Improve DASH manifest parsing.

- Parse all attributes that may exist in either the AdaptationSet or
  in the child Representation elements at both levels.
- Correctly infer TYPE_TEXT for Representation elements whose mimeType
  is application/mp4 and whose codecs attribute indicates a known text
  codec type.

Issue: #689

demo/src/main/java/com/google/android/exoplayer/demo/player/DashRendererBuilder.java

@@ -272,7 +272,7 @@ public class DashRendererBuilder implements RendererBuilder {
         List<String> codecs = new ArrayList<>();
         for (int i = 0; i < audioRepresentations.size(); i++) {
           Format format = audioRepresentations.get(i).format;
-          audioTrackNameList.add(format.id + " (" + format.numChannels + "ch, " +
+          audioTrackNameList.add(format.id + " (" + format.audioChannels + "ch, " +
               format.audioSamplingRate + "Hz)");
           audioChunkSourceList.add(new DashChunkSource(manifestFetcher, audioAdaptationSetIndex,
               new int[] {i}, audioDataSource, audioEvaluator, LIVE_EDGE_LATENCY_MS,

library/src/main/java/com/google/android/exoplayer/chunk/Format.java

@@ -69,7 +69,7 @@ public class Format {
   /**
    * The number of audio channels, or -1 if unknown or not applicable.
    */
-  public final int numChannels;
+  public final int audioChannels;
 
   /**
    * The audio sampling rate in Hz, or -1 if unknown or not applicable.
@@ -131,20 +131,20 @@ public class Format {
    * @param height The height of the video in pixels, or -1 if unknown or not applicable.
    * @param frameRate The frame rate of the video in frames per second, or -1 if unknown or not
    *     applicable.
-   * @param numChannels The number of audio channels, or -1 if unknown or not applicable.
+   * @param audioChannels The number of audio channels, or -1 if unknown or not applicable.
    * @param audioSamplingRate The audio sampling rate in Hz, or -1 if unknown or not applicable.
    * @param bitrate The average bandwidth of the format in bits per second.
    * @param language The language of the format.
    * @param codecs The codecs used to decode the format.
    */
-  public Format(String id, String mimeType, int width, int height, float frameRate, int numChannels,
-      int audioSamplingRate, int bitrate, String language, String codecs) {
+  public Format(String id, String mimeType, int width, int height, float frameRate,
+      int audioChannels, int audioSamplingRate, int bitrate, String language, String codecs) {
     this.id = Assertions.checkNotNull(id);
     this.mimeType = mimeType;
     this.width = width;
     this.height = height;
     this.frameRate = frameRate;
-    this.numChannels = numChannels;
+    this.audioChannels = audioChannels;
     this.audioSamplingRate = audioSamplingRate;
     this.bitrate = bitrate;
     this.language = language;

library/src/main/java/com/google/android/exoplayer/smoothstreaming/SmoothStreamingChunkSource.java

@@ -392,10 +392,10 @@ public class SmoothStreamingChunkSource implements ChunkSource {
         csd = Arrays.asList(trackElement.csd);
       } else {
         csd = Collections.singletonList(CodecSpecificDataUtil.buildAacAudioSpecificConfig(
-            trackFormat.audioSamplingRate, trackFormat.numChannels));
+            trackFormat.audioSamplingRate, trackFormat.audioChannels));
       }
       MediaFormat format = MediaFormat.createAudioFormat(mimeType, MediaFormat.NO_VALUE,
-          trackFormat.numChannels, trackFormat.audioSamplingRate, csd);
+          trackFormat.audioChannels, trackFormat.audioSamplingRate, csd);
       return format;
     } else if (streamElement.type == StreamElement.TYPE_TEXT) {
       return MediaFormat.createTextFormat(trackFormat.mimeType, trackFormat.language);

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

@@ -50,6 +50,7 @@ public final class MimeTypes {
 
   public static final String TEXT_VTT = BASE_TYPE_TEXT + "/vtt";
 
+  public static final String APPLICATION_MP4 = BASE_TYPE_APPLICATION + "/mp4";
   public static final String APPLICATION_ID3 = BASE_TYPE_APPLICATION + "/id3";
   public static final String APPLICATION_EIA608 = BASE_TYPE_APPLICATION + "/eia-608";
   public static final String APPLICATION_SUBRIP = BASE_TYPE_APPLICATION + "/x-subrip";
@@ -113,14 +114,4 @@ public final class MimeTypes {
     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);
-  }
-
 }