I'm moving some videos across the screen with a color matte background behind them. All of a sudden since I upgraded Premiere 2 days ago it doesn't see the background when I render and it only gives me black. I can see the background in the timeline when I play it. I tried exporting from Media Encoder and from Premiere. The only way I found to fix it is take it into AE and drop a background behind the project file in the timeline. Then it renders perfectly. What happened?
OK figured it out. It's a bug. If I bring the footage up in the effects control panel for some reason (Speed) is checked on, like I'm adding keyframes to it. If I check it off and render out of Premiere all is good. If I save it and try to re-render out of Premiere or the Media Encoder it defaults back to having (Speed) checked on and the alpha channel is not reading, so no background. Therefore my frustration button is checked to ON too!