I had Sky+ ?
:lease:
Over HDMI the standard SD output is 576p, where the Sky HD stb's Broadcom chipset deinterlaces 576i to 576p before output; unfortunately this chipset isn't very good at 50Hz deinterlacing and 2:2 cadence detection therefore it produces moire artefacts on film materials (e.g. movies, and US dramas) and combing artefacts on video materials (e.g. sports, news, studio based programmes).

Scart output is plain old 576i and on the Sky+ boxes was excellent and clear, and a good display could produce an excellent picture with the signal. However, the Thomson Sky HD box outputs a very soft 576i picture over scart and component output that is far inferior to the Sky+ one.

The only way to solve this problem is to go the route of external video processor (formerly known as "scalers") where products such as Lumagen Radiance can trick the Sky HD box into outputting 576i over HDMI or the DVDO iScan VP50 has a feature called 'PReP' that can extract the original 576i signal from a poorly processed 576p one; there are other brands of VP with similar features. These external video processors have top-class deinterlacers, scalers, colour correctors, noise reduction, and many other features built into them which can make the 576i over HDMI look pretty darn good. Check out the VP/Scaler forum on this site for more info.

StooMonster
 

StooMonster

Prominent Member
Why does the component output do 576i, but the HDMI only do 576p.
The component output becomes 576p if you plug an HDMI cable into the box.

576i (and 480i) over HDMI was only added to the specification after its initial launch, therefore older HDMI displays will not process the signal. So in the interests of "compatibility" the Sky HD box defaults to 576p which has always been part of the HDMI spec.

The Sky HD box, and many other HDMI devices, can be tricked into providing 576i/480i over HDMI by setting EDID (a series of codes provided by a display to a source device that tells it which signals it can accept) to 576p=NO and 576i=YES (if both are set to YES, 576p is used by default).

Interestingly (if you're geeky) 576i and 480i over HDMI work by a cheat, as both resolutions are too low for the protocol and use less than the minimum bandwidth, so they use pixel doubling to make up bandwidth. 576i is 50 fields per second of 720x288 pixels, but when transmitted over HDMI the horizontal resolution is doubled by repeating each pixel twice to 1440x288 and the receiver chip then converts the signal back to 720x288 pixels.

StooMonster
 

Slates71

Established Member
Over HDMI the standard SD output is 576p, where the Sky HD stb's Broadcom chipset deinterlaces 576i to 576p before output; unfortunately this chipset isn't very good at 50Hz deinterlacing and 2:2 cadence detection therefore it produces moire artefacts on film materials (e.g. movies, and US dramas) and combing artefacts on video materials (e.g. sports, news, studio based programmes).

Scart output is plain old 576i and on the Sky+ boxes was excellent and clear, and a good display could produce an excellent picture with the signal. However, the Thomson Sky HD box outputs a very soft 576i picture over scart and component output that is far inferior to the Sky+ one.

The only way to solve this problem is to go the route of external video processor (formerly known as "scalers") where products such as Lumagen Radiance can trick the Sky HD box into outputting 576i over HDMI or the DVDO iScan VP50 has a feature called 'PReP' that can extract the original 576i signal from a poorly processed 576p one; there are other brands of VP with similar features. These external video processors have top-class deinterlacers, scalers, colour correctors, noise reduction, and many other features built into them which can make the 576i over HDMI look pretty darn good. Check out the VP/Scaler forum on this site for more info.

StooMonster

So without spending anymore money trying to improve the PQ what do you recommend? I've changed the HD resulution setting on the HD box from 1080i to automatic as several people have said SD improves with this, I'm not entirely convinced of that tho. Maybe I should give the RGB scart a trial for a week or so.I have a Samsung M86 and have increased the Dynamic Contrast to 'High' and that does improves things. In fact tonight most of the channels looked ok so now I'm wondering if it's down to certain programs on certain channels - this does get confusing! :suicide:
 

StooMonster

Prominent Member
Changing output to 1080i is the worst of all worlds.

A typical "upscaling" process works like this: 576i deinterlaced to 576p, 720x576 resolution changed with interpolation to 1920x1080 pixels, reinterlaced for output as 1080i. Then your display may only display 1080i as seperate fields of 1920x540 pixels if it cannot deinterlace 1080i properly, and other issues can happen too. Note that the same deinterlacing problems from the stb's built in chipset (moire in film, combing in video) continue to appear but are compounded by the additional video processing steps.

So, no ... it's not better.

To answer your question, the choice is not easy:

HDMI is clearest and sharpest picture but has horrible deinterlacing for SD, and judders and has all sorts of artefacts going on.

Scart (RGBcvS) is blurry but your display will probably do a better job of handling it.

Component is easy to use, like HDMI, because no need to change inputs on the display when you switch from SD to HD channels and vice versa. Although component HD is very good, and not too dissimilar to HDMI the SD is similarly soft as scart.

I'd go for component for ease of use, but to check which is better component/scart go to the main Sky menu and look at the coloured square boxes at the bottom and look for colour bleed (this is something you don't want); on your old Sky+ these boxes would be razor sharp but on Sky HD they are softened.

Note: if you use component, you must have HDMI cable unplugged otherwise the component output for SD is the same 576p as HDMI -- do not use component for SD and HDMI for HD.

I do wonder if they deliberately soften the analogue SD output, although the new Sky HD boxes do not have component output anymore so we won't be able to choose if boxes need replacing.

StooMonster
 

Slates71

Established Member
Changing output to 1080i is the worst of all worlds.

A typical "upscaling" process works like this: 576i deinterlaced to 576p, 720x576 resolution changed with interpolation to 1920x1080 pixels, reinterlaced for output as 1080i. Then your display may only display 1080i as seperate fields of 1920x540 pixels if it cannot deinterlace 1080i properly, and other issues can happen too. Note that the same deinterlacing problems from the stb's built in chipset (moire in film, combing in video) continue to appear but are compounded by the additional video processing steps.

So, no ... it's not better.

To answer your question, the choice is not easy:

HDMI is clearest and sharpest picture but has horrible deinterlacing for SD, and judders and has all sorts of artefacts going on.

Scart (RGBcvS) is blurry but your display will probably do a better job of handling it.

Component is easy to use, like HDMI, because no need to change inputs on the display when you switch from SD to HD channels and vice versa. Although component HD is very good, and not too dissimilar to HDMI the SD is similarly soft as scart.

I'd go for component for ease of use, but to check which is better component/scart go to the main Sky menu and look at the coloured square boxes at the bottom and look for colour bleed (this is something you don't want); on your old Sky+ these boxes would be razor sharp but on Sky HD they are softened.

Note: if you use component, you must have HDMI cable unplugged otherwise the component output for SD is the same 576p as HDMI -- do not use component for SD and HDMI for HD.

I do wonder if they deliberately soften the analogue SD output, although the new Sky HD boxes do not have component output anymore so we won't be able to choose if boxes need replacing.

StooMonster

I spent some time on this last night and have noticed a slightly sharper image when having the HD box set to 'Automatic' instead of '1080i'. HD remains perfect and SD has improved slightly. I can't use component as that is used for my Xbox360 . I'll leave automatic on the HD box for a week or so and see how things look. I might try the scart out after a few days if I'm not happy .Thanks for your advice anyway.
 

dazbear

Standard Member
Did you get this sorted?

I have just got SKY HD after a Toppy PVR and (what I thought) was upgraded to a nice 42" plasma from my old CRT.

I have spent hours fiddling with settings on my TV (much to my other halfs annoyance) but the SD channels still look as bad as a VHS recording. Its not too bad on close ups but wide shots are shocking.

HD picture is brilliant and interestingly recordings are also better than live.

Looking at this thread, I am thinking of getting component cables in a hope this will improve SD but concerned HD will suffer?!?!?
 

mattclarkie

Distinguished Member
Did you get this sorted?

I have just got SKY HD after a Toppy PVR and (what I thought) was upgraded to a nice 42" plasma from my old CRT.

I have spent hours fiddling with settings on my TV (much to my other halfs annoyance) but the SD channels still look as bad as a VHS recording. Its not too bad on close ups but wide shots are shocking.

HD picture is brilliant and interestingly recordings are also better than live.

Looking at this thread, I am thinking of getting component cables in a hope this will improve SD but concerned HD will suffer?!?!?

Many HD tvs have shocking SD performance. Is it only the Sky HD that has really poor SD or all sources.
 

Slates71

Established Member
Did you get this sorted?

I have just got SKY HD after a Toppy PVR and (what I thought) was upgraded to a nice 42" plasma from my old CRT.

I have spent hours fiddling with settings on my TV (much to my other halfs annoyance) but the SD channels still look as bad as a VHS recording. Its not too bad on close ups but wide shots are shocking.

HD picture is brilliant and interestingly recordings are also better than live.

Looking at this thread, I am thinking of getting component cables in a hope this will improve SD but concerned HD will suffer?!?!?

I decided to set the HDbox at 'Automatic' and so far I feel it is slightly sharper, a little less blurry and easier to watch TV. I still feel my old Sky+ box using scart was better. I will try out the scart cable tomorrow and trial it for a few days. I can't use componet as my TV input is used up for my Xbox360. Give automatic a try and let me know how you get on with it

In the end its annoying that Sky+ offers excellent PQ and with the 'Upscaled HD box' I expected SD to be near perfection..... god I was so wrong :(
 

mattclarkie

Distinguished Member
For 7 days I my Sky+160 box was connected up to my TV waiting for HD to be installed and the picture via Scart was stunning, the SD from the HD box is definately not as good.
 

Bogyoch

Standard Member
For 7 days I my Sky+160 box was connected up to my TV waiting for HD to be installed and the picture via Scart was stunning, the SD from the HD box is definately not as good.


I agree. My old Grundig's SD picture was super. The SD picture from the HD box is not as good. To get the best from the HD box, I use S-video for SD and the HDMI output for HD stuff, but that's not very often.

Someone has already mentioned it in this thread, but I wouldn't be at all surprised if the SD performance isn't made deliberately poor to make HD look much better.

It will be very interesting to note how the other manufacturer's boxes perform when they come out compared to the Thomson. I guess that they will all have problems, either the same as the Thomson's or have some other glitchs.
 

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