FFmpeg's loudnorm filter can be used. Basic syntax is
ffmpeg -i in.mp4 -c:v copy -af loudnorm=I=-23:LRA=1 -ar 48000 out.mp4
The loudness range (LRA) should be 2 x max deviation.
Also see the ebur128 filter for measuring loudness.
Yes. You can use FFmpeg, a free command-line tool, like so:
ffmpeg -i video.wmv -c:v copy -af dynaudnorm out.wmv
dynaudnorm is a dynamic audio normalizer, which will maintain the original range dynamics and avoid clipping while applying the maximum gain possible given those constraints.
In general loudness correction is a two step process. (There's a little more to it for full EBU R128 compliance, but I work exclusively in the US and this all that is required for A/85 / CALM Act compliance.)
Measure the long term/infinite loudness of the asset.
Shift the level of the asset by the difference between the measured loudness and the target.
This is a copy and paste from a similar previous question which I answered:
In order to even out the audio of a single stream; you will want to either mix by hand as noted above; or you can use dynamics; specifically Compression.
Within the PPro audio mixer, apply dynamics to the audio tracks, or master track.
You can then use the compressor within the ...
Audition has a couple of tools that lets you measure loudness. There's the Amplitude Analysis window that lets you scan a whole mix or sound file, and tells you the LUFS loudness (which is the same as LKFS, aparently):
There's also the "Loudness Radar" that has a sexy GUI, but seems to only scan in real time (though I might be using it wrong).
If you use ...
I'm not sure about leveling the audio automatically. You could probably find an effect that does this, after all audio normalisation is a pretty common feature even in audio players, let alone editors. However, I doubt that it would give the exact result you want and given that you are using Premiere Pro, you will probably want more flexibility and manual ...