AVS Forum banner
Status
Not open for further replies.
1 - 9 of 9 Posts

·
Registered
Joined
·
414 Posts
Discussion Starter · #1 ·
Is 1080i programming, as it is shown now, done in video mode or by taking a single 1080p frame and sending both sets of 540 lines in sequence?


If it is the latter, then it would allow 2-2 pull-down detection for de-interlacing and restore the original 1080p frame. I would presume that this kind of technique would be used for films transfered to HD (with 3-2 pull-down). This would provide the capability for a higher quality image, although perhaps with more work in video encoding.
 

·
Registered
Joined
·
1,881 Posts
Since 1080i is 60i, I think it's done in video mode with the odd and even fields not corresponding to the exact same point in time.


Films transferred to HD would probably use the exact same pulldown method used to transfer 24p to 60i in NTSC video.


It would be nice if HDTVs supported 1080/24p. Then all that deinterlacing and pulldown would be a thing of the past. Maybe someday.
 

·
Registered
Joined
·
3,325 Posts
HDTVs _DO_ support 1080/24p. It's part of the ATSC standard. Scanning TVs (or the set-top box) generate their own pull-down for 24p material - it's an easy thing to do.


As of yet no broadcasters are using any of the 24p modes.
 

·
Registered
Joined
·
414 Posts
Discussion Starter · #4 ·
Quote:
Originally posted by balazer
HDTVs _DO_ support 1080/24p. It's part of the ATSC standard. Scanning TVs (or the set-top box) generate their own pull-down for 24p material - it's an easy thing to do.


As of yet no broadcasters are using any of the 24p modes.
It's too bad that the broadcasters are not using a 24p mode. I have read a number of editorials in magazines which end up favoring 720p over 1080i because of the progressive nature yielding higher resolution.


The advantage 720p has over 1080i would seem to be overcome by using this 24p encoding, yielding a very high resolution picture.


It is too bad that broadcasters are not using this mode for their video production.
 

·
Registered
Joined
·
4,038 Posts
24p is only good for transferring film to video. If you try to do sports motion fluidity is horrible. The same pretty much applies to 30p. Besides 24p and 30p flicker terribly, that is why you need to add 2:3 pulldown to 24p and 2:2 pulldown to 30p but motion suffers even more due to judder created by pulldown. This is the reason that video is shot at 60 fields a second in interlaced and 60 frames per second in progressive. Progressive advantage is that all vertical scan lines are on the screen at the same time unlike interlaced when either odd or even lines are displayed. There has been many threads discussing which is better. Most here including me see 1080i as clearly better but I think it is due to the fact that 720p has only 1280 horizontal lines comparing 1920 for 1080i. It is a difference of 640 lines and horizontal resolution is mostly responsible for clarity and detail in a picture.
 

·
Registered
Joined
·
3,102 Posts
CKNA, I disagree with you on because I believe it has been stated by broadcasters that the most they can get out of the 1080i standard is an actual 1440 x 1080i, not the 1920, due to filtering and compression I think ( believe Sony wanted the standard changed to say this as not to confuse customers). This makes it a bit closer to the 1280 X 720p that everyone compares it to.
 

·
AVS Forum Special Member
Joined
·
11,139 Posts
Quote:
Originally posted by CKNA

Progressive advantage is that all vertical scan lines are on the screen at the same time unlike interlaced when either odd or even lines are displayed. There has been many threads discussing which is better. Most here including me see 1080i as clearly better but I think it is due to the fact that 720p has only 1280 horizontal lines comparing 1920 for 1080i. It is a difference of 640 lines and horizontal resolution is mostly responsible for clarity and detail in a picture.
Hi CKNA. Agree with your comment about 1080i looking better, and wish more posts here would distinguish between interlace and progressive as clearly as you have.


Seems like squishing mercury, but for years here I've been trying to pin down how much of 1080i's potential we're actually getting. Wonder if you agree or disagree with what I've started calling 'resolvable 1920 resolution', or if you could add anything to it. It's my understanding most 1080i programming has been prefiltered by Sony's HDCAM filter, either editing or original taping, restricting frequencies and resulting resolutions to
 

·
Registered
Joined
·
1,881 Posts
Quote:
Originally posted by mdmaclean
It's too bad that the broadcasters are not using a 24p mode. I have read a number of editorials in magazines which end up favoring 720p over 1080i because of the progressive nature yielding higher resolution.


The advantage 720p has over 1080i would seem to be overcome by using this 24p encoding, yielding a very high resolution picture.


It is too bad that broadcasters are not using this mode for their video production.
Not really. Remember that 720p is 60p, not 24p. Plus, there is no advantage to starting with a progressive signal if you are going to transmit it in interlaced mode (except that it can be deinterlaced perfectly); you actually lose temporal resolution, because you are capturing full fields at 30 (or 24) per second rather than fields (half frame) at 60 per second. Originating at 24p is the worst of all alternatives from a video standpoint, since not only is the temporal resolution poorer than for standard 720p or 1080i, but you have to use 3:2 pulldown to feed a standard TV display, which introduces judder.
 

·
Registered
Joined
·
1,881 Posts
"HDTVs _DO_ support 1080/24p. It's part of the ATSC standard. Scanning TVs (or the set-top box) generate their own pull-down for 24p material - it's an easy thing to do. "


No TVs will actually display 1080/24p though. It's nice to hear that they'll accept the signal though. Does this mean HD-DVDs will be stored on disk as 1080/24p and let the player or the TV handle the interlacing? I sure hope so.
 
1 - 9 of 9 Posts
Status
Not open for further replies.
Top