On 28.06.2017 01:11, Russell Coker via luv-main wrote:
Is there a way of balancing loudness of different mp4 files? While it's impossible to do this perfectly (there is no general agreement on how to measure it) it is possible to give a good approximation.
My music video collection that I downloaded from youtube has videos of significantly different loudness, so when I watch a selection of videos that suit my mood with mplayer I have to change the system volume every few videos because I get to one that's either too loud or too quiet for the current settings.
I'd like to run a script across my video collection to get the average loudness of each video so the mplayer softvol setting can be adjusted to compensate. Then of course I'd do some manual adjustment like increasing the volume of The Divinyls and The Angels.
Vorbisgain sort of does this for ogg files (from the man page)..... Vorbisgain calculates the ReplayGain values for the named Ogg Vorbis input files and writesback the result in the form of tags (comments) in the file. These values can be used by a play-back program to maintain a uniform sound level during play. (See http://www.replaygain.org/ Not very many players support this though, I put this up as it may give any one interested a starting point for further work as it clearly has already been considered an issue. For any music I download, I convert it to an ogg file with Audacity but first use Effect>Amplify to normalise the gain, in order to get a reasonably close range of loudness. I use Audacity rather than one of the converter programs particularly for its Amplify command. Lindsay