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how can i tell if an avi clip is interlaced or progressive?
I am doing a little work with some clips digitized by another company.
The clips are 720 x 480 29.97fps but how can i tell if an avi clip is interlaced or progressive? -
2 Replies
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Import into AE and interpret the file (file>interpret footage>main) with field separation off. Look for thin comb-like lines where you see fast motion. If you see thin lines, it’s interlaced.
If you want to look under the fields hood, re-interpret the footage, separating fields lower first. Then alt+double-click on the footage in the project window. In the window that appears, step through the footage using the PageDn key.
– If the footage moves forward on every keystroke, you’ve interpreted correctly.
– If it jumps back and forth, separate fields again, but with the other order: upper first in this case.
– If it moves forward on every second keystroke, the footage is progressive.
– if it moves in an odd 3+2 pattern, then the footage has had pulldown applied, which may need to be removed depending on what you want to do to the footage.
By the way, you need to separate fields on interlaced footage if you are planning to do anything that will change the shape or position of the pixels. This means moving, rotating, blurring or distorting. But you knew that. 🙂
Now if the thin lines alternate fat/thin, you’re hosed. That means that somebody scaled the interlaced footage up or down without separating fields first. Very bad and impossible to fix. You’d need the footage before they scaled it in order to re-do the scaling properly. Once somebody imported 720×486 interlaced footage then actually scaled it up to 720×540 and gave it to me. Yuck.
Does that help?
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Hey! THANKS Steve – that was a great help.
Should solve most if not all of my interlacing issues.THANKS AGAIN,
Kevin
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