PNG File Issue

Hi,

I have an Blackmagic ATEM Television Studio PRO HD Switcher. When attempting to use PNG file for Chroma keying, the file appears with a white BG instead of being transparent. Can anyone help with this issue please? I have tried using different graphics but all of them have white BG's.

Thanks,
Kris.

Hi,

I have an Blackmagic ATEM Television Studio PRO HD Switcher. When attempting to use PNG file for Chroma keying, the file appears with a white BG instead of being transparent. Can anyone help with this issue please? I have tried using different graphics but all of them have white BG's.

Thanks,
Kris.

you need a png file of the proper dimensions (1920*1080), and an alpha channel in that png file.
also, you need to set "premultiplied alpha" in the atem

Thank you for your reply Raphaël
"you need a png file of the proper dimensions (1920*1080), and an alpha channel in that png file.
also, you need to set "premultiplied alpha" in the atem"

I had been using PS 2019 V20.0.5 to design & export the PNG files. I made the adjustments mentioned above, the white BG still appeared in ATEM. However when using Adobe Illustrator to design & save for web, the PNG file issue has been resolved.

Thank you for your reply Raphaël
"you need a png file of the proper dimensions (1920*1080), and an alpha channel in that png file.
also, you need to set "premultiplied alpha" in the atem"

I had been using PS 2019 V20.0.5 to design & export the PNG files. I made the adjustments mentioned above, the white BG still appeared in ATEM. However when using Adobe Illustrator to design & save for web, the PNG file issue has been resolved.

hah.
I use the Gimp myself, which doesn't show those issues

I must admit that I also have problems with Photoshop alpha channel. There surely is a way to do it, but even the BMD tutorial lead to targas with white background. I must do something wrong.

With Gimp I have instant success. Add a layer, do the graphics, hide the background layer, export to png, drop into the ATEM Software, done.

This is a bug of the ATEM software since the beginning:
PNGs can only have straight alpha channel per definition (so photoshop is correct here!) but ATEM software expects it to be premultiplied...
So please do not use PNG format as long as BMD does not fix this (it needs to be premultiplied by ATEM software prior to the upload to the mixer).
You can use TGA format instead.

This is a bug of the ATEM software since the beginning:
PNGs can only have straight alpha channel per definition (so photoshop is correct here!) but ATEM software expects it to be premultiplied...
So please do not use PNG format as long as BMD does not fix this (it needs to be premultiplied by ATEM software prior to the upload to the mixer).
You can use TGA format instead.

well, photoshop is stupid, this should be an option

***Update on PNG File Issue***

First of all, thanks guys for your input, very much appreciated.

I have found the solution to exporting PNG files from PS to use with ATEM. I had been using a separate MAC to the MAC that has ATEM installed on. I had been unaware that when installing ATEM a plugin is added to PS so that PNG files can be successfully exported without the white BG issue as mentioned earlier in the discussion. The plugin uses the correct Pre Multiply Alpha & lets you export PNG files directly in the media pool in ATEM.

Kind regards,
Kris.

I might be having a related issue.

I'm creatig my PNGs with Inkscape 1.2.2. With old versions of Inkscape, everything was good. But then after some update, Inkscape started creating PNGs which are RGBA, but the alpha channel gets display as greenish semi transparent mess, or yellowish, or I think pinkish in my Atem Mini Pro ISO.

My workaround is to open these PNGs in Gimp and export them again as PNG, then the issue goes away. I can't figure out what the difference between the files of Gimp vs. Inkscape actually is, neither exiftool nor mediainfo reveal significant differences.

It is annoying because it's an extra manual step, that – when forgotten – leads to failure. Also I'm creating the SVGs for Inkscape automatically, then converting them to PNG automatically with some shell scripts, so basically everything's automated but not the thing with Gimp of course. I might try ImageMagick's convert tool.

(Oh, and btw, Gimp nerds… if you love 32bit float editing as a default setting in Gimp as much as I do, make sure to select 8bit RGBA pixel format in the PNG export dialog.)

I don't have Photoshop and I don't want to have it either.

But if anybody has ideas how do debug this issue further, I'd be thankful.

Maybe it will be fixed in the ATEM software one day...

Until that: Do not use PNGs with ATEM. It is (still) broken and violating the PNG specs.

I might be having a related issue.
I'm creatig my PNGs with Inkscape 1.2.2. With old versions of Inkscape, everything was good. But then after some update, Inkscape started creating PNGs which are RGBA, but the alpha channel gets display as greenish semi transparent mess, or yellowish, or I think pinkish in my Atem Mini Pro ISO.

EDIT: In an earlier version of this post today I thought I had figured out the issue but actually I was plain wrong. Deleted that part.

What I have learned is that when uploading PNG witch OpenSwitcher to my Atem Mini Pro ISO, my PNGs do work. However, OpenSwitcher at the moment does not always reliably upload stills, it is still undergoing development.

So the issue seems to be not so much the Atem Mini but actually Atem Control converting the PNG into something that is used by the hardware, and this conversion seems to be problematic with the PNGs from Inkscape and Atem Software 9.x