Add support for the TPOS/TPA (disc number) id3 tag.
diff --git a/include/media/mediametadataretriever.h b/include/media/mediametadataretriever.h
index 113c452..022b849 100644
--- a/include/media/mediametadataretriever.h
+++ b/include/media/mediametadataretriever.h
@@ -54,6 +54,7 @@
     METADATA_KEY_VIDEO_WIDTH     = 20,
     METADATA_KEY_WRITER          = 21,
     METADATA_KEY_MIMETYPE        = 22,
+    METADATA_KEY_DISC_NUMBER     = 23,
     // Add more here...
 };
 
diff --git a/include/media/stagefright/MetaData.h b/include/media/stagefright/MetaData.h
index 3b21468..8f423f7 100644
--- a/include/media/stagefright/MetaData.h
+++ b/include/media/stagefright/MetaData.h
@@ -59,6 +59,7 @@
     kKeyAlbumArtMIME      = 'alAM',  // cstring
     kKeyAuthor            = 'auth',  // cstring
     kKeyCDTrackNumber     = 'cdtr',  // cstring
+    kKeyDiscNumber        = 'dnum',  // cstring
     kKeyDate              = 'date',  // cstring
     kKeyWriter            = 'writ',  // cstring
 };
diff --git a/media/libstagefright/MP3Extractor.cpp b/media/libstagefright/MP3Extractor.cpp
index accd94d..79b7674 100644
--- a/media/libstagefright/MP3Extractor.cpp
+++ b/media/libstagefright/MP3Extractor.cpp
@@ -737,6 +737,7 @@
         { kKeyYear, "TYE", "TYER" },
         { kKeyAuthor, "TXT", "TEXT" },
         { kKeyCDTrackNumber, "TRK", "TRCK" },
+        { kKeyDiscNumber, "TPA", "TPOS" },
     };
     static const size_t kNumMapEntries = sizeof(kMap) / sizeof(kMap[0]);
 
diff --git a/media/libstagefright/StagefrightMediaScanner.cpp b/media/libstagefright/StagefrightMediaScanner.cpp
index 3451383..22f701c 100644
--- a/media/libstagefright/StagefrightMediaScanner.cpp
+++ b/media/libstagefright/StagefrightMediaScanner.cpp
@@ -191,6 +191,7 @@
         };
         static const KeyMap kKeyMap[] = {
             { "tracknumber", METADATA_KEY_CD_TRACK_NUMBER },
+            { "discnumber", METADATA_KEY_DISC_NUMBER },
             { "album", METADATA_KEY_ALBUM },
             { "artist", METADATA_KEY_ARTIST },
             { "composer", METADATA_KEY_COMPOSER },
diff --git a/media/libstagefright/StagefrightMetadataRetriever.cpp b/media/libstagefright/StagefrightMetadataRetriever.cpp
index dfba74f..f617fe8 100644
--- a/media/libstagefright/StagefrightMetadataRetriever.cpp
+++ b/media/libstagefright/StagefrightMetadataRetriever.cpp
@@ -305,6 +305,7 @@
     static const Map kMap[] = {
         { kKeyMIMEType, METADATA_KEY_MIMETYPE },
         { kKeyCDTrackNumber, METADATA_KEY_CD_TRACK_NUMBER },
+        { kKeyDiscNumber, METADATA_KEY_DISC_NUMBER },
         { kKeyAlbum, METADATA_KEY_ALBUM },
         { kKeyArtist, METADATA_KEY_ARTIST },
         { kKeyAuthor, METADATA_KEY_AUTHOR },