I recently tried to share a video over Zoom using the Zoom built in video sharing feature from a Windows 10 PC. I received a message saying unsupported video format. After some searching I found that the following command using the FFmpeg package created a new file that did work.
ffmpeg -i input.mov -preset slow -codec:a aac -b:a 128k -codec:v libx264 -pix_fmt yuv420p -b:v 4500k -minrate 4500k -maxrate 9000k -bufsize 9000k -vf scale=-1:1080 -filter:a "volume=1.5" output.mp4
I know very little about video file formats or about the FFmpeg package so I'm afraid I can't explain the parameters, except for -filter:a "volume=1.5" which increased the audio volume.