diff --git a/youtube_dl/extractor/__init__.py b/youtube_dl/extractor/__init__.py
index 7d0909b5d..c712b907f 100644
--- a/youtube_dl/extractor/__init__.py
+++ b/youtube_dl/extractor/__init__.py
@@ -386,6 +386,7 @@ from .rutube import (
     RutubePersonIE,
 )
 from .rutv import RUTVIE
+from .sandia import SandiaIE
 from .sapo import SapoIE
 from .savefrom import SaveFromIE
 from .sbs import SBSIE
diff --git a/youtube_dl/extractor/sandia.py b/youtube_dl/extractor/sandia.py
new file mode 100644
index 000000000..9c88167f0
--- /dev/null
+++ b/youtube_dl/extractor/sandia.py
@@ -0,0 +1,117 @@
+# coding: utf-8
+from __future__ import unicode_literals
+
+import itertools
+import json
+import re
+
+from .common import InfoExtractor
+from ..compat import (
+    compat_urllib_request,
+    compat_urlparse,
+)
+from ..utils import (
+    int_or_none,
+    js_to_json,
+    mimetype2ext,
+    unified_strdate,
+)
+
+
+class SandiaIE(InfoExtractor):
+    IE_DESC = 'Sandia National Laboratories'
+    _VALID_URL = r'https?://digitalops\.sandia\.gov/Mediasite/Play/(?P<id>[0-9a-f]+)'
+    _TEST = {
+        'url': 'http://digitalops.sandia.gov/Mediasite/Play/24aace4429fc450fb5b38cdbf424a66e1d',
+        'md5': '9422edc9b9a60151727e4b6d8bef393d',
+        'info_dict': {
+            'id': '24aace4429fc450fb5b38cdbf424a66e1d',
+            'ext': 'mp4',
+            'title': 'Xyce Software Training - Section 1',
+            'description': 're:(?s)SAND Number: SAND 2013-7800.{200,}',
+            'upload_date': '20120904',
+            'duration': 7794,
+        }
+    }
+
+    def _real_extract(self, url):
+        video_id = self._match_id(url)
+
+        req = compat_urllib_request.Request(url)
+        req.add_header('Cookie', 'MediasitePlayerCaps=ClientPlugins=4')
+        webpage = self._download_webpage(req, video_id)
+
+        js_path = self._search_regex(
+            r'<script type="text/javascript" src="(/Mediasite/FileServer/Presentation/[^"]+)"',
+            webpage, 'JS code URL')
+        js_url = compat_urlparse.urljoin(url, js_path)
+
+        js_code = self._download_webpage(
+            js_url, video_id, note='Downloading player')
+
+        def extract_str(key, **args):
+            return self._search_regex(
+                r'Mediasite\.PlaybackManifest\.%s\s*=\s*(.+);\s*?\n' % re.escape(key),
+                js_code, key, **args)
+
+        def extract_data(key, **args):
+            data_json = extract_str(key, **args)
+            if data_json is None:
+                return data_json
+            return self._parse_json(
+                data_json, video_id, transform_source=js_to_json)
+
+        formats = []
+        for i in itertools.count():
+            fd = extract_data('VideoUrls[%d]' % i, default=None)
+            if fd is None:
+                break
+            formats.append({
+                'format_id': '%s' % i,
+                'format_note': fd['MimeType'].partition('/')[2],
+                'ext': mimetype2ext(fd['MimeType']),
+                'url': fd['Location'],
+                'protocol': 'f4m' if fd['MimeType'] == 'video/x-mp4-fragmented' else None,
+            })
+        self._sort_formats(formats)
+
+        slide_baseurl = compat_urlparse.urljoin(
+            url, extract_data('SlideBaseUrl'))
+        slide_template = slide_baseurl + re.sub(
+            r'\{0:D?([0-9+])\}', r'%0\1d', extract_data('SlideImageFileNameTemplate'))
+        slides = []
+        last_slide_time = 0
+        for i in itertools.count(1):
+            sd = extract_str('Slides[%d]' % i, default=None)
+            if sd is None:
+                break
+            timestamp = int_or_none(self._search_regex(
+                r'^Mediasite\.PlaybackManifest\.CreateSlide\("[^"]*"\s*,\s*([0-9]+),',
+                sd, 'slide %s timestamp' % i, fatal=False))
+            slides.append({
+                'url': slide_template % i,
+                'duration': timestamp - last_slide_time,
+            })
+            last_slide_time = timestamp
+        formats.append({
+            'format_id': 'slides',
+            'protocol': 'slideshow',
+            'url': json.dumps(slides),
+            'preference': -10000,  # Downloader not yet written
+        })
+        self._sort_formats(formats)
+
+        title = extract_data('Title')
+        description = extract_data('Description', fatal=False)
+        duration = int_or_none(extract_data(
+            'Duration', fatal=False), scale=1000)
+        upload_date = unified_strdate(extract_data('AirDate', fatal=False))
+
+        return {
+            'id': video_id,
+            'title': title,
+            'description': description,
+            'formats': formats,
+            'upload_date': upload_date,
+            'duration': duration,
+        }
diff --git a/youtube_dl/utils.py b/youtube_dl/utils.py
index 4358137a0..238b6556b 100644
--- a/youtube_dl/utils.py
+++ b/youtube_dl/utils.py
@@ -1616,6 +1616,15 @@ def args_to_str(args):
     return ' '.join(shlex_quote(a) for a in args)
 
 
+def mimetype2ext(mt):
+    _, _, res = mt.rpartition('/')
+
+    return {
+        'x-ms-wmv': 'wmv',
+        'x-mp4-fragmented': 'mp4',
+    }.get(res, res)
+
+
 def urlhandle_detect_ext(url_handle):
     try:
         url_handle.headers
@@ -1631,7 +1640,7 @@ def urlhandle_detect_ext(url_handle):
             if e:
                 return e
 
-    return getheader('Content-Type').split("/")[1]
+    return mimetype2ext(getheader('Content-Type'))
 
 
 def age_restricted(content_limit, age_limit):