A simple question!!!

[admin_exported]

Thanks Whathifi for the brilliant tv reviews, you finally made my mind up for me, anyway, back to my simple question( though the answer maybe far from so). How come the equipement that makes up our home cinemas systems are able to upscale videos from SD, but the likes of Sky and now Freesat don't upscale before they broadcast their programs?, Then everthing wound be in HD, if they could i think Freesat have really missed an opportunity to take the lead in HD viewing.

Can anyone shed some light on this? looking forward to the answers.

 

[professorhat]

Upscaled SD isn't HD - the difference is an HD picture has the full 720 / 1080 lines of information whereas an upscaled SD image still only has 576 lines of information (assuming it's a PAL signal) which the upscaler is processing to enlarge that image so it fits the TV. Different upscalers do this in different ways, some better than others. Your HDTV will have its own scaler in it to ensure the picture always fits the TV, so in this sense, everything you watch on it is upscaled. I suspect the makers of the Freesat box didn't put an upscaler in as it would increase the price of the unit. I'm pretty sure the Sky HD box can upscale, but it's generally considered to not be a very good upscaling unit.

 

[Anonymous]

Thanks professorhat, still a little confused, i though that some equipement could upscale to 1080p, is that not HD then? or is that up convertion, guess i'm barking up the wrong tree!!

 

[professorhat]

Upscaling to 1080p basically means it is processing the picture so it will fit a Full HD television i.e. one that has 1080 lines of horizontal resolution. It will also be turning an interlaced signal it receives into a progressive signal. However, it obviously can't add information that isn't there, so if it's receiving a PAL signal, there's still only 576 lines of information and the scaler is processing that to fit on to the TV. A true HD picture would have either 720 or 1080 horizontal lines of information being received.

Upconversion is the term generally used when something is turning an interlaced signal into a progressive signal, but is not changing the resolution at all e.g. a 576i signal would become a 576p signal.

 

[Anonymous]

Thanks again, great discripetion on how it works so now i understand it, just one more question,do you think that an upscaled signal is better than an sd one?

 

[professorhat]

Do you mean one which is upscaled by the broadcaster before being broadcast? Inevitably, this tends to be much improved from the original SD broadcast as the broadcasters will have a lot of expensive kit to process the picture that you wouldn't find in the home.