TFF / BFF What's the real story?

[ggrussell01]

I've been editing home video for years. Up until recently, the video was always from my own camcorder and captured as DV AVI. I am working on an anniversary video for my nephew and the video is from tree sources: my camcorder (DV AVI BFF), a JVC Everio (MPEG2 TFF) and the church video camera recorded directly to DVD (MPEG 2 TFF).

My question is: Should the final output to DVD be TFF or BFF? This is NTSC (USA). I've read and heard conflicting information. The only reason I am asking is because I am having trouble getting the 3 videos to work in one project. I'm getting jittery video and horizontal lines. From what I have researched, this could be caused by the conversion of TFF to BFF, etc.

[jagabo]

DVD MPEG2 can be either TFF or BFF. If you're mixing TFF and BFF sources it's probably easiest to convert your BFF video to TFF.

The jittery problem is caused by displaying TFF video as BFF, or vice versa.

[Abond]

Well, DVDs are usually TFF. But in fact it doesn't matter sofar the VTS is bff or tff for all the included video segments. Load the video files in restream to see if they are bff or tff. Play them in media player to look for jittery appearance. If there is some then I think you can change it with restream.
The horisontal lines are interlacing. Usually the TV is designed to show the interlaced material.
You aimed to DVD Video which content is mpeg 2. It support interlaced material. If you see the interlaced lines on TV then the conversion method is not correct.

[ggrussell01]

Definitely isn't interlace 'jaggies'. It's more like a 'slightly' diagonal line that rolls down the screen usually at the top. This was with footage from the JVC and edited in Adobe Premiere Elements. Almost like a poor satellite reception.

I have Sonic DVDit Pro HD which seems to create either TFF or BFF according to the file. The problem seems to occur in the editors which ALL default to BFF. Really odd.

[SLK001]

IIRC, BFF is the more common capture using DV, while most MPEG is TFF. What editing program are you using?

[edDV]

Definitely isn't interlace 'jaggies'. It's more like a 'slightly' diagonal line that rolls down the screen usually at the top. This was with footage from the JVC and edited in Adobe Premiere Elements. Almost like a poor satellite reception.

I have Sonic DVDit Pro HD which seems to create either TFF or BFF according to the file. The problem seems to occur in the editors which ALL default to BFF. Really odd.

Some issues. Most of this depends on the editor you are using. I don't have Premiere Elements but I suspect it may be locked to DV (bff) project format. I might be wrong. If it is and if it is the latest version that supports DVD MPeg (tff) import, then the program should be doing the tff to bff conversion.

The goal is to get everything bff or tff on the editor timeline. My approach would be to test the Elements software to see if it does the conversion on MPeg2 import. If not the conversion would need to be made before import.

[byteguy]

My approach would be to test the Elements software to see if it does the conversion on MPeg2 import. If not the conversion would need to be made before import.

The few NLEs I've worked with always have trouble mixing BFF and TFF files in the same project.

ReStream ONLY changes the flag on the file, it does not actually convert from one format to another. You can actually make it a lot worse. That feature was designed to fix an incorrect flag only; I asked the author himself about it.

VirtualDub has a good "field order reversal" plugin that is fast and delivers a very clear file. I have a capture program that only does BFF and a slide-show program that only does TFF. When I mix them in the same project I always have to run one of them through VDUB.

[thecoalman]

BFF is the more common capture using DV,

I'm pretty sure that's more like 100%, but I could be wrong. Other non harware encoders like the Leadtek tuners are TFF. There's a great thread here about it: https://forum.videohelp.com/viewtopic.php?t=257631&highlight=

No mention of MPEG recorders though.

[jagabo]

You can convert BFF to TFF (or vice versa) by removing one scanline from the top of the frame and adding a blank scanline at the bottom.

[Abond]

ReStream ONLY changes the flag on the file, it does not actually convert from one format to another. You can actually make it a lot worse. That feature was designed to fix an incorrect flag only; I asked the author himself about it.

VirtualDub has a good "field order reversal" plugin that is fast and delivers a very clear file. I have a capture program that only does BFF and a slide-show program that only does TFF. When I mix them in the same project I always have to run one of them through VDUB.

BFF and TFF are flags only. If you think VirtualDub makes something different that changing the flags you are wrong.

[jagabo]

BFF and TFF are flags only. If you think VirtualDub makes something different that changing the flags you are wrong.

No, you are wrong. Field order is a property of the interlaced fields. Field order flags are only flags that tell a program what the field order is. VirtualDub can reverse the field order by the method I described.

[Abond]

Ah, I see what you mean. Of course the field order is property of the interlaced frames. What I meant is that it does matter if the flags match the properties. There are even DVDs with exchange of the properties and the flags during playback. So IMO it is enough to change the flags - no pain

[creakndale]

It's always troublesome getting TFF or BFF correct when mixing footage from different sources. So after outputting a project and burning a DVD, I always check the results on a standard (not upconverting) DVD player connected to an interlaced, picture tube, type TV. For the jittery/jumpy clips that you suspect are of the wrong field order, back in Adobe PE3, select the clip and check, "Reverse Field Dominance". See Adobe Premiere Elements Help under "Field Option Command".

[ggrussell01]

Thanks for that info. I really don't use PrEL 2 much so haven't looked at that option.

[Alex_ander]

Of course the field order is property of the interlaced frames. What I meant is that it does matter if the flags match the properties.

True.

So IMO it is enough to change the flags - no pain

Only in case you want to correct dismatching flags and properties.
If you have a properly working BFF e.g. MPEG and try to change it to TFF by setting flags in Restream you'll get that pain at playback. 'Properties' is a real thing: if a field in true interlaced video was shot earlier in time, it should be shown also earlier and simple changing flags forces showing motion in alternating order.
There are physical things to change properties so that they match new flags. One way (mentioned above) is removing the upper line, another way is dropping the first field of the first frame and re-arranging the rest fields into frames. This physically changes field order without reversing motion phases.

There are even DVDs with exchange of the properties and the flags during playback.

It is safe to combine TFF/BFF material by putting in different titles.

[ggrussell01]

VirtualDub has a good "field order reversal" plugin that is fast and delivers a very clear file. I have a capture program that only does BFF and a slide-show program that only does TFF. When I mix them in the same project I always have to run one of them through VDUB.

VirtualDub seems to only handle AVI files. I need to convert two MPEG files that are TFF to DV AVI BFF. Any ideas? I'm stuck and can't find anything that will do this. Preferably free since I won't be doing this again. LOL

I just tried VirtualDub on the DV AVI file and reversed teh fields. Output looked REALLY BAD.

[jagabo]

VirtualDubMPEG2 or VirtualDubMod.

Note that the "Field Swap" filter is not for reversing field order. It is for fixing a specific bug of some old capture cards. Reverse the field order in VirtualDub by removing one scanline from the top of the video and adding one scanline to the bottom.

[NY2LA]

I might understand this a little better if someone could explain . . . is the data for top and bottom fields inside a DV video frame interleaved? Or is all of the bottom field data first, followed by all the top field data?

The difference in time between the fields might suggest it has to be the latter. But, after all, video and audio data is interleaved in DV, so I wonder whether the fields might be too.

[manono]

Interleaved.