If you upload a video without an audio file, it will not get processed. For the video to get processed, you need to add a dummy silent audio track. To add a dummy silent audio track to a video you can follow the below steps:

  1. Download ffmpeg software from https://www.ffmpeg.org/download.html depending on the OS (Operating System) you are using.
  2. Install the ffmpeg software.
  3. Use this command to add silent track: 

ffmpeg -i input.mp4 -f lavfi -i anullsrc -c:v copy -c:a aac -shortest output.mp4

Wherein,
input.mp4->This is input file without audio track in .mp4 format.
output.mp4->This is output file containing silent audio track in .mp4 format.

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