Support multiple EXT-X-MAP tags

Issue:#4182

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=194223312

RELEASENOTES.md

@@ -77,6 +77,8 @@
     ([#4145](https://github.com/google/ExoPlayer/issues/4145)).
   * Preeptively declare an ID3 track in chunkless preparation
     ([#4016](https://github.com/google/ExoPlayer/issues/4016)).
+  * Add support for multiple #EXT-X-MAP tags in a media playlist
+    ([#4164](https://github.com/google/ExoPlayer/issues/4182)).
 * Fix ClearKey decryption error if the key contains a forward slash
   ([#4075](https://github.com/google/ExoPlayer/issues/4075)).
 * Fix crash when switching surface on Huawei P9 Lite

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsChunkSource.java

@@ -320,7 +320,7 @@ import java.util.List;
     }
 
     DataSpec initDataSpec = null;
-    Segment initSegment = mediaPlaylist.initializationSegment;
+    Segment initSegment = segment.initializationSegment;
     if (initSegment != null) {
       Uri initSegmentUri = UriUtil.resolveToUri(mediaPlaylist.baseUri, initSegment.url);
       initDataSpec = new DataSpec(initSegmentUri, initSegment.byterangeOffset,

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/offline/HlsDownloader.java

@@ -94,14 +94,16 @@ public final class HlsDownloader extends SegmentDownloader<HlsMasterPlaylist, Re
         continue;
       }
 
-      HlsMediaPlaylist.Segment initSegment = mediaPlaylist.initializationSegment;
-      if (initSegment != null) {
-        addSegment(segments, mediaPlaylist, initSegment, encryptionKeyUris);
-      }
-
+      HlsMediaPlaylist.Segment lastInitSegment = null;
       List<HlsMediaPlaylist.Segment> hlsSegments = mediaPlaylist.segments;
       for (int i = 0; i < hlsSegments.size(); i++) {
-        addSegment(segments, mediaPlaylist, hlsSegments.get(i), encryptionKeyUris);
+        HlsMediaPlaylist.Segment segment = hlsSegments.get(i);
+        HlsMediaPlaylist.Segment initSegment = segment.initializationSegment;
+        if (initSegment != null && initSegment != lastInitSegment) {
+          lastInitSegment = initSegment;
+          addSegment(segments, mediaPlaylist, initSegment, encryptionKeyUris);
+        }
+        addSegment(segments, mediaPlaylist, segment, encryptionKeyUris);
       }
     }
     return segments;

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/HlsMediaPlaylist.java

@@ -17,6 +17,7 @@ package com.google.android.exoplayer2.source.hls.playlist;
 
 import android.support.annotation.IntDef;
 import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.drm.DrmInitData;
 import java.lang.annotation.Retention;
@@ -38,8 +39,12 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
      */
     public final String url;
     /**
-     * The duration of the segment in microseconds, as defined by #EXTINF.
+     * The media initialization section for this segment, as defined by #EXT-X-MAP. May be null if
+     * the media playlist does not define a media section for this segment. The same instance is
+     * used for all segments that share an EXT-X-MAP tag.
      */
+    @Nullable public final Segment initializationSegment;
+    /** The duration of the segment in microseconds, as defined by #EXTINF. */
     public final long durationUs;
     /**
      * The number of #EXT-X-DISCONTINUITY tags in the playlist before the segment.
@@ -78,11 +83,12 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
      * @param byterangeLength See {@link #byterangeLength}.
      */
     public Segment(String uri, long byterangeOffset, long byterangeLength) {
-      this(uri, 0, -1, C.TIME_UNSET, null, null, byterangeOffset, byterangeLength, false);
+      this(uri, null, 0, -1, C.TIME_UNSET, null, null, byterangeOffset, byterangeLength, false);
     }
 
     /**
      * @param url See {@link #url}.
+     * @param initializationSegment See {@link #initializationSegment}.
      * @param durationUs See {@link #durationUs}.
      * @param relativeDiscontinuitySequence See {@link #relativeDiscontinuitySequence}.
      * @param relativeStartTimeUs See {@link #relativeStartTimeUs}.
@@ -94,6 +100,7 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
      */
     public Segment(
         String url,
+        Segment initializationSegment,
         long durationUs,
         int relativeDiscontinuitySequence,
         long relativeStartTimeUs,
@@ -103,6 +110,7 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
         long byterangeLength,
         boolean hasGapTag) {
       this.url = url;
+      this.initializationSegment = initializationSegment;
       this.durationUs = durationUs;
       this.relativeDiscontinuitySequence = relativeDiscontinuitySequence;
       this.relativeStartTimeUs = relativeStartTimeUs;
@@ -183,10 +191,6 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
    */
   public final DrmInitData drmInitData;
   /**
-   * The initialization segment, as defined by #EXT-X-MAP.
-   */
-  public final Segment initializationSegment;
-  /**
    * The list of segments in the playlist.
    */
   public final List<Segment> segments;
@@ -210,7 +214,6 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
    * @param hasEndTag See {@link #hasEndTag}.
    * @param hasProgramDateTime See {@link #hasProgramDateTime}.
    * @param drmInitData See {@link #drmInitData}.
-   * @param initializationSegment See {@link #initializationSegment}.
    * @param segments See {@link #segments}.
    */
   public HlsMediaPlaylist(
@@ -228,7 +231,6 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
       boolean hasEndTag,
       boolean hasProgramDateTime,
       DrmInitData drmInitData,
-      Segment initializationSegment,
       List<Segment> segments) {
     super(baseUri, tags);
     this.playlistType = playlistType;
@@ -242,7 +244,6 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
     this.hasEndTag = hasEndTag;
     this.hasProgramDateTime = hasProgramDateTime;
     this.drmInitData = drmInitData;
-    this.initializationSegment = initializationSegment;
     this.segments = Collections.unmodifiableList(segments);
     if (!segments.isEmpty()) {
       Segment last = segments.get(segments.size() - 1);
@@ -296,9 +297,22 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
    * @return The playlist.
    */
   public HlsMediaPlaylist copyWith(long startTimeUs, int discontinuitySequence) {
-    return new HlsMediaPlaylist(playlistType, baseUri, tags, startOffsetUs, startTimeUs, true,
-        discontinuitySequence, mediaSequence, version, targetDurationUs, hasIndependentSegmentsTag,
-        hasEndTag, hasProgramDateTime, drmInitData, initializationSegment, segments);
+    return new HlsMediaPlaylist(
+        playlistType,
+        baseUri,
+        tags,
+        startOffsetUs,
+        startTimeUs,
+        /* hasDiscontinuitySequence= */ true,
+        discontinuitySequence,
+        mediaSequence,
+        version,
+        targetDurationUs,
+        hasIndependentSegmentsTag,
+        hasEndTag,
+        hasProgramDateTime,
+        drmInitData,
+        segments);
   }
 
   /**
@@ -311,9 +325,21 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
     if (this.hasEndTag) {
       return this;
     }
-    return new HlsMediaPlaylist(playlistType, baseUri, tags, startOffsetUs, startTimeUs,
-        hasDiscontinuitySequence, discontinuitySequence, mediaSequence, version, targetDurationUs,
-        hasIndependentSegmentsTag, true, hasProgramDateTime, drmInitData, initializationSegment,
+    return new HlsMediaPlaylist(
+        playlistType,
+        baseUri,
+        tags,
+        startOffsetUs,
+        startTimeUs,
+        hasDiscontinuitySequence,
+        discontinuitySequence,
+        mediaSequence,
+        version,
+        targetDurationUs,
+        hasIndependentSegmentsTag,
+        /* hasEndTag= */ true,
+        hasProgramDateTime,
+        drmInitData,
         segments);
   }
 

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/HlsPlaylistParser.java

@@ -474,6 +474,7 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
         segments.add(
             new Segment(
                 line,
+                initializationSegment,
                 segmentDurationUs,
                 relativeDiscontinuitySequence,
                 segmentStartTimeUs,
@@ -491,10 +492,22 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
         hasGapTag = false;
       }
     }
-    return new HlsMediaPlaylist(playlistType, baseUri, tags, startOffsetUs, playlistStartTimeUs,
-        hasDiscontinuitySequence, playlistDiscontinuitySequence, mediaSequence, version,
-        targetDurationUs, hasIndependentSegmentsTag, hasEndTag, playlistStartTimeUs != 0,
-        drmInitData, initializationSegment, segments);
+    return new HlsMediaPlaylist(
+        playlistType,
+        baseUri,
+        tags,
+        startOffsetUs,
+        playlistStartTimeUs,
+        hasDiscontinuitySequence,
+        playlistDiscontinuitySequence,
+        mediaSequence,
+        version,
+        targetDurationUs,
+        hasIndependentSegmentsTag,
+        hasEndTag,
+        /* hasProgramDateTime= */ playlistStartTimeUs != 0,
+        drmInitData,
+        segments);
   }
 
   private static SchemeData parseWidevineSchemeData(String line, String keyFormat)

library/hls/src/test/java/com/google/android/exoplayer2/source/hls/playlist/HlsMediaPlaylistParserTest.java

@@ -247,4 +247,35 @@ public class HlsMediaPlaylistParserTest {
     assertThat(playlist.segments.get(2).hasGapTag).isTrue();
     assertThat(playlist.segments.get(3).hasGapTag).isFalse();
   }
+
+  @Test
+  public void testMapTag() throws IOException {
+    Uri playlistUri = Uri.parse("https://example.com/test3.m3u8");
+    String playlistString =
+        "#EXTM3U\n"
+            + "#EXT-X-VERSION:3\n"
+            + "#EXT-X-TARGETDURATION:5\n"
+            + "#EXT-X-MEDIA-SEQUENCE:10\n"
+            + "#EXTINF:5.005,\n"
+            + "02/00/27.ts\n"
+            + "#EXT-X-MAP:URI=\"init1.ts\""
+            + "#EXTINF:5.005,\n"
+            + "02/00/32.ts\n"
+            + "#EXTINF:5.005,\n"
+            + "02/00/42.ts\n"
+            + "#EXT-X-MAP:URI=\"init2.ts\""
+            + "#EXTINF:5.005,\n"
+            + "02/00/47.ts\n";
+    InputStream inputStream =
+        new ByteArrayInputStream(playlistString.getBytes(Charset.forName(C.UTF8_NAME)));
+    HlsMediaPlaylist playlist =
+        (HlsMediaPlaylist) new HlsPlaylistParser().parse(playlistUri, inputStream);
+
+    List<Segment> segments = playlist.segments;
+    assertThat(segments.get(0).initializationSegment).isNull();
+    assertThat(segments.get(1).initializationSegment)
+        .isSameAs(segments.get(2).initializationSegment);
+    assertThat(segments.get(1).initializationSegment.url).isEqualTo("init1.ts");
+    assertThat(segments.get(3).initializationSegment.url).isEqualTo("init2.ts");
+  }
 }