Today a colleague sent me a screen-capture tutorial on using a new system. Unfortunately their microphone was way too quiet for me to hear anything so I needed to find a way to boost the audio level of the video without wanting to reduce the quality of the video.
Using ffmpeg we can re-encode just the audio to increase/decrease the audio level without re-encoding the video, which means that we won't lose video quality, and the process will be really quick. Here are the commands to do so:
Increase Audio Level
ffmpeg -i [input file] \ -vcodec copy -af "volume=10dB" \ [output file]
Decrease Audio Level
Exactly the same as before, just use a
ffmpeg -i [input file] \ -vcodec copy -af "volume=-10dB" \ [output file]