@@ -116,6 +116,18 @@ const ff_asf_guid ff_asf_language_guid = {

     0xa9, 0x46, 0x43, 0x7c, 0xe0, 0xef, 0xfc, 0x4b, 0xb2, 0x29, 0x39, 0x3e, 0xde, 0x41, 0x5c, 0x85

 };

+const ff_asf_guid ff_asf_content_encryption = {

+    0xfb, 0xb3, 0x11, 0x22, 0x23, 0xbd, 0xd2, 0x11, 0xb4, 0xb7, 0x00, 0xa0, 0xc9, 0x55, 0xfc, 0x6e

+};

+

+const ff_asf_guid ff_asf_ext_content_encryption = {

+    0x14, 0xe6, 0x8a, 0x29, 0x22, 0x26, 0x17, 0x4c, 0xb9, 0x35, 0xda, 0xe0, 0x7e, 0xe9, 0x28, 0x9c

+};

+

+const ff_asf_guid ff_asf_digital_signature = {

+    0xfc, 0xb3, 0x11, 0x22, 0x23, 0xbd, 0xd2, 0x11, 0xb4, 0xb7, 0x00, 0xa0, 0xc9, 0x55, 0xfc, 0x6e

+};

+

 const AVMetadataConv ff_asf_metadata_conv[] = {

     { "AlbumArtist", "artist"    },

     { "AlbumTitle" , "album"     },

@@ -160,6 +160,9 @@ extern const ff_asf_guid ff_asf_ext_stream_audio_stream;

 extern const ff_asf_guid ff_asf_metadata_header;

 extern const ff_asf_guid ff_asf_my_guid;

 extern const ff_asf_guid ff_asf_language_guid;

+extern const ff_asf_guid ff_asf_content_encryption;

+extern const ff_asf_guid ff_asf_ext_content_encryption;

+extern const ff_asf_guid ff_asf_digital_signature;

 extern const AVMetadataConv ff_asf_metadata_conv[];

@@ -532,6 +532,15 @@ static int asf_read_header(AVFormatContext *s, AVFormatParameters *ap)

         } else if (url_feof(pb)) {

             return -1;

         } else {

+            if (!s->keylen) {

+                if (!guidcmp(&g, &ff_asf_content_encryption)) {

+                    av_log(s, AV_LOG_WARNING, "DRM protected stream detected, decoding will likely fail!\n");

+                } else if (!guidcmp(&g, &ff_asf_ext_content_encryption)) {

+                    av_log(s, AV_LOG_WARNING, "Ext DRM protected stream detected, decoding will likely fail!\n");

+                } else if (!guidcmp(&g, &ff_asf_digital_signature)) {

+                    av_log(s, AV_LOG_WARNING, "Digital signature detected, decoding will likely fail!\n");

+                }

+            }

             url_fseek(pb, gsize - 24, SEEK_CUR);

         }

     }