diff --git a/imageio_ffmpeg/_definitions.py b/imageio_ffmpeg/_definitions.py
index 578971a..c9ea900 100644
--- a/imageio_ffmpeg/_definitions.py
+++ b/imageio_ffmpeg/_definitions.py
@@ -1,25 +1,27 @@
 import platform
 import struct
-import sys
 
 __version__ = "0.5.0"
 
 
 def get_platform():
     bits = struct.calcsize("P") * 8
-    if sys.platform.startswith("linux"):
+    if platform.system().lower().startswith("linux"):
         architecture = platform.machine()
         if architecture == "aarch64":
             return "linuxaarch64"
         return "linux{}".format(bits)
-    elif sys.platform.startswith("freebsd"):
+    elif platform.system().lower().startswith("freebsd"):
         return "freebsd{}".format(bits)
-    elif sys.platform.startswith("win"):
+    elif platform.system().lower().startswith("win"):
         return "win{}".format(bits)
-    elif sys.platform.startswith("cygwin"):
+    elif platform.system().lower().startswith("cygwin"):
         return "win{}".format(bits)
-    elif sys.platform.startswith("darwin"):
-        return "osx{}".format(bits)
+    elif platform.system().lower().startswith("darwin"):
+        if platform.processor().lower().startswith("arm"):  # Apple Silicon
+            return "osx-arm{}".format(bits)
+        else:
+            return "osx-{}".format(bits)
     else:  # pragma: no cover
         return None
 
@@ -34,7 +36,8 @@ def get_platform():
 
 # Platform string -> ffmpeg filename
 FNAME_PER_PLATFORM = {
-    "osx64": "ffmpeg-osx64-v4.2.2",  # 10.10+
+    "osx-arm64": "ffmpeg-osx-arm64-v7.0", # Apple Silicon
+    "osx64": "ffmpeg-osx-x86-v7.0",  # 10.9+
     "win32": "ffmpeg-win32-v4.2.2.exe",  # Windows 7+
     "win64": "ffmpeg-win64-v4.2.2.exe",
     # "linux32": "ffmpeg-linux32-v4.2.2",
@@ -42,13 +45,15 @@ def get_platform():
     "linuxaarch64": "ffmpeg-linuxaarch64-v4.2.2",
 }
 
-osxplats = "macosx_10_9_intel.macosx_10_9_x86_64.macosx_10_10_intel.macosx_10_10_x86_64"
+osxplats = "macosx_10_9_intel.macosx_10_9_x86_64"
+osxarmplats = "macosx_11_0_arm64"
 
 # Wheel tag -> platform string
 WHEEL_BUILDS = {
     "py3-none-manylinux2010_x86_64": "linux64",
     "py3-none-manylinux2014_aarch64": "linuxaarch64",
-    "py3-none-" + osxplats: "osx64",
+    "py3-none-" + osxplats: "osx64",  # Apple Intel
+    "py3-none-" + osxarmplats: "osx-arm64",  # Apple Silicon
     "py3-none-win32": "win32",
     "py3-none-win_amd64": "win64",
 }