diff --git a/copyparty/__main__.py b/copyparty/__main__.py
index 6ff0439a..cec09537 100644
--- a/copyparty/__main__.py
+++ b/copyparty/__main__.py
@@ -437,6 +437,7 @@ def run_argparse(argv, formatter):
     ap2.add_argument("--no-vthumb", action="store_true", help="disable video thumbnails")
     ap2.add_argument("--th-size", metavar="WxH", default="320x256", help="thumbnail res")
     ap2.add_argument("--th-mt", metavar="CORES", type=int, default=cores, help="num cpu cores to use for generating thumbnails")
+    ap2.add_argument("--th-convt", metavar="SEC", type=int, default=60, help="conversion timeout in seconds")
     ap2.add_argument("--th-no-crop", action="store_true", help="dynamic height; show full image")
     ap2.add_argument("--th-no-jpg", action="store_true", help="disable jpg output")
     ap2.add_argument("--th-no-webp", action="store_true", help="disable webp output")
diff --git a/copyparty/mtag.py b/copyparty/mtag.py
index 9d86b14f..a4099197 100644
--- a/copyparty/mtag.py
+++ b/copyparty/mtag.py
@@ -8,7 +8,7 @@ import shutil
 import subprocess as sp
 
 from .__init__ import PY2, WINDOWS, unicode
-from .util import fsenc, fsdec, uncyg, REKOBO_LKEY
+from .util import fsenc, fsdec, uncyg, runcmd, REKOBO_LKEY
 from .bos import bos
 
 
@@ -73,7 +73,7 @@ class MParser(object):
             raise Exception()
 
 
-def ffprobe(abspath):
+def ffprobe(abspath, timeout=10):
     cmd = [
         b"ffprobe",
         b"-hide_banner",
@@ -82,10 +82,8 @@ def ffprobe(abspath):
         b"--",
         fsenc(abspath),
     ]
-    p = sp.Popen(cmd, stdout=sp.PIPE, stderr=sp.PIPE)
-    r = p.communicate()
-    txt = r[0].decode("utf-8", "replace")
-    return parse_ffprobe(txt)
+    rc = runcmd(cmd, timeout=timeout)
+    return parse_ffprobe(rc[1])
 
 
 def parse_ffprobe(txt):
diff --git a/copyparty/th_srv.py b/copyparty/th_srv.py
index af926ef2..4b5a34f2 100644
--- a/copyparty/th_srv.py
+++ b/copyparty/th_srv.py
@@ -349,7 +349,7 @@ class ThumbSrv(object):
 
     def _run_ff(self, cmd):
         # self.log((b" ".join(cmd)).decode("utf-8"))
-        ret, sout, serr = runcmd(cmd)
+        ret, sout, serr = runcmd(cmd, timeout=self.args.th_convt)
         if ret != 0:
             m = "FFmpeg failed (probably a corrupt video file):\n"
             m += "\n".join(["ff: {}".format(x) for x in serr.split("\n")])
diff --git a/copyparty/util.py b/copyparty/util.py
index ceec44cb..8d9a2951 100644
--- a/copyparty/util.py
+++ b/copyparty/util.py
@@ -1324,9 +1324,17 @@ def guess_mime(url, fallback="application/octet-stream"):
     return ret
 
 
-def runcmd(argv):
+def runcmd(argv, timeout=None):
     p = sp.Popen(argv, stdout=sp.PIPE, stderr=sp.PIPE)
-    stdout, stderr = p.communicate()
+    if not timeout or PY2:
+        stdout, stderr = p.communicate()
+    else:
+        try:
+            stdout, stderr = p.communicate(timeout=timeout)
+        except sp.TimeoutExpired:
+            p.kill()
+            stdout, stderr = p.communicate()
+
     stdout = stdout.decode("utf-8", "replace")
     stderr = stderr.decode("utf-8", "replace")
     return [p.returncode, stdout, stderr]