Transparency at DVinfo.net

Justin Deming · September 13th, 2008, 04:03 PM

I'm wondering if anyone can tell me what I am doing wong here.

I created a video for a bottom third to go over footage of a boxing match. The video I created has "nothing" outside the graphics & text I inserted using a PSD file & the media generator. When I rendered it, the file shows my bottom third stuff, with black everywhere else. So far so good.

I inserted this into the top video layer of a preliminary version of the Boxing video, and it works great! The only place it covers anything is where my graphics & text are. So I decided to try on it on the newest version of the video & for some reason it covers everything, no transparency. I can use chroma key to erase the black background from the overlay, but I don't want to do it that way.

So my question is why does one file allow it to be transparent with no chroma key filter & the other one needs a mask to "erase" the black background? Apparently I did something in the layers that is making this happen, but I have checked the properties carefully & i can't find anything different, besides that I added color correction filters. Mostly this is just an academic question, I have already finished this project, I just wanted to make some better graphics for the next time I do this (in a few weeks) and I was hoping to re use the project file, and just change the overlays.

Maybe it would just be better to start from scratch? Anyone have any ideas?

Ian Briscoe · September 13th, 2008, 05:19 PM

Hi Justin

I think what you're saying is that you effectively want to treat the black as an alpha channel?

I think to do this you need to render as Quicktime. When you've selected "Qucktime" from the Render screen - click on "Custom" - then click the "Video tab" - select "Animation" as the Video Format.

Then when you bring it into your next project - right click on the event and select "Properties" -> "Media". Then select any of the bottom 3 options - no idea what the difference is - but they all seem to work.

Ian

Justin Deming · September 13th, 2008, 06:35 PM

Thanks Ian, I will try that. I rendered as an AVI Intermediate file, and it worked for some magic reason in one project, but not another.

I just wish I knew what was different that made the second one not work.

Edward Troxel · September 13th, 2008, 08:21 PM

If you're rendering the lower third to an AVI file, change it to UNCOMPRESSED, open the "custom" screen, and make sure the "Alpha channel" is turned on.

Justin Deming · September 14th, 2008, 04:20 AM

That works, Thanks a ton!

September 13th, 2008, 04:03 PM	#1
Justin Deming Regular Crew Join Date: Mar 2006 Location: Minneapolis, MA Posts: 84	Transparency I'm wondering if anyone can tell me what I am doing wong here. I created a video for a bottom third to go over footage of a boxing match. The video I created has "nothing" outside the graphics & text I inserted using a PSD file & the media generator. When I rendered it, the file shows my bottom third stuff, with black everywhere else. So far so good. I inserted this into the top video layer of a preliminary version of the Boxing video, and it works great! The only place it covers anything is where my graphics & text are. So I decided to try on it on the newest version of the video & for some reason it covers everything, no transparency. I can use chroma key to erase the black background from the overlay, but I don't want to do it that way. So my question is why does one file allow it to be transparent with no chroma key filter & the other one needs a mask to "erase" the black background? Apparently I did something in the layers that is making this happen, but I have checked the properties carefully & i can't find anything different, besides that I added color correction filters. Mostly this is just an academic question, I have already finished this project, I just wanted to make some better graphics for the next time I do this (in a few weeks) and I was hoping to re use the project file, and just change the overlays. Maybe it would just be better to start from scratch? Anyone have any ideas?

September 13th, 2008, 08:21 PM	#4
Edward Troxel Sponsor: JET DV Join Date: Dec 2001 Location: Southern Illinois Posts: 7,953	If you're rendering the lower third to an AVI file, change it to UNCOMPRESSED, open the "custom" screen, and make sure the "Alpha channel" is turned on. __________________ Edward Troxel [SCVU] JETDV Scripts/Scripting Tutorials/Excalibur/Montage Magic/Newsletters

September 13th, 2008, 05:19 PM	#2
Ian Briscoe Major Player Join Date: May 2005 Location: Southport - UK Posts: 208	Hi Justin I think what you're saying is that you effectively want to treat the black as an alpha channel? I think to do this you need to render as Quicktime. When you've selected "Qucktime" from the Render screen - click on "Custom" - then click the "Video tab" - select "Animation" as the Video Format. Then when you bring it into your next project - right click on the event and select "Properties" -> "Media". Then select any of the bottom 3 options - no idea what the difference is - but they all seem to work. Ian

September 13th, 2008, 06:35 PM	#3
Justin Deming Regular Crew Join Date: Mar 2006 Location: Minneapolis, MA Posts: 84	Thanks Ian, I will try that. I rendered as an AVI Intermediate file, and it worked for some magic reason in one project, but not another. I just wish I knew what was different that made the second one not work.

September 14th, 2008, 04:20 AM	#5
Justin Deming Regular Crew Join Date: Mar 2006 Location: Minneapolis, MA Posts: 84	That works, Thanks a ton!