TFF/BFF issue after frameserving with progr./interl. material...

[Fudoh]

Hi fellows,

I'm using Neatvideo's denoiser on some analogue captures I've done some time back, so I open the MPEG2 files in VB, apply some filtering and frameserve back into CCE.

Now I've noticed that the bunch of VDub filters I use give me a swapped field order.

When I check the field order before frameserving into CCE using AVISynth I notice that the field order in video-based material has changed from TFF to BFF, but hasn't changed in film-based material (or in other words, neither Asume BFF nor Asume TFF give any juddering movement).

I now wonder how can adopt this to my CCE re-enconde sessions. Of course I choose Offset = 1 for the BFF video-based material, but what do I do about the film-based stuff.... Does it matter anyway ??

VDub probably has changed the field order there too, it's just not noticeable since it's progressive (no movement in between fields). Is it safer to set CCE to line offset = 1 as well or should I set it to 0 as with true TFF material ???

Thanks for any advice !!
Fudoh

[unskinnyboy]

CCE Faq Q11.

[Fudoh]

I know the FAQ, actually I've been working with CCE for years.

I just don't know wether to use offset line = 1 or in this special case or not. The original video is TFF, VDub has definitely changed the field order, but a check with AVISynth (AsumeBFF/TFF) showed no difference between asuming TFF and BFF.

?????

Or maybe the better question: why can a wrong TFF/BFF setting in CCE give me trouble with DVDs when working with progressive material ?

[unskinnyboy]

Let me get this straight. You have 2 captures, one interlaced and one progressive, right?

For the interlaced one, the VirtualDub filters you used changed the field-order but it didn't for the progressive one, right? If so, first thing I'd look at is to see how the field-order got changed when using the filter (it shouldn't, so check if there were any user errors). If you are still stuck with a wrong field-order, you need to change the field dominance using DG's Reverse Dominance Filter (if in VirtualDub) or stickboy's JDL_ReverseFieldDominance function (if in Avisynth).

For the progressive one, it doesn't matter whether you say TFF or BFF, because the content is frame-based and both the fields belong to the same temporal moment.

[Fudoh]

For the interlaced one, the VirtualDub filters you used changed the field-order but it didn't for the progressive one, right?

well, it probably did, but you wouldn't notice anyway with progressive material, would you ?

If you are still stuck with a wrong field-order, you need to change the field dominance using DG's Reverse Dominance Filter (if in VirtualDub)

I'll check this - thanks !!

For the progressive one, it doesn't matter whether you say TFF or BFF, because the content is frame-based and both the fields belong to the same temporal moment.

sounds good though I remember once encoding a progressive video with line offset = 1 in cce and it gave me the typical wrong playback on a standalone DVD player....

THANKS !

[unskinnyboy]

well, it probably did, but you wouldn't notice anyway with progressive material, would you ?
No. Which is why later on I had explained why you wouldn't notice a difference.

sounds good though I remember once encoding a progressive video with line offset = 1 in cce and it gave me the typical wrong playback on a standalone DVD player....
Interesting. True that it shouldn't make a difference. But as per the FAQ, progressive content should be encoded with offset = 0, same as TFF. Offset = 1 will shift the frame by 1 pixel upwards (which you don't want in normal circumstances), but I don't see how your DVD player could have a problem with that.

If you don't want to re-encode an already done wrongly ordered encode, you can look at Restream or pulldown.exe to reverse the field order without reencoding.

[Fudoh]

Ok, thanks for the help !

One last question: any advantages / disadvantages of using Reverse Field Dominance in VDub before serving to CCE instead of simply putting the line offset in CCE to 1 ??

[unskinnyboy]

Does the video look OK after the VirtualDub filters changed the field-order? Are you sure that the field-order has been changed? Do you need to use VirtualDub filters at all? Why not do all filtering in Avisynth? I think you want to fix the problems here rather than encoding as BFF, something which was TFF to start with.