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Jaggies on interlace playback

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Jim Wiseman
Jaggies on interlace playback
on Dec 19, 2009 at 10:05:54 am

Hello all,

I noticed that when playing back 1080i 29.97 ProRes HQ footage imported into M100 Suite the titles and indeed the whole image had jagged edges, as if only showing one field in the LCD video monitors (Sony Bravia and Lacie 324 HDMI). These jaggies do not show on the Record or Source monitors on the computer screen, only on the Kona output. After much experimentation, I found that the only way to see a clean image on the video monitors without the artifacts was to drop the interlaced 1080i files on a 1080p timeline with Preferenes set to 1080i/1080psf on the Video Output. M100 then asks if you want the mismatched files interpreted as progressive. They then display cleanly on the video monitors. Can this damage the original files? It appears not to. My LaCie monitor reports that this video when played back from the Progressive timeline is indeed interlace 1080i 29.97, not Psf.

My question is, what happens when I render this Progressive Timeline with interlaced footage interpreted as progressive to a file for broadcast? What codec do I use? ProRes HQ I assume. Will it change to progressive on render? If so, this would not be acceptable for broadcast. Then how does one monitor the video through the LHi without jaggies? Will the Interlace timeline render with smooth edges even though it displays as jaggy on the video monitors? It appears clean when displayed on the computer monitor.

An observation: When I put the same interlaced files in Final Cut 6.0.6, the interlace 1080i 29.97 files playback with no jaggies in an interlace timeline with the same specs as the media. It apparently does deinterlacing in on the fly playback. Better use of the Kona LHi, or software?

In both the M100 and FCP the 1080p material plays back with no jaggies. In Final Cut both progresive and interlace playback without jaggies. In the M100 Suite, only the progressive material in a progressive timeline or interlace material interpreted as progressive with 1080i/psf plays back cleanly. In M100 Suite with an interlace timeline, the interlace material has jaggies when playing backwith 1080i/Psf. Playback with Preferences set to 1080p doesn't sync with either monitor, even with an AJA Hi5-3G miniconverter.

I will continue this tomorrow and do some rendering. It is midnight here now. Any thoughts?

Thanks in advance, sorry for the long post.

Has anyone else noticed this? If so how have you dealt with it?

Jim Wiseman


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Floh Peters
Re: Jaggies on interlace playback
on Dec 20, 2009 at 6:19:42 pm

You definitely should check your footage on an interlaced monitor, like a CRT display or a hi-end LCD like the FSI displays, to see what really is going on there. Or you could post a short clip somewhere, and I could have a look at it on our CRT display. I am not really sure what the Sony LCDs are doing to interlaced footage. Problem is, that even if the footage looks "better" in FCP it does not mean that it is correct as long as you don´t really know what your display is doing to your signal. It really right now is a mess with "cheap" displays (or with all displays that don´t show interlaced footage correctly) combined with interlaced footage.



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Jim Wiseman
Re: Jaggies on interlace playback
on Dec 20, 2009 at 7:33:18 pm

Hi Floh,

Thanks for the response. There really is quite a difference between the way the footage looks in an interlace timeline in FCP and the way it looks in M100 Suite. It is of course, most noticeable on the titles,simple lower third in white from Red 4 in M100 Suite 1.1.2. In FCP in a 1080i timeline they look like they do in the 1080psf timeline, that is, perfect, smooth and anti-aliased. In a M100 Suite 1080i timeline there is noticeable stair-stepping. This is on both the LaCie 324 (not a cheap monitor, true 10 bit with Faroujda processing for interlace), and on the Sony XBR, which has never shown aliasing on 1080i broadcast material, including titles.

As I said before, when the footage is interpreted in a Progressive timeline in M100 as 1080psf it looks perfect. If I export quicktime as interlace from that timeline in M100, the stair-stepping returns in M100/Kona LHi playback when re-imported to M100. This is whether exported or conformed, upper and lower field, all iterations. The stair-stepping can be seen on diagonal lines throughout the picture, not just on titles.

However, when I open the same exported quicktime from the M100 1080i timeline in Quicktime 7.6, there is no stair-stepping in the computer monitor. There is also no stair-stepping on the source or record monitors in M100, even when enlarged. It is only when played through the Kona LHi in interlace mode on the video monitors, which is of course how the footage is intended to be viewed.

This seems like a problem with the way the Kona card is being told to handle the interlace. I have no way of knowing if this would occur on transfer to tape for broadcast, as I have no HD VTR. If I were to send you a second or so of the footage, how would you like it?

Thanks much.

Jim Wiseman
Sony PMW-EX1,Pana AJ-D810 DVCPro, DVX-100, Final Cut Studio 2 and 3, Media 100 Suite 1.1.2, AJA ioHD, AJA Kona LHi Avid MC, Macbook Pro Core2Duo, G5 Quadcore PCIe, Media 100i/XR


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Jim Wiseman
Re: Jaggies on interlace playback
on Dec 21, 2009 at 2:50:04 am

I have also posted a timeline with multiple copies of the interlaced file trimmed at wiseman.co@gmail.com PW media100
Makes it easier to see.

Jim Wiseman
Sony PMW-EX1,Pana AJ-D810 DVCPro, DVX-100, Final Cut Studio 2 and 3, Media 100 Suite 1.1.2, AJA ioHD, AJA Kona LHi Avid MC, Macbook Pro Core2Duo, G5 Quadcore PCIe, Media 100i/XR


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Floh Peters
Re: Jaggies on interlace playback
on Dec 21, 2009 at 12:03:53 pm

Jim,

tested your footage on a Kona 3 and on a LHe, and it plays back on both systems correctly as 1080i. It looks perfect on our HD-CRT Sony displays.
Now of course the good question is if there is a difference with the Kona LHi, which we currently don´t have in the office. Maybe Wick or Matthew can confirm if this works on the LHi also…



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Jim Wiseman
Re: Jaggies on interlace playback
on Dec 21, 2009 at 5:42:29 pm

Hi Floh,

Thanks very much for testing the footage on both cards. It is reassuring to know it is correct on an HD CRT. They are quite rare here in Hawaii. Wick has come up with the answer. My bad for not knowing where to look for quality settings. I don't recall ever changing it so maybe that is the default. Or I did and forgot?

Thanks again,

Jim Wiseman
Sony PMW-EX1,Pana AJ-D810 DVCPro, DVX-100, Final Cut Studio 2 and 3, Media 100 Suite 1.1.2, AJA ioHD, AJA Kona LHi Avid MC, Macbook Pro Core2Duo, G5 Quadcore PCIe, Media 100i/XR


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Floh Peters
Re: Jaggies on interlace playback
on Dec 21, 2009 at 5:45:13 pm

[Jim Wiseman] " I don't recall ever changing it so maybe that is the default. Or I did and forgot? "

Usually this does not switch automatically. But I think I remembered once that it changed on one of our systems without a good reason.
Anyway, usually you should be able to see if it is correct by the color bar under the TC field in the Record viewer. If it is green then it is full quality, and if it is red than you are using the reduced quality.



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Jim Wiseman
Re: Jaggies on interlace playback
on Dec 21, 2009 at 2:13:10 am

Floh or others,

I have posted the ProRes 422 export of just over one second to my wiseman.co@gmail address as an attachment of 23.3mb (25mb is the limit in Gmail). Log into the account using the password:

media100

download the attachment, it should be the only email in the account.

Timeline is also attached in second email.

Drop in a HD 1080i 29.97fps 48k timeline. Video output settings HD 10801/psf, HDMI out. Notice the jagged edges on the type and especially the thin fence wire above her right shoulder. Especially noticeable on a large screen. These are perfectly smooth when played in FCP or when interpreted as progressive in M100 Suite. A still frame of this looks the same as playback to me on Media Suite 100. Looks smooth in FCP.

Thanks



Jim Wiseman
Sony PMW-EX1,Pana AJ-D810 DVCPro, DVX-100, Final Cut Studio 2 and 3, Media 100 Suite 1.1.2, AJA ioHD, AJA Kona LHi Avid MC, Macbook Pro Core2Duo, G5 Quadcore PCIe, Media 100i/XR


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Wickham Strub
Re: Jaggies on interlace playback
on Dec 21, 2009 at 3:30:07 pm

Hey Jim,

Here's something to check:

- Go to Media 100 Suite > Project Settings > Real Time...
- Is "Play Real Time Effects and Titles at Draft Quality" checked?
- If so, uncheck it and try again.
- If not, let me know so I can "uncheck" my brain and try again;-)

~Wick



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Jim Wiseman
Re: Jaggies on interlace playback
on Dec 21, 2009 at 5:35:57 pm

Wick,

You get a gold star! That did the trick on the LCD's. FCP was in High quality playback, thus the difference.
Thanks much!

Jim Wiseman
Sony PMW-EX1,Pana AJ-D810 DVCPro, DVX-100, Final Cut Studio 2 and 3, Media 100 Suite 1.1.2, AJA ioHD, AJA Kona LHi Avid MC, Macbook Pro Core2Duo, G5 Quadcore PCIe, Media 100i/XR


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Wickham Strub
Re: Jaggies on interlace playback
on Dec 21, 2009 at 5:44:32 pm

DAMN!! One of the engineers and I were just about to submit for a trip to your place to solve the problem!

I must admit that the star goes to a couple of our engineers who were waiting to suggest this idea when I came in this morning. Just one of the great advantages of having such direct contact with the entire team.

OK Jim, I don't want to jinx you but... maybe now you can get back to the reason you bought this darn thing in the first place! ;-)

~ Wick



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Wickham Strub
Re: Jaggies on interlace playback
on Dec 21, 2009 at 7:36:21 pm

Hmmmm... this has me thinking...

I tend not to open up the door to feature requests like this on a public forum but...

I figure most people aren't going to dig this deep down a thread that's already been solved so it's likely that only the truly committed are reading this. ;-)

Can anyone suggest a "better" way to indicate that this draft mode is set? The first thing that comes to mind for me is some sort of "watermark" on the sub-sampler display. Not on the video output and not in exports, just on the Source/Record/Monitor windows.

Thoughts?



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