720p, 1080i or 1080p

poe

Hello for England

Just a query, I hope you can help me (naturally) regarding HD formats

There are 3 formats that we could use (I know there are loads of others too but these are the 3 that I am concerned with):

720p for sporting programmes
1080i for movies (50Hz or 60Hz)

what's stopping both genre of programme being on 1080p, surely this is the best format for all types of programming so reducing the need for having 2 different requirements depending on the programme material or am I very wrong
regardless of the bandwidth required to transmit 1080p surely it really is the only way forward and is more fail safe for future domestic tv set developements? Or are there issues with vision errors if you use 1080p for movies and/or sporting programmes?

Thanks for any help you might be able to give me

Poe xx

Edited to add: also is HD Cam suitable for 1080p? or would it have to go onto D5 ?

rbinck

The problem with 1080p here in the States is one of bandwidth for the OTA signals. The current allotment barely allows for 1080i at about 8:1 compression. Trying to go to 1080p would look terrible. Also the manufacturers are staying with 1080i for most of the TV they are producing and converting 720p signals to 1080i. It's a matter of cost vs benifit. Someday 1080p may be in the cards.

dpujals

Sorry, but, I don't know the difference between 1080i and 1080p.

Is this provided for the field frecuency ??? or the frame rate ???

Can somebody tell me about the meaning of 'i' and 'p' ?

Thanks to everybody.

Tails NZ

Yep, i means interlaced. That means instead of drawing all 720 lines on the TV every frame for example, it just draws every 2nd line, and then on the next frame it draws every other line. p means progressive (progressive scan) which is where the TV draws all 720 lines every frame.

Interlaced (frames 1 & 2, X being an example of a line on the TV):

12
X
X
X
X
X

Progressive:

12
XX
XX
XX
XX

Prequires a lot more data to be sent at once, because it sends the full frame rarther than every even line, then odd etc... at 1080p, this goes over the US bandwidth limit rbinck mentioned.

dpujals

Thanks for that info.

But, are you sure you need more information ??
As I understood (like in SDTV), you send every digitalized frame and the TV set scans the screen in 'i' or 'p' mode. This one is better for your eyes since the picture remains longer in the screen. But I think the information you send is the same frame even for 'i' and 'p' mode.

Can anybody check if that is true ??

Thanks

David

rbinck

It takes two scans to form an interlaced frame. In the same time, the progressive scan would have sent two frames. Here's a good link for more info: http://alvyray.com/DigitalTV/Naming_Proposal.htm

poe

Thank you for all your help

Pieman

i spoke to a guy from the BBC at a trade fair in the uk. Apparently a progreesive plasma can handle 1.5 gigabytes of data a second. So where it used to be that our recordings... or bought prerecordings were never as good as watching them through your aerial because of the poor magnetic tape....makers of home cinema are set to be forced to create a system that has to download the signal before it can be watched because of the bandwidth limitations on a satellite transponder - 27Mhz/sec,
just wondering if i'm wrong or out of date...opinions please

Filmreviewer

As nearly all aspects of your Q have been answered pretty well all that is left for me is to tell you that both Sony's HDCAM as well as the higher resolution HDCAM SR (which has a bitrate comparable to Panasonic's HD-D5 but a better, or lower, compression ratio and may force its competitor off the market) are capable of handling 1080 lines at 24 (23.96) psf (60Hz) as well as at the rarely used 25 psf at 50Hz.

Torsten

Torsten Kaiser
----------------------------------------
Managing Editor
THE LASER EXAMINER
Review & Newspaper - Productions in High Definition & for DVD
www.DVDScan.com
e-mail: editor1@dvdscan.com
_______________________________________