choddo2006
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I think this is an interesting area, so let's have another thread for it to avoid derailing tryingtimes'
I'm going to ignore the distinction between 576i and 1080i and instead talk about handling of 50Hz signals as I understand it.
So the source for UK TV broadcasts is either film (25p once sped up) or video (50Hz interlaced) - the latter might be captured at 50p but it never reaches us like that and therefore my guess is that in the broadcast chain they might choose to save the bandwidth & use 50i all the way along. Maybe. It's irrelevant anyway. What we get is effectively from a 50i video source.
Now the actual signal delivered is 50i of course, irrespective of what the source was.
A film should be converted back to a full progressive frame at 25fps, but almost certainly the signal carried to the screen (or processed inside the TV) will be at 50Hz, just with 2:2 repeat where each of the 25 frames has been blended together from consecutive odd & even fields.
Sport at 25fps would be horrible. Movies limit the speed of pans to avoid to large a jump between frames because of the relatively low framerate. You can't do that with sport, it has to follow the speed of the action, so in that case what you want and get is 50 progressive frames per second where the deinterlacing has filled in the blank lines in the field using whatever algorithm it has available.
So there's a big difference between 1080i/50 and 1080p/25 and each has their place. Of course, if you could have sport at 1080p/50 or 1080p/60... then I think it's fair to say that would be a good deal preferable but it's not an option yet.
Nick, I'm really unsure what point you was making there.
If you have a source of PAL 576/50, it will convert that into 576/25, especially on a LCD/DLP as interlasing really does'nt make any sense, on a CRT things are different.
PAL is actually a lot simpler than our USA friends who have to worry about the 3:2 pulldown etc, so PAL is not like NTSC. But even then a it's not a total loss.
Have a look here->
http://www.hometheaterhifi.com/forum/showthread.php?t=3851
eg. SKY uses 1080i/50, now SKY do a lot of sports programmes, if 1080i/50 was causing interlasing artifacts they would be a lot of unhappy subscribers out there. A 1080i/50 will look just as clean and smooth as a 1080p/25.
I'm going to ignore the distinction between 576i and 1080i and instead talk about handling of 50Hz signals as I understand it.
So the source for UK TV broadcasts is either film (25p once sped up) or video (50Hz interlaced) - the latter might be captured at 50p but it never reaches us like that and therefore my guess is that in the broadcast chain they might choose to save the bandwidth & use 50i all the way along. Maybe. It's irrelevant anyway. What we get is effectively from a 50i video source.
Now the actual signal delivered is 50i of course, irrespective of what the source was.
A film should be converted back to a full progressive frame at 25fps, but almost certainly the signal carried to the screen (or processed inside the TV) will be at 50Hz, just with 2:2 repeat where each of the 25 frames has been blended together from consecutive odd & even fields.
Sport at 25fps would be horrible. Movies limit the speed of pans to avoid to large a jump between frames because of the relatively low framerate. You can't do that with sport, it has to follow the speed of the action, so in that case what you want and get is 50 progressive frames per second where the deinterlacing has filled in the blank lines in the field using whatever algorithm it has available.
So there's a big difference between 1080i/50 and 1080p/25 and each has their place. Of course, if you could have sport at 1080p/50 or 1080p/60... then I think it's fair to say that would be a good deal preferable but it's not an option yet.