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| HairyTroll |
| Posted: Mar 7 2003, 01:17 AM |
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Unregistered
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What is the default field order used by VirtualDub ?
My interlaced source is displayed correctly in VirtualDub so I know VirtualDub is handling the fields correctly. However I am unable to determine if the field order is A or B/top bottom/odd even, whatever.
Anyone know what the default field order is ? |
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| phaeron |
| Posted: Mar 7 2003, 03:17 AM |
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Virtualdub Developer
Group: Administrator
Posts: 7773
Member No.: 61
Joined: 30-July 02
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The field order is determined by whatever generated the interlaced material, usually the capture driver. VirtualDub itself doesn't generally work in fields and doesn't have a notion of field polarity. The few places that it does (field bob, field-based preview, etc.) have user-controllable polarity where you enable the option.
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| HairyTroll |
| Posted: Mar 7 2003, 03:26 AM |
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And that's what confuses me. I have set field-based preview to Progressive, Field A and Field B - but this makes no difference.
I know for a fact that the source material is 1080i (1920x1080 interlaced 60 fields/second). |
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| HairyTroll |
| Posted: Mar 7 2003, 04:07 AM |
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I think I have determined the field dominance in my source material: and if anyone else is interested, here is how I did it.
First, read Field Dominance
Then download the ViewFields plugin for VirtualDub provided by Simon Walters. This plugin very handily splits the top and bottom fields into seperate images.
Now, examine a frame with a lot of movement. Look to see what image is further advanced. I.e. Determine in which frame an object that is moving is is further advanced in time.
If this is the bottom frame then it follows that F2 (bottom frame) follows F1 (top frame), I.e The top frame comes before the bottom frame in time. You then have "Top field", "Field A" or "F1" dominance. |
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