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View Full Version : Interlaced Fields arbitrary and switching HELP!


petermg
14th December 2001, 18:45
Hi, I have an Asus V7100 Combo Deluxe, and whenever I capture interlaced clips, the field order is arbitrary. Sometimes it's odd field first.. other times it's even first... I even have a clip where the field order changes in the SAME CLIP!! Making it impossible to use as source material for an interlaced SVCD. Anyone have any ideas? Anyone ever heard of this before? I'm capturing NTSC at 720*480. Using the WDM drivers that come with Asus Digital VCR (but I'm using AVI_IO and VirtualDUB to do the capturing), on W2K, 256 MEGS of RAM, any ideas, speculations, etc.???

Cart
22nd December 2001, 00:12
This sounds to me like a case of poor drivers and/or hardware. (Gotta love ASUS.) First, try your best ot avoid frame drops, which may be causing the mid-capture changes.

To actaully correct the problem, Avisynth may be able to help. It has commands like complementparity() that switch the field dominance. If you search the archives of this forum or the old one, you'll find a post where this was discussed in great detail. Unfortunately, your problem isn't very easy solve, and you may want to to simply deinterlace if your videos are especially bad.

-Cart
http://www.geocities.com/lukesvideo/index.html

petermg
22nd December 2001, 03:00
Thanks.. but when I try to do a search in the forum I get a message that says:

vBulletin Message
Sorry. The search function has been disabled by the administrator.

Cart
22nd December 2001, 08:00
Okay, you can use Avisynth's ComplementParity() command to alter the field dominance. You should be able to apply it to different portions of the video by using trim() command. You can find more information about Avisynth at my site and at the official Avisynth site.

Please note that I don't think it's possible to save correct dominance from an Avisynth script to an AVI. However, it hopefully will work when you feed the video to your MPEG-2 encoder.

-Cart
http://www.geocities.com/lukesvideo/index.html

Guest
2nd January 2002, 20:29
That sounds unlikely. Are you sure you don't have a PAL telecined source where the phase is simply changing? If so, the Telecide filter can help.