(Down) scaling

Posted by: Neil Bennett on 14 May 2008

Reading various other treads I infer:

*that Sky HD outputs 1080i,
*that older HD screens deinterlace and downscale to 7xxp (can't remember whether it was 720 or 768)
*that Sky HD can output at 720p if set to do so.

So is it better to let the Sky HD downscale or the screen? (My TV is an 18-month old 37" Panasonic plasma).

Neil
Posted on: 15 May 2008 by Mike1380
Try it, & let us know.....

Seriously I reckon your Pana "Should" do a better job.
It also should do a better job of upscaling your non-HD Sky channels.....

If you set the sky box HD output res to "Auto" then it'll either feed 576P (SD) or 1080i(HD) to your TV and let the screen's scaler do all the work.

Try it, and let us know if it gives any difference visible to YOUR eyes on SD & HD footage.... my bet is it will be better than setting the Sky Box to output 720P... but it's all down to YOUR perception.

Mike
Posted on: 15 May 2008 by Neil Bennett
Mike,

Will do when I get home (I'm currently at an exhibition for work in Seoul, occupying the slow bits of the day at the Internet cafe!)

Neil
Posted on: 19 May 2008 by Frank Abela
IIRC, according to Paul Miller of HiFi News the best thing to do is set the unit to Auto if available. This gets the unit to negotiate with the display which tells the unit its preferred reception stream. The display then re-scales the picture to fit on the screen.

The broadcast definition for high def is actually either 720p or 1080i. It's not a given that you'll have one or the other. Screens, however, vary in pixel resolution 'Normal' HD Ready screens have between 720 and 768 lines, although the majority are 768 I believe. Horizontal resolution changes too - some are 1024 but they can be anything up to 1366 wide (1366 = square pixels). This isn't the be all and end all of the story though. One of the best screens on the planet is still the Pioneer 428XD which has among the lowest of the above resolutions at 1024 x 768.

FullHD screens which can take full advantage of Blu-ray have 1080 lines and 1920 pixels horizontally. The one problem I struggle with is what these poor screens have to do to resolve down to standard definition or 'broadcast HD' sources? In these situations those screens have to work pretty hard to scale up to the full screen resolution which they have to do to fill the screen! If the scaler isn't that hot, this could lead to poorer pictures simply because the electronics can't cope that well. It might prove stunning on Blu-ray but limited on everything else and since broadcast HD is unlikely to move to 1080p in the foreseeable future, this still means that the vast majority of your viewing would need quality scaling applied.