Transparent GIFs?

[holographic]

Hello, nice people.

I wanted to ask: am I doing something wrong or transparent animated GIFs don't show as transparent?
It looks like any transparent GIF I throw at it gets shown as without alpha channel and with a white background.

It looks like I can somehow get it to use the transparency when I put the layer blending mode that has the GIF in it to Displace with an Opacity of 100%.

Thanks for reading and have an extra nice day!

[Zoltán]

Thanks for reporting this,
indeed it looks like this is broken, I created a ticket. (#10164)

[Arvol]

Would an automask FX work in the meantime?

[Oaktown]

If the alpha channel is showing up in the clip and you’re getting white instead of transparent, have you tried to set up to straight instead of pre-multiplied?

[Zoltán]

If the alpha channel is showing up in the clip and you’re getting white instead of transparent, have you tried to set up to straight instead of pre-multiplied?

It's not showing up, unfortunately.

[Oaktown]

Then it may be best to replace the transparent layer with a chroma green until you can get it fixed.

[Oaktown]

I remembered running into this a few years back so I did some research and it turns out GIF doesn’t support alpha:

http://whatis.techtarget.com/definition/transparent-GIF

So, in your case, the color white is the “transparency” which is why you don’t see an alpha channel. So either, you key the white or you can replace it with a chroma green (or blue) which is easier to key than white.

[Joris]

turns out GIF doesn’t support alpha

Pretty sure it does and this is just a bug where we don't display the transparency correctly.

[Oaktown]

Pretty sure it does and this is just a bug where we don't display the transparency correctly.

My understanding is that GIF is only 24-bit and the transparency is palette-based transparency so you have to define a background color that is the "transparency" and do background matting to replace the background color with alpha.

So, yes it works as "transparency" but it's not an alpha layer which would require an add'l 8-bit.

As far as I undesrtand, the quickest way to use a GIF with transparency besides keying the background color is to open it in photoshop, select all the images and export>render video. I'm attaching two clips (one GIF with white transparency and the same rendered with Photoshop in QuickTime Animation codec)

[Joris]

Yes, you were referring specifically to an alpha channel.

To a less technically versed person, your post could be interpreted as transparency in gifs is not supported. I just wanted to make clear that that is not the case.