Telecine of 18fps material

[bratloaf]

***Admin** crud. I posted this in dev by accident. I reposted in usage. Please delete this thread (I cant).




I have been busily capturing a whole slew of super8 and 8mm film. The method I have been using to capture it produces a frame-perfect capture at a true 18fps progressive. The .avi files I have been able to produce have been an order of magnitude cleaner and clearer than anything I have seen short of professional telecine (Rank) transfer.

However, I'm now stuck. I need to convert the 18fps progressive video (Full D1 res, 720x480, 24bit) to 29.97fps interlaced NTSC. There is no sound to worry about (thank god).

I have found one tool that looks to be perfect, and does the "correct" 18fps telecine but it's $69. And I got to thinking last night, I bet avisynth can do this. I KNOW avisynth can do this. But so far my knowledge of avisynth has been limited to using it for resizing, and as a filter processor (like cleaning, despeckling, etc) nothing like frame rate conversion...

Here is the suggested pulldown schemes:

Begin quote from dodcap website:

Option...............Non Interlaced .. Interlaced
16 fps on PAL Video......4:2 ......3:3
15 fps on NTSC Video.....4 ........4
18 fps on PAL Video......4:2:2 ....3:3:2
18 fps on NTSC Video.....4:4:2 ....4:3:3 *
24 fps on PAL Video......2 ........2
24 fps on NTSC Video.....4:2:2:2 ...2:2:3:3

* = what I'm interested in.

NOTE: In the patterns above, each place separated by a colon ":" represents an original captured frame. The numeric values themselves represent how many fields of this frame are output. For example, "3:3:2" above represents three original captured frames--let's call them A, B, and C. The numbers indicate that frame A is
displayed (output) for 3 frames, B is displayed for 3 frames, and C is displayed for 2 frames. The total number of input frames was 3, and the total number of output frames are 4 (i.e., 3 + 3 + 2 = 8 fields = 4 frames). In the output file, each frame of PAL or NTSC video consists of two fields: a top field and a bottom field. We will label these fields "t" and "b", respectively. In the 3:3:2 example just described, the input pattern, showing both top and bottom fields, was "AtAb BtBb CtCb." This represents 2 fields of A, 2 of B, and 2 of C, or three whole progressive frames. The output after the pattern is applied would be "AtAb AtBb BtBb CtCb."

End quote

Now, I understand what is needed, and what this all means. And I just read about pulldown, interleve and select every... and I know the answer is in here somwhere. But I'm at a loss where even to start.

What I'd like is a function to convert 18fps progressive to 29.97fps in either progressive or interlaced. I guess I really dont care about progressive if it makes it more difficult, as I can play the 18fps source on my pc at 18fps.

The intention is to produce DVD compliant MPEG from the above interlaced material. That I can handle once I get the frame rates and interlacing right. I tired this with premiere, and did not like the results (jerky). I have tried the dodcap tool (trial limited to 350 frames) and it works beautifully.

I would really appreciate any help in writing this function...

Thanks in advance!!!

-Jeff

[kassandro]

I think your problem can be solved within Avisynth as long as your clip has not YV12 as its color space. Rather than writing an awkward script, which first separates the fields, then inserts some copies of fields and finally puts the fields together again, it is much better to write a C++ filter, which can be configured, to handle all the above (and perhaps some more) telecine examples (with 3 frames only). One thing is missing, though, from your description. You have also to specify the field order, which you would like to have, i.e. top field first or bottom field first. The field order will ultimately determine, which fields have to be copied.

[gvm]

@bratloaf,

you said "The method I have been using to capture it produces a frame-perfect capture at a true 18fps progressive."

Can you explain your method please?

[stickboy]

See his other thread (http://forum.doom9.org/showthread.php?s=&threadid=69876).

[gvm]

@stickboy, his method is not explained there. I want to know how he created his original video file

[stickboy]

I thought he did when he talked about modifying a projector?

Regardless, discuss it in the other thread, and let this one die.