diff --git a/gallery_dl/postprocessor/ugoira.py b/gallery_dl/postprocessor/ugoira.py
new file mode 100644
index 00000000..ac8f5343
--- /dev/null
+++ b/gallery_dl/postprocessor/ugoira.py
@@ -0,0 +1,60 @@
+# -*- coding: utf-8 -*-
+
+# Copyright 2018 Mike Fährmann
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 as
+# published by the Free Software Foundation.
+
+"""Convert pixiv ugoira to webm"""
+
+from .common import PostProcessor
+import subprocess
+import tempfile
+import zipfile
+
+
+class UgoiraPP(PostProcessor):
+
+    def __init__(self, pathfmt, options):
+        PostProcessor.__init__(self)
+
+    def run(self, pathfmt):
+        if pathfmt.keywords["extension"] != "txt":
+            return
+
+        framelist = []
+
+        # get frames and their durations
+        with pathfmt.open("r") as file:
+            for line in file:
+                name, _, duration = line.partition(" ")
+                framelist.append((name, int(duration.rstrip())))
+            # list the last frame twice to prevent it from only being
+            # displayed for a very short time
+            framelist.append((name, int(duration.rstrip())))
+
+        with tempfile.TemporaryDirectory() as tempdir:
+            # extract frames
+            pathfmt.set_extension("zip")
+            with zipfile.ZipFile(pathfmt.realpath) as zfile:
+                zfile.extractall(tempdir)
+
+            # write ffconcat file
+            ffconcat = tempdir + "/ffconcat.txt"
+            with open(ffconcat, "w") as file:
+                file.write("ffconcat version 1.0\n")
+                for name, duration in framelist:
+                    file.write("file '{}'\n".format(name))
+                    file.write("duration {}\n".format(duration / 1000))
+
+            # invoke ffmpeg
+            pathfmt.set_extension("webm")
+            args = ["ffmpeg", "-i", ffconcat, pathfmt.realpath]
+            subprocess.Popen(args).wait()
+
+        # mark framelist file for deletion
+        pathfmt.delete = True
+
+
+__postprocessor__ = UgoiraPP