Originally Posted by Quidam67
So in no particular order:
For NTSC and PAL
, we have 60 and 50hz respectively. I'm assuming the same holds true for 720p and 1080i/p signals? If this is so:
Yes - and no.
1080/50i (and to a lesser degree 720/50p) are the HD BROADCAST formats used for transmission of HD in Europe, Australia and other 50Hz HD regions. (i.e. those that previously used 50Hz PAL
or SECAM) Additionally there is an HD video production standard in 1080/25p (and 720/25p) which is used in production where previously 25fps film may have been used.
1080/60i and 720/60p are the HD BROADCAST formats used for transmission of HD in North America, Japan and Korea, and other 60z regions. (i.e. those that previously used 60Hz NTSC or possibly 60Hz PAL
in the case of Brazil) Additionally there are HD production standards of 1080/24p (and 720/24p) as well as the less-widespread 1080/30p (and 720/30p) which are used in production where previously 24fps film may have been used.
Additionally there are 1080/24p, 1080/50p and 1080/60p HD INTERCONNECT standards, that can be used to connect sources to displays via Component, VGA and HDMI/DVI cabling etc.
For Hi Def movies, are the same solutions required/used to map a 48hz film to a 60 or 50hz display device? (eg 3:2 pull down; 4% speed up or 2:2:2:2:2:2:2:2:2:2::2:3 pull-down)
For BROADCAST - Yes.
In 50Hz territories, movies shot 24fps are BROADCAST at 1080/50i (or 720/50p) with 2:2 and 4% speed-up mainly. Original TV content shot on film or HD video with "a film look" is shot at 25p and broadcast in 1080/50i (or 720/50p) with no speed-up.
In 60Hz territories, movies shot at 24fps are BROADCAST at 1080/60i or 720/60p with 3:2 and no speed-up. Original TV content shot on film or HD video is usually shot at 24fps and with 3:2 pull-down and no speed up.
HOWEVER - things are different for HD DVD and BluRay. This is because most displays sold in 50Hz territories also support 60Hz video - in fact in Europe this is a demand to be licensed "HD Ready" - the Europe-wide HD licensing scheme.
This means that most (so far all?) 24fps movie material released in both 50 and 60Hz regions has been released as 24p "on disc". This can be output either in 1080/60i with 3:2 field pull-down, 1080/60p or 720/60p with 3:2 frame repetition - with some players and displays additionally supporting 1080/24p connections, with display refresh rates potentially at 48, 72, 96 or 120Hz. The 1080/24p material on-disc is NOT converted to 1080/50i or 1080/50p (or 720/50p)
On these discs a lot of the extras are still 480/60i - but again most 50Hz displays will accept these (and all EU "HD Ready" displays will)
My understanding is that 1080/60i and 1080/50i, 720/60p and 720/50p are all also valid HD-DVD and BluRay standards - though I'm not sure that 1080/25p is.
How are Hi Def movies stored on Blu Ray? Are they stored in the native 24 fps? Or is it more like DVD, where they are they stored as interlaced fields that the Blu Ray player puts back together (eg. progressive scan)?
BluRay stores 1080/24p natively. I believe HD DVD does something slightly different to BluRay - but can equally cope with generating a 1080/24p output.
Some players cheat and generate a 1080/60i signal internally which is then de-interlaced back to 1080/24p.
The PS3 currently outputs 24p material at 60Hz - and doesn't offer 24p output - though this may come with a future update.
What does it mean when a Blu Ray (or HD DVD player) is advertised as being able to handle 1080p/24, as versus 1080p/60? I got the impression that 1080p/24 is better, but surely this still requires pull-down manipulation etc in order to be played on the small screen, so why is it better?
24p output is only a benefit over 60p output if you have a display capable of displaying at a multiple of 24Hz - say 72Hz or 120Hz - as in doing so you remove the 3:2 cadence judder inherent in 60Hz rendition of 24p material, where one film frame is displayed for longer than the next, un-naturally weighting it. In Europe, where 2:2 cadence with speed up is more common, we're not used to this 3:2 judder - and it really sticks out the first time you see it - particularly on linear pans etc.
If you haven't got a display that will cope properly with 24p (i.e. not convert it back to 60Hz) - then there is no benefit over 60p interconnection AIUI.