Good bob deinterlace method?

[andy_blah]

Is there any method to deinterlace a video with a bob without getting those annoying flickers (how the image shakes a little)?

[manono]

Have you tried the AviSynth Smart Bobbers? A regular Bob does as you describe. That's why it's called a bob - because the picture bobs up and down. Or are you talking about a different kind of shaking - the kind where thin lines "shimmer" or "alias"? If so, then the better the bobber (and the slower the encoding), the less of that effect you'll get, but you'll never be entirely rid of it, I don't think.

[andy_blah]

Thank-you for your reply. Yes, I was talking about the shimmering lines. Can you suggest one of those smart "bobbers", please?

[manono]

I don't know what you've tried already, and how demanding you are. The fastest decent ones and the only ones fast enough to actually use, in my opinion (for full length movies, anyway), are the bobber in TDeint, the bobber in Yadif, and LeakKernelBob, part of LeakKernelDeint. I use Yadif almost always. For much slower and slightly better ones, there's MCBob, MVBob, TempGaussMC, and several others. Info and links can be found here:

http://avisynth.org/mediawiki/External_filters#Deinterlacing

[andy_blah]

Before I tried VirtualDub's built-in bob, which as you said it is a regular one. Now I've tried DGBob, IBob (doesn't work at all), MCBob and MVBob and TempGaussMC(very good quality and FAST). Those that work deliver fabulous quality, the only problem is that they don't convert the fields to frames (I have a DVD with 50 fields per second and if I use those filters, it still encodes 25 frames, or 50 frames, but it uses only half of the fields).

[jagabo]

(I have a DVD with 50 fields per second and if I use those filters, it still encodes 25 frames, or 50 frames, but it uses only half of the fields).

It sounds like you have 25 fps progressive material that was captured out of phase (for example a top field first broadcast captured as bottom field first), resulting in what looks like an interlaced source. You want to use a PAL phase correcter to combine fields from different frames to reconstruct the original progressive frames. I forget the name of this filter. But you can do it manually with:

SeparateFields()
Trim(1,0)
Weave()

[manono]

Or realign the fields with:

Telecide()#from Decomb, or:

TFM()#from TIVTC.

Or, if you're not sure about what you have, upload a small piece of the source for us to have a look.

[andy_blah]

It seems that I fixed it using DGIndex, VirtualDub's bob and blur filter, and it seems that it looks very smooth. But I still want to see if there is any alternative to this.


@jagabo: I don't know if it is what you say it might. How could I find out? Should I post a GSpot screenshot?

@manono: not sure how to cut a part from a .vob file

[jagabo]

@jagabo: I don't know if it is what you say it might. How could I find out? Should I post a GSpot screenshot?

Use AviSynth's simple Bob() filter. If you always see pairs of nearly identical frames you have out-of-phase PAL.

[manono]

To cut a VOB, open it in DGIndex, use the [ and ] buttons to isolate a small 10 second or so piece, and then File->Save Project and Demux Video. Upload the resulting M2V to a 3rd party hosting site such as MediaFire and post the link here.

[andy_blah]

@jagabo: I will do that later as my computer is busy with another task

@manono: The sample

[manono]

Well, it's not phase-shifted. It's real PAL interlaced video. So, your earlier comment:

...the only problem is that they don't convert the fields to frames (I have a DVD with 50 fields per second and if I use those filters, it still encodes 25 frames, or 50 frames, but it uses only half of the fields).

makes no sense at all to me.

Just out of curiosity, why do you want to bob this thing anyway? What are you planning to do with it? And are you trying to encode it with something as 50fps? I hope you're not trying to encode as MPEG-2 at 50fps.

[andy_blah]

Sorry for my puzzling talk, it happens sometimes.

What I wanted to say is that the DVD has 25 frames per second and 50 fields per second. Those filters did not convert those 50 fields to frames in the encoded avi. But in the end I think this was caused by using DirectShowSource in the AviSynth script.

To answer your questions:
I want to bob deinterlace this DVD because of quality reasons, if you know what I mean. With this, I plan to back-up the DVD on my HDD. Just want to convert the DVD to avi, not to MPEG-2 at 50 frames.

[jagabo]

All of the smart bob deinterlacers for AviSynth support 25i to 50p. After a quick:

TDeint(mode=1, order=1)
BilinearResize(480,360)

and compression with Xvid:

50p.avi

[manono]

Oh, DVD to AVI at 50fps. Then make a D2V project file with DGIndex, use the DGDecode.dll together with MPEG2Source, and then put on the bobber you're using. If you do it that way then I know of no reason at all why you won't get 50fps out of it.

Although there are ways to make DirectShowSource do what you want, why bother when MPEG2Source is better and easier?

[andy_blah]

Yes, I did what you both said, just did it half in AviSynth (loading the .vob) and VirtualDub (bob filter+resize), only that I resized the video to 5:4, because it looks better IMHO, and by this, I got what I initially wanted. So, after all it turns out to be my mistake, using DirectShowSource

Thank-you both for your help!

[manono]

Once you start with AviSynth, go all the way and do all the filtering in the script as well. Set VDub(Mod) for Video->Fast Recompress and the result will be 30% or so faster encoding and slightly better quality output.

And I really doubt that it's meant to be watched in some 5:4 ratio, rather than a 4:3 one such as 480x360 or 640x480. Benny Hill is a bit too slender at 5:4.

Using ITU resizing, removing the black bars, and then cropping an additional 2 pixels into the video both top and bottom to lower the Aspect Error, I get a perfect 4:3:

Crop(20,2,-8,-6)
LanczosResize(512,384)#or 480x360 or 640x480

[andy_blah]

Well, I suppose that he would look off better being slender than being bloated

Seriously now, I will try your advice tomorrow to see if it is better. Thank-you for the suggestion ^_^