Feature request: Add "Set background color" feature for video with alpha

Feature description: A checkbox either in the Video section or Effects section of Media Encoder labeled "Render Background Color". Checking the box would enable a color selector where the user could specify a background color to render. Any video with alpha would be rendered with the specified background color instead of transparent (for output formats that support alpha channels). For output formats that don;t support alpha (like h264), the background color would be used instead of the default black that Media Encoder renders in place of transparency.

This mostly refers to my workflow in After Effects, but I could see it being a helpful feature if I had to do similar things coming from Premiere.

I have clients who need video with alpha for final delivery, but they need to preview submittals in h264. The stakeholders don't have video players that can render the alpha correctly - anyting that isn't 100% transparent will be rendered solid. For example, if something is supposed to fade in, it is displayed as 100% opacity as soon as it has any opacity at all, so things pop on and off, they don't fade. I have recommended other players but they will not change.

So I always need to deliver two files for review - one for the editors, which has alpha, and one h264 for the other stakeholders.

Media Encoder will encode the h264 versions with a black background, but the clent doesn't always want a black background - depending on the content, they would like different colors in the background for review. (They send me design templates with multiple compositions. I don't create the original templates for these clients.)

I could add solids as the bottom layer in each comp in AE and render from ME with those layers turned on, and then again with them turned off, but the projects I work on have dozens of comps I ned to render. I have to go into each of them, turn on the background layers, set a new color for them if needed, then set up a a second render for each one. It's a lot of time and a lot of extra clicking.

It would save me and my clients a ton of time if there was a simple checkbox in Media Encoder to "Render background color" with a color selector to choose the color. It could then be saved in a preset. Then I could render all my submittals both ways in a single ME job just by using a couple presets, rather than having to click into each comp, enable the background, change it if they need a different color, then send the comp to ME.

I don't know how hard it would be to add such a thing, but Media Encoder already knows to use black for output formats that don't support alpha.