diff -up chromium-49.0.2618.8/media/base/mime_util.cc.matroska-avi chromium-49.0.2618.8/media/base/mime_util.cc
--- chromium-49.0.2618.8/media/base/mime_util.cc.matroska-avi	2016-01-09 09:01:29.000000000 +0100
+++ chromium-49.0.2618.8/media/base/mime_util.cc	2016-01-14 22:37:15.949619299 +0100
@@ -46,7 +46,11 @@ class MimeUtil {
     HEVC_MAIN,
     VP8,
     VP9,
-    THEORA
+    THEORA,
+    DTS,
+    MP2,
+    MPEG4_SP,
+    MPEG4_ASP
   };
 
   bool IsSupportedMediaMimeType(const std::string& mime_type) const;
@@ -264,6 +269,8 @@ static const MediaFormat kFormatCodecMap
     {"audio/ogg", COMMON, "opus,vorbis"},
     {"application/ogg", COMMON, "opus,theora,vorbis"},
 #endif
+    { "video/x-matroska", COMMON, "avc1.42E00A,avc1.4D400A,avc1.64000A," "mp4a.66,mp4a.67,mp4a.68,mp4a.69,mp4a.6B,mp4a.40.2,mp4a.40.5" ",opus,vorbis,vp8,vp8.0,vp9,vp9.0,ac-3,ec-3,dts,mp3,mp2" },
+    { "audio/x-matroska", COMMON, "mp4a.66,mp4a.67,mp4a.68,mp4a.69,mp4a.6B,mp4a.40.2,mp4a.40.5" ",opus,vorbis,ac-3,ec-3,dts,mp3,mp2" },
 #if defined(USE_PROPRIETARY_CODECS)
     {"audio/mpeg", PROPRIETARY, "mp3"},
     {"audio/mp3", PROPRIETARY, ""},
@@ -273,6 +280,7 @@ static const MediaFormat kFormatCodecMap
     {"audio/x-m4a", PROPRIETARY, kMP4AudioCodecsExpression},
     {"video/mp4", PROPRIETARY, kMP4VideoCodecsExpression},
     {"video/x-m4v", PROPRIETARY, kMP4VideoCodecsExpression},
+    { "video/x-msvideo", PROPRIETARY, "avc1.42E00A,avc1.4D400A,avc1.64000A," "mp4a.66,mp4a.67,mp4a.68,mp4a.69,mp4a.6B,mp4a.40.2,mp4a.40.5" ",mp4v.20.9,mp4v.20.240,ac-3,ec-3,dts,mp3,mp2"},
 #if BUILDFLAG(ENABLE_MSE_MPEG2TS_STREAM_PARSER)
     {"video/mp2t", PROPRIETARY, kMP4VideoCodecsExpression},
 #endif
@@ -328,7 +336,11 @@ static const CodecIDMappings kUnambiguou
     {"vp8.0", MimeUtil::VP8},
     {"vp9", MimeUtil::VP9},
     {"vp9.0", MimeUtil::VP9},
-    {"theora", MimeUtil::THEORA}};
+    {"theora", MimeUtil::THEORA},
+    {"dts", MimeUtil::DTS},
+    {"mp2", MimeUtil::MP2},
+    {"mp4v.20.9", MimeUtil::MPEG4_SP},
+    {"mp4v.20.240", MimeUtil::MPEG4_ASP}};
 
 // List of codec IDs that are ambiguous and don't provide
 // enough information to determine the codec and profile.
@@ -682,6 +695,9 @@ bool MimeUtil::IsCodecProprietary(Codec
     case H264_MAIN:
     case H264_HIGH:
     case HEVC_MAIN:
+    case DTS:
+    case MPEG4_SP:
+    case MPEG4_ASP:
       return true;
 
     case PCM:
diff -up chromium-49.0.2618.8/net/base/mime_util.cc.matroska-avi chromium-49.0.2618.8/net/base/mime_util.cc
--- chromium-49.0.2618.8/net/base/mime_util.cc.matroska-avi	2016-01-09 09:01:29.000000000 +0100
+++ chromium-49.0.2618.8/net/base/mime_util.cc	2016-01-14 22:40:00.270595513 +0100
@@ -78,6 +78,9 @@ static const MimeInfo kPrimaryMappings[]
     {"audio/webm", "webm"},
     {"audio/wav", "wav"},
     {"audio/flac", "flac"},
+    {"video/x-matroska", "mkv"},
+    {"audio/x-matroska", "mkv"},
+    {"video/x-msvideo", "avi"},
     {"application/xhtml+xml", "xhtml,xht,xhtm"},
     {"application/x-chrome-extension", "crx"},
     {"multipart/related", "mhtml,mht"}};
@@ -425,6 +428,7 @@ static const char* const kStandardAudioT
   "audio/vorbis",
   "audio/wav",
   "audio/webm",
+  "audio/x-matroska",
   "audio/x-m4a",
   "audio/x-ms-wma",
   "audio/vnd.rn-realaudio",
@@ -442,6 +446,7 @@ static const char* const kStandardVideoT
   "video/webm",
   "video/x-dv",
   "video/x-m4v",
+  "video/x-matroska",
   "video/x-mpeg",
   "video/x-ms-asf",
   "video/x-ms-wmv"
--- chromium-49.0.2623.87/media/base/mime_util.cc.bak	2016-03-09 08:16:11.423967976 +0100
+++ chromium-49.0.2623.87/media/base/mime_util.cc	2016-03-21 21:04:40.666507883 +0100
@@ -704,6 +704,7 @@
     case VP8:
     case VP9:
     case THEORA:
+    case MP2:
       return false;
   }