No transparency exporting with AE or ME

[maev_]

I've spent the better half of the day trying export a file with transparency. Please help!

Preparing the file for export

• I've toggled on AE's Transparency Grid to see the checkered background.
• I've also changed the composition's background color within Composition Settings to be a magenta color, just to make sure it's not exporting the background. 

Export

• After adding to Render Queue, I select 'RGB + Alpha' and 'ProRes 4444' (also tried 'Animation'), but the exported file always shows a solid black background and no transparency. I also noticed that AE doesn't preserve the 'RGB + Alpha' channel setting (when looking at the settings after the finalized export in Render Queue) unless I select the Color to be 'Straight (Unmatted).'
• Adding to Media Encoder, I do the same process, essentially: I choose 'Quicktime' and then 'Apple ProRes 4444 with alpha'
• Usually, I deselect 'Export Audio', sometimes I select 'Match Source' and/or 'Use Maximum Render Quality' or none of those. It always shows the file in Finder or Quicktime with a jet black background.

I thought for a while that Finder was just not showing the transparency, but when in the browser it shows the black background, too. Am I doing anything wrong? Is there some sort of bug? I've tried over and over and over.

The images show the corner of the doc, which is the rounded corner of an iphone img with the back background. I've tried the process with other animation files that contain a lot more transparency and they are all still exported with the black background...

[maev_]

I forgot to mention—

• I've tried the Output Module as 'Lossless with alpha,' but that shows the composition background (magenta, in this case).

Also, I understand that most media players will show the transparency as black, but Finder has always rendered the transparent background, so thought for a while that Finder was just not showing the transparency, but when in the browser it shows the black background, too. 

I've also taken the exported files a step further using both FFmpeg and Shutter Encoder to convert to WebM (since they both allow Alpha). And after making sure to enable the alpha layer on the file conversion, opening them in various browsers, the black background is still present.

[Rick Gerard]

If you use the High Quality with Transparency Output Module template or accurately set up your own template, Finder and media players will show the transparency as black for most codecs. Some codecs will display the Composition Background color, but that is rare. Unless you are an expert at video formats and compression, please use the Output Module (or even Media Encoder) presets to avoid fouling things up.

The only way to check transparency accurately is to import the rendered movie into Premiere Pro, After Effects, Davinci, or another Video Editing or Video Effects program and see if transparency exists. You cannot rely on Finder or Windows Explorer previews or media players. They are not reliable. 

[maev_]

Thanks for your response.