NTSC HDTV is usually broadcast at 23.976fps, yes?

[txporter]

I think I understand what I need to do now, even if I can't totally wrap my mind around packaged progressive content, et al.

The second part of this post might help you understand what interlaced video actually is:

https://forum.videohelp.com/threads/316415-Check-Over-My-Options-From-DVD-to-XviD-Conve...=1#post1958565

Excellent. Thanks for that link. Nice detail.

[Gew]

Sorry, this may well be a little bit off issue, but it's still within this frame-duplication-to-gain-29.97-fps-area so I figured I'd just "push it in" instead of starting a new thread, since the answer is prolly something silly easy, something I just have misunderstood, like always.

See, I've been lying in bed thinking. When doing "3:2 telecine", where does the "3:2" really come from. Because, ~6 frames are duplicated for each ~24 (24/1001) being passed along, right? My easy math then says that 24/6 = 4/1, and these figures I cannot seem to find in my logical sense to bring to 3:2 (or 2:3), in whichever way I turn them around up and down. So, what little puzzle piece am I missing out on here?

[poisondeathray]

See, I've been lying in bed thinking. When doing "3:2 telecine", where does the "3:2" really come from. Because, ~6 frames are duplicated for each ~24 (24/1001) being passed along, right? My easy math then says that 24/6 = 4/1, and these figures I cannot seem to find in my logical sense to bring to 3:2 (or 2:3), in whichever way I turn them around up and down. So, what little puzzle piece am I missing out on here?

3 field repeats, 2 field repeats, 3 field repeats, 2 field repeats...

a-a-a-b-b-c-c-c-d-d ...

http://www.doom9.org/images/pulldownB.gif

[edDV]

Think field repeats not frames. The actual rates in the diagram below should be 23.976p film play rate to 29.97 frame per sec video (59.94 fields per sec). The asterisk video frames (2 and 3) have fields from different film frames.

[edDV]

For broadacast 480p and 720p full frames are repeated 2 then 3 for film material.

23.976p film ABCD

59.940p video AABBBCCDDD


The uneven frame repeats cause "judder". 120Hz (119.88 actually) HDTV sets repeat 5x with no judder.

119.88p video AAAAABBBBBCCCCCDDDDD

"120Hz" sets have modes for 5x frame repeat or frame interpolation.


The only 1080p ATSC or Blu-Ray standard is at 23.976p or ABCD. HDTV sets that accept 23.976p, frame repeat or interpolate from ABCD.

[Gew]

The diagram was quite self-explanatory and pedagogical, ty. Tbh second post with "abcd" "aaabbbccc" similes plus adding the hertz factor into play was mostly making me more uncertain/confuzed! Trying to make most sense possible out of the diagram for now.

[edDV]

The diagram was quite self-explanatory and pedagogical, ty. Tbh second post with "abcd" "aaabbbccc" similes plus adding the hertz factor into play was mostly making me more uncertain/confuzed! Trying to make most sense possible out of the diagram for now.

The diagram is for interlace video (480i or 1080i) which has a frame rate of 29.97 and a field rate of 59.94.

Film sourced interlace video has a field sequence as shown in the diagram.

Progressive video (480p, 720p, 1080p) is sent with full frames in a frame repeat sequence.

Does that help?

[Gew]

The diagram is for interlace video (480i or 1080i) which has a frame rate of 29.97 and a field rate of 59.94.

Film sourced interlace video has a field sequence as shown in the diagram.

Progressive video (480p, 720p, 1080p) is sent with full frames in a frame repeat sequence.

Does that help?

Helps indeed. Narrows the terms down a bit, sort of.

Some random Yahoo Ask! bubble got me "When you watch a movie on your TV it's not like it is at the theater; for every four movie frames, they blend a few of them to make a "fake" fifth one (because 24*5/4=30)." which (last part) perhaps was the math I was looking for when tumbling n fumbling with 3:2 and 24/6 in mixed directions. However, the asterix part in diagram confuzed, so I'm simply ignoring these asterixes.

As I've come to understand it, [in diagram picture] it takes first odd and first even field from film and puts it into NTSC frame #1, and then film's first odd field (again!) and repeats it into NTSC frame #2, and the pattern repeats itself, sort of.

[edDV]

Video frame 1 = Film frame 1 top and bottom field (same as progressive)

Video frame 2 = Film frame 1 top and frame 2 bottom field (mixed)

Video frame 3 = Film frame 2 top and frame 3 bottom field (mixed)

Video frame 4 = Film frame 3 top and bottom field (same as progressive)

Video frame 5 = Film frame 4 top and bottom field (same as progressive)