It uses the same technique as our Auto Volume. However, movies are easier because they typically only do 1 default audio track and people already do it when they upload the movie (google ReplayGain). For karaoke, there isn't much people out there that deals with it (except Asians maybe?) so I have to write my own tool to do it for both audio tracks.

I think the audio analysis uses the rms value to determine the volume level. If a song has more soft than loud, I wonder it the loud portions get distorted or clipped. Will try..

Starting with build 33, the volume.data file will come built-in with TKaraokeUSB so you don't have to download it and put it on your hard drive. This file will be up-to-date on each new build that comes out. To add additional volume data or overwrite the built-in data, you can put the JSON file inside the "Volume Data" folder.

You can always adjust the device volume using the up/down key. Pre-amp volume is even before the device volume in the pipeline and currently the user can’t adjust. I thought about letting that user override the preamp volume but didn’t want to make the GUI more complex/confusing.

BTW, if you encounter a song that you don’t like the adjusted volume, I’m curious which song is it because the adjusted volume is well within the safety margin so the chance that it will clip if virtually zero. There are logic in the Auto Volume to prevent gains over a threshold so unless the song is a speech with 80% silent and 20% talking really loud, it shouldn’t be a problem. The assumption is what you are playing is a song of some kind, not a speech

Up to 2 audio tracks. If your song has more than 2, track 3, track 4, etc. will play w/ their default volume.