Trying to Deinterlace VHS, Hybrid says it’s BFF, MeGUI says it’s TFF

[macramore]

I am using the Hauppauge Live2 USB to Capture home videos on AmarecTV and trying to deinterlace the footage. However, common wisdom in this forum seems to be that these videos are most likely Top Field First. I’m confused if my setup is randomly doing it backwards, or if Hybrid’s analyzer tool is wrong - especially since MeGUI’s analyzer is saying that it is TFF.

[themaster1]

Anything that come out of a vcr always is Top field first but it can't be written in the AVI (Flag), you have to correct manually.
Unless you have used a DV codec to compress because Dv is BFF by default (that's asking for troubles if so)

[lollo]

you can check by yourself, rather then rely on what a software says: https://web.archive.org/web/20140214142648/http://neuron2.net/faq.html#order

[Selur]

Hybrid uses MediaInfo and if MediaInfo doesn't report it tries an educated guess.

Here's something that might help:

Typical interlace patterns:

1. content is progressive:
   • applying AssumeTFF().Bob()* you will see: stop -> forward_movment -> stop -> forward_movement **
   • applying AssumeBFF().Bob()* you will see: stop -> forward_movment -> stop -> forward_movement **
2. content is field shifted:
   • applying AssumeTFF().Bob()* you will see: backwards_movment -> forward_movment -> backwards_movment -> forward_movment **, ***
   • applying AssumeBFF().Bob()* you will see: forward_movment -> stop -> forward_movement -> stop **, ***
3. content is interlaced TFF:
   • applying AssumeTFF().Bob()* you will see: forward_movment -> forward_movment -> forward_movment -> forward_movement **
   • applying AssumeBFF().Bob()* you will see: forward_movment -> backwards_movment -> forward_movement -> backwards_movment **
4. content is interlaced BFF:
   • applying AssumeTFF().Bob()* you will see: forward_movment -> backwards_movment -> forward_movement -> backwards_movment **
   • applying AssumeBFF().Bob()* you will see: forward_movment -> forward_movment -> forward_movment -> forward_movement **
5. content is interlaced XFF with blending:
   • same as the corresponding interlaced pattern, but you will also see some blended (= ghosted) frames in-between
6. content is telecine:
   • applying AssumeTFF().Bob()* you will see 3 times forward_movement 2 still frames
7. content is mixed:
   applying AssumeB/TFF().Bob()* you will see a mix of any of the above.

* in Hybrid you would use QTGMC+Bob and use the Avisynth/Vapoursynth preview.
** then moving through the content
*** or vice versa

Cu Selur

Ps.: share a small sample (with horizontal movement) and folks can tell you what your content is

[Alwyn]

you can check by yourself, rather then rely on what a software says:

You do not need AVISynth just to check the field order.

Simply open the file in VDub, load the internal Deinterlace filter, set it on "Interpolate using Yadif" and "Double Frame Rate TFF" and step thru the video. Forward then backward motion will indicate the incorrect filed order has been set. Choose the other (Double Frame Rate BFF) and it should be all-forward. That is the file's field order.

[lollo]

Simply open the file in VDub, load the internal Deinterlace filter, set it on "Interpolate using Yadif" and "Double Frame Rate TFF" and step thru the video. Forward then backward motion will indicate the incorrect filed order has been set. Choose the other (Double Frame Rate BFF) and it should be all-forward. That is the file's field order.

In this way you (unnecessarily) deinterlace the frames. It may not be appropriate for a low motion sequence in videos with telecine, phase-shift, dynamic phase shift, blending, etc.

Better to work with the original fields without any manipulation.

[jagabo]

The AVI container generally doesn't flag the field order (or even the fact that video is interlaced). In the absence of a field order flag AviSynth assumes BFF. If Hybrid is using an AviSynth script it will see the unflagged AVI as BFF.

[Alwyn]

It may not be appropriate for a low motion sequence in videos with telecine, phase-shift, dynamic phase shift, blending, etc.

Are they going to get any of these with a VHS capture thru Amarectv??

KISS.

[lollo]

Are they going to get any of these with a VHS capture thru Amarectv??

Yes, with recordings of brodcasted programs, and pre-recorded commercial tapes. TVs did and still do all kind of "weird" film to video transfer

edit: replaced "esotish" with "weird"

[bar72]

The AVI container generally doesn't flag the field order (or even the fact that video is interlaced). In the absence of a field order flag AviSynth assumes BFF. If Hybrid is using an AviSynth script it will see the unflagged AVI as BFF.

Many thanks. fully answered my question as a noob to AviSynth / Hybrid, I tried info() and was reporting BFF from my PAL VHS Cap using a GV-USB2.