Sometimes recorded video, screecasts etc have a low volume, if you want to increase the volume without getting into too much complication, you can simply use ffmpeg for the same.
The command:
ffmpeg -i foo.mp4 -filter:a "volume=5.0" foo-high-volumet.mp4
Here:
ffmpeg is the command
-i assigns input file i.e. foo.mp4
-filter: for audio filter
volume-x used to specify the volume
Lastly the file name to which the output is to be stored.
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