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  1. Member
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    Hello. I hope some of you guys can help me here, because I can't seem to get my head round this whole interlace thing.

    At the moment I'm capturing PAL60 video from my 360 using Dscaler. I use a WinTV express capture card. The quality and clarity looks fine in the preview window, but when I play the captured video back in media player or VirtualDub, it's horribly interlaced.

    Here's a screenshot of me slowly panning the game camera from left to right:


    No matter what I try, I can't seem to get rid of it. And with my old capture device (ADSTech VideoXpress), which unfortunately broke, I didn't have any hassles like this at all. The picture was always clean and clear.

    So far, the best I've been able to do is re-encode the video straight away in Adobe Premiere, with HuffYuv, and the interlacing is almost gone, but still slightly visible. Is there anything I can do to completely remove it?

    Thanks.
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  2. Mod Neophyte Super Moderator redwudz's Avatar
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    Have you tried playing it back with a player that handles interlaced video properly like VLC or Power DVD? Or you could try Smart Deinterlacer with VD and see if that helps with computer playback. http://neuron2.net/smart/smart.html

    Or if you plan to use it on a TV set, leave it interlaced.
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  3. Member
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    Wow! That Smart Deinterlacer has pretty much done the trick. Cheers, man.
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  4. Each frame of interlaced video contains two half-pictures -- called fields. One field is in all the even numbered scanlines, one in the odd numbered scanlines. When you watch these on an interlaced TV you see only one field at a time, in sequence:



    This GIF is simply alternating between the pair. Obviosly, in a video you would see each field once then move on to the next pair.

    On the computer you may see both fields at the same time, creating "comb" artifacts like in your sample. Many programs hide the interlacing by showing only one of the fields.

    VirtualDub's Smart Deinterlace filter will reduce the frame rate from 60 (half) pictures per second to 30 (full) pictures per second. Playback will be noticably less smooth. If size isn't a concern, but smoothness is, you might try the Bob Doubler filter. There are other ways too.
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  5. Member
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    Thanks for the info, Jagabo. It's starting to make a little sense now.

    I just tried Bob's Double filter but the results didn't seem as good as the Smart Deinterlacer. Maybe I didn't set it right. I guess it doesn't matter, for now I'm more than happy with the Smart Deinterlacer.

    Shame I have to go through this process now, when I didn't have to with my old capture device. But at least I can get clean, smooth video now.

    Thanks, guys.
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  6. Member
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    PAL60 is used when you capture NTSC content via a PAL capture device.

    For example: you have a NTSC VHS tape and play it back with your PAL VCR. The output of your VCR is not NTSC. It is a hybrid format between PAL and NTSC called PAL60.

    NTSC content usually has ~30 (29,997 to be specific) frames per second. 3 frames progressive followed by 2 frames interlaced (only every even or odd lines contain data) and so on ...

    You have to IVTC (inverse telecine) the video to "convert" the 2 interlaced frame into one progressive if you want to play it back mostly on computer monitors - if you want to watch it on your TV you can leave the video alone. This will lead to 30*5/4 = around 24 frames per second (23,976 to be specific) in the resulting video.

    Read here how you can IVTC using VirtualDub: http://www.doom9.org/index.html?/virtualdub_procedures.htm
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  7. Originally Posted by Bagshot
    Thanks for the info, Jagabo. It's starting to make a little sense now.

    I just tried Bob's Double filter but the results didn't seem as good as the Smart Deinterlacer. Maybe I didn't set it right. I guess it doesn't matter, for now I'm more than happy with the Smart Deinterlacer.
    Try the ELA setting. That works pretty well. But many computers will have problems playing 60 fps video smoothly. In any case, here's an example of 60 fps (on the top) vs 30 fps (on the bottom):

    comp2.avi

    Originally Posted by Bagshot
    Shame I have to go through this process now, when I didn't have to with my old capture device.
    Your old device probably only captured one field.
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  8. Originally Posted by chupacabra
    NTSC content usually has ~30 (29,997 to be specific) frames per second. 3 frames progressive followed by 2 frames interlaced (only every even or odd lines contain data) and so on ...

    You have to IVTC (inverse telecine) the video to "convert" the 2 interlaced frame into one progressive if you want to play it back mostly on computer monitors
    His source is a video game -- so IVTC probably doesn't apply.
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