Compositing with alpha and RGB image streams or AVI's
Posted: Wed, 21st Jan 2009, 1:53pm
Post 1 of 10
This is a big problem for me. VisionLab will not import Image streams. It crashes with the dreaded 'Director player' error. Also, I have found a long winded work around but, I've been told by a friend of mine that all compositing software should have a 'premultiply' setting. I cannot find this on VisionLab anywhere. Alpha images don't work right either. Black should be transparent and its not.
Posted: Wed, 21st Jan 2009, 3:13pm
Post 2 of 10
If you import an image with a proprer alpha channel, it will be pre-multiplied. VisionLab will automatically detect the alpha and apply it to the footage.
Please provide a sample of one of the images that is giving you trouble. Also, please explain in as much detail as possible the format of the image, and where it was originated.
Posted: Wed, 21st Jan 2009, 3:20pm
Post 3 of 10
I've sent an email with enclosed samples to the support team. They Originate from LW CGI graphics program and are it tga format.
Posted: Thu, 22nd Jan 2009, 12:00am
Post 4 of 10
Right then, I'll leave it to them to sort out. I'm sure they can find the answer more effectively than me anyway.
Posted: Thu, 22nd Jan 2009, 12:57pm
Post 5 of 10
I hope they can, but so far after 2 emails I have not heard a reply. Maybe they are looking into it at present. It would perhaps be better if the premultiply was not automatic, but left manual as it is in other composite programs. May help sort this kind of issue, as its obviously not reading the files correctly. Sometimes I have imported avi files with stars in the background, only to have Visionlab automaticaly treat it as an alpha channel when I don't need it.
Posted: Thu, 22nd Jan 2009, 1:35pm
Post 6 of 10
Thanks for sending the TGA images over.
I think the problem lies with Lightwave, as we weren't able to open the TGA images correctly in the Lab products or in GIMP.
Photoshop was able to open them, however. We then saved them out of Photoshop again as TGAs and they then worked completely fine in all other programs. This suggests that Lightwave is doing something unusual with the TGAs which might be worth looking into.
Posted: Thu, 22nd Jan 2009, 1:43pm
Post 7 of 10
Yes, I found that if I use photoshop to convert the alpha images to RGB greyscale 8 bit and invert them, they would import, but the alpha still didn't seem to work. Some friends of mine use adobe after effects with lightwave and they don't have any problems importing RGB and alpha from Lightwave, so I guess Visionlab isn't compatible with Lightwave.
Posted: Thu, 22nd Jan 2009, 1:46pm
Post 8 of 10
I've recently downloaded a trial of their latest version of Lightwave 3d 9.6. So I will test this out, and see if their new software still has the same problem with Visionlab.
Posted: Thu, 22nd Jan 2009, 1:51pm
Post 9 of 10
Both TGAs seem to include an alpha channel, too, which is a little unnecessary as you're using a separate image for the alpha. Why don't you just include the alpha inside the TGA, so that you don't have to have two files floating around?
Posted: Thu, 22nd Jan 2009, 2:01pm
Post 10 of 10
You get two settings, one box for the RGB save, and another for the alpha channel save. I notice in the newer version of Lightwave that there is a setting in the RGB channel for alpha on or off.
However, if I export just the RGB, Visionlab still doesn't always import the file. Sometimes it does, another time it is just a black object, or it crashes with director player error.
I will try out this demo of LW to see if it works any better with VisionLab.