Help Identifying Interlacing Pattern

[supervehicle]

I need help identifying the interlacing pattern in this clip, as I'm interested in attempting to make it look better. This is my theory on the sequence of events: originally shot on 8/16mm film (24p), then transferred to VHS (probably 25i), then converted from VHS to digital (23.976i). Any help is appreciated. Thanks.

https://drive.google.com/file/d/1N4jEyvjFxA0pVfJ54QoH-mhNPzQRmgRG/view?usp=sharing

[jagabo]

I'd love to see that King Crimson video but it's been mangled way too much. You're not going to fix it. Find a better copy.

Are later parts of the video cleaner? https://www.youtube.com/watch?v=MM_G0IRLEx4

[supervehicle]

The rest of the video is not much better. This clip was taken from the Blu-ray Disc of the "Complete 1969 Recordings" set. I figured this is the best transfer of that VHS we're going to get. To find a better copy would mean going back to the original film, but I don't think that's available.

[supervehicle]

Found a better source. Anyone know what's the best method to utilize for de-interlacing this footage? Could Virtual Dub do the job? I'm using that program, and I see the following options, but not sure which ones to select.

https://drive.google.com/file/d/1ckN36bae3-blOY2m7NPNLmYJ7aCSHcy4/view?usp=share_link.


[Attachment 75485 - Click to enlarge]

[hello_hello]

Even that copy isn't great as there's a few repeated fields in places in addition to the blurring, which is caused by a frame rate conversion using field blending, but the duplicate fields are probably changing the blending pattern and therefore SRestore in the attached sample below isn't removing all of it, but it's at least an improvement.

So you know, when the frame rate is converted using field blending, only one field per frame should contain blending at any time. So the idea is to use bob deinterlacing to convert each field into a full frame, doubling the frame rate, then SRestore picks out the frames without any blending. There's a lot going on to make it hard for SRestore in that clip though.

MKVToolNix produced a bucket load of warning messages regarding skipping invalid audio data when I remuxed it with encoded video, although the audio sync still seems okay.

If you use Avisynth+ here's the script I used to encode the attached "KC Clip.mkv" sample with SRestore converting the frame rate back to 23.976fps. I don't think there's a non-Avisynth equivalent of SRestore. I also cropped a lot of the flickering lines at the bottom while resizing, but that's just me.....

AssumeTFF()
TDeint(Mode=1, tryweave=true, metric=1)
VInverse()
SRestore(24000.0/1001.0)
CropResize(0,0, 6,2,-4,-28, InDAR=15.0/11.0)

This is the script used to encode the attached "De-interlacing only.mkv" sample at 29.97fps (no SRestore).

AssumeTFF()
TDeint(tryweave=true, metric=1)
VInverse()
CropResize(0,0, 6,2,-4,-28, InDAR=15.0/11.0)

For Virtualdub, try the Interpolate methods to see which one works best. It might come down to which one leaves the fewest fine combing lines behind. That'll probably happen to some extent, given the quality. I deinterlaced with TDeint and then used VInverse to clean up most of the fine combing the deinterlacer missed.
On the right side of your Virtualdub screenshot, if you only keep one field you'll end up with 29.97fps. If you keep both you'll end up with 59.94fps.

Below are some field blending examples for you.
The first pic shows the full frame before de-interlacing.


[Attachment 75498 - Click to enlarge]

The second pic shows the same frame with the fields separated. After they're both converted to full size frames by deinterlacing to 59.94fps, SRestore should pick out the bottom one to keep.


[Attachment 75499 - Click to enlarge]

The third pic shows one of the problems with the sample. Near where there's a field repeated for some reason, there's also a few places where both fields have blending, so between that sort of thing and the blending pattern changing, SRestore won't be able to remove all of the blending. Whether it removes enough to make a crash course in learning Avisynth worthwhile, is up to you.


[Attachment 75500 - Click to enlarge]

[supervehicle]

Thank you for your input, much appreciated.

I was previously under the impression that the footage was originally shot at 24fps, but considering this is an 8mm source, I reckon it is most likely 16p originally, then converted to videotape at 25i.

[hello_hello]

I have an Avisynth function that lets me do what SRestore does, only manually. You have to specify the frames to keep and if the blending pattern changes it'll remove the wrong frames. I tried using it on a single scene without perfect success, but for that scene at least, 23.976fps seemed to be the output frame rate the resulted in the most clean frames. Lowere frame rates resulted in more blends left behind.

Who knows though.... that source could've been put through more than one process and/or edited in between.

[supervehicle]

It was definitely edited, that I can confirm, because this video popped up recently:

https://www.youtube.com/watch?v=PTtvQvh5fEQ

I downloaded this to check it out, and it also runs at 25fps, but it looks like there are artifacts there to begin with, probably due to transferring the 8mm source to 25fps.

[Selur]

side note: I played around with it, see: GoogleDrive, script: https://pastebin.com/5ig6hg5x (to see how DDColor performs); https://forum.selur.net/thread-3502-post-20425.html

[supervehicle]

Fascinating results, thank you! The color is rather inconsistent, but still interesting to observe.