Vegas Field Order and Print To Tape
 

Our National Broadcaster had to delay the transmission of some of my footage today because of the following problem:

Over the weekend I created a disk that contained a .AVI file that was a PAL DV render of some footage.

This file was supposed to be used as the source for transfer to Betacam tape for broadcast.

This morning I was informed that there was very bad 'interlace flicker' on my footage.

I said that I would have another look at the footage and my render settings (in case I made a mistake). My render settings were fine i.e. Vegas PAL DV.

Instead of rendering and copying the resulting file to a disk I used the 'Print to Tape' option and output to my Sony FX1E, gave them the MiniDV tape, and the conversion went through fine (no interlace flicker and I had not changed any of my render settings at all).

My first question is this:

Does Vegas do anything differently when 'Printing to Tape'? (In my opinion I cannot see how the end result is different when rendering to a file).

I also tried to use MainConcept's DVCPro 25 and DVCPro 50 from within Vegas and these files were also unuseable. Does anyone know anything about these codecs? No matter what setting I use for rendering with regard to field order Vegas detects the field order of DVCPro 25 and a DVCPro 50 files as 'Interlaced, Upper Field First' (and checking the 'Change Field Order' in the codecs' settings also does not seem to make a difference i.e. I cannot create a rendered file with the field order set to 'Interlaced, Lower Field First' using these codecs and Vegas).

Input?

Regards,

Dale.

this sounds complicated, dale did you record in hdv first? then downconvert to dv?

Hi Charles,

Thanks for the reply.

No - I did not shoot in HDV - no downconverting - just straight PAL DV.

I have a sneaky suspicion that the studio doing the conversion to the Betacam tape either did not have the correct equipment or the knowhow to do this.

There was absolutely no difference between (at least) one of the files on disk (that was rendered as straight PAL DV) and the resultant footage of 'Print to Tape'.

Why did the footage that came from the tape look great and they say that the footage that I output to disk had interlace flicker and artefacts? It has just dawned on me that if they did not have MainConcepts Encoder(s) installed on the workstation it would not have worked anyway.

I created a DVD for the client to keep using the identical disk files that apparantely did not work and that DVD is perfect!

Put it this way - there was always a possibility that the DVCPro 25 and DVCPro 50 files had a problem because, like I said before, no matter what settings I use in Vegas (and no matter what settings I change in the DVCPro 25 and DVCPro 50 Encoder) the resulting file ALWAYS has a field order of Upper/Top/Odd Field First (according to Vegas anyway). This theoretically means that the DVCPro 25 and DVCPro 50 files had the field order reversed but the PAL DV file definitely had a field order of Lower/Bottom/Even Field First (likewise all of the clips in the project) so there should have been no problem with that file.

Does anyone know of some software that CORRECTLY judges the field order of a file (other than Vegas which I know to have issues sometimes)? Someone once showed me how to use TMPEGenc to judge the field order but this is by no means accurate.

Regards,

Dale.

Use G spot. Just like Vegas, it tells you in plainly written text what the field order of the clip is. Although it's certainly possible, I've never seen Vegas mis judge field order. I've seen lower field media have upper field, and Vegas thought it was lower field, but that was due to operator error in actually starting order off wrong.
HTH

Thanks for the reply.

A while ago I did use G Spot but if memory serves me correctly it only works on MPEG files (or am I wrong).

Edit by self:

Douglas - I just downloaded G Spot again - I was wrong about it only working on MPEG files BUT how or where does it show you whether the .AVI file is interlaced or progressive and if interlaced what the field order is?

Also please read on.

I need to check the field order of DV not MPEG and in particular MainConcept's DVCPro 25 and DVCPro 50.

In addition to the above I have asked the following question on numerous occasions on numerous boards but never had a reply:

What exactly does the 'Deinterlace method' in Vegas do (and, no offence to anyone, but please do not explain to me the difference between the methods - I know what deinterlacing is and the different methods of doing it).

Correct me if necessary on the following:

The 'Deinterlace method' in Vegas is the type of deinterlacing to be performed IF YOU INTEND DEINTERLACING YOUR FOOTAGE AT RENDER TIME?

In other words if you are not going to render to progressive then whatever 'Deinterlace method' is selected in your project properties should have no effect whatsoever on your footage when rendered? Correct?

That is my understanding!

BUT:

I have spent hour upon hour upon hour, day upon day, month upon ... (you get the picture) doing various tests and have come up with the following:

Using Vegas to convert HDV to PAL DV (and rendering to PAL DVD MPEG2) - if 'Deinterlace method' is set to 'None' - there is definite visible interlace flicker (and I did check the field order i.e. it should be, and was, 'Upper Field First'). In other words 'Deinterlace method' must be set to 'Blend fields' or 'Interpolate fields' for this exercise to work. Make sense? No!

Now because of this new problem (the problem that prompted the start of this thread) I did some more testing with PAL DV, DVCPro 25 and DVCPro 50, and the result (when re-rendering to PAL DV or MPEG2):

If the 'Deintelace method' in Vegas is set to anything OTHER than 'None' - again there is definite visible interlace flicker BUT ONLY ON THE DVCPRO25 AND DVCPRO 50 FOOTAGE! (All media in the project was 'Interlaced, Bottom Field First' and the same field order was used when rendering).

My point is this - in none of the above execises have I tried to render to progressive so why does the setting of 'Deinterlace method' even matter???

After even more digging I realised that when I rendered the files for the studio I used 'Blend fields' BUT this should theoretically have made no difference as I was rendering from PAL DV to PAL DV, DVCPro 25, DVCPro 50 all Lower/Bottom/Odd/Field B first!

Please - this issue has been getting to me for the last couple of years so I am either understanding this wrong or the 'Deinterlace method' does a whole lot more than it is supposed to.

Regards,

Dale.

I won't lie to you - this message was posted to get my query relating to 'Deinterlace method' exposure again.

Anyone have any thoughts on what is happening (above)? DSE?

Regards,

Dale.

Do you have any pan/cropping going on in the main image? Track Motion? It's possible to upset the pixel offset to create problems in the field order.

From what I understand, this is how Vegas works:

1- File --> Render as can override your project settings.

Project settings: Here you can specify what 'format' your project is in... i.e. upper/lower field first, deinterlace method, etc.

File --> Render as settings can override the project settings.

2- Vegas always tries to detect the format of your footage and convert it into the right format for the project.
So if you have have 24p footage (with pulldown) in a 60i project, Vegas will convert from 24p to 60i. It uses interpolation/Vegas' secret sauce instead of leaving the footage like it is.

3- You can right click an event and check "reduce interlace flicker".
Under file --> properties, deinterlace method sets the deinterlace method for the operation above.

When you have 60i footage in a progressive project, Vegas will also de-interlace footage. Recall in #2 that Vegas will make the footage fit the project.
Again, deinterlace method under file --> properties will set the deinterlace method.

Thank you both for the replies.

DSE - no in my test footage I was just using the media generator i.e. 10 seconds of large scrolling text.

Glenn - thanks for the reply.

However - I'm not sure if I do not understand what you are telling me or if I am not explaining myself well.

Are you saying that based on Vegas' judgment Vegas may INDEED be performing a deinterlace (and thereby using whatever setting for 'Deinterlace method' is selected even although YOU as the user are not actually instructing Vegas to render interlaced footage to a progressive file?

Regards,

Dale.

Sorry, that's a really long question. I believe this is the answer:

Yes, in some cases Vegas will deinterlace your footage. i.e. when you put 60i footage into a progressive project.

I'm not sure what caused your problem. Your problem could even be one of two things:
A- Interlace flicker. This is caused by 1-pixel horizontal lines that flicker on a CRT TV. De-interlacing is one way to solve this.
B- Reversed field order. Everything looks wrong when the fields are displayed in the wrong order... i.e. 2 1 4 3 instead of 1 2 3 4.
The way to fix this is to choose the right field order.

Glenn,

Hello, sorry, but I would really like to have this sorted out in my mind (and you are one of the first (only) people (person) that has actually taken on the challenge)!!!

I know all about field order and the like. That is not the issue.

Let me give you another radical example of why I say that either 'Deinterlace method' does MORE than it is supposed to or does not work the way I understand it to work.

The following works without fail i.e. I can replicate the issue no problem every time:

Vegas Project - HDV 1080-50i (PAL)
Vegas Project - Field order - Upper field first
Footage in Project - 1080-50i (from Sony FX1E captured with Vegas to .m2t)

Render the above to a MPEG2 file with the following render settings:

PAL DVD changing Aspect ratio to 16:9 display with Field order Interlaced, top field first.

Here is THE issue:

If 'Deinterlace method' is set to 'None' in the above project the resultant MPEG2 will have definite and noticable interlace flicker.

If 'Deinterlace method' is set to ANYTHING OTHER THAN 'None' i.e. 'Blend fields' there is no problem with the MPEG2 file.

And here is MY issue:

In the above example you will notice that at no point have I told Vegas to deinterlace my footage and the field order has not been changed anywhere in the project no in the render template SO WHY DOES THE SETTING OF 'DEINTERLACE METHOD' IMPACT ON THE RESULTING MPEG2 FILE? In my mind it should not make any difference to the resulting footage in this case.

I could understand that if I changed the field order in the render template to 'Progressive' for example that the setting of 'Deinterlace method' would make a difference i.e. I am then telling Vegas to deinterlace the footage at render time and use the method set in 'Deinterlace method'.

But, like I said before, in my example I am using the same field order throughout the project and rendering with the same field order so 'Deinterlace method' should not come into play BUT IT DOES and this is where I am possibly lacking understanding.

One thing that I don't understand is that I cannot be the only person in the whole wide world that has noticed this or has this issue (or does not understand the issue). Maybe this is why we see so much footage on our TV screens (over here anyway) that definitely has field order problems i.e. much 'shimmer' and 'shake'!!!

Regards,

Dale.

1. HDV is always upper field first.
2. Deinterlacing quality will depend on several things, but in great part, the deinterlace mode.
3. you haven't specified where you're monitoring the media.
4. You haven't specified your EXACT workflow and desired output format. Or if you have, I've missed it in the posts.

Until this post, I was unaware you were dealing with HDV footage, which makes a significant difference. You mentioned handing off a DV tape, which implied that you were shooting DV, and therefore, it's a different animal. If you're using DVCPro 50, how did you hand that off on a DV tape? Whose tool did you use to capture the DVCPro, and how did you get from HDV to DVCPro? Why did you go from HDV to DVC Pro?
Your render settings override your project settings.
what specifically are you doing from shoot, to capture, to print to tape?
I'm confused, because HDV, DVCPro shouldn't be related. Then you throw delivery on DVD into the mix, but you also comment on output to DVD.
so many variables, not enough information, it's difficult to answer the question. Or questions, of which there seem to be more than one?

Hello,

Sorry about the confusion.

I suppose that I should have started another thread for this.

My actual (initial) problem that started this thread is irrelevant to the current discussion.

Also the particulars of what footage etc. etc. are also of no consequence.

Let me state my query another way:

No matter what source material I am using - as long as the source is 'Interlaced, X field first', the Field order in the Vegas Project Properties is 'Interlaced, X field first', and the Field order in the Vegas Render Template is 'Interlaced, X field first', then it should not matter what the 'Deinterlace method' is set to in Vegas and it should not make any difference to my final output. That is my understanding. Is this correct?

Please just comment on the above for now so that we can do this step by step.

Regards,

Dale.

This is correct. It does not matter what you have your deinterlace setting value set to for your project, nor for your final render, unless you've got a project setting of "progressive" and you've dropped interlaced footage on the timeline.

Yep. Of course, Vegas could have a bug or be doing something really un-intuitive.

I haven't tried your workflow so I don't know if I would get your problem or not.