footage has lines around edge of people moving

G

glkl

Active member
My 60i footage looks fine in my fcp5 sequence but when I export it to quicktime and open it in the quicktime player it has very pronounced lines around the edges of anybody moving. I guess that is called aliasing?

Why does it do in quicktime player but not in fcp sequence. I export using easy set-up presets.--DV/DVCPRO, interlaced, the field dominance is lower, although I tried it on upper and it was just as bad. Set at none is the worse of all. The lines show up right in fcp then even before exporting. The frame rate is 29.97.

What can I do about this. It is promo reel for potential work so I want to look its best.

Thanks.
 
glkl said:
My 60i footage looks fine in my fcp5 sequence but when I export it to quicktime and open it in the quicktime player it has very pronounced lines around the edges of anybody moving. I guess that is called aliasing?

Why does it do in quicktime player but not in fcp sequence. I export using easy set-up presets.--DV/DVCPRO, interlaced, the field dominance is lower, although I tried it on upper and it was just as bad. Set at none is the worse of all. The lines show up right in fcp then even before exporting. The frame rate is 29.97.

What can I do about this. It is promo reel for potential work so I want to look its best.

Thanks.
Click to expand...


Without seeing the actual footage with the artifact, what I guess is going on, is that you are seeing the 'motion interlace' artifact that is typical of 'video'. It is less noticible on 'real'(tm) TV displays, but still there. The origin of the artifact is from the fact that in interlace mode, each field is acquired at a different time, and so if there is motion, there is 1/60th of a second's worth of motion difference in between the fields. For 'fast' motion, the lines are more visible.

Capturing the original in 'progressive' modes would eliminate this type of artifact. There is still the artifact of the low res (by today's standards) of the 480x720 rasterization.

There may be some form of filter that someone has come up with to mitigate the interlace artifact...

In terms of 'showing your capabilities', if you have the ability to shoot the scene over, and capture in a progressive mode, that would be perhaps better. If you can only capture in interlace mode... then calculating what amount of motion is 'acceptable', and shoot in such a way that the amount of apparent motion of individuals on the screen never exceeds that value.

I've not tried this but perhaps some form of filter that filters 'across frames' may assist. This would induce some sort of softening of the image, so it may be something you would do for just the 'in motion' clips.

As a note, the lines due to motion between fields is a form of 'aliasing', but it is 'time aliasing' rather than spatial aliasing, such as the jaggies on lines cutting across the rasterized image.
 
Is the promo reel going to go on DVD or going to go up on your website? If it's going on DVD don't worry about the interlacing because that won't show up on a regular TV. If it's going up on your web site then just de-interlace when you compress the video for the web.

The reason that it doesn't show up, or show up as much, inside FCP is because what you see in FCP is just a proxy image typically displaying only one field. If you set your Canvas window to 100% then FCP will show both fields.


-A
 
Also keep in mind there are different viewing modes in FCP and Quicktime that can affect playback quality when using DV or DVCPRO footage. In FCP, the RT tab in the upper left corner of the timeline can be set to full quality, but you will only see interlace fields if your canvas or viewer window is set to 100 percent. In Quicktime, in preferences, you can check Use high-quality settings when available. If you don't select high quality in FCP or Quicktime, it will play at a lower rez setting to make things easier on your processor, but the original footage will still be high quality.
 
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