Clip with Alpha

[Bart]

Edius 4.24

Here's a small experiment with Alpha and I don't understand the results:
1. I put a PAL DV-clip alone on the timeline and apply a chromakey to it. (+ checked the clip to be sure that a great part of the clip is transparant)
2. I export this clip as an uncompressed RGB clip. (export to HQ => same result)
3. The info on the exported clip says clearly: alpha present.
4. When using this exported clip over another clip the alpha parts are not transparant but black.

What is going wrong?

The strange thing is that a clip with apparently the same caracteristics: uncompressed RGB with Alpha created through other applications (e.g. Imaginate) do behave as expected.

[Aristotelis]

nothing is wrong Bart, this is a limitation of Edius...You can find more info in other threads on this forum as well

[Bart]

I know that Edius has a limited Alpha support but what's the difference between 2 uncompressed RGB clips (same story for HQ clips) with an Alpha-channel.

Is it the Edius exporter?

[GrassValley_KH]

It is the nature of EDIUS, that all timelines are "flattened" at file export - regardless of whether there are clips with alpha or not.

This applies to sequences also.

That said, there are a few tricks you can employ to create a clip with a proper alpha channel - it does require that you first render a masking video clip with the "show key" option enabled on the source that you are chroma keying.

Ultimately, to create a clip with true alpha in EDIUS, you must use the 'Convert->File' option with the Bin Window's right-click context menu.

[Bart]

Thank you, now it's clear.