Device that turns 30P video into 60i output - which deinterlacing method?

[poisondeathray]

Yadif 2x retains the original fields, so you can reconstruct the original progressive frames later if you had to (you discard the interpolated fields that yadif generated , and weave the original ones)

Interesting... From the multiple descriptions I've read on various websites, yadif fills in the missing lines, so if you do 2X it does that for every "field" but also keeps the original lines as they are. Is that correct? So to reconstruct the original data you would take the original lines out of the 60p video and then interleave those back together. So I guess it's "lossless" but still easy to record and view.

Does BWDIF not keep the original lines?

Yes, both yadif (2x) and bwdif (2x) separate the fields, then spatially interpolate the missing field, and the original scanlines are kept and unfiltered, but temporally displaced compared to the input stream

If progressive input was aligned, capital letter is top field , lower case bottom field

A B C
a b c

Yadif 2x or bwdif 2x creates this pattern for a TFF stream, where "i" is the interpolated field. To "reverse" it back to the original, you just select the original fields (discard the "i"'s) and weave them

A i B i C i
i a i b i c

So it's "lossless" in terms of the original input scanlines (if you used lossless compression, same pixel format) - but often looks like crap because the deinterlacing/interpolation artifacts (yadif usually worse than bwdif for subjective appearance)



But for pure 29.97p content, it makes little sense to double rate deinterlace to 59.94p (extra bandwidth; double if you're using uncompressed output; and lower visual quality - unless you discard the interpolated fields, and reconstruct the original progressive frames)

1080p29.97 content, sent as 1080i29.97 ( if the fields are sent aligned) can be treated as progressive. You can interpret it as progressive , or flag it progressive as suggested earlier . If it's misaligned, then fieldmatch . If it's mixed content, then you have other decisions to make

[daygecko]

Thank you! What I've learned is that many broadcasts are a mix of interlaced and progressive video. I recorded a segment from MSNBC and most of it was 30p originally but they had a 60fps video from the Olympics, followed by a 30fps clip of the same sport from a different angle!

So I guess generally recording in Yadif 2x with OBS makes sense. The only downside I can think of is the doubled frames when not necessary as you said, but with x264 or HEVC the birate doesn't go up much.

For the things that I know are 30p originally I'll try just changing the flag

[manono]

When I say 1080i 60fps I'm referring to each of the interlaced halves as a frame. I know some people say 1080i30

You don't get to redefine the terms to suit yourself and confuse others that know better. fps stands for Frames Per Second and nothing else. Those "interlaced halves" are called fields and they aren't interlaced, although they might come from different points in time and when put together as frames show interlacing. There is no 1080i 60fps being broadcast. I see you doing the same thing in other threads besides just this one.

Again, 1080i can refer to both interlaced or progressive content. When the content is really interlaced, like your YouTube video (which you should have deinterlaced before upload), it's easy to say so.

I recorded a segment from MSNBC and most of it was 30p originally but they had a 60fps video from the Olympics, followed by a 30fps clip of the same sport from a different angle!

Nope. You could just as easily have said it was a mix of progressive and interlaced content. It was all 1080i 30fps.

[daygecko]

When I say 1080i 60fps I'm referring to each of the interlaced halves as a frame. I know some people say 1080i30

You don't get to redefine the terms to suit yourself and confuse others that know better. fps stands for Frames Per Second and nothing else. Those "interlaced halves" are called fields and they aren't interlaced, although they might come from different points in time and when put together as frames show interlacing. There is no 1080i 60fps being broadcast. I see you doing the same thing in other threads besides just this one.

Again, 1080i can refer to both interlaced or progressive content. When the content is really interlaced, like your YouTube video (which you should have deinterlaced before upload), it's easy to say so.

I recorded a segment from MSNBC and most of it was 30p originally but they had a 60fps video from the Olympics, followed by a 30fps clip of the same sport from a different angle!

Nope. You could just as easily have said it was a mix of progressive and interlaced content. It was all 1080i 30fps.

Good grief, sorry I made a mistake. I'm new to dealing with these legacy broadcast formats. I thought each line was a field, because I think I've seen the term used in that context. Edit: for example https://medium.com/hd-pro/progressive-vs-interlaced-e18e2924800e
In any case, I see 1080i30 referred to as 1080i60 frequently. Wikipedia has both https://en.wikipedia.org/wiki/1080i

The sports content I was referring to originally is literally 1080p60 or 4k60 to begin with because no modern professional camera generates 1080i.
Everyone knows what 1080i is so there's no need to be pedantic.

And the video I uploaded to Youtube was not interlaced. I've only just realized that OBS, when set to "no deinterlacing", just does a simple weave. So that means a lot of what I thought was really 30p was really interlaced and probably originally recorded at 4k60

[jagabo]

segment from MSNBC and most of it was 30p originally

Almost nothing is broadcast as 30p. Sometimes computer generated overlays are at 30p but any live video behind it will be 30i or 60p.

[EDIT]
Online streaming video is very often 30p.
[/EDIT]

[Cornucopia]

Agreed. Also, nascent ATSC 3.0 notwithstanding, regardless of what the camera originals are/were, all the stuff that is actually being broadcast is at best HD. Not 4k.


Scott

[manono]

And the video I uploaded to Youtube was not interlaced.

Now you're contradicting yourself:

I can create compressed recordings with OBS but it doesn't support interlaced. I originally recorded with no deinterlacing and this was the result https://www.youtube.com/watch?v=H2lGEZOOHwI&lc=Ugz72vLhL_bCnsCPWV94AaABAg
You can see the combing effects