Video Shutters While in Timeline and in Hard Drive

[Ron Evans]

If you want to use a still that has been captured from an interlace project take it into Photshop or some other photoediting software and de interlace and save a de interlaced file. This wil now not have the problem.

Interlace video seems to cause all sorts of confusion not least of which is the misconception that the 29.97fps of interlace video actually is 29.97P. The frame sync for interlace is every two fields to let the CRT's of the time know when to start the field sequence for display. Other wise they would not know whether to start with an odd or even line sequence. However an interlace 60i video is taking the same number of images as a 60P video they just are half the vertical resolution a field.

Flat panel displays need a progressive image so somehow NLE's etc have to create this progressive image either taking a field and interpolating etc. If you just add the two fields together you get the jaggies everyone knows about. Pause on some point on the timeline and very often the screen will flicker as it cannot decide which field to display. Fancy TV's with high refresh rates have the time to interpolate a progressive image over several fields. Any decode of interlace needs this frame sync to know how to display.

I take Photoshop format stills from the timeline then deinterlace in Photoshop for any further use.


Ron Evans

[7hbg]

Rob, did you try the Shake1 project that I posted, yet? I'm curious if that plays for you.

not yet. it was 3am when I looked at the post.
I'll try it later today.

[student101]

Could it be that the shuddering is from a 25p footage in a 30p timeline (or vice versa). How do I check to make sure the footage and timeline are synced together?

[Jerry]

Thanks to Derek for sending me the original footage so I could do the test.
I made 3 different still captures: .tiff, .png, and .bitmap.
The stills were acquired by clicking the camera icon with the folder on it to indicate save as.
All 3 are clean and playback fine on my overlay as well as on my external monitor.

You can try these:
Still tests.zip

As far as the original video goes, what I see is tearing on the edges on the overlay. I don't have screen jitter or the image bouncing back and forth as Derek reported that he had.
However, the playback on my external monitor is fine. Watching the Edius overlay on the computer monitor shows the tearing. That tearing, which is basically talent motion, is shown on my external monitor as a slight blur. This is indicative of the frame rate, 4:2:0 recording, digital recording of motion in general, and it is perfectly normal.
The talent rocks back an forth on the screen creating the motion tears on the Edius overlay. If these were not there, this topic for this clip would not have come up.
The way this is resolved is by having an I/O card from either GV or Black Magic. AJA and Matrox are supported but they are expensive. This has been around for a long time.
After you get the card you will need an external monitor. This can be either a decent Flat Panel television or a broadcast monitor. Flat panel televsions are easily had for under $400, depending on the size.


Once again I would like to think Derek for supplying the original clip.

[student101]

Jerry, I sent you the video to your website www.sgdvtutorials.com, did you get it? I could not upload it to this site. I hope that was ok to send to your website.

Thank you for everthing!

[Jerry]

I watched the video and I get a couple of jerks but that is pretty much it. My I/0 card doesn't support 60p out so I can't say that the image would be stable. But, based on years of using I/O cards, I would bet that it is.
It comes down to the overlay issue as described in the earlier post. The easiest way to avoid the problem is to have an output card and external television (or broadcast monitor) to which you would feed the signal.
In your case, you will need a card that supports 1080 50/60p out to handle your frame rates. Doing 4K 60p will require a more specific card.
To see if the overlay is better in 29.97p, create a project for that frame rate and import your 59.94p footage into it.

[7hbg]

I think I now have full understanding what is happening, but no magic solutions, just a suggestion.
And it is not the same problem as OP.

First to recap the problem: An interlaced project (1080i60) with interlaced still on the timeline (makes no difference if it is bmp, tiff or anything else). When I played the timeline, on the computer screen only (not the final output) I noticed that the image was jumping/shifting left and right. Not in sync with frame rate, just randomly without any apparent reason. See the two videos I made illustrating the problem: Shake1 (wmv 1.6MB) and Interlaced (wmv 12MB). Again, only the computer screen is effected, not the output or file.

After lots of tests I finally ended up concentrating on how EDIUS is displaying interlaced video inside the program on the computer’s ‘progressive’ screen. I found it to be the source of my problem.
To test my theory I created a bitmap. It is 1920 by 1080 (same as my project), with some very carefully positioned text and graphics. Assumption was that either EDIUS or Windows is not displaying/updating the screen as needed therefore I am not seeing what I was expecting and not understanding what I did see. Again, I was seeing the interlaced image shifting but not at the rate and amount I was expecting. Back to my bitmap, it has ‘UPPER’ and ‘LOWER’ words in it. Each word only appears when the right field is being displayed. So the ‘UPPER’ word is only visible when paused or displaying upper field and the ‘LOWER’ word when paused or displaying lower field. When playing or paused in ‘Frame’ mode, both words should be visible. I wrote “… should be …” because that’s what I found not happening correctly. I was expecting to see these words flashing rapidly. 60 times a second, same as my display refresh rate is set to. But to my dismay the display is updated randomly (!?) and not even in correct order (… ULULUL ….). As far as I can tell, the computer preview monitor (recorder and player) is updated a lot less than it should and often wrong information is displayed. If you load my image into an interlaced project and look at it on interlaced monitor, you will see both fields flickering so fast that it will appear that nothing is moving when playing or paused in ‘field’ mode. And that or something similar is what I was expecting to see on the computer screen. Not. What I did see was a lot of flickering, but at wrong frequency and favoring one field over the other. So instead of seeing ULULULUL… I was seeing UUUUUUUULUULUUUULLLLULUL and so on, making me see an image that is shifting randomly depending on the field being displayed at a moment. To be fair to EDIUS, developers have seen the problem and to accommodate it there are two modes we can choose from when working with interlaced and progressive projects. We all were told to set:

Settings -> User Settings ->Preview -> Overlay -> Update Frequency = Field

and that is correct for a Progressive project because each ‘field’ = ‘frame’, so the screen update can happen for each Field.

To accommodate the interlaced project, the setting should be set:

Settings -> User Settings ->Preview -> Overlay -> Update Frequency = Frame

Because: ‘upper field’ + ‘lower field’ = ‘frame’, you need both fields to make a frame.

But there is a problem with that: How to display 2 fields onto progressive display? Simple, combine upper with lower into a single picture and display it on the progressive screen. That has a potential to create some ugly looking images when even a hint of motion is captured between fields.



We all dismiss it because it is ‘Interlaced’ and that what it looks like on a progressive screen. Well that’s not entirely why it looks like that: The image has to fit into the ‘window’. It has to be scaled. It’s the method used for scaling that make it look like it is. If you adjust the size of the player/recorder window, you will see different patterns emerging due to Moire effect.

Now that we know what image should look like in each setting, then: Why when playing interlaced video in interlaced project (but update frequency is set to Field) the screen is not updating correctly? Because when update frequency is set to ‘Field’ software assumes that the source picture is ‘Progressive’ meaning that upper and lower fields of that picture (lines 1,3,5… for upper and 2,4,6… for lower) are part of the same picture, hence no need to worry what field to update (the update can happen any time, randomly) with no consequences. But if the source picture is interlaced and it has motion in it (like my example), the random field updates make it look like random shifting. That’s why if you put ‘de-interlaced’ picture on the same timeline no movement is observed (because in a simple de-interlace where either odd or even lines are duplicated then line 1=2, line 3=4, line 5=6 and so on).

To summarize it:

• Progressive project: Update Frequency = Field. Looks good, no problems whatsoever.
  
• Interlaced project: Update Frequency = Frame. Looks ok, potential for weird patterns to be displayed where none exists.

Here are two new videos:

1. Interlaced project, interlaced image, wrong Update Frequency = Field (wmv 4MB). When I started to screen capture the update frequency dropped significantly but you can still see exactly what I was looking at on the screen, it is true representation.
   
2. Interlaced project, interlaced image, correct Update Frequency = Frame (wmv 12MB). I work through different pause modes and towards the end I change the player/recorder window size to demonstrate the Moire patterns visible on both screens.

And finally here is the still: Image1.png (I saved it as png so it is small size and has no compression artifacts) but anything else will do the same.

So I am SOLVED!

[createmedia]

1920 by 1080 50i project

Layouter is particularly bad with the teeth on the vertical edge exactly as per your big included still, but I don't see the teeth effect in the REC Wiondow just in layouter.

On view>full frame with normal footage I also see the juddering in the REC window which is annoying. However using the Decklink 4K Extreme the TV output is combed edge on full frame which is correct.

However on your PNG on the TV output I am not seeing every other line it is in groups of light and dark in the Upper text and Star but the red circle is still.

In full frame on the TV both upper and lower show but again in groups of light and dark including now above and below the red circle. The interlace is not showing correctly from the still.

Mike

[Jerry]

Mike try these stills and tell me what you get. These stills were captured directly from the original video by me.
http://forum.grassvalley.com/forum/a...2&d=1435079803
Test them in both interlaced and progressive projects.

[createmedia]

Jerry,

Ok stills tested 50i/50p

No juddering in view>full frame on REC monitor or in Upper field first.

Looking closely at the 40 inch 4K Panasonic TV via the Decklink card, the Bitmap file has the cleanest edges on the lapels edge to the black T shirt. Both the TIFF and the PNG show interlacing comb but again in groups not all the way down evenly particularly on the jacket lapel almost white edge the lavalier mic is on. This crit is looking closely at the TV picture, at normal viewing distance it is hardly noticeable.

In Layouter no interlace showing on the Bitmap on the PNG an evenly spaced interlaced comb, on the TIFF an unevenly spaced Interlace comb.

What was the source? - I ask as there is surprisingly little detail in the jacket.

Just for fun I tried Chroma key and the guy is standing far too close to the green cloth so round the right ear and upper arm are very difficult to key.

Mike

[Jerry]

That was all discussed in this thread:
http://forum.grassvalley.com/forum/s...ad.php?t=35530

Mike, here is the Media Infor for the original video:
Media Info for Original file.png

Mke, also try the stills in a progressive project.

[Jerry]

For all of you guys who have the Edius overlay issue, download the Edius 8 trial and load it onto a system drive that does not have Edius installed.
Open your project and see if the playback is better. The Overlay has been improved in Edius 8.

[7hbg]

Rob, did you try the Shake1 project that I posted, yet? I'm curious if that plays for you.

@Jerry: Sorry, I was unusually busy at work... Yes I did play it and it did look good.

[Jerry]

Try the Edius 8 trial. The overlay is much improved.