Capturing VHS with OBS and deinterlacing with Yadif 2x

[ArmerRitter]

I have a question about deinterlacing with OBS using Yadif 2x.

I have captured an old TV Recording (PAL-Region) using a GV-USB2 with Input of 25 fps, (weave setting).
Ouptput is mp4 with same size but 50 fps and using Yadif 2x.
The resulting mp4 now is on 50 fps but all frames are doubled. The doubled frames are looking nearly the same (not exactly but nearly).

Does Yadif 2x work like this? I thought the deinterlacer makes a frame out of each field. The ouptput does not make sense to me ...

Thanks in advance for enlightenment !

[jagabo]

PAL video is often progressive even if it's transmitted as interlaced. In cases like this you don't want to deinterlace, you want to combine the fields to restore the progressive frames at 25 fps. Using Yadif 2x will deliver exactly what you are seeing. You want to use a field matcher instead. In AviSynth you can use TFM(), included with the TIVTC package. If your software doesn't support field matching use Yadif 1x.

[ArmerRitter]

Thanks for your reply.

The captured source is defitively interlaced (see attached picture).
In addition, the recorded brodcast on VHS tape is from 1991. So I can not belive it was prior progressive before transmitting.
I think OBS struggles with handling the two fields seperately. I think I must chosse an other capturing program.


[Attachment 80015 - Click to enlarge]

[lollo]

The content on video can be “progressive” (the two fields are from the same moment in time) or interlaced. In general what is shot on film is the first, while what shot on cameras is the second. Since ever.

In one of our recent threads we examined a capture from Alwin and concluded that OBS did not handle correctly the interlaced source (in that case). Switch to AmarecTV 3.10 and, if needed, deinterlace later with QTGMC in AviSynth.

[Sharc]

+1.
Use AmarecTV instead of OBS for lossless capturing into YUV 4:2:2.
The screenshot looks like an upscaled interlaced frame. Vertical upscaling without deinterlacing it before damages the original interlaced structure.

[jagabo]

the recorded brodcast on VHS tape is from 1991. So I can not belive it was prior progressive before transmitting.

Aside from news and live sports, most TV content was shot on film then transmitted as interlaced video. With PAL video that was done by speeding the film from 24p to 25p and transmitting one field at a time. That means pairs of fields come from the same film frame and you can restore the original progressive film frames via field matching.

Given a sequence of film frames:

A, B, C, D, E, F...  (each letter represents a film frame)

Sped up to 25 fps and transmitted top field first, field fields per second:

A a B b C c D d E e F f... (capitol letter = top field, lower case letter = bottom field)

If you capture that transmission as top field first and pack pairs of fields into frames:

Aa Bb Cc Dd Ee Ff...

You have all progressive frames. You're done.

But if you capture bottom field first and pack into frames you get:

aB bC cD dE eF (each pair of letters represents a video frame)

Note how each video frame consists of a bottom field from one film frame and a top field from the next film frame. So every frame looks interlaced when there is motion.

But you can easily restore the original film frames (except the first and last) by simply recombining the fields. First separate fields:

a B b C c D d E e F

Throw out the first field:

B b C c D d E e F

Then recombine pairs:

Bb Cc Dd Ee

You have now restored the progressive film frames.

On the other hand, if you really have interlaced content (as opposed to progressive content transmitted interlaced) it may be that OBS is screwing up. Your sample image has been scaled from the captured 720x576 which has screwed up the interlacing. We can't tell if OBS is the problem or the way you prepared the sample image. So upload a short video sample directly from OBS (not a re-encoded cap).

[VHSvideocapture]

PAL video is often progressive even if it's transmitted as interlaced. In cases like this you don't want to deinterlace, you want to combine the fields to restore the progressive frames at 25 fps. Using Yadif 2x will deliver exactly what you are seeing. You want to use a field matcher instead. In AviSynth you can use TFM(), included with the TIVTC package. If your software doesn't support field matching use Yadif 1x.

Interlaced and progressive is a bit confusing to me because lossless codecs do not flag interlacing correctly.

Is all PAL captured video progressive? Even if the software shows interlaced?

What if it shows interlacing? When you deinterlace progressive video it plays back with ghosting.
Would it be better to blend or interpolate fields and encode progressive?
I wouldn't de-interlace with OBS I would use Hybrid for de-interlacing or Virtuldub

[rgr]

I have a question about deinterlacing with OBS using Yadif 2x.

I have captured an old TV Recording (PAL-Region) using a GV-USB2 with Input of 25 fps, (weave setting).
Ouptput is mp4 with same size but 50 fps and using Yadif 2x.
The resulting mp4 now is on 50 fps but all frames are doubled. The doubled frames are looking nearly the same (not exactly but nearly).

Does Yadif 2x work like this? I thought the deinterlacer makes a frame out of each field. The ouptput does not make sense to me ...

Thanks in advance for enlightenment !

We can only guess. Post samples (both source and target MP4).

[jagabo]

Is all PAL captured video progressive?

No. As I mentioned before, live sports and news is usually truly interlaced (50 different half-pictures per second). Note that all analog PAL video was transmitted interlaced -- one field every 1/50th second. When you watched that on a CRT TV you saw one field at a time, never both fields simultaneously. What differentiates interlaced content from progressive content is whether two consecutive fields come from a different point in time (interlaced) or from the same point in time (progressive).

What if it shows interlacing?

As I described above, it could be interlaced or progressive.

When you deinterlace progressive video it plays back with ghosting.

That depends on how you deinterlace. One simple deinterlacing method is to blur the two fields together. That leads to ghosting whenever there is motion.

Would it be better to blend or interpolate fields and encode progressive?

What looks best depends on the source properties and your personal taste. That's why there are so many different algorithms.

I wouldn't de-interlace with OBS I would use Hybrid for de-interlacing or Virtuldub

Yes, QTGMC is one of the best deinterlacers for most material. But there is no perfect method. And there never will be. There's no way to know for certain what was lost.

[Sharc]

Is all PAL captured video progressive? Even if the software shows interlaced?

No. PAL is basically a TV broadcast standard.
In the wider sense "PAL" (as used for PAL DVDs for example) can be
- true interlaced
- PsF (Progressive segmented Frames) = progressive video but encoded and flagged as interlaced for PAL standard compliance
- Phase shifted video (looks like interlaced frames, but is in fact progressive video)
- Telecined, for converting 24fps film frames to 25fps video (Euro pulldown aka 2:2:2:2:2:2:2:2:2:2:2:3 pulldown)
Re-read post #6 (except for the telecined case).

Captured home video (tapes) is usually true interlaced (50 fields per second for PAL).

And never trust the flags or what tools report. Flags are often wrong, and tools usually just report what the (possibly wrong) flags suggest, or they make a 'best guess'.
ALWAYS separate the fields, then step through the fields and draw your conclusions based on the fields sequence which you observe.

P.S. and take the "warnings" which you find in previous posts about using OBS for capturing analog video serious .....

[ArmerRitter]

+1.
Use AmarecTV instead of OBS for lossless capturing into YUV 4:2:2.
The screenshot looks like an upscaled interlaced frame. Vertical upscaling without deinterlacing it before damages the original interlaced structure.

Yes, indeed, my fault. I have taken a screenshot with snipping tool. The screen bleow now is a "real" captured screen from this video (768x576).

@ jagabo
Thanks for good explanation about the interlacing process.

@ lollo
I will make a try with AmarecTV the next days and post a short clip.

Never thought this will get so time consuming


[Attachment 80038 - Click to enlarge]

[VHSvideocapture]

No. As I mentioned before, live sports and news is usually truly interlaced (50 different half-pictures per second). Note that all analog PAL video was transmitted interlaced -- one field every 1/50th second. When you watched that on a CRT TV you saw one field at a time, never both fields simultaneously. What differentiates interlaced content from progressive content is whether two consecutive fields come from a different point in time (interlaced) or from the same point in time (progressive).

What if it's a PAL commercial movie not available on DVD or a personal home recording? Will it be progressive?

The problem is lossless codecs like Lagrith don't flag interlacing they show the footage as progressive this confuses video editors and software like hybrid that use media info tool, because the software is seeing progressive it's.deinterlacing progressive footage which damages it and causes it to ghost (shimmer) I don't know what the correct technical term is.

That depends on how you deinterlace. One simple deinterlacing method is to blur the two fields together. That leads to ghosting whenever there is motion.

Blend does lead to ghosting but it does always removing the shimmering, I use upper field first -TFF for VHS capture but if I fo that in Hybrid I get shimmering, it only fixes it if I use 'reduce interlace flicker' then encode and import in hybrid.

What looks best depends on the source properties and your personal taste. That's why there are so many different algorithms.

That's the problem I don't know what to choose and why this is where I'm getting stuck 😢

Yes, QTGMC is one of the best deinterlacers for most material. But there is no perfect method. And there never will be. There's no way to know for certain what was lost.

QTGMC is popular and used the most but Yadif in virtuldub is very easy and never has the shimmering issue but it has quite a few algorithms and options, blend, bob interpolation, blend is cleaner in Yadif at least from my limited tests.

[VHSvideocapture]

No. PAL is basically a TV broadcast standard.
In the wider sense "PAL" (as used for PAL DVDs for example) can be
- true interlaced
- PsF (Progressive segmented Frames) = progressive video but encoded and flagged as interlaced for PAL standard compliance
- Phase shifted video (looks like interlaced frames, but is in fact progressive video)
- Telecined, for converting 24fps film frames to 25fps video (Euro pulldown aka 2:2:2:2:2:2:2:2:2:2:2:3 pulldown)
Re-read post #6 (except for the telecined case).

Captured home video (tapes) is usually true interlaced (50 fields per second for PAL).

And never trust the flags or what tools report. Flags are often wrong, and tools usually just report what the (possibly wrong) flags suggest, or they make a 'best guess'.
ALWAYS separate the fields, then step through the fields and draw your conclusions based on the fields sequence which you observe.

P.S. and take the "warnings" which you find in previous posts about using OBS for capturing analog video serious .....

This is all very difficult stuff to understand because nothing is what it seems, I always thought PAL was progressive?
What should we do with 'phase shifted video' ? How will we get to know it's phase shifted video? I'm just learning please explain in non technical language on how I can spot phase shifted video and what filter I can use in Hybrid to check and solve this?

PAL also has sub alphabet categories like PAL B PAL I PAL M that's to do with how it handles color on analogue broadcast I think?
I don't trust flags media info flags Huff BFF when it's not and it flsgs Lags as progressive when it probably isn't.

I have separated fields in virtualdub and TFF always works the BFF option skips that means it's the wrong option.

[Alwyn]

The problem is lossless codecs like Lagrith don't flag interlacing they show the footage as progressive this confuses video editors and software like hybrid that use media info tool, because the software is seeing progressive it's.deinterlacing progressive footage which damages it and causes it to ghost (shimmer) I don't know what the correct technical term is.

You have to work it out for the programs. Open it in VDub, set the Deinterlace to Yadif Double Frame Rate (converts each field to a frame), and step thru the video. You'll then be able see what it is: progressive, PSF or Interlaced (and which way, TFF or BFF)).

Yadif in virtuldub is very easy and never has the shimmering issue but it has quite a few algorithms and options, blend, bob interpolation, blend is cleaner in Yadif at least from my limited tests.

Yadif double frame rate is an excellent option for motion; it doubles the number of frames covering the motion so it smooths it out. The improvement is noticeable.

[Sharc]

No. PAL is basically a TV broadcast standard.
In the wider sense "PAL" (as used for PAL DVDs for example) can be
- true interlaced
- PsF (Progressive segmented Frames) = progressive video but encoded and flagged as interlaced for PAL standard compliance
- Phase shifted video (looks like interlaced frames, but is in fact progressive video)
- Telecined, for converting 24fps film frames to 25fps video (Euro pulldown aka 2:2:2:2:2:2:2:2:2:2:2:3 pulldown)
Re-read post #6 (except for the telecined case).

Captured home video (tapes) is usually true interlaced (50 fields per second for PAL).

And never trust the flags or what tools report. Flags are often wrong, and tools usually just report what the (possibly wrong) flags suggest, or they make a 'best guess'.
ALWAYS separate the fields, then step through the fields and draw your conclusions based on the fields sequence which you observe.

P.S. and take the "warnings" which you find in previous posts about using OBS for capturing analog video serious .....

This is all very difficult stuff to understand ....

Yes, initially.
So here some examples you may want to inspect (e.g. using Alwyn's method in post#14, or by just separating and stepping through the fields):
(0) is the original 24fps progressive film
(1) is the same as (0) but sped up to 25fps
(2) is PsF = progressive video encoded as interlaced
(3) is true interlaced 25i, TFF
(4) is the same as (1) but phase-shifted (sometimes called field-shifted)
(5) is Euro pulldown

Note: The files are mpeg4 (x264) encoded in .mp4 container. For PAL DVD they should be mpeg2 encoded in .vob container. This doesn't matter for the fields structure demo though.
VHS consumer videocam captures (PAL) are usually of type (3).
Commercial movies (captured from VHS or on PAL DVD) are typically of type (2).

[Alwyn]

What's the verdict on the attached (a DVB-T recording)? Is it PSF? I've used VDub Yadifx2 and SeparateFields and every second frame is "almost" the same as the previous, like the OP's.

[jagabo]

It's progressive frames encoded interlaced.

[lollo]

What's the verdict on the attached (a DVB-T recording)? Is it PSF? I've used VDub Yadifx2 and SeparateFields and every second frame is "almost" the same as the previous, like the OP's.

Is PSF. When separating the fields and stepping field-by-field you see the "bobbing" vertival effect, that's why you probably wrote "almost" (the top field contains the odd lines of the frame, the bottom the even). In PAL, almost all videos originated by a film source are "progressive" (the two fields are at the same moment in time)

[Sharc]

What's the verdict on the attached (a DVB-T recording)? Is it PSF? I've used VDub Yadifx2 and SeparateFields and every second frame is "almost" the same as the previous, like the OP's.

PsF. The same type as (2) in my examples, but encoded as mpeg2.

[Alwyn]

Thanks all, I did have a look at all of yours, Sharc, just wanted to make sure I was on the right track with a base file.

[VHSvideocapture]

You have to work it out for the programs. Open it in VDub, set the Deinterlace to Yadif Double Frame Rate (converts each field to a frame), and step thru the video. You'll then be able see what it is: progressive, PSF or Interlaced (and which way, TFF or BFF)).

I've done that and it plays correctly with upperfield first but when I export it upper field first and then deinterlace it again upper field in Hybrid then I get jagged lines.

Maybe it's because I export the lossless codecs in DV mode exporting then 729x570 leaves black spaces in each side.

Yadif double frame rate is an excellent option for motion; it doubles the number of frames covering the motion so it smooths it out. The improvement is noticeable.

Yadif deinteelace gives it a plastic look.

[VHSvideocapture]

No. PAL is basically a TV broadcast standard.
In the wider sense "PAL" (as used for PAL DVDs for example) can be
- true interlaced
- PsF (Progressive segmented Frames) = progressive video but encoded and flagged as interlaced for PAL standard compliance
- Phase shifted video (looks like interlaced frames, but is in fact progressive video)
- Telecined, for converting 24fps film frames to 25fps video (Euro pulldown aka 2:2:2:2:2:2:2:2:2:2:2:3 pulldown)
Re-read post #6 (except for the telecined case).

Captured home video (tapes) is usually true interlaced (50 fields per second for PAL).

And never trust the flags or what tools report. Flags are often wrong, and tools usually just report what the (possibly wrong) flags suggest, or they make a 'best guess'.
ALWAYS separate the fields, then step through the fields and draw your conclusions based on the fields sequence which you observe.

P.S. and take the "warnings" which you find in previous posts about using OBS for capturing analog video serious ..

Yes, initially.
So here some examples you may want to inspect (e.g. using Alwyn's method in post#14, or by just separating and stepping through the fields):
(0) is the original 24fps progressive film
(1) is the same as (0) but sped up to 25fps
(2) is PsF = progressive video encoded as interlaced
(3) is true interlaced 25i, TFF
(4) is the same as (1) but phase-shifted (sometimes called field-shifted)
(5) is Euro pulldown

Note: The files are mpeg4 (x264) encoded in .mp4 container. For PAL DVD they should be mpeg2 encoded in .vob container. This doesn't matter for the fields structure demo though.
VHS consumer videocam captures (PAL) are usually of type (3).
Commercial movies (captured from VHS or on PAL DVD) are typically of type (2).

Thanks for the videos I've had a look none of them have the shimmering I'm talking about maybe I should find a video online with that issue? It captures fine in VD I think it's a Moviestudio setting or export setting that is messing something up?

I think my issue is I'm encoding DV profile 720x576 if I encode standard 720x576 with a lossless codec in Movie studio I get black spaces on each side, but if I use the 720x480 profile I don't get the black spaces.

My captures are 720x576 both virtualdub and Moviestudio are reporting that in file properties, my VD is set to capture 720x576 I only use Virtuldub and capture lossless, so sensible person would use OBS it's not a capture software it's more of a streaming gaming software with a choice of strange codecs.

Maybe both fields are recorded at the same moment because it's Pal progressive couid that mean I don't need to de-interlace and I should just encode upper field progressive scan?

[Sharc]

Maybe both fields are recorded at the same moment because it's Pal progressive couid that mean I don't need to de-interlace and I should just encode upper field progressive scan?

Upload a few seconds of your unprocessed source (your captured video) so someone can give advice. Select a scene with motion.

[VHSvideocapture]

Maybe both fields are recorded at the same moment because it's Pal progressive couid that mean I don't need to de-interlace and I should just encode upper field progressive scan?

Upload a few seconds of your unprocessed source (your captured video) so someone can give advice. Select a scene with motion.

Here you gohttps://files.videohelp.com/u/308503/Rice-Advert1.avi
My original lossless file was 12mb over the 500 mb site limit
This is a second one all I've done is denoised it, I did not get the jagged effect this time when compressing to.mp4
I just want to know is this clip interlaced or progressive or something else?
Taken from an old VHS tape.
I'll try to upload a lossless shorter version if needed.
https://files.videohelp.com/u/308503/Rice-Advert1.avi
Thanks to all for helping 👍

[lollo]

This clip is progressive.
Is there any reason to be in RGB colorspace?

[VHSvideocapture]

This clip is progressive.
Is there any reason to be in RGB colorspace?

I cleaned it up color corrected it in movie studio I'm sure the VD original is yuv2
I will upload the original short VD capture.
I could because it was 512mb this site only allows 500mb per clip.

[lollo]

For what concerns the fields architecture is irrelevant, no need for additional upload

[VHSvideocapture]

For what concerns the fields architecture is irrelevant, no need for additional upload

I think I have messed up.
The original VD capture is YUY2 .
It could have captured progressive
because source was PAL captured
720x576 25FFPS from VHS 📼

It looks interlaced I can see interlacing

[lollo]

Clip is progressive

[VHSvideocapture]

Clip is progressive


[Attachment 80345 - Click to enlarge]

Thanks for that .
Most of my captures are like this
How should progressive source be handled?