Favorite clips that are pre-keyed with alpha channel...

This topic is for showing your best pre-keyed (chroma-keyed) files that include an alpha channel (32 bit png with alpha). You should see the keyed background in a checkerboard pattern when this is done correctly (during playback of the clip only). Note: Green screen backgrounds, or any color background are not keyed files and should not be entered here.

Here is the first example:


Please, one entry at a time or per day max. Strut your stuff! :)

I don't see the checkerboard pattern.

It appears when the clip is played.... the black background is there for just the thumbnail capture.

I suspect the system is just capturing the 24 bit RGB data of the clip for the thumb.

Turns out not all clips show the checkerboard and it has nothing to do with how long they have been up. For example:
does not show the transparency as a checkerboard. - But if one loads this into an editor of any kind - it can be set to "straight (unmatted)" and it will become transparent. In some cases the codec that any given software uses may present this differently. I have been noticing many variables in various software apps from Adobe AE to Particle Illusion to Sony Vegas. Each app handles things a bit differently. It is weird and the only way to figure stuff out is to experiment and test.

Update 10/01/10 - Marcus had a look at this issue. Look ma - it's transparent. Turns out that this was a fluke. It got caught in a "black hole" for the lack of a better term and just didn't make it through the second rendering process. It's quite more complex than that, but for the purpose of explaining here, I figured I would keep it simple.

Vadervideo, thanks for the interesting thread. What is the benefit, of using the alpha checkerboard matte rather than keying the object on white, or a green/blue screen?

To answer that in simplest form, it is less work for the buyer as they don't have to do the keying, which in some cases can be quite challenging. Basically, if you offer something that can immediately be used for compositing, buyers will pay bit extra as this saves them (usually) lots of time in post production. Hence, since the transparency is already done for them, they no longer have to worry about keying the clip themselves, or worry about matching up a matte etc. Talk to anyone that has had to do roto-scoping, keying, luma mattes etc.. they will tell you that if this is done, they really appreciate it.

That's great information. I am working on some object loops on a white background - as the counter guy in my local photo supply store told me white if fact was the easiest source to key from (?). Anyway, I had planned to offer the loop on 100% white. Now I'll try to create the checkerboard alpha channel in FCP. There's always something new to learn! Would you offer it both ways? Thanks!