More flexible mimeType handling in mpd parser.

- Allow the content type of an adaptation set to be inferred
from the mimeTypes of the contained representations.
- Ensure the contained mimeTypes are consistent with one
another, and with the adaptation set.

Ref: Issue #2

library/src/main/java/com/google/android/exoplayer/dash/mpd/MediaPresentationDescriptionParser.java

@@ -18,9 +18,11 @@
 import com.google.android.exoplayer.ParserException;
 import com.google.android.exoplayer.chunk.Format;
 import com.google.android.exoplayer.upstream.DataSpec;
+import com.google.android.exoplayer.util.Assertions;
 import com.google.android.exoplayer.util.MimeTypes;
 
 import android.net.Uri;
+import android.text.TextUtils;
 
 import org.xml.sax.helpers.DefaultHandler;
 import org.xmlpull.v1.XmlPullParser;
@@ -163,43 +165,32 @@ private AdaptationSet parseAdaptationSet(XmlPullParser xpp, String contentId, Ur
       throws XmlPullParserException, IOException {
     Uri baseUrl = parentBaseUrl;
     int id = -1;
-    int contentType = AdaptationSet.TYPE_UNKNOWN;
 
     // TODO: Correctly handle other common attributes and elements. See 23009-1 Table 9.
     String mimeType = xpp.getAttributeValue(null, "mimeType");
-    if (mimeType != null) {
-      if (MimeTypes.isAudio(mimeType)) {
-        contentType = AdaptationSet.TYPE_AUDIO;
-      } else if (MimeTypes.isVideo(mimeType)) {
-        contentType = AdaptationSet.TYPE_VIDEO;
-      } else if (MimeTypes.isText(mimeType)
-          || mimeType.equalsIgnoreCase(MimeTypes.APPLICATION_TTML)) {
-        contentType = AdaptationSet.TYPE_TEXT;
-      }
-    }
+    int contentType = parseAdaptationSetTypeFromMimeType(mimeType);
 
     List<ContentProtection> contentProtections = null;
     List<Representation> representations = new ArrayList<Representation>();
     do {
       xpp.next();
-      if (contentType != AdaptationSet.TYPE_UNKNOWN) {
-        if (isStartTag(xpp, "BaseURL")) {
-          baseUrl = parseBaseUrl(xpp, parentBaseUrl);
-        } else if (isStartTag(xpp, "ContentProtection")) {
-          if (contentProtections == null) {
-            contentProtections = new ArrayList<ContentProtection>();
-          }
-          contentProtections.add(parseContentProtection(xpp));
-        } else if (isStartTag(xpp, "ContentComponent")) {
-          id = Integer.parseInt(xpp.getAttributeValue(null, "id"));
-          String contentTypeString = xpp.getAttributeValue(null, "contentType");
-          contentType = "video".equals(contentTypeString) ? AdaptationSet.TYPE_VIDEO
-              : "audio".equals(contentTypeString) ? AdaptationSet.TYPE_AUDIO
-              : AdaptationSet.TYPE_UNKNOWN;
-        } else if (isStartTag(xpp, "Representation")) {
-          representations.add(parseRepresentation(xpp, contentId, baseUrl, periodStart,
-              periodDuration, mimeType, segmentTimelineList));
+      if (isStartTag(xpp, "BaseURL")) {
+        baseUrl = parseBaseUrl(xpp, parentBaseUrl);
+      } else if (isStartTag(xpp, "ContentProtection")) {
+        if (contentProtections == null) {
+          contentProtections = new ArrayList<ContentProtection>();
         }
+        contentProtections.add(parseContentProtection(xpp));
+      } else if (isStartTag(xpp, "ContentComponent")) {
+        id = Integer.parseInt(xpp.getAttributeValue(null, "id"));
+        contentType = checkAdaptationSetTypeConsistency(contentType,
+            parseAdaptationSetType(xpp.getAttributeValue(null, "contentType")));
+      } else if (isStartTag(xpp, "Representation")) {
+        Representation representation = parseRepresentation(xpp, contentId, baseUrl, periodStart,
+            periodDuration, mimeType, segmentTimelineList);
+        contentType = checkAdaptationSetTypeConsistency(contentType,
+            parseAdaptationSetTypeFromMimeType(representation.format.mimeType));
+        representations.add(representation);
       }
     } while (!isEndTag(xpp, "AdaptationSet"));
 
@@ -360,4 +351,42 @@ private static Uri parseBaseUrl(XmlPullParser xpp, Uri parentBaseUrl)
     }
   }
 
+  private static int parseAdaptationSetType(String contentType) {
+    return TextUtils.isEmpty(contentType) ? AdaptationSet.TYPE_UNKNOWN
+        : MimeTypes.BASE_TYPE_AUDIO.equals(contentType) ? AdaptationSet.TYPE_AUDIO
+        : MimeTypes.BASE_TYPE_VIDEO.equals(contentType) ? AdaptationSet.TYPE_VIDEO
+        : MimeTypes.BASE_TYPE_TEXT.equals(contentType) ? AdaptationSet.TYPE_TEXT
+        : AdaptationSet.TYPE_UNKNOWN;
+  }
+
+  private static int parseAdaptationSetTypeFromMimeType(String mimeType) {
+    return TextUtils.isEmpty(mimeType) ? AdaptationSet.TYPE_UNKNOWN
+        : MimeTypes.isAudio(mimeType) ? AdaptationSet.TYPE_AUDIO
+        : MimeTypes.isVideo(mimeType) ? AdaptationSet.TYPE_VIDEO
+        : MimeTypes.isText(mimeType) || MimeTypes.isTtml(mimeType) ? AdaptationSet.TYPE_TEXT
+        : AdaptationSet.TYPE_UNKNOWN;
+  }
+
+  /**
+   * Checks two adaptation set types for consistency, returning the consistent type, or throwing an
+   * {@link IllegalStateException} if the types are inconsistent.
+   * <p>
+   * Two types are consistent if they are equal, or if one is {@link AdaptationSet#TYPE_UNKNOWN}.
+   * Where one of the types is {@link AdaptationSet#TYPE_UNKNOWN}, the other is returned.
+   *
+   * @param firstType The first type.
+   * @param secondType The second type.
+   * @return The consistent type.
+   */
+  private static int checkAdaptationSetTypeConsistency(int firstType, int secondType) {
+    if (firstType == AdaptationSet.TYPE_UNKNOWN) {
+      return secondType;
+    } else if (secondType == AdaptationSet.TYPE_UNKNOWN) {
+      return firstType;
+    } else {
+      Assertions.checkState(firstType == secondType);
+      return firstType;
+    }
+  }
+
 }

library/src/main/java/com/google/android/exoplayer/util/MimeTypes.java

@@ -20,25 +20,47 @@
  */
 public class MimeTypes {
 
-  public static final String VIDEO_MP4 = "video/mp4";
-  public static final String VIDEO_WEBM = "video/webm";
-  public static final String VIDEO_H264 = "video/avc";
-  public static final String VIDEO_VP9 = "video/x-vnd.on2.vp9";
-  public static final String AUDIO_MP4 = "audio/mp4";
-  public static final String AUDIO_AAC = "audio/mp4a-latm";
-  public static final String TEXT_VTT = "text/vtt";
-  public static final String APPLICATION_TTML = "application/ttml+xml";
+  public static final String BASE_TYPE_VIDEO = "video";
+  public static final String BASE_TYPE_AUDIO = "audio";
+  public static final String BASE_TYPE_TEXT = "text";
+  public static final String BASE_TYPE_APPLICATION = "application";
+
+  public static final String VIDEO_MP4 = BASE_TYPE_VIDEO + "/mp4";
+  public static final String VIDEO_WEBM = BASE_TYPE_VIDEO + "/webm";
+  public static final String VIDEO_H264 = BASE_TYPE_VIDEO + "/avc";
+  public static final String VIDEO_VP9 = BASE_TYPE_VIDEO + "/x-vnd.on2.vp9";
+
+  public static final String AUDIO_MP4 = BASE_TYPE_AUDIO + "/mp4";
+  public static final String AUDIO_AAC = BASE_TYPE_AUDIO + "/mp4a-latm";
+
+  public static final String TEXT_VTT = BASE_TYPE_TEXT + "/vtt";
+
+  public static final String APPLICATION_TTML = BASE_TYPE_APPLICATION + "/ttml+xml";
 
   private MimeTypes() {}
 
+  /**
+   * Returns the top-level type of {@code mimeType}.
+   *
+   * @param mimeType The mimeType whose top-level type is required.
+   * @return The top-level type.
+   */
+  public static String getTopLevelType(String mimeType) {
+    int indexOfSlash = mimeType.indexOf('/');
+    if (indexOfSlash == -1) {
+      throw new IllegalArgumentException("Invalid mime type: " + mimeType);
+    }
+    return mimeType.substring(0, indexOfSlash);
+  }
+
   /**
    * Whether the top-level type of {@code mimeType} is audio.
    *
    * @param mimeType The mimeType to test.
    * @return Whether the top level type is audio.
    */
   public static boolean isAudio(String mimeType) {
-    return mimeType.startsWith("audio/");
+    return getTopLevelType(mimeType).equals(BASE_TYPE_AUDIO);
   }
 
   /**
@@ -48,7 +70,7 @@ public static boolean isAudio(String mimeType) {
    * @return Whether the top level type is video.
    */
   public static boolean isVideo(String mimeType) {
-    return mimeType.startsWith("video/");
+    return getTopLevelType(mimeType).equals(BASE_TYPE_VIDEO);
   }
 
   /**
@@ -58,7 +80,27 @@ public static boolean isVideo(String mimeType) {
    * @return Whether the top level type is text.
    */
   public static boolean isText(String mimeType) {
-    return mimeType.startsWith("text/");
+    return getTopLevelType(mimeType).equals(BASE_TYPE_TEXT);
+  }
+
+  /**
+   * Whether the top-level type of {@code mimeType} is application.
+   *
+   * @param mimeType The mimeType to test.
+   * @return Whether the top level type is application.
+   */
+  public static boolean isApplication(String mimeType) {
+    return getTopLevelType(mimeType).equals(BASE_TYPE_APPLICATION);
+  }
+
+  /**
+   * Whether the mimeType is {@link #APPLICATION_TTML}.
+   *
+   * @param mimeType The mimeType to test.
+   * @return Whether the mimeType is {@link #APPLICATION_TTML}.
+   */
+  public static boolean isTtml(String mimeType) {
+    return mimeType.equals(APPLICATION_TTML);
   }
 
 }