It depends on the TV you have. My TV is HD ready, not full HD and I've found that setting the output to 720p has been best for me. However, as ever, it's usually personal preference, so try both and see if which you prefer.
all (or certainly most) sky hd content is 1080i by default. So by selecting 720P the sky hd box would have to DOWNSCALE and DEINTERLACE (make it into progressive)
The scaling software is not very good and the deinterlacer is even worse so the best setting is 1080i so that it neither scales nor deinterlaces
As for SD content ~
The skybox wont output in 576i (which is the standard). It FORCES it to deinterlace to 576P. So for that fact you need to also select 1080i so that it upscales but doesnt deinterlace.
so moving on from there if i am sending the signal through a onkyo 876 to a 720p projector at some point either the onkyo or projector will have to downscale the image to fit?
You want the projector to downscale if you can (else it will be scaled twice, once through the amp and upscaled slightly to fit the projector (unless its a true 720 screen?))
My advice would be to set your Sky+HD box output to "AUTOMATIC" this way it will output the channel you ae watching at its native resolution as IMHO your TV will do a better job at either upscaling SD or deinterlacing(and if need be downscaling if your TV is not 1080p) HD over the rather rubbish scaling chipset that is in the Sky+HD box.
D.J.KRIME:My advice would be to set your Sky+HD box output to "AUTOMATIC" this way it will output the channel you ae watching at its native resolution as IMHO your TV will do a better job at either upscaling SD or deinterlacing(and if need be downscaling if your TV is not 1080p) HD over the rather rubbish scaling chipset that is in the Sky+HD box.
As ive tried to explain ~ the skybox deinterlaces SD content. As its deinterlacer is so bad its actually better to scale to 1080i as its scalers better than its deinterlacer
D.J.KRIME:My advice would be to set your Sky+HD box output to "AUTOMATIC" this way it will output the channel you ae watching at its native resolution as IMHO your TV will do a better job at either upscaling SD or deinterlacing(and if need be downscaling if your TV is not 1080p) HD over the rather rubbish scaling chipset that is in the Sky+HD box.
prob with that is everytime you change channel either my onkyo or projector or both resets the picture so you get like 5 secs of blue screen before everything adjusts which is a real pain
D.J.KRIME:My advice would be to set your Sky+HD box output to "AUTOMATIC" this way it will output the channel you ae watching at its native resolution as IMHO your TV will do a better job at either upscaling SD or deinterlacing(and if need be downscaling if your TV is not 1080p) HD over the rather rubbish scaling chipset that is in the Sky+HD box.
prob with that is everytime you change channel either my onkyo or projector or both resets the picture so you get like 5 secs of blue screen before everything adjusts which is a real pain
My Plaz also does this but personally I would rather put up with that as my TV definatly does a superiour job when upscaling SD over the Sky box internal scaler