interlace on PC

[guns1inger]

manono - I think you need to go back a re-read this thread. He states in his first post that this is animation he has rendered out himself at 30fps progressive. Given that this is his creation from the ground up, I'd give him the benefit of the doubt for the moment that he at least knows the frame rate he rendered at.

[manono]

Oh yeah, now I see:

I have an original source CGI animation I made

I apologize for wasting your time. Thank you guns1inger.

By the way, I might suggest that sharktacos try another player besides PowerDVD to play the video. A friend was having problems with a newer version of PowerDVD playing an interlaced video correctly, and sent me a sample which played fine on my older version. His was playing jerky, like the field order was incorrect. It played fine for both of us on different players, and upon installing the older Ver 4.0 of PowerDVD, it then played fine for him also. There was something wrong with that newer version of PowerDVD that all the tinkering he did couldn't fix.

[sharktacos]

but perhaps your monitor does interlaced picture at 60Hz at some resolutions?

I've never heard of that. It shouldn't. Progressive scan is a lot better than interlace.

p.s. you win the prize for "most distracting avatar"

[sharktacos]

Oh yeah, now I see:

I have an original source CGI animation I made

I apologize for wasting your time. Thank you guns1inger.

No problem.

I would also like to note that when I say I am interlacing it I do not mean I am creating interlaced video from a progressive scan with some algorithm, I mean I am completely re-rendering it with interlace thus changing the nature of the original source. Something you can only do with CGI.

[junkmalle]

you get strobing in extreme case - like in mine where I have a horizontal camera pan across a picket fence.

Ah! Now I know what your problem is. It's similar to what you see in old westerns where the wagon wheels appear to spin backwards when the wagon is moving at certain speeds. A temporal aliasing. The sample interlaced image you posted don't seem to have enough motion for that to be a problem though.

I think the only solution to your problem is to change the animation. Have the camera pan more slowly, use larger slats in your fence, use a different type of fence, pull the camera back a little, zoom out a little, etc.

[Cornucopia]

I really think you should (assuming you're going to std. DVD) just render progressively at 23.976, with a little motion blur. Then encode as progressive with the 2:3 pulldown. This will give you the standard "progressive/movie" look on PC's and progressiveDVDplayer/LCDdisplays and the standard "movie telecine" look on interlaced TV's.

The other option would be to render at 59.94fps interlaced (with very little motion blur) and encode as interlaced 29.97 mpeg.

The difference depends on how important clear motion is to your project. That's why sports programs look more "fluid" as 59.94 interlaced than as 23.976 progressive.

The strobing (picket fence/wagon wheel effect) that you're referring to has to do with the aliasing of the motion, compared to the Nyquist (2x sampling rate). Just like in audio--if you were to have an unfiltered (read: un-blurred) frequency of 29kHz in the source stream of a signal sampled at 44100Hz (which shouldn't allow anything over 22050), then you'll get an artifact signal at 15100Hz--a nice high pitched whine or "birdies"!
The motion blurring acts as a LowPass filter on the Horizontal movement, limiting it's time resolution to less than the frame sampling rate (24fps). <<<edit: actually 12fps>>>
BTW, you do want to try using a Horizontal-only motion blur, leaving the Vertical movement untouched (or have 2 different settings/applications)

So, basically reiterating and agreeing with what edDV already said.

Scott

[junkmalle]

Sharktacos, I took the deinterlaced sample image you posted, pasted several copies side by side, then created panning animations with approximately the same amount of motion as your interlaced sample. I create animations with interlaced 59.94 fields per second, progressive 29.97 frames per second, and progressive 23.976 frames per second marked for 3:2 pulldown.

Indeed the interlaced version played back much more smoothly on TV. The progressive versions were noticably...stroby if you want to call it that.

This isn't the temporal aliasing (wagon wheel) issue I thought it might be earlier. It's simply a matter of 30 fps not being sufficient to give smooth motions with that type of shot. You can see this in movie theaters or on broacast TV with similar scenes.

[sharktacos]

First off I do want to say thanks to everyone for their help. This is an awesome forum!

This isn't the temporal aliasing (wagon wheel) issue I thought it might be earlier. It's simply a matter of 30 fps not being sufficient to give smooth motions with that type of shot. You can see this in movie theaters or on broadcast TV with similar scenes.

Right. And with at 60 fields per second interlaced NTSC it looks perfect on a TV. But the deinterlace algorithm on a PC DVD is apparently done in a blurry way so it looks awful. Not quite sure why since just about any deinterlacer can do a better job.

I tried playing it on different computers with different software, I tried switching from bob to weave on PowerDVD. No dice. All look blurry.

I also tried rendering out the sequence at 24fps and then encoding it to do a pull-down at playback (the famous "Telecine" thing). And, as I predicted it looked MORE "strobey" not less because logically it has with 24fps a lot less to work with then it does with 60 fields of information. Also with the 24-pull-down it even strobes on a PC player(!). So clearly that is not the answer because the telecine solution is solving a very different problem - how to convert film to video.

As far as my problem - how to get interlaced video to play nicely on a progressive scan DVD, I am out of ideas

[junkmalle]

Did the BOB deinterlaced output from PowerDVD look much worse than the equivalent progressive scane image? In terms of clarity. BOB deinterlaces should be about the same as the deinterlaced sample you posted earlier.

[sharktacos]

Did the BOB deinterlaced output from PowerDVD look much worse than the equivalent progressive scane image? In terms of clarity. BOB deinterlaces should be about the same as the deinterlaced sample you posted earlier.

Both the "bob" and "weave" outputs from PowerDVD look awful (blurry).
I also tried the DVD on winDVD as well as on a Mac. All looked equally awful.

[junkmalle]

You're aware that video always looks "awful" on a PC monitor right?

Televisions are designed to display low resolution video so they all include sharpening filters. Computer monitors are designed to display crystal clear, high resolution output from graphics cards so they don't sharpen the picture. So when they're used to display video the picture is fuzzy because there's no sharpening.

In addition PC monitors have very different gamma curves than televisions so video will look dark and low contrast on a computer monitor unless the software is adjusting the video on-the-fly.

[Cornucopia]

Can you post a HuffYUV-encoded avi of ~5second clip? Or a zip of png-still image series?
Try rendering it at either 48fps progressive or 72fps progressive (with little to no motion blur)...

I have a guess about a way to do it right, but don't want to make a fool of myself if I'm wrong, and I won't know that unless I have a small sample of source files.

Scott

>>>Good artistry, BTW!<<<

[sharktacos]

You're aware that video always looks "awful" on a PC monitor right?

If I was saying that all of my DVD looked awful, then that would make sense. However I am saying that 95% looks fantastic and only this one section looks awful.

Compare the pictures I posted. 95% looks like the picture on the bottom. This one "awful" section looks like the blurred image at the top.

[sharktacos]

Can you post a HuffYUV-encoded avi of ~5second clip? Or a zip of png-still image series?

I'm not sure what those are, but I'll work on posting an mpg2 clip

Try rendering it at either 48fps progressive or 72fps progressive (with little to no motion blur)...

This would of course work since it is essentially that same solution as interlacing, while keeping it progressive. The problem is that I really cannot re-render the entire animation which is 10 minutes long all at a new frame rate because it would take months to process. With interlace I can render out only this one section with interlace and keep the rest at 30fps progressive. How could I do something like that if this clip was bumped to 72fps?

I have a guess about a way to do it right, but don't want to make a fool of myself if I'm wrong, and I won't know that unless I have a small sample of source files.

I'll work on that, but please do share in the mean time regardless.

>>>Good artistry, BTW!<<<

why thank you. If you are interested click on the link in my signature and you can see the trailer for the film

[junkmalle]

Compare the pictures I posted. 95% looks like the picture on the bottom. This one "awful" section looks like the blurred image at the top.

If the BOB deinterlaced video looked the same as the blend deinterlaced image you posted then the BOB wasn't working. A BOB deinterlaced image would look just like your Photoshop deinterlaced image.

[Cornucopia]

Thank you, but don't try an MPG2 clip, as that's part of the equation I would be trying to bypass in order to clearly troubleshoot.

It seems you're using a studio quality 3d modelling/rendering/animation program (maya, 3dsmax, etc). In the render options it ought to give you choices about render file formats (AVI, QT, Still picture sequence, etc). Within each would be options for resolution etc., but also options for codec. HuffYUV is a popular lossless codec that commonly makes the files 1/2 to 1/3 filesize yet fully retaining the original quality. That's why I suggested that option--you could use others.
Also, I meant that whatever you posted would only need to be 5 seconds worth--mainly during the "difficult" motion area. You should be able to re-render (at whatever fps) a SUBSET of the full video, right?

Not being as familiar with those 3d apps, I don't know what motion blur and rendering options are available. Taking Adobe AfterEffects as a good 2D benchmark--which has a number of fine controls for those things, it would be a good test to see if a 48 or 72fps progressive render subclip, when nested inside a 24fps composition, were to exhibit the correct sort of motion. This would give a subtle amount of motion blur without introducing the strobing that you want to avoid. Just a guess...

An audio analogy would be "Downsampling with optimized dither and bandpass filtering".

Scott

[sharktacos]

Compare the pictures I posted. 95% looks like the picture on the bottom. This one "awful" section looks like the blurred image at the top.

If the BOB deinterlaced video looked the same as the blend deinterlaced image you posted then the BOB wasn't working. A BOB deinterlaced image would look just like your Photoshop deinterlaced image.

I'm not quite sure what to do with this since bob most definitely did look blurry.
Maybe it shouldn't theoretically, but as my uncle Ray used to say
If "ifs" and "buts" where candy and nuts, we'd all have a merry Christmas"

[sharktacos]

Thank you, but don't try an MPG2 clip, as that's part of the equation I would be trying to bypass in order to clearly troubleshoot.

ok how about an interlaced image sequence?

It seems you're using a studio quality 3d modelling/rendering/animation program (maya, 3dsmax, etc).

Yes. Maya.

Also, I meant that whatever you posted would only need to be 5 seconds worth--mainly during the "difficult" motion area.

right

You should be able to re-render (at whatever fps) a SUBSET of the full video, right?

of course

It would be a good test to see if a 48 or 72fps progressive render subclip, when nested inside a 24fps composition, were to exhibit the correct sort of motion.

I'm not sure I follow how exactly I would nest this in? In a compositing program I have image sequences. If I take a clip at 30fps and append it to one at 72fps and make a movie it will all be a one speed and thus play the other part of it too fast or too slow. So I must be missing something in what you are saying...

This would give a subtle amount of motion blur without introducing the strobing that you want to avoid. Just a guess...

In Maya you can set the motion blur to what ever you like. I tried several levels and found that in order to get rid of the strobing on a TV I had to add in so much motion blur that it simply looked out of focus. So I conclude that blurring is not the answer in this case. A higher frame rate is. The question is how to have a higher frame rate for only this seqeunce...

[junkmalle]

If the BOB deinterlaced video looked the same as the blend deinterlaced image you posted then the BOB wasn't working.

I'm not quite sure what to do with this since bob most definitely did look blurry.

I don't have PowerDVD. Is it possible that it's using an external MPEG codec to decode the video? Many DirectShow MPEG decoders have their own deinterlacing filters built it. Maybe a decoder is blend deinterlacing the video before PowerDVD gets a chance to BOB it.

You can try using VideoLan's player (VLC Media Player). It uses its own MPEG decoder and has several different deinterlacing options. It's BOB filter works quite well.

Of course, that doesn't solve the problem for DVDs that you plan to distribute. There is no solution that will work perfectly on TV and computers. Your best solution is probably to do what works best on TV since most people will be watching the DVD there. If you're happy with 30 progressive frames per second for the rest of the animation leave it as is. Rerender the short picket fence section as 59.94 fields per second interlace (which you've already done). Encode your final result as interlaced MPEG2. On a TV the progressive sections will play back fine (except for some minor interlace colorspace issues) and the interlaced section will too. On the computer the progressive section will look fine but the interlaced section will vary depending on what deinterlace technique the player uses. But presumably users are used to seeing what they get on the computer.

[sharktacos]

Of course, that doesn't solve the problem for DVDs that you plan to distribute.

Right. That is my sole concern.

Your best solution is probably to do what works best on TV since most people will be watching the DVD there.

Do you know if that is statistically true? I certainly prefer to watch on TV since I get a bigger picture. But my impression was that since DVDs come free with most computers and most people have computers, that a large number of people watched DVDs on their computer instead of on a TV where they just have a VCR. But maybe I'm crazy.

[junkmalle]

Your best solution is probably to do what works best on TV since most people will be watching the DVD there.

Do you know if that is statistically true? I certainly prefer to watch on TV since I get a bigger picture. But my impression was that since DVDs come free with most computers and most people have computers, that a large number of people watched DVDs on their computer instead of on a TV where they just have a VCR. But maybe I'm crazy.

I don't have real statistics for you. But I'm pretty sure the general public would rather watch on TV. Everyone I know would rather watch on TV. But your customer base might be different if your major sales outlet is via the internet.

By the way, I dropped by your web site. It looks like you're doing some nice stuff. I tried to view the "Say Cheese" video but the link didn't work.

[sharktacos]

Can you post a HuffYUV-encoded avi of ~5second clip? Or a zip of png-still image series?

ok I have posted a zipped jpg interlaced image sequence which you can find here:

http://sharktacos.com/Emelia/test2/

it is 200 frames @ 30fps interlace and all together the zip is 42m

[junkmalle]

Sharktacos, I noticed your JPG files were rendered bottom field first. When I used TMPGEnc to convert the image sequence to an MPEG file (with the source field order set to either TFF or BFF) the resulting MPEG files did not play properly on the computer (via the BOB deinterlace in VideoLAN).

So I used VirtualDubMod to change the field order to TFF (by shifting the image up one scanline) and saved as uncompressed AVI. After converting that to an MPEG file in TMPGEnc (source = TFF) the file played perfectly.

Try rerendering the image sequence as TFF -- or if you want to use VirtualDub to convert the field order use the following filters:

Null Transform --> Cropping --> Y1 offset = 1. That leaves you with a 720x479 frame. Follow with:

Resize --> 720x479, nearest neighbor, expand frame and letterbox to 720x480. That adds one scanline of black (or whatever color you chose) to the bottom.

[sharktacos]

[quote="junkmalle"]Sharktacos, I noticed your JPG files were rendered bottom field first. When I used TMPGEnc to convert the image sequence to an MPEG file (with the source field order set to either TFF or BFF) the resulting MPEG files did not play properly on the computer (via the BOB deinterlace in VideoLAN).

Did you try to play the interlace on a TV? On my TV (NTSC) it plays properly, but if I reverse them it does not...

[sharktacos]

junkmalle,

Here's what I did, please let me know where I am messing this up because I am still getting a blurry result

1) In my compositing software I croped one pixel/scanline off the top,
then added one pixel/scan line bellow. And then wrote out the new sequence. Basically taking a scan line from the top and putting on the bottom.
2) in TMPGEnc I made this sequence into a MPG2 with
interlace, TFF, 4:3 525 line (NTSC) in the advanced tab
3) I autored this in dvd-lab and then played it in PowerDVD with "force BOB" on.

It still looks blurry there. Can you point me to where I am not doing the same thing you are please?

[junkmalle]

It looks like you're doing pretty much the same thing I am. Except that you're using PowerDVD and I'm using VideoLAN. Here's the MPEG file I made:

http://s6.yousendit.com/d.aspx?id=2L9WLPZTIGWN32I3PX6Q7EGY4M

[sharktacos]

It looks like you're doing pretty much the same thing I am. Except that you're using PowerDVD and I'm using VideoLAN. Here's the MPEG file I made:

http://s6.yousendit.com/d.aspx?id=2L9WLPZTIGWN32I3PX6Q7EGY4M

Thanks for posting that and for the time you are taking to help me, I really appreciate it

I downloaded your mpg and tried playing it in powerDVD. It was blurry.
So I authered the mpg with DVD-lab and tried playing it. Also blurry.
So I downloaded VideoLAN and tried playing both the mpg as well as the VOB files there. Also blurry. It seems I am not able to get the results you are...

[sharktacos]

Correction: I went into the advanced settings for VideoLAN (not the most intuitive GUI...) and added a deinterlace filter and it does look a lot better.

So why can't I get powerDVD or winDVD to look like that with them set to forceBOB?

[junkmalle]

Yeah, VideoLAN's player has an awkward UI. I right click on the video while it's playing and select Deinterlace -> Bob.

I suspect what's happening on your system is that a DirectShow MPEG decoder is installed that is blend deinterlacing the picture as it decompresses it, before it's given to PowerDVD to BOB deinterlace and display.

If you have Windows Media Player installed try playing the MPG file with mplayer2.exe (the old Media Player 6.4, usually found in "C:\Program Files\Windows Media Player\mplayer2.exe"). Open the MPG file, stop the player, right click on the picture, and select Properties. Go to the Advanced tab and look at the "Filters in use" section. Double click on whatever MPEG decoder you see there. Look to see if there is a Deinterlace option you can control.

[sharktacos]

If you have Windows Media Player installed try playing the MPG file with mplayer2.exe (the old Media Player 6.4, usually found in "C:\Program Files\Windows Media Player\mplayer2.exe"). Open the MPG file, stop the player, right click on the picture, and select Properties. Go to the Advanced tab and look at the "Filters in use" section. Double click on whatever MPEG decoder you see there. Look to see if there is a Deinterlace option you can control.[/quote]

when I go there the only filters are:
Default DirectSound Device (sound stuff)
InterVideo Video Decoder (video capture)
MPEG Audio Decoder (more sounds stuff)
Video Renderer (video quality but no ineralace)