Deinterlace 60i -> 60p, yes, 60p, not 30p.

[123Mike]

I'd like to know if this is new to people, and/or if people have seen this sort of de-interlacing in the various video converter solutions that are out there.
Some might have a gut reaction that de-interlacing 60i would result in 30p, but that isn't necessarily so.
You *CAN* convert to 60p and really experience *more* fluent motion that what you experience in 30p.

Camcorders, like my Canon HF100, often record in 60i.
The way I see it, is that the camera makes a snap shot of the world, 60 times per second. A frame has 2 fields. You might only have 30 "frames", but each "field" (odd and even lines of video) is taken 60 times per second.
As such, the world moves 60 times per second, so to say.

Now, I see most people convert this to 30p video. What ends up happening then, is that things move on the video with only half the motion resolution. Visually, your brain is being sent updates of world changes 30 times per second. This is half as smooth as 60 times per second.
My HF100 can record in 30p and 60i. When I play back this video on my 50" plasma, I can clearly see that video recorded in 60i looks a lot smoother for things that move than 30p video. 30p looks jittery, no two ways about it.
A plasma tv however, can not really display interlaced video, so the computer inside the television has a de-interlacer. It has a very good de-interlacer, which actually produces real 60p video. Otherwise I would not be seeing so much difference between my 30p and 60i recordings.

So, one option would be to keep all my video content interlaced. But that's not feasible. Video editing tools often don't work with interlaced content, because they often must de-interlace the content, and more often than not, half the perceived frame rate is gone.
Also, my DVI video output of my computer, which I hook up to my plasma television to watch home videos, can not produce interlaced video.
So the only way to see 60 fps video, is for my video files to be 60p.

I've been using mencoder for most of my video conversions. I find it has more video filters and options than anything out there. It seems it has more conversion options than any other software out there.
One option in particular that solved my 60p problem, is the "yadif" de-interlacer. It can convert 60i to 60p, preserving all the perceptual motion that the camcorder recorded. It observed the world 60 times per second, and the end result on my plasma sends me 60 times world updates to my brain.
Yadif does this *without* cutting the resolution in half by the way !

So, questions:
- some people think ffmpeg is the best converter, why? Especially if mencoder does way more, and uses some of the same video conversion code?
- does ffmpeg have a de-interlacer that does not half the frame rate? It seems to me that proper de-interlacing is completely overlooked.
- can the commercial video editors convert to 60p? pinnacle, sony, etc?

To me, it seems properly de-interlacing is a concept that's almost completely overlooked, or just not understood in depth enough.
I'm very interested to know what others think about all this.

~Mike

[jagabo]

You *CAN* convert to 60p and really experience *more* fluent motion that what you experience in 30p.

It's called Bob. The best so far is AviSynth's TempGaussMC(). It is very slow though.

[edDV]

Be warned that a non-processed pure BOB can flicker during low motion. Motion adaptive deinterlacers switch to something closer to a weave in picture areas with low motion. Your HDTV does this automatically so the better solution in normal cases is to leave the source interlaced. BOB is often needed for scaling and special effects processing.

[edDV]

Further,

Most good editors (e.g. Premiere. Vegas, etc.) handle interlace video fine. Some filters or effects will deinterlace. This needs to be managed during editing.

It is true that many computer display cards* handle interlace poorly. A work around is to export to interlace DVD or an interlace file for playback from a media player (e.g. WD or a MCE extender).

- can the commercial video editors convert to 60p? pinnacle, sony, etc?

Yes for Vegas Pro and Premiere Pro but the conversion needs to be managed and depends on source motion or lack of motion. Otherwise flicker can result.


* The later NVidia PureVideo HD and ATI AVIVO HD display cards do better for pass through interlace to HDMI or analog component. All VGA gets deinterlaced.

[jagabo]

This post:

https://forum.videohelp.com/topic365493-30.html#1949705

Links to an AVI file that demonstrates several different bob deinterlacing methods. In that particular video the frame rate was reduced from 50 fps to 25 fps to make the flickering more obvious and the video easier to play.

[manono]

I'd like to know if this is new to people, and/or if people have seen this sort of de-interlacing in the various video converter solutions that are out there.
.
.
I'm very interested to know what others think about all this.

None of this is new to anyone that knows anything about video. You're trying to reinvent the wheel here. Learn some AviSynth and use a SmartBob (if for some strange reason it has to be deinterlaced before being processed). In general, though, the better the quality, the slower the encode. jagabo already gave you the name of the best AviSynth bobber (one of whose main purposes is to get rid of that flicker edDV mentioned).

And it's more properly called 30i (at least where I come from) - 30 interlaced frames per second.

[jagabo]

And it's more properly called 30i (at least where I come from) - 30 interlaced frames per second.

I agree. Unfortunately all the camcorder manufacturers' are calling it 60i now. It's the usual number inflation in marketing.

[minidv2dvd]

what they are calling 60i is 60 fields per second, not 60 frames per second. a field only contains half of a frame, as in every other scan line. so no you can't make real 60p out of 60i. you can fake it by combining 2 60i fields to make a frame and then duplicating it so you end up with 30 full frames each played twice in a row. real 60p is a different beast.

[jagabo]

what they are calling 60i is 60 fields per second

Yes, but in the past that was called 30i -- 60 different fields packaged into 30 frames per second. The number indicated the frames per second and the i/p indicated whether the frames were progressive (one picture per frame) or interlaced (two pictures per frame). The switch to calling it 60i is simply marketing. People who don't know what it means will simply assume 60i is better than 30i. But the difference is only in the name.

[manono]

what they are calling 60i is 60 fields per second, not 60 frames per second.

I can't tell who you're disagreeing with, me and jagabo, or 123Mike. 30 interlaced frames per second is 60 fields per second.

so no you can't make real 60p out of 60i.

What do you think a bobber does?

you can fake it by combining 2 60i fields to make a frame and then duplicating it so you end up with 30 full frames each played twice in a row. real 60p is a different beast.

A good bobber creates 60 different and unique frames per second from a 30i source. It creates a real 60p.

Or are you somehow talking about something different?

[edDV]

Yes the pure BOB interpolates a frame in place of each field. It can do this from data only in the field but good BOBers look across several fields and use motion detection. Idea is to go with field data for fast motion areas and multi field interpolation for low motion areas of the frame. This preserves vertical resolution and prevents flicker.

It should be noted that almost every current progressive TV does the 60 fps (or 120 fps) Bob with variable quality*. Better HDTV sets will have multiple frames of memory for motion analysis.


*The worst older HDTV sets do a blend deinterlace without motion detection. This causes motion areas to blur out.

[minidv2dvd]

i wasn't disagreeing with anyone. just making a point that so called 60i is the same as what is normally referred to as 30i, in that every individual field of 60i is only half a frame, so you can't make "real" 60p out of it. it only has half the picture, not the complete picture as 60p would.

a straight bob loses half the vertical resolution. a bob and weave needs to be played at 60fps. i don't see any pluses with either method of making progressive out of it.

[edDV]

a straight bob loses half the vertical resolution. a bob and weave needs to be played at 60fps. i don't see any pluses with either method of making progressive out of it.

There is no such thing as a 30p progressive TV display. All "NTSC" progressive TV sets display 60p or 120p (ignoring film for now). So the TV must deinterlace or repeat frames. If you feed it interlace, it will optimally interpolate for 60p or 120p display. If you feed it 30p, it will frame repeat to 60p or 120p. Some 120p sets may attempt intermediate frame interpolation. Either way, 30p will always appear more motion stepped vs. 30i/60p (aka 60i/60p).

But the main point is 30i can be processed to 60p with 60 real motion samples and the better HDTV processors will produce results very close to native 60p.

[minidv2dvd]

ok. i guess it depends on what you are playing the file with to feed it to the tv. all my work goes ends up going onto dvd for tv, or streaming online. i think if i wanted/needed 60p i'd go with one of the jvc 720 60p cams.

[manono]

i don't see any pluses with either method of making progressive out of it.

I don't work much with interlaced material myself, but the OP has a very real need for 60p because (he says) his editing programs won't work with interlaced material. Many, many other people have interlaced material that they like to make progressive (for AVI, for example), and by using a good "smart bobber" you keep the full and fluid movement.

[minidv2dvd]

i've been shooting everything in HDV 30p so i can make fairly good video, with fast motion, for both dvd and conversion to online streaming h264 mp4. seems to be a fair compromise.

[edDV]

ok. i guess it depends on what you are playing the file with to feed it to the tv. all my work goes ends up going onto dvd for tv, or streaming online. i think if i wanted/needed 60p i'd go with one of the jvc 720 60p cams.

Streaming is a different ball game but DVD is either 30i or 30p represented as 30i (again ignoring film). The main issue is 30i will get more fluid motion when paired with a good progressive TV.

For high definition, 1080i when paired with a good HDTV processor will give 1x playback results very close to native 1080p/60 for "normal" programming. Vertical resolution is retained along with 60 motion samples. The better the HDTV processor the less artifact errors are introduced. Artifacts are at their worse for sports programming especially when the camera is in constant pan/zoom (e.g. Basketball, Hockey and Football). For that 720p/60 is much better. For Golf and Baseball most shots are locked down* allowing 1080i to hold resolution. Jib cam movements in sports and concerts are constrained to a narrow motion vector allowing for better TV deinterlacer performance.

Jib Cam


* Except the instant replay action cams that ideally are 1080p/60 or higher.

[123Mike]

I think it's bad to rename 60i to 30i. 30i makes it seem like it's some sort of inferior 30p flavor. 30 frames done through interlacing.
I notice that a *LOT* of people all over the net are just getting how interlaced works. I'm seeing people make comments that suggests it's about taking a 30p recording and then broadcasting that in interlaced.
That is NOT how interlacing works at all.
Pause one frame and you'll see the evidence right there: the comb like scanline blinds effect. The frame consists of 2 fields that were each taken at a different point in time.
60i (forget about this 30i nonsense), is taking 60 fields per second. Each field is a different 1/60 point in time.
So your spatial resolution is 60, fields per second that is.
You can convert that to 60p fairly decently, without introducing too many artifacts or resolution loss.

What I also find peculiar, that I hardly ever see anyone change their mind on things. People seem to have their opinion or idea about how something works. And instead of exploring and trying to learn, each defends their standpoint, even when they're wrong.
What is wrong with saying something like "hey, that's interesting, I haven't thought about it that way. Now that you put it that way, I'm seeing it in ways I haven't thought of before. Hmmm, guess I had interlacing all wrong. I'll have to rethink some of the things I though about it."
Why the egos....

[jagabo]

I think it's bad to rename 60i to 30i.

I think it's bad to rename 30i to 60i. The terms 30i/30p have been around for ages. 30 corresponds to the number of frames per second. "i" means each frame is interlaced, "p" means each frame is progressive. People who don't understand interlaced video won't be helped by renaming 30i to 60i.

[manono]

Why the egos....

Why the ignorance? At least 30i means something. 60i is completely meaningless. TV stations broadcast in 60i (to use your terminology), at least most formats are your 60i. NTSC DVD outputs 60i. It doesn't matter what the source is. Progressively encoded 23.976 with pulldown (soft telecine) is output at 60i for DVD and for TV. Already telecined 23.976fps film (hard telecine) is output as 60i for TV and for DVD. Progressive sourced 29.97p material, whether encoded as interlaced or as progressive, is output at 60i. And truly interlaced 29.97i video is output as 60 fields per second. By your definition it's all 60i. All distinctions are lost.

Each field is a different 1/60 point in time.

Nope, that's not what it means at all. It just means 60 fields per second. They can be repeated fields.

I think it's bad to rename 60i to 30i.

It's the other way around - 30i being renamed as 60i. As jagabo said earlier, the camera manufacturers have taken it up as a way to make it sound like something new and special, where it's just the same old 30i.

I'm seeing people make comments that suggests it's about taking a 30p recording and then broadcasting that in interlaced. That is NOT how interlacing works at all.

It is, indeed, one way in which it works.

You can convert that to 60p fairly decently, without introducing too many artifacts or resolution loss.

People (myself included) have been doing that for years. That's what bobbers are all about. The TV stations that broadcast in 720p output a full 60 frames per second. And some might be repeated frames or they might all be unique frames, depending on the source.

[jagabo]

All analog NTSC video is broadcast as 60 fields per second. The only frame that exists in analog video is the front of the TV screen. And only half of it is lit up at any one time*.

* Actually this isn't really true. The spot size of the electron beam on most CRT displays is close to two scan lines thick. This means that the theoretically "blank" lines are at least partially lit by the scan lines above and below them. This reduces flicker and makes for a brighter picture.