Short version

Do not directly output MP4 or other video formats.

Output the PNG sequence and compose it through Blender, Davinci Resolve, Adobe AfterEffect or Adobe Premiere Pro.

Long version

Setting

• Set a directory where you want to output sequence frames.
• Output .PNG for file format
  • Decide if you need a transparent channel(RGB/RGBA)
• If you want compositing, you can output the EXR format.
  • The corresponding channel must be opened to store information

Render

When you're done with the setup, you can start rendering.

Next, go to the folder you set up and you can see that each frame is rendered.

Composite frames(using Blender)

Start a new Blender, set the new project with the video editing template.

Open the selection panel by press Add > Image/Sequence

Select the sequence from top to bottom.

Before exporting, you can make any other effects you want in Blender.

You need to make sure 0001.png comes first.

Output MP4/Webm

By default, you can output MP4 normally, please make sure your project Settings are the same as the original project.

You are free to change the format of the output.

Then, once again, render the animation.

That's all, have fun.