My first interlaced DVD

[JensG.]

I am still confused about interlacing. But as long as I wasn't concerned it did not matter.
Now I have the German PAL DVD "Buena Vista Social Club", which I want to convert to Divx using GordianKnot. This DVD is interlaced.
Since I did not understand which method would be best to get rid of this interlacing, I am trying several methods, which all look okay when watching the avs (Telecide, GreedyHMA, VerticalReduceBy2, SmartDeinterlace). Then I convert them all to Divx using quant 2. (Conversion is in progress now.)
==> I thought that the best deinterlacing method should give the best compressibility, resulting in smallest file size of the avi. Is this correct?

Another thing I tried is the preview possibility of DVD2SVCD, where you can instantly compare different deinterlacing methods. There the option SeparateFields gives the sharpest picture. For example, in one scene there is a fire extinguisher in the background of the studio, and only using SeparateFileds the writing on it is sharp. What does that mean?
==> Should I use SeparateField and then only use even frames to encode?

Next thing I will try is to follow the methods in here: http://forum.doom9.org/showthread.php?s=&threadid=20032

[hakko504]

Originally posted by JensG.
==> I thought that the best deinterlacing method should give the best compressibility, resulting in smallest file size of the avi. Is this correct?
That depends on what you mean by 'best' deinterlacing. It will surely give you the method that smooths the picture the most.
==> Should I use SeparateField and then only use even frames to encode?I usually only recommends this if you want a fast conversion and is aiming for a small final resolution, like 512x288, 384x288 or even 352x288 and only if you don't crop the original DVD. You simply thow away half the information from the DVD by doing this and it is usually better to set blend=false with some of the other methods instead if you are aiming for a large resolution.
Note that this goes for VerticalReduceBy2() also, but in that case blend=true will do just as nicely. When I use fielddropping with a DVD I almost always use the following script:0Mpeg2Source(dvd.d2v) #PAL source
Separatefields.SelectEven
Crop(8,0,704,288)
HorizontalReduceBy2()This one is really fast! (I'm about to try it with AviSynth2.5 now to see how much can be won in using YV12 instead.)

[LigH]

About SeparateFields, you may find some parts of the following thread useful, which tries to solve a different problem, but includes some explanation of this filter:

http://forum.doom9.de/viewtopic.php?t=1497&separatefields

(Just because you are located in Germany; and you may find much more here if you take enough time to search.)

[sh0dan]

Originally posted by hakko504
[...] HorizontalReduceBy2()This one is really fast! (I'm about to try it with AviSynth2.5 now to see how much can be won in using YV12 instead.)

HorizontalReduceBy2() doesn't work with YV12 (yet) - it's on the todo-list of course, but not high priority. Use bilinearresize instead for speed, or bicubic/lanczos for quality.

[hakko504]

This was a pure speed test, so Bilinear will have to do.

[JensG.]

Thanks for your responses!
So far after my basic deinterlacing trials, which have not finished yet, I am about to decide that I will not convert the movie to Divx finally. All quant 2 conversions at 512x288, neutral bicubic resize, look really okay, but they are at least 1,26 GB large (with GreedyHMA, followed by VerticalReduce 1,27 GB). This looks not like a compressible movie at all. The included subtitles, which are part of the video stream only make it worse.

Well, since I am the owner of the DVD, it is not that bad for me and I will take this challenge just out of curiosity.

Next thing in the VirtualDub pipeline is a 50 fps SeparateField version.

The whole movie was shot with a Sony DigiBeta Cam, MiniDV. So there probaly will never be a non-interlaced version of it.

[sh0dan]

Try out "Smooth Deinterlace" for AviSynth - the best filter I've tried for making 50fps clips. You should try this combined with a convultion3d to make it more compressible.

[JensG.]

Originally posted by sh0dan
Try out "Smooth Deinterlace" for AviSynth - the best filter I've tried for making 50fps clips. You should try this combined with a convultion3d to make it more compressible. Thanks for this advice! You mean I should "Smooth Deinterlace" instead of "Separate Fields"? About convolution 3d I always wondered why it should be used. So now is the time to try it.
Probably learning it the hard way is the best way...:confused:

[sh0dan]

You mean I should "Smooth Deinterlace" instead of "Separate Fields"?

Yes. Separatefields produces a very jumpy result, when you use all 50 frames per second, and it kills all information from the second field, when you use it as 25fps.

FieldDeinterlace() from the decomb package also produces very good deinterlaced images, and it's very fast.

Try out some different stuff.

About convolution 3d I always wondered why it should be used.

Your life will never be the same. It's a very good smoother, since it preserves a great deal of detail.

[JensG.]

With FieldDeinterlace, Bilinear Resize to 448*240, and Convolution3D I finally compressed it with acceptable qualitity to one 90 minute CD.
Thanks for your help!