How to de-interlace converted video from a DV or Digital 8 c

[lchiu7]

I am trying to convert some captured video (from a Digital 8 camcorder) transferred across raw using a firewire connection into more manageable DivX format. I tried using VDub with the DivX encoder and while it works the picture has significant combing artifacts. I can't see any way to remove them using the settings in VDub or the encoder. Is there a better way?

Thanks

Larry

[Medical]

Hi !

If you can live with a horizontal resolution of 288 (PAL)
you can use VirtualDub's DeInterlace-Filter Option
"Discard field 1". No comb-artifacts at all and it is
progressive (Non-Interlace) for sure.
If you have a clip 720*576 you get 720*288 and you can
resize to 352*288 to get the right aspect ratio again.

I assume you could resize from 720*288 to 720*576
but I bet the quality will be bad, though still
progressive.

I hope I could help
Med.

[lchiu7]

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR size=1 color=black></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>
On 2001-12-29 14:37:23, Medical wrote:
Hi !

If you can live with a horizontal resolution of 288 (PAL)
you can use VirtualDub's DeInterlace-Filter Option
"Discard field 1". No comb-artifacts at all and it is
progressive (Non-Interlace) for sure.
If you have a clip 720*576 you get 720*288 and you can
resize to 352*288 to get the right aspect ratio again.

I assume you could resize from 720*288 to 720*576
but I bet the quality will be bad, though still
progressive.

I hope I could help
Med.
</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR size=1 color=black></TD></TR></TABLE>

Sorry but the video is NTSC. I tried a number of those options (dropping various frames) but I always get combing on motion - there must be another way to get rid of this artifact

Thanks anyway

Larry

[Medical]

Hi !

NTSC: 720*480 -> 352*240

Combing artifacts occur when you have a fast moving object
so that the difference between field A and field B is
noticeable. If you put both fields together to form one
field (lines 1,3,5,7... AND lines 2,4,6,8...) you get
those combing artifacts.

If you discard one field it is imposible to still get
combing artifact because there is no second field.
The only two possibilities are:
.) You didn't deinterlace/discard one field right.
.) Your video source was shot with long shutter-times
(this normally occurs when filming fast moving objects
in low light places).

If you "discard one of the fields" (with VirtualDub's
Deinterlace filter) you discard one half of the video
Information and you reduce the horizontal resolution
to the half (720*480 -> 720*240 NTSC).

I hope this time I could help
Good luck!!
Med.

[humdinger]

i use vdubs smart deinterlace filter, and set it to blend the 2 fields together. that way you still get the full resolution, but no artifacts

[lchiu7]

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR size=1 color=black></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>
On 2001-12-30 04:31:06, humdinger wrote:
i use vdubs smart deinterlace filter, and set it to blend the 2 fields together. that way you still get the full resolution, but no artifacts
</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR size=1 color=black></TD></TR></TABLE>
Hmm - I didn't see any de-interlace filters in VDUB but I dug around and found these - are the ones you are talking about?

http://sauron.mordor.net/dgraft/smart.html

I haven't been able to test them yet since I deleted my original uncompressed DV source since it was taking up so much disk space

Larry

[Medical]

blend the 2 fields together. that way you still get the full resolution, but no artifacts
!!!
This is definitly the way to full combing artifacts!!!
!!!

But, yes, you get the full resolution

Combing artifacts are because of the difference
between the two fields. Each field is 1/60 of a second.
If the object is fast moving you get a noticeable
change during this 1/60 second.
If you put both fields (A + B) together you get one
frame!!! If there is a big difference between the two
fields, you get a frame which is definitly not clear.
This isn't too hard to understand, is it?

If you throw away one field (and therefore half
the resolution) it is impossible to get combing
artifacts! There can't be any difference between the
two fields because there is only one left...

I hope I did make myself clear (uh, my bad english).
Med.

P.S.: In NTSC you don't have 30fps but 29,97fps and
therefore not every 1/60 sec. a filed but every
59,94 sec. one field.
I wanted to mention this just for the records

[Medical]

I meant VirtualDub's built in filter!
Load the clip, then go to menu:
video - filter - add
Select deinterlace, then select discard field 1
And I promise NO COMBING ARTIFACTS!

Happy New Year to all boardies!!!
Med.

[themamboman]

I've found that, under some circumstances, the 3rd party vdub plugin called area-based deinterlacing gives better results than the smart deinterlacer.