WinLoud

You can also use the Command Line version "WinLoudCLI".
It is distributed in the same package.

Here is the manual for the CLI:

>WinLoudCLI.exe -h
Win(-dows) Loud(-norm ffmpeg filter) Command Line Interface
version 1.0.0.0 CC-NC-BY Muxson.com 2016 <muxson@g******>
Usage: WinLoudCLI [Options] Infile Outfile
Supported input filetype: aac, aiff, flac, m4a, mp2, mp3, mp4, ogg, wav, wma
Supported output filetypes: mp3, wav
Filetype is specified by the extension of Outfile
The defalut process is 1 Pass. Optionally, the 2 Pass process can be switched on
Even SMARTer: let the program decide if a 2nd pass is needed
Dependency: ffmpeg.exe with libebur128 (which is standard since Oct 2016)
has to be found in the same folder as WinLoudCLI.exe
Options: (can appear in any order)
-h Print this help
-Lk <Lk> Integrated Loudness in LUFS (Default: -16)
-TP <TP> Max True Peaks in dBTP (Default: -1.5)
-LRA <LRA> Loudness Range in LU (Default: 8)
-FREQ <freq> Sample Frequency in Hz (Default: 44100)
<freq>: 32k, 44100, 48k
If not specified: as original
-CBR <bitrate> Constant Bit Rate in bps (Default: 128k)
<bitrate>: 32k, 64k, 96k, 128k, 192k, 256k
-mono Force mono encoding (Default: as original)
-SMART 2nd Pass only if needed (Default: 1 Pass)
2nd pass if target_offset > 1LU, output_lra > LRA or output_tp > TP
-2P 2 Passes in any case. Overrides -SMART (Default: 1 Pass)
-OW Overwrite Outfile if already exists (Default: Generates unique filename)