Saving Green screen file with alpha channel

David Jimerson · March 22nd, 2012, 01:08 PM

Quote:

Originally Posted by Renton Maclachlan

I have 13 sessions of 15 > 30 minutes which each have four cameras needed to be chroma keyed. I will be switching between cameras but at this point do not know where the switching will occur...and will not know untilI have my graphics in place etc.

I would suggest not attempting any FX until you have your edit in place.

Seth Bloombaum · March 22nd, 2012, 01:52 PM

Quote:

Originally Posted by Renton Maclachlan

I had 'Video for windows (*.avi) > PAL DV Widescreen' selected then in 'Customise Template' chose under 'Video Format', 'Matrox MPEG-2 I-Frame plus alpha'...('Render Alpha Channel' was not selectable...

Jeff Pulera? Had you seen this codec render with transparency in Vegas?

Renton, if you saw transparency in your project, and in the render were unable to select it in the configuration for the Matrox codec (did you try all versions of the codec?), that would be a dead end.

OTOH, we use avi uncompressed + alpha because it works and hard drives are cheap. Quicktime with the Animation codec and 32bpp works too, this is essentially QT uncompressed.

But, if you are just in Vegas, there are different ways to structure a workflow that don't require an intermediate file with transparency. We needed it because at the time we were cutting keys in a specialty program, but wanted to composite in Vegas.

Jon Shohet · March 23rd, 2012, 01:24 AM

The "Matrox Uncompressed HD/SD + Alpha" codecs should work with an alpha channel in Vegas.
Another workaround is to use Debugmode Frameserver (be sure to select RGB32 format) and then encoding to Lagarith in Virtualdub (be sure to configure Lagarith to RGBA mode).

It's a shame Vegas does not correctly recognize Lagarith, UT video etc. as alpha channel capable codecs.

Cineform, btw, can also get alpha channel from vegas in version 11 (not in version 9 it seems, I don't use version 10), however I think only the more expensive versions of Cineform support RGB+Alpha. I have NeoScene and I can get an encode with an alpha channel, but it's watermarked with a license error message.

cheers.

Jeff Pulera · March 23rd, 2012, 07:44 AM

On my old Matrox edit system, I did have Vegas installed and I did render to the Matrox .avi codec with success, but I can't say that I ever tried the avi + alpha codec in Vegas, sorry. Could be as simple as changing some settings in the Export dialog, don't have Vegas installed to test at this point

Jeff Pulera

[QUOTE=Seth Bloombaum;1722510]Jeff Pulera? Had you seen this codec render with transparency in Vegas?

March 23rd, 2012, 01:24 AM	#18
Jon Shohet Major Player Join Date: Dec 2007 Location: London, UK Posts: 277	Re: Saving Green screen file with alpha channel The "Matrox Uncompressed HD/SD + Alpha" codecs should work with an alpha channel in Vegas. Another workaround is to use Debugmode Frameserver (be sure to select RGB32 format) and then encoding to Lagarith in Virtualdub (be sure to configure Lagarith to RGBA mode). It's a shame Vegas does not correctly recognize Lagarith, UT video etc. as alpha channel capable codecs. Cineform, btw, can also get alpha channel from vegas in version 11 (not in version 9 it seems, I don't use version 10), however I think only the more expensive versions of Cineform support RGB+Alpha. I have NeoScene and I can get an encode with an alpha channel, but it's watermarked with a license error message. cheers. Last edited by Jon Shohet; March 23rd, 2012 at 01:55 AM.

March 23rd, 2012, 07:44 AM	#19
Jeff Pulera Major Player Join Date: Jun 2008 Location: Milwaukee WI Posts: 691	Re: Saving Green screen file with alpha channel On my old Matrox edit system, I did have Vegas installed and I did render to the Matrox .avi codec with success, but I can't say that I ever tried the avi + alpha codec in Vegas, sorry. Could be as simple as changing some settings in the Export dialog, don't have Vegas installed to test at this point Jeff Pulera [QUOTE=Seth Bloombaum;1722510]Jeff Pulera? Had you seen this codec render with transparency in Vegas?