creating transparent backgrounds for an overlay track

Moderator: Ken Berry

Post Reply
rbridge
Posts: 8
Joined: Mon Jul 11, 2011 9:28 pm
operating_system: Windows 7 Professional
System_Drive: C
32bit or 64bit: 64 Bit
motherboard: Hewlett-Packard 3048h
processor: Intel Core2 Duo CPU E8500 3.16 Ghz
ram: 4GB
Video Card: Intel Q45 Q43 Express Chipset
sound_card: Realtek High Definition Audio
Hard_Drive_Capacity: 250
Monitor/Display Make & Model: HP LE2001w

creating transparent backgrounds for an overlay track

Post by rbridge »

First i will explain what i am trying to do:

I am making a montage of previous logos for a piece of software. As one can guess there will be a lot of pieces I want transparent. The montage will be a moving animation-like video, making it look at though you are moving towards the most recent logo.

Here is what I have done to create the effect i am looking for:

I have created .png files of each logo (exporting from CorelDraw 11) making their backgrounds transparent. I then drag and drop the clip on to an overlay track. (I used an instant project and it came with overlay tracks which have an option checked called "Apply filter to Alpha channel," which I'm not sure how to do myself without using this instant project... that might help if i knew how that worked..) With the "Apply filter to Alpha channel," option checked I set the overlay track to fit the screen and then click the maintain aspect ratio. At this point all the places where the original picture isn't is transparent, but not the background of the picture. I'm making the overlay track size the size of the screen so I can have the logo move across the screen within the picture-in-picture filter which I then add to the overlay track. When I customize the PIP filter I have the logo fade in for the first half second or so in the middle of the screen, then move and tilt to the right or left (I alternate every other logo). At this point I think that the "Apply filter to Alpha channel," is still on, I then create a chroma key with the adjust colour similarity at 100 to make the background of my image transparent (I'm not sure why that part isn't automatic; I'm using two Corel products and I have created an alpha channel in the .png file so that as soon as I put on the timeline it should be transparent, but that doesn't happen, it goes back to the colour I originally made transparent in CorelDraw). Once I have created this chroma key, the space that was originally transparent due to the "Apply filter to Alpha channel" option, goes black. (this area is the spaced enclosed by the extents of the overlay track size and the edge of the .png file). When I right click on the logo in the timeline, there is no option to "Apply filter to Alpha channel" which I guess means you can't have a chroma key and this Alpha filter on at the same time. To remedy the black space I go to the transparency slider and set the value to "1" which gets rid of the black immediately and doesn't seem to make the rest of the image transparent at all (I'm sure technically speaking it does but 1% transparency isn't enough to notice in the .png file).

And now, the problem:

There is a white-ish boarder at the edge of the .png picture. and try as i might, I cannot get rid of it. It really ruins the transparent effect. Is there a way to remedy this? or a better way of getting the effect I want which doesn't need to use both the transparency and the chroma key? I've just thought of making a really large .png file with the logo at its center and zooming in quite far in, so there is a white back ground wherever i move the logo and then using a single chroma key to get ride of the background. This seems like a lot of work to go to, is there not an easier way?

thanks for any suggestions,

Ryan


[UPDATE]

It is the NewBlue PIP that is creating this boarder even when you turn off all boader, shadow and reflection there it is with the boarder of the transparent portions. I also tried rendering this portion to see if it still showed up and its still there even after rendering. Also my idea of making a large picture didn't work, you can't go bigger than 100% when in the PIP editor so the border is still there, closer tot he edges of the screen, but still there none the less.
Black Lab
Posts: 7429
Joined: Wed Dec 15, 2004 3:11 pm
operating_system: Windows 8
System_Drive: C
32bit or 64bit: 64 Bit
Location: Pottstown, Pennsylvania, USA

Re: creating transparent backgrounds for an overlay track

Post by Black Lab »

I have used many a png image in my videos and I never had to do anything extra to get the transparency after dropping them on the timeline. I have never used the Instant Project.

As for the PiP causing a border on your images, I have never used png images with that new filter.

I initially had problems with the PiP filter. See if this helps.
http://forum.corel.com/EN/viewtopic.php ... ip#p211729
rbridge
Posts: 8
Joined: Mon Jul 11, 2011 9:28 pm
operating_system: Windows 7 Professional
System_Drive: C
32bit or 64bit: 64 Bit
motherboard: Hewlett-Packard 3048h
processor: Intel Core2 Duo CPU E8500 3.16 Ghz
ram: 4GB
Video Card: Intel Q45 Q43 Express Chipset
sound_card: Realtek High Definition Audio
Hard_Drive_Capacity: 250
Monitor/Display Make & Model: HP LE2001w

Re: creating transparent backgrounds for an overlay track

Post by rbridge »

Thanks for the reply, I read that over, but it doesn't really address custom NewBlue PIP. It is very strange because I have found a .png file that I used earlier in my video and the outline of the picture doesn't show up. I then tried copy and pasting its attributes to the ones I'm having trouble with and the outline still appears.

Any other suggestions out there?

thanks


-Ryan
21clg
Posts: 2
Joined: Wed Dec 21, 2011 11:21 pm
operating_system: Windows 7 Home Premium
System_Drive: C
32bit or 64bit: 64 Bit

Re: creating transparent backgrounds for an overlay track

Post by 21clg »

I am burning mad because I am having the same problem with overlaying a .png with transparent parts, and there are white borders (about a pixel wide/high) around the edges, looks really tacky

I am NOT using PIP or anything like that, just importing a .png image and putting that in the overlay track

I tried exporting the .png from Photoshop (and GIMP) in several ways to remedy but to no avail

WTF? Corel's support sucks btw
21clg
Posts: 2
Joined: Wed Dec 21, 2011 11:21 pm
operating_system: Windows 7 Home Premium
System_Drive: C
32bit or 64bit: 64 Bit

Re: creating transparent backgrounds for an overlay track

Post by 21clg »

Ok, I figured out a trick/workaround to GET RID OF WHITE BORDERS on .png images with transparency in an overlay track (for example using Photoshop or GIMP to edit the .png)

Instead of making the undesired parts of the .png completely transparent, just make them extremely low opacity

i.e. when editing your .png in Photoshop or GIMP or whatever, instead of selecting the undesired parts and deleting/clearing them completely, simply select the undesired parts and make them EXTREMELY low opacity (typically by making it a separate layer)

I was able to make this successful (no white borders between undesired/desired parts of the .png) using as low as .5% opacity ( I was personally using GIMP)

even using fly-in effects on the .png overlay, I wasnt able to see the square image edge borders of the .png overlay

...nor did it cause any darkening

I suppose the 'extremely-low-opacity-parts' are technically still there, just not visible to the human eye or something like that

try it out and tell me if it worked for you!
Trevor Andrew

Re: creating transparent backgrounds for an overlay track

Post by Trevor Andrew »

Hi

The problem of white borders has nothing to do with Video Studio.
Your PNG image contains the white pixels and that is what VS is displaying.

Use Photoshop or PSP to correctly edit your image before importing to VS.

Attach your image to the forum post so we can view it,
Or send the image to me via e-mail and I will have a gander, view my Quick Guides for address.
Post Reply