Issues in converting 480i video to 1080i

[sdx12349]

Well... Some reason, when I convert 480i source to 1080i in Premiere Pro, this happens. (Click to see original image, because preview image is worse resolution than original, so you couldn't see same phenomenon in preview.)

This is originally 480i Cable TV TS Capture, but I resized to 1080i using Premiere Pro.

and most of TV Channel in South Korea also have this problem after late 2023~2024.

This is original 1080i TV Broadcasting.

but, if I convert it to 480i again, it does not seem to original quality.
I thougnt It would be better deinterlace filter, but when I used QTGMC, it seems just the same using Bob filter.
How can I convert it to original quality or similar?
I couldn't found the way, except keep resize untill it seems good and use QTGMC... but it isn't perfect way.
I want to get 480i video that looking just same as original 480i source, not the progressive video.
Could anyone tell me what's the problem, and how can I recover it to original quality?

[aramkolt]

Hmm. I haven’t really heard of many use cases for 1080i in modern times other than perhaps certain older TVs that can do 1080i and not 1080p or 720p. I would think the better path might be upscaling/deinterlacing to 1080p at 50/59.94fps (depending on if PAL or NTSC) before it even goes into Premiere using QTGMC.

[sdx12349]

Hmm. I haven’t really heard of many use cases for 1080i in modern times other than perhaps certain older TVs that can do 1080i and not 1080p or 720p. I would think the better path might be upscaling/deinterlacing to 1080p at 50/59.94fps (depending on if PAL or NTSC) before it even goes into Premiere using QTGMC.

Well, the reason I'm having trouble with this is because I can't manipulate it. South Korea's TV Channel is also have this issue when they broadcast old show/animation, and they don't convert 480i to perfectly in 1080i. Even if I could find the same scaling value, there's another problem: the video quality isn't the same or similar as the original.

I want to get nearly the same quality as the 480i source from a Korean TV channel's strangely converted 1080i video.

I attached korean TV channel's weird SD to HD converted broadcast feed source in first thread, and in this thread I attached the 480i video that I adjusted as much as possible with the Premiere Pro resize filter.

(sorry for the bad english)

[sdx12349]

I know after I resize video and use QTGMC, It's quality is much better then before. but it is not I really want. I want to get clean 480i source.

[jagabo]

Something like this 480i to 1080i?

[sdx12349]

Something like this 480i to 1080i?

well.. this thing is pretty great, but not so same what I want. It looks like applied some filter, so not suitable in my standard...
I think I chose wrong thread title, What I really want is "Convert 1080i video (that weirdly resized 480i video) to most likely to 480i source". not 480p, because I can get better 480p video by using QTGMC.
To better help, I attached original 480i source video, and video that weirdly converted original 480i video to 1080i by me.
It is not same as korean TV Channels do because I'm not employee of Broadcasting Company, but I think it is similar condition.
I know It's hard challenge, but I really want to resolve this problem strongly.

[poisondeathray]

To make Example_1080I_SD.mov similar to Example_480i_Origianl.mov, separate the fields, resample (downscale), the correct the colors for SD, weave

Something like this (you can correct for the borders, or use other resampling algorithms if you want it sharper/less sharp)

LSmashVideoSource("Example_1080I_SD.mov")
AssumeTFF().SeparateFields()
DebilinearResizeMT(720,240)
Colormatrix(mode="rec.709->rec.601", clamp=0)
Weave()

The other versions posted earlier are slightly different

[sdx12349]

To make Example_1080I_SD.mov similar to Example_480i_Origianl.mov, separate the fields, resample (downscale), the correct the colors for SD, weave

Something like this (you can correct for the borders, or use other resampling algorithms if you want it sharper/less sharp)

LSmashVideoSource("Example_1080I_SD.mov")
AssumeTFF().SeparateFields()
DebilinearResizeMT(720,240)
Colormatrix(mode="rec.709->rec.601", clamp=0)
Weave()

The other versions posted earlier are slightly different

Well.. It's Pretty not bad! but... It's not different what I can do in Premiere Pro.. I tried similar way in Premiere, and got similar or better result.
There's nothing another way better than this?

[poisondeathray]

Well.. It's Pretty not bad! but... It's not different what I can do in Premiere Pro.. I tried similar way in Premiere, and got similar or better result.
There's nothing another way better than this?

They are all bad to some extent, but there are literally hundreds of ways you can do it...

In what way do you want it "better" ? Try to do a better description

Another common way is to double rate deinterlace, downscale, reinterlace. That would be similar to PP, but you have higher quality choices for deinterlacers and scaling algorithms

Even without other operations, and you disregard lossy compression, upscaling then downscaling , is a lossy process unless you use nearest neighbor scaling on powers of 2. The "source" examples definitely did not, so you will never get similar to REAL original source on fine detail, such as small text. Perhaps you can train an AI to recreate those in the future, but there is no conventional way to fix those details

[poisondeathray]

If you look at the 1st post examples of the credits /text e.g. "2 - 투니버스_20250809_235546.ts" , both fields are missing data on static text. There is no conventional way to fix that properly. Maybe some anime folks trained some AI , I'm not up to date on that

If it were me, I would IVTC and ignore the text. That way you get the highest quality progressive content for the main parts, and you don't degrade everything by deinterlacing. This is anime - the original content is 24p , not interlaced. If you need sd interlaced format, you can downscale progressively after IVTC, and reapply the pulldown for 29.97i

Gamma aware downscaling will reduce the loss on thin white or bright text lines and characters. e.g. in avisynth a simple way is to use ResampleHQ , but you can linearize with AvsResize as well, apply scaling, then delinearlize . But that will not necessarily help thin dark text as well as bright details or lines

LWLibavVideoSource("2 - 투니버스_20250809_235546.ts")
TFM(pp=0)
TDecimate()
ResampleHQ(720,480)
colormatrix(mode="rec.709->rec.601", clamp=0) # if you want SD color


#If you need to apply pulldown for 29.97i
#ChangeFPS(60000,1001)
#AssumeTFF().SeparateFields().SelectEvery(4,0,3).W eave()