Originally Posted by kjgarrison
Dumb question(s), but those are the kind you learn the most form often: Why does it matter how it "gets there" (from 1080p/24 to 1080p/120) as long as it does and passes the HQV tests? Isn't the 1080p/24 already 2:3 format?
Originally Posted by HDTV1080P24 Good question. A 5:5 process where 1080P/24 is frame doubled 5 times will result in less judder and a look that is closer to 70MM and 35mm film. When a 3:2 pulldown process is used 1080P/24 material will experience slight artifacts like judder and the image will not be as smooth. So converting to 60HZ and then converting to120HZ has no benefit since the 3:2 process causes motion artifacts. In fact if the 3:2 pulldown process is better quality in the BLU-RAY/HD-DVD player compared to the 3:2 process in a display then it would be better to set the BLU-RAY/HD-DVD player to 60HZ output if one owns a display that does not refresh 1080P/24 at correct multiplies to match film quality.1080P/24 output on a player should only be used when one owns a display that refreshes 24fps material at multiplies of the original frame or when one owns a 60HZ display that does a better job of converting 24 fps to 60 fps then what the BLU-RAY/HD-DVD player is capable of doing.On some 120HZ displays some people like to use a motion enhancer technique to make film material look like super smooth 60HZ video. Those that own the Sony 120HZ displays that want the display to frame multiple 24fps material 5X turn off the motion enhancer feature so they get the look of film.
OK, HDTV1080p24, I have been studying some. Here is my current understanding (from 40,000 feet). Telecine is the process where 2:3 pulldown is performed on a 1080p/24hz film source, where 2 frames (A B) of the original are turned into 5 frames of 1080i/60hz. This is done by both splitting (interlacing) the 2 frames (AA BB), which yields 4 frames, then adding a duplicate of the second frame for a total of 5 frames (AA BBB), thus 2:3 (or more commonly called 3:2). This 2/5 ratio matches 24/60.
I think the purpose of the 2:3 cadence is mostly to get it up to 60hz, but this cadence pattern is also used as a 'signal' which is recognized by capable video processors which reverse the process (called inverse telecine) taking the 5 frames back to the original 2, or the 60hz back to the original 24.
Watching telecined 1080i/60hz video has an artifact called judder because the 1:1 ratio of the first two frames (AB) becomes 2:3 (AABBB). Furthermore, even though the video is interlaced, deinterlacing alone doesn't really change the telecined ratio, and it creates a hybrid half A and half B frame. So 1080p/60hz still will have judder. Doubling to 120hz will also, but less apparent.
If a TV accepts 1080p/24hz (more commonly called 24p) and multiplies by 5 x to get 120hz (for some reason that I find confusing because of the similarity to the completely different 3:2 pulldown, this is generally called 5:5 pulldown) then there will be no telecine judder. Any other method of displaying video that has been telecined from 24p will leave this artifact (judder).
All TVs will of course need to accept telecined video because that is what will come OTA and via satellite, so they do need to be able to inverse telecine, create 24p, and then 3x, 4x, or 5x if they are going to do it best. Otherwise they just start multiplying the telecined 1080ip/60hz video (and adding motion fixes?).
So my original question was actually an uninformed one. It does matter how you get there, because there is only one way to get there and that is through 24p. Either accept 24p input, or take 1080i/60hz input and inverse telecine to reconstruct 24p, and then multiply.
Do I understand this correctly now?
omg, I just re-read your response .... jeez ... you said the same thing only simpler