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byronpetch
04-17-2005, 04:48 AM
Hi All

My problem really has two parts but I think they both relate to interlacing problems. I seem to have on going problems getting the interlacing correct when sending clients (vid production companies) LW animations I often get the interlacing in the wrong order because LW uses different terms to describe the interlacing order to most apps. (odd and even rather than upper and lower)

1. Could someone please tell me what Lightwaves odd and even relate to? ie does even = upper or lower field. I often search web sites for this info but they seem to contradict each other a lot.

2. my current project requires me to provide client with an animated transparent plastic beachball. They want it with an Alpha channel so they can comp it onto some footage. Im rendering it out as interlaced footage using the Animation codec with Alpha channel. When the client or I import this footage into an application such as AfterEffects the Edge of the ball looks a bit feathery around the edges. I don't mean the problem you get if you get fields the wrong way round its more sort of soft and slightly jaggy with a few halo effects a small distance from the edge.

When I do photoshop file tests the Alpha works perfectly interlaced or otherwise.

Can anyone throw any light on these issues.

many thanks

Mat

Mylenium
04-17-2005, 11:30 AM
1. Could someone please tell me what Lightwaves odd and even relate to? ie does even = upper or lower field. I often search web sites for this info but they seem to contradict each other a lot.


What norm? Which editing system? Without that info, any attempt of advice is pointless.



2. my current project requires me to provide client with an animated transparent plastic beachball. They want it with an Alpha channel so they can comp it onto some footage. Im rendering it out as interlaced footage using the Animation codec with Alpha channel. When the client or I import this footage into an application such as AfterEffects the Edge of the ball looks a bit feathery around the edges. I don't mean the problem you get if you get fields the wrong way round its more sort of soft and slightly jaggy with a few halo effects a small distance from the edge.

When I do photoshop file tests the Alpha works perfectly interlaced or otherwise.

Can anyone throw any light on these issues.

many thanks

Mat

Tell your client to set their footage interpretation/ import settings correctly. Looks like they are trying to use a straight alpha while yours is premultiplied. Also make sure, you only use black or white background. Unmultiplying a colored background still creates color bleed. Also not setting the background color coreectly causes fuzzy edges - if you rendered against white, you have to tell your program. Otherwise most progs simply assume a black "canvas". Other than that I can only think of the CoDec responsible for this. The Animation CoDec will introduce dithering and banding if quality is set to anything below "Best". This will also screw your edges.

Mylenium

byronpetch
04-18-2005, 08:47 AM
Thanks

Well I now know that in this case the client requires upper field first but Lightwave uses the terms odd and even but I dont know if upper is odd or even.

I must admit ive never really under stood the different matting options. ive always just used the one that seems to work ill look into that.

Thanks

Matt

Mylenium
04-18-2005, 11:41 AM
Thanks

Well I now know that in this case the client requires upper field first but Lightwave uses the terms odd and even but I dont know if upper is odd or even.

I must admit ive never really under stood the different matting options. ive always just used the one that seems to work ill look into that.

Thanks

Matt

Ah yeah, so "even" should be the one to use (scanlines counted from the bottom of the frame buffer in LW versus from top in most other prgrams that use "upper/ odd" terminology). Still, beware, this might not work since these days many editing systems internally work with "lower" field internal processing (to maintain DV compatibility). You never know until you try...

Mylenium