diff --git i/r128gain/__init__.py w/r128gain/__init__.py
index 53fc3ef..f144e15 100755
--- i/r128gain/__init__.py
+++ w/r128gain/__init__.py
@@ -78,7 +78,7 @@ def get_ffmpeg_lib_versions(ffmpeg_path=None):
   Example: 0x3040100 for FFmpeg 3.4.1
   """
   r = collections.OrderedDict()
-  cmd = (ffmpeg_path or "ffmpeg", "-version")
+  cmd = (ffmpeg_path or "@ffmpeg@/bin/ffmpeg", "-version")
   output = subprocess.run(cmd,
                           check=True,
                           stdout=subprocess.PIPE,
@@ -156,7 +156,7 @@ def get_r128_loudness(audio_filepaths, *, calc_peak=True, enable_ffmpeg_threadin
                                      os.devnull,
                                      **additional_ffmpeg_args,
                                      f="null"),
-                       cmd=ffmpeg_path or "ffmpeg")
+                       cmd=ffmpeg_path or "@ffmpeg@/bin/ffmpeg")
 
   # run
   logger().debug(cmd_to_string(cmd))
@@ -740,7 +740,7 @@ def cl_main():
                           help="Maximum number of tracks to scan in parallel. If not specified, autodetect CPU count")
   arg_parser.add_argument("-f",
                           "--ffmpeg-path",
-                          default=shutil.which("ffmpeg"),
+                          default="@ffmpeg@/bin/ffmpeg",
                           help="""Full file path of ffmpeg executable (only needed if not in PATH).
                                   If not specified, autodetect""")
   arg_parser.add_argument("-d",