I found an old iPhone screen recording with microphone video but the volume is too low. When I look up a software it’s always paid or asks for a subscription. Anyone knows a free app or software that can increase the sound of a video?
If you are on iPhone, iPad or Mac, you should be able to use iMovie for that.
ffmpeg-normalize for a permanent edit. Can be difficult to setup though. There may be other GUI tools that can do EBU normalize but I haven’t looked as I use cmd line tools mostly.
It might be a bit much, but Davinci Resolve is a top-notch video editor with a fantastic free version that can handle this easily.
i would strongly recommend…DaVinci Resolve.
Are you looking to just play the video louder or actually change the file? You can use VLC media player to boost the volume beyond 100% without altering the file.
you can give fxsounds a try 