Resizing Interlaced Video

[koberulz]

I want to get rid of the pillarboxing and the ticker. But it's interlaced, so I'm assuming it's not as simple as a crop-and-resize by the relevant number of pixels.

[hello_hello]

After asking, why not de-interlace it first.....

Interlaced video can be cropped but for YV12 the height cropping has to be multiples of 4.

If you want to keep it interlaced and resize, I think you could use the IResize function.
https://forum.doom9.org/showthread.php?p=1185790#post1185790
Not that I've used it myself as I always de-interlace.

[koberulz]

The game before this one ran long. So I've got the live, ticker-free broadcast of the last three quarters, and the delayed broadcast of the first quarter, with the ticker. I'm trying to get them to match. Obviously switching between interlaced and progressive doesn't really do that.

[Bernix]

Hi,
if you want keep it 1920x1080 and result as progresive than deinterlace first, then crop and then resize. I measure roughly the picture and it is 1,875:1 ratio. Resizing croped result to 1920/1080 you have 1,7777777777:1 ratio, so resized picture should be 1920x1024px


But it is slow proces. Can be solved without reencoding on software player or remuxing level. But not for TVs, just for watching on PC



Bernix

[poisondeathray]

oops, nevermind

[johnmeyer]

You either have to deinterlace first, then crop and re-size, or else crop and then use IResize as hello_hello recommended. I'd forgotten about IResize. I've used it before and rather like it, but only if you want to have interlaced video as the final output. I am not a fan of deinterlacing unless you really need to do it (to deliver on the Internet, for instance). It always degrades the video. IResize makes no attempt to estimate pixels and therefore produces a result that is a little more faithful to the original. However, lots of people prefer deinterlacing, and I don't want to start another discussion about that, so try it both ways and see what you prefer.

[jagabo]

I would use QTGMC/crop/resize rather than anything involving iResize. If you crop before QTGMC() be sure to use mod4 on all sides.

This is slightly faster:

Crop(96,0,-96,-108).QTGMC().Spline36Resize(1920,1080)

than:

QTGMC().Crop(96,0,-96,-108).Spline36Resize(1920,1080)

Even if I needed interlaced output I would use QTGMC/crop/resize/reinterlace. That will give better results than using iResize. The latter basically just blurs the video vertically to reduce aliasing artifacts.

[LMotlow]

You mean you're going to stretch that video vertically and stretch it proportionately more horizontally? And screw up the original aspect ratio?
The usual goofy stuff for this forum.
Glad it's not my video.
Enjoy.

[koberulz]

Your condescension is appreciated.

TBH I hadn't actually done the math, I just assumed ESPN weren't idiots and had included the full 1920x1080 original image.

[Bernix]

Hi,
yes, they are not stupid and picture is really 1920x1080, but it depends how things are inserted. Imagine the bottom banner can be inserted over video or video can be squeezed to make space for this banner. What is better solution and how it affected AR you can imagine. If you know how the banner is put in video, then nothing is easiest to resolve this issue.


Edit and i measured the picture you posted and can tell you that without black borders and bottom banner it is 1,875 ratio. So no 1920/1080 = 16/9 but 1,875 is equal to 1920x1024...


Bernix

[johnmeyer]

TBH I hadn't actually done the math, I just assumed ESPN weren't idiots and had included the full 1920x1080 original image.

You didn't say how you got this video onto your computer, and what source it was from. If it was from a cable or satellite broadcast, there should be zero pillarboxing on the side. The fact that you DO have pillarboxing suggests something is wrong in your capture chain. If this is from a DVR, then you should go back and re-do the capture, because I'm pretty sure that ESPN doesn't broadcast pillarboxed material, except on their "classic" channel, where they show video from pre-HD days.

Another thing you should pay VERY special attention to is whether the image that will remain after you remove the crawl is the correct aspect ratio. I do a lot of work for a sports film collector, and sometimes need to do something very similar to what you're doing. What I've found is that sometimes ESPN squishes the image vertically in order to make room for the crawl. Other times they merely crop off the bottom. You need to figure out which applies to your video. If it was squished, your re-size operation is going to have to undo the squish, either before the resize or as part of that operation. On the other hand, if what you are looking at appears to be the correct proportions (i.e., a perfect circle still looks like a circle), then you can do a simple resize after the crop.

[edit]I see Bernix posted something similar about "squishing" while I was writing my post

[Bernix]

Made better measure and result is 1,855 but not for sure 16/9

[_Al_]

Photoshop says that cut is 1802x972 (one or two lines plus mines).

[koberulz]

Yes, it's capped from a cable box, and yes, it's broadcast pillarboxed. Presumably this is an ESPN Australia thing. On replays, they add that ticker to the bottom, and pillarbox it so as to avoid obscuring whatever graphics need to be seen at the bottom of the screen. Live broadcasts omit the ticker.


Live broadcast:


Replay:

[_Al_]

Then you should be OK, except that live image has about 10 lines missing at the bottom or it was broadcasted like that. Or you just made up that image?

[Bernix]

I see the top is cropped. Bottom not.
Edit - Actually even bottom is affected.
Bernix

[_Al_]

oh, not straight forward to resurrect ar precisely ....

[Bernix]

I think when you have this two pictures and using some program to made proper measure, you can get correct AR, but not without black bars. Can't be rocket science. Some basic math. My opinion.


Bernix

[Bernix]

I played with this in krita and when you get rid of black bars and bottom crawl precisely and then resize to 1920x103?7? and add 1/2 of remaining 43 pixels on top and bottom you should get right AR.
Images comming soon in this as edit.


I wasn't much precise. There is also problem what is considered to be black bar and what not. Dark transition.
Here is result. Original bottom layer and resized relay on top substracted. Logo is exact i think, yes there is bit shift, but i think it is very small and whole layer can be centered also it is affected by progresive and interlaced content.
If i were you i would play with it bit more.

[Attachment 46935 - Click to enlarge]
For someone probably horrible, for me acceptable result. Of course without black bars on top and bottom



Bernix

[hello_hello]

Yeah, obviously they zoom out a bit when adding the stuff at the bottom, while also cropping a little from the height, but it still results in black bars down each side. The aspect ratio looks fine.

In Avisynth-speak, and keeping the cropping mod4, I worked it out to be

crop(88, 0, -88, -100)
Spline36Resize(1920,1080)

That leaves a few rows of black at the bottom, similar to the "live" screenshot. To remove the black at the bottom completely

crop(96, 0, -96, -108)
Spline36Resize(1920,1080)

Which is exactly what jagabo suggested yesterday. Maybe he was overshadowed by the bad assumption that followed.

[jagabo]

crop(96, 0, -96, -108)
Spline36Resize(1920,1080)

Which is exactly what jagabo suggested yesterday. Maybe he was overshadowed by the bad assumption that followed.

Yes, I guessed the inset video was still square pixel and cropped/resize accordingly. Of course, koberulz might prefer to leave black letterboxing at the top/bottom instead. Personally, I'd downscale to 1280x720 rather than upscale to 1920x1080. Even the original broadcast wasnt't very sharp so the downscale isn't going to hurt it.

[_Al_]

What about that live feed vs. letterboxed one? They do not match. This is not simple zoom out

[jagabo]

It's a zoom out and crop top/bottom. You can't restore the full original 16:9 picture. If you want a 16:9 frame without distortion you have to crop some of the picture at the left/right, or leave some black borders top/bottom.

letterboxed (picture registered with the original broadcast for A/B flipping, not centered):


[Attachment 46939 - Click to enlarge]

zoomed:

[Attachment 46940 - Click to enlarge]

[_Al_]

yes jagabo, I get it, but cutting 36pixels left and 36 pixels right yet again to get 16:9 ? (for crop(96, 0, -96, -108))

that "shadowy" discussion was about to figure out how to perhaps not to screw up ar, instead to add some black bars at the bottom and top after resize, he posted real image so it might be doable, that's all, I am not going to do that math because I don't need it

[_Al_]

you added those pictures in your previous post, that first picture, .... that is what I mean

[jagabo]

I did the math, the cropping and resizing are correct. A/B flip between koberulz's live broadcast image and my letterboxed image. You'll see they are the same within a pixel or so -- aside from the black borders (and the fact that they aren't the exact same frame).

[_Al_]

ok cropping the first post image I get 1802x972 for the real footage, that means cropping left and right is about (1920-1802)/2 ~ 60 pixels, not 88, not 96 I don't get that , you used something else - that is the "math" we are talking about?

[hello_hello]

_Al_,

If you want to crop the "replay" image (post #14) to exactly 16:9 so you can resize to 16:9 dimensions such as 1920x1080 without distorting it, you need to crop extra picture from the sides. He wants to replace an existing section with a cropped version, and without any pillarboxing, as per his opening post, therefore it must remain 16:9 so it can be resized to match the rest of the video. The end result is effectively zooming in to lose the unwanted stuff at the bottom. In this case zooming in also removes some picture from the sides (so what remains is 16:9), but don't freak out, that's how it works.

1920 - 96 - 96 = 1728
1080 - 108 - 972
1728 / 972 = 1.7777777

The 1728x972 image can be resized back to 1920x1080 without any distortion.
Or can you see aspect distortion in the cropped/resized version jagabo posted?

[hello_hello]

Personally, I'd downscale to 1280x720 rather than upscale to 1920x1080. Even the original broadcast wasnt't very sharp so the downscale isn't going to hurt it.

I'd do the same, especially if it's de-interlaced to 50fps. There's generally very little lost through de-interlacing and downscaling to 720/50p, and when de-interlacing with QTGMC, chances are the 720/50p version will look better.

[koberulz]

Personally, I'd downscale to 1280x720 rather than upscale to 1920x1080. Even the original broadcast wasnt't very sharp so the downscale isn't going to hurt it.

The vast majority of the footage I have is from the live broadcast, so I'd much rather leave that alone at 1080i and edit the first little bit to match.