Most videos on YouTube are loud enough and I can hear them perfectly well, but some have got the volume down too low even with the YouTube volume slider on max and the PC volume set to maximum too. In theory it must be possible to increase the volume, but does such software actually exist?
If you have VLC player, you don't have to download the video. Just open VLC → File → Open Network, paste the YouTube URL and click Open. Doing this will stream the YouTube video through VLC, allowing you to use the VLC audio settings.
Presumably flash is accessing you audio at the driver level so the only change you could make would be there i.e. using a driver that lets you route the audio through processing (It might be worth looking into this http://jackaudio.org/ I'm not sure this will do do the job).
I use this bookmarklet:
Apparently, YouTube videos are normalized, so the video volume is not 1.0, it ranges from 0.4 to 0.7 on some videos.
I explained this here
protected by Community♦ Dec 1 '15 at 7:58
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