Q:

use ffmpeg to create Zoom virtual background video

Using ffmpeg, I created a video from a list of PNG images to use as a Zoom virtual background. However, when I try to upload it to Zoom, it says "Unsupported format. Please upload a different file." Here is the command that I used:
ffmpeg -framerate 1 -i img%04d.png output.mp4 

I get the same error if I try to output a .mov file. Am I missing some option in the ffmpeg command?

A:

PNGs store pixel color data as RGB values. Videos store color data as YUV. However, when converting an RGB input, ffmpeg chooses a YUV format which is incompatible with most players (it does this to preserve full signal fidelity). The user has to set a compatible pixel format with a reduced chroma resolution. Also, framerate 1 isn't compatible by some players, so duplicate frames to increase output framerate.
ffmpeg -framerate 1 -i img%04d.png -r 5 -pix_fmt yuv420p output.mp4 

