Check language/role flags before merging adaptation sets

The spec technically allows to mark adaptation sets with the switching
property if they allow seamless switching with non-overlapping
segments. This is typically only used for compatible content (e.g.
different codecs), but the spec allows it to be used for other
content as well (e.g. different languages, roles). ExoPlayer's concept
of a TrackGroup only allows formats with the same language and role
flags to be merged, so we should check that before merging.

Issue: androidx/media#2222

#cherrypick

PiperOrigin-RevId: 736564055

RELEASENOTES.md

@@ -51,6 +51,9 @@
 *   RTMP extension:
 *   HLS extension:
 *   DASH extension:
+    *   Fix issue where adaptation sets marked with `adaptation-set-switching`
+        but different languages or role flags are merged together
+        ([#2222](https://github.com/androidx/media/issues/2222)).
 *   Smooth Streaming extension:
 *   RTSP extension:
 *   Decoder extensions (FFmpeg, VP9, AV1, etc.):

libraries/exoplayer_dash/src/main/java/androidx/media3/exoplayer/dash/DashMediaPeriod.java

@@ -72,6 +72,7 @@ import java.util.Arrays;
 import java.util.HashMap;
 import java.util.IdentityHashMap;
 import java.util.List;
+import java.util.Objects;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -624,7 +625,9 @@ import java.util.regex.Pattern;
             @Nullable
             Integer otherAdaptationSetIndex =
                 adaptationSetIdToIndex.get(Long.parseLong(adaptationSetId));
-            if (otherAdaptationSetIndex != null) {
+            if (otherAdaptationSetIndex != null
+                && canMergeAdaptationSets(
+                    adaptationSet, adaptationSets.get(otherAdaptationSetIndex))) {
               mergedGroupIndex = min(mergedGroupIndex, otherAdaptationSetIndex);
             }
           }
@@ -650,6 +653,20 @@ import java.util.regex.Pattern;
     return groupedAdaptationSetIndices;
   }
 
+  private static boolean canMergeAdaptationSets(
+      AdaptationSet adaptationSet1, AdaptationSet adaptationSet2) {
+    if (adaptationSet1.type != adaptationSet2.type) {
+      return false;
+    }
+    if (adaptationSet1.representations.isEmpty() || adaptationSet2.representations.isEmpty()) {
+      return true;
+    }
+    Format format1 = adaptationSet1.representations.get(0).format;
+    Format format2 = adaptationSet2.representations.get(0).format;
+    return Objects.equals(format1.language, format2.language)
+        && format1.roleFlags == format2.roleFlags;
+  }
+
   /**
    * Iterates through list of primary track groups and identifies embedded tracks.
    *

libraries/exoplayer_dash/src/test/java/androidx/media3/exoplayer/dash/DashMediaPeriodTest.java

@@ -94,6 +94,31 @@ public final class DashMediaPeriodTest {
     MediaPeriodAsserts.assertTrackGroups(dashMediaPeriod, expectedTrackGroups);
   }
 
+  @Test
+  public void
+      adaptationSetSwitchingProperty_withIncompatibleFormats_mergesOnlyCompatibleTrackGroups()
+          throws IOException {
+    DashManifest manifest = parseManifest("media/mpd/sample_mpd_switching_property_incompatible");
+    DashMediaPeriod dashMediaPeriod = createDashMediaPeriod(manifest, /* periodIndex= */ 0);
+    List<AdaptationSet> adaptationSets = manifest.getPeriod(0).adaptationSets;
+
+    // Only the two matching pairs of adaptation sets should be merged.
+    TrackGroupArray expectedTrackGroups =
+        new TrackGroupArray(
+            new TrackGroup(/* id= */ "0", adaptationSets.get(0).representations.get(0).format),
+            new TrackGroup(
+                /* id= */ "1",
+                adaptationSets.get(1).representations.get(0).format,
+                adaptationSets.get(3).representations.get(0).format),
+            new TrackGroup(
+                /* id= */ "2",
+                adaptationSets.get(2).representations.get(0).format,
+                adaptationSets.get(4).representations.get(0).format),
+            new TrackGroup(/* id= */ "5", adaptationSets.get(5).representations.get(0).format));
+
+    MediaPeriodAsserts.assertTrackGroups(dashMediaPeriod, expectedTrackGroups);
+  }
+
   @Test
   public void trickPlayProperty_mergesTrackGroups() throws IOException {
     DashManifest manifest = parseManifest("media/mpd/sample_mpd_trick_play_property");

libraries/test_data/src/test/assets/media/mpd/sample_mpd_switching_property_incompatible

@@ -0,0 +1,42 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<MPD availabilityStartTime="2014-06-19T23:07:42" type="dynamic">
+    <Period start="PT7462826.784S" id="0">
+        <AdaptationSet id="0" lang="fr" contentType="video">
+            <Role schemeIdUri="urn:mpeg:DASH:role:2011" value="commentary"/>
+            <SupplementalProperty
+                schemeIdUri="urn:mpeg:dash:adaptation-set-switching:2016"
+                value="1,2,3,4,5"/>
+            <Representation id="0"/>
+        </AdaptationSet>
+        <AdaptationSet id="1" lang="fr" contentType="video">
+            <SupplementalProperty
+                schemeIdUri="urn:mpeg:dash:adaptation-set-switching:2016"
+                value="0,2,3,4,5"/>
+            <Representation id="1"/>
+            </AdaptationSet>
+        <AdaptationSet id="2" lang="en" contentType="video">
+            <SupplementalProperty
+                schemeIdUri="urn:mpeg:dash:adaptation-set-switching:2016"
+                value="0,1,3,4,5"/>
+            <Representation id="2"/>
+        </AdaptationSet>
+        <AdaptationSet id="3" lang="fr" contentType="video">
+            <SupplementalProperty
+                schemeIdUri="urn:mpeg:dash:adaptation-set-switching:2016"
+                value="0,1,2,4,5"/>
+            <Representation id="3"/>
+        </AdaptationSet>
+        <AdaptationSet id="4" lang="en" contentType="video">
+            <SupplementalProperty
+                schemeIdUri="urn:mpeg:dash:adaptation-set-switching:2016"
+                value="0,1,2,3,5"/>
+            <Representation id="4"/>
+        </AdaptationSet>
+        <AdaptationSet id="5" lang="en" contentType="audio">
+            <SupplementalProperty
+                schemeIdUri="urn:mpeg:dash:adaptation-set-switching:2016"
+                value="0,1,2,3,4"/>
+            <Representation id="4"/>
+        </AdaptationSet>
+    </Period>
+</MPD>