transparent backgrounds

[john]

Is it possible to get transparent backgrounds in SA? I'd like to be able to create animations in SA and composite them back into Final Cut projects.

[Synthetik]

Sure, you can choose whether you want to work with an alpha channel (or not) in studio artist. And you can choose how it is generated if you want to create processed movie files with an embedded alpha channel. Studio Artist is more flexible than the adobe apps as far as working with alpha, since you can choose to work with it or not.

In layer preferences (file :preferences :layer preferences) you can turn on or off the paint alpha fill status. If you want you paint strokes to affect the current layer alpha channel you turn that on. And in process file setting dialog (under main action menu), you can set the Out Alpha popup for what is placed in the embedded alpha channel layer of the processed output movie. It defaults to full on, so you would want to switch it to layer alpha if that's what you wanted to place in there. You also need to choose a codec for output that supports alpha, not all do.

[john]

I guess I just need to learn more about how to generate alpha channels from my videos that I want to process in Studio Artist. Thanks for a generous answer.

[Synthetik]

Some of the videos on tutorial disc #2 deal with alpha in layers and in processed movies.

[Thorrific]

You can generate alpha channels easily using Region Selection for example.
Generate a Region Selection and then go up to Canvas > Set Layer Alpha To > Current Region Selection. Recording those steps in a PASEQ and makng sure your settings are correct as per John Dalton's post, a .mov generated should have an alpha channel in it... There are other ways to get alpha channel like in Image Operations too.

[Synthetik]

That's actually a good point about Ip Ops. Most people don't realise that you can use any of Studio Artist's Ip Ops (image operations) to generate and/or process alpha channels. Same goes for creating or modifying selection masks.

[john]

Wow, thanks for all the info! Very helpful. I am only replying now, because I've been experimenting with all of the tips.

Here's what I'm doing: taking a photo of cracked mud that I made grey-scale in Photoshop, then in SA, I am creating a new video clip by generating frames while tweaking the Warp>'Vertical Wave Translate' . Then using the resulting clip as a 'luma travel matte' in Final Cut. This is way fun!

But... in trying to generate an alpha channel by using region select and the Animation codec, I am still not getting alpha channel information when I open the clip in Final Cut. Here's what I'm trying:
1.hit record on the PASeq
2. erase to source image, Make a region selection, Layer>Alpha> from current selection
3. process movie with PASeq
Final Cut doesn't recognize any alpha information from the resulting video.I have the layer set to Alpha in the layers tab, still nothing. I can stil use it as a luma matte, so that's okay.

Is it possible to get less eradic results from using region select>texture image in thePASeq?

Thanks for all your time and help.

[Thorrific]

I think your problem is using the Animation codec. If you use NO compression, with Millions of Colors +, it should work.

[Synthetik]

And you need to make sure you have the Process File Settings dialog Out Alpha popup set to the correct setting for what you are doing. Fo this case you would want it set to layer alpha.

[john]

Here is the cracked mud I am trying to use. I have had some cool results compositing this back into FCP using'travel matte luma', but I guess I am just trying to understand alpha layers and I am getting hung up on this because my alpha channel is blank in the FCP viewer if I set it to alpha only, where as I can see it in SA.???

cracked_mud_small0002

[Victor Ingrassia]

If I might stick my noe into this discussion. I checked your clip in SA to see if its alpha shows up there. It does. And then I opened it in FCP and placed another layer underneath with "Straight Alpha" set in the sequence menu and it seems to work. Hmm. see attached screen shot, in case that might give a clue. I'm no expert in FCP... but maybe you can glean some info from the screenshot.

~Victor

alpha_in_FCP_4_John.jpg