why is it 1080i? at DVinfo.net

Ben Gurvich · April 1st, 2004, 03:24 AM

Just wondering,

why is HD 720 Progressive but 1080 is interlaced ?

Seems its going backwards, obviously there is a reason for this.

HDCAM is 1080P?

Cheers
Ben Gurvich

Dan Brown · April 1st, 2004, 08:25 AM

Just a guess, but maybe the 720p is 16/9 and the 1080i is 4/3. Note that (720*2)/1080=1.33 and that (16/9)/(4/3)=1.33.

Graeme Nattress · April 1st, 2004, 08:33 AM

720 and 1080i are both 16:9. There's also 1080p that's used for "film" aquisition. Why i then? because it offers greater temporal resolution - 60fields per second as opposed to 24 or 30, hence better for sporting action, like the 720p 60fps, which due to being lower resolution, can do 60 frames rather than 60 fields.

interlaced is not the problem it used to be, especially now that there are a number of high quality de-interlacers....

Graeme

David Stoneburner · April 1st, 2004, 08:36 AM

It's due to size. The size of an 1080p signal is quite big. Also some have stated that 720p looks as good as 1080i with less bandwidth. At least that's some of the things that I have heard. I have also heard that they are using 1080p for shooting movies in HD.

Rob Belics · April 1st, 2004, 10:11 AM

The reason is you can't fit 1080p into the bandwidth allotted.

720p is better than 1080i because you are presented with only 640 lines per frame at a time with 1080i.

Ignacio Rodriguez · April 1st, 2004, 11:48 AM

I thought the question and answers in this thread would be about the number itself. I wonder where 1080, 1920, 720, 480, 576 and all those actually come from. I mean why those numbers and not others?

April 1st, 2004, 03:24 AM	#1
Ben Gurvich Major Player Join Date: Dec 2003 Location: Australia Posts: 329	why is it 1080i? Just wondering, why is HD 720 Progressive but 1080 is interlaced ? Seems its going backwards, obviously there is a reason for this. HDCAM is 1080P? Cheers Ben Gurvich

April 1st, 2004, 08:25 AM	#2
Dan Brown Major Player Join Date: Dec 2003 Location: Fort Worth, Texas Posts: 235	Just a guess, but maybe the 720p is 16/9 and the 1080i is 4/3. Note that (720*2)/1080=1.33 and that (16/9)/(4/3)=1.33. __________________ dB

April 1st, 2004, 08:33 AM	#3
Graeme Nattress RED Problem Solver Join Date: Sep 2003 Location: Ottawa, Canada Posts: 1,365	720 and 1080i are both 16:9. There's also 1080p that's used for "film" aquisition. Why i then? because it offers greater temporal resolution - 60fields per second as opposed to 24 or 30, hence better for sporting action, like the 720p 60fps, which due to being lower resolution, can do 60 frames rather than 60 fields. interlaced is not the problem it used to be, especially now that there are a number of high quality de-interlacers.... Graeme __________________ www.nattress.com - filters for FCP

April 1st, 2004, 11:48 AM	#6
Ignacio Rodriguez Contributor Join Date: Sep 2003 Location: Santiago, Chile Posts: 932	I thought the question and answers in this thread would be about the number itself. I wonder where 1080, 1920, 720, 480, 576 and all those actually come from. I mean why those numbers and not others? __________________ Ignacio Rodríguez in the third world. @micronauta on Twitter. Main hardware: brain, eyes, hands.

April 1st, 2004, 08:36 AM	#4
David Stoneburner Major Player Join Date: Jun 2003 Location: Orlando, FL Posts: 493	It's due to size. The size of an 1080p signal is quite big. Also some have stated that 720p looks as good as 1080i with less bandwidth. At least that's some of the things that I have heard. I have also heard that they are using 1080p for shooting movies in HD.

April 1st, 2004, 10:11 AM	#5
Rob Belics Major Player Join Date: Apr 2003 Location: St. Louis, MO Posts: 581	The reason is you can't fit 1080p into the bandwidth allotted. 720p is better than 1080i because you are presented with only 640 lines per frame at a time with 1080i.