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Old 10th November 2022, 02:10   #61  |  Link
Katie Boundary
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Actually, here's a fun experiment for you to try, with the numbers adjusted for PAL/SECAM material

Code:
A=mpeg2source("whatever.d2v").bob()

B=mpeg2source("whatever.d2v").converttorgb(interlaced=true).separatefields()

C=B.selecteven().bicubicresize(720,576,src_left=0,src_top=0.25,src_width=720,src_height=288)
D=B.selectodd().bicubicresize(720,576,src_left=0,src_top=-0.25,src_width=720,src_height=288)

E=interleave(C,D)

Compare(A,E)
You'll find naught but rounding errors
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Old 10th November 2022, 14:20   #62  |  Link
flossy_cake
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What I meant was, you're shifting the top field up by 0.25 and the bottom field down by 0.25, which in theory should be equivalent to shifting only the bottom field down by 0.5, which is how I was doing it (which is equivalent to shifting it down by 1.0 after the field is upscaled 2x vertically, which helps me visualise in my mind that the field alignment is preserved).

I was just curious to know why you did the 0.25/-0.25 split instead of 0/-0.5 split, whether that had any benefits (I was thinking, maybe that would help with line flicker at the top and bottom most rows of pixels?)

Last edited by flossy_cake; 10th November 2022 at 15:20.
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Old 10th November 2022, 15:20   #63  |  Link
flossy_cake
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Quote:
Originally Posted by Katie Boundary View Post
Actually, here's a fun experiment for you to try, with the numbers adjusted for PAL/SECAM material

You'll find naught but rounding errors
Test clip: https://drive.google.com/file/d/1WfW...usp=share_link

Script
Code:
clip = "576i 1-1 cadence.ts"
source = LWLibavVideoSource(clip)

A=source.bob()

B=source.separatefields()
C=B.selecteven().bicubicresize(720,576,src_left=0,src_top=0.25,src_width=720,src_height=288)
D=B.selectodd().bicubicresize(720,576,src_left=0,src_top=-0.25,src_width=720,src_height=288)
E=interleave(C,D)

Compare(A,E)
Result



I am not sure why PSNR is showing that value or what it means exactly, but if I replace last line with Compare(A,A) I get the same result.

Then compared the 0.25/-0.25 split vs 0/-0.5 split and they are not the same, obviously. But I think that is just because both bobbed frames are sitting 0.25 higher in the former.
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Old 23rd November 2022, 12:12   #64  |  Link
flossy_cake
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Quote:
Originally Posted by hello_hello View Post
Are you familiar with the resizing mess for DVDs?
The short story is DVDs can have a generic aspect ratio, which makes a 4:3 DVD exactly 4:3, or an ITU aspect ratio which follows the standard for digitising video, and as a result the aspect ratio could be ~1.36 instead of 1.33 (before any cropping). I'm pretty sure I went with an ITU aspect ratio for the DVD version, and the first thing I noticed when comparing it to the Bluray was the difference in aspect ratio, which looks to be exactly the difference between a generic and ITU aspect ratio for DVDs. Here's a couple of screenshots. Have a look at the clock-face on the left. I'll leave you to decide in which screenshot it looks round, or for that matter, if it's even supposed to be round.

https://i.ibb.co/tJXf43p/DVD-Encode.png
https://i.ibb.co/61qLbTy/Bluray.png

Out of curiosity I bought the newest version of the DVD ("remastered" one, specifically this one which was referenced here as being superior to the BD).

Well, the DVD aspect is identical to the BD, except the BD is slightly zoomed in to remove a few pixels of blanking at the bottom edge present on the DVD.

Oddly though, the external shots are a lot worse on DVD in terms of colour and resolution, except for the intro sequence.

Edge enhancement seems present in the DVD too, but diminished probably as a result from the downscale from 1080 to 576. Noise reduction is not present in the DVD it seems.

Screenshots:

DVD: https://i.lensdump.com/i/RR6Hyr.png
BD: https://i2.lensdump.com/i/RR6Oe7.png

DVD: https://i3.lensdump.com/i/RR6S73.png
BD: https://i1.lensdump.com/i/RR6zRF.png

DVD: https://i2.lensdump.com/i/RR6eU0.png
BD: https://i.lensdump.com/i/RR6vID.png

Clips:

DVD: https://drive.google.com/file/d/1qcU...usp=share_link
BD: https://drive.google.com/file/d/1a-N...usp=share_link

DVD: https://drive.google.com/file/d/1pAw...usp=share_link
BD: https://drive.google.com/file/d/1tw9...usp=share_link

Last edited by flossy_cake; 23rd November 2022 at 12:17.
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Old 23rd November 2022, 18:00   #65  |  Link
hello_hello
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Yeah it looks like they started again with the outside shots for the Bluray but not for the DVD. Like they decided to go back to the original film negative or something.

The inside shots do seem to have the same display aspect ratio but the outside shots are a tad different. The Bluray version is a little wider, but not 1.36 vs 1.33 wider. It's something in-between. Sigh....
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Old 23rd November 2022, 20:40   #66  |  Link
flossy_cake
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Well, on balance I think I prefer the bluray version. What do you think?
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Old 23rd November 2022, 20:45   #67  |  Link
hello_hello
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I haven't tried de-interlacing the DVD sample to see if de-interlaces more "cleanly", but assuming it doesn't, yes I'd prefer the bluray, at least for the outside shots.
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Old 24th November 2022, 06:13   #68  |  Link
flossy_cake
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For those screenshots I was using AMD DXVA deint, and now that I look closely I'm seeing some weird squiggly line patterns in the video noise on Basil's coat. BWDIF(thr=2) doesn't have that and seems to be producing a better result. imo the best fast real-time video mode deinterlacers are, from best to worst:

1. BWDIF(thr=2) (can optionally add edeint=nnedi3 for antialiasing on moving pixels... but I don't like the shapes it makes on certain patterns...but still impressive what it can do)
2. TDeint
3. DXVA (AMD/NVidia implementation... I can only get this through MadVR... maybe someone should make an Avisynth filter for this? )

But without the thr param I would pick TDeint over BWDIF as it weaves a lot more.

Last edited by flossy_cake; 24th November 2022 at 06:22.
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Old 24th November 2022, 12:54   #69  |  Link
hello_hello
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Quote:
Originally Posted by flossy_cake View Post
3. DXVA (AMD/NVidia implementation... I can only get this through MadVR... maybe someone should make an Avisynth filter for this? )
Is cuvid still I thing? I'm using on old version of MPC-HC as the newer flavours don't support XP. DXVA2 doesn't work but Cuvid DXVA does in LAV filters and the deinterlacing works but my old video card can barely de-interlace to 25fps at 1080p.

For funzies I enabled the old ffdshow DXVA decoder and it worked. I couldn't get it to decode with MADVR rendering for some reason, but using WMR9 it did (EVR doesn't play on XP any more). The video was being de-interlaced and it played a 1080p source smoothly even though I'm pretty sure it was de-interlacing to 50fps, although it has no de-interlacing options. It also only supports h264 and VC1.

It's been so long since I've wanted to watch interlaced video I had to work out why MPC-HC wasn't de-interlacing any video at all before I started.... given my "de-interlace once, do it properly, re-encode as progressive and it's done for good" philosophy.

Now I've had another look with de-interlacing enabled I'll take back what I said about the DVD quality. The video sections look better on the bluray too. Less noise and artefacts etc.

PS Did you try my decoding and deinterlacing suggestion in the TIVTC thread? Even if you just use TDeint and none of the other filtering I'm curious to learn if it works for the whole video. I think the sample encode I uploaded looks better in general than the original DVD, although there's probably still some room for a slight improvement. I didn't experiment much with filter options.

Last edited by hello_hello; 24th November 2022 at 13:09.
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Old 28th November 2022, 21:28   #70  |  Link
flossy_cake
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Quote:
Originally Posted by hello_hello View Post
Interesting. The consensus has always been DVD video doesn't contain that sort of information. I don't think any encoding GUIs look for it. I'll check any DVDs I encode from now on.
You were right about this -- it must have been the ripping software that changed the aspect ratio for Garth Marenghi's Darkplace to 1.30:1 as I have the original DVD disc now and the dwpictAspectRatioX/Y is 4/3, 720x576 with active picture area 704x576.
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