Add support for KEYFORMAT and SAMPLE-AES (only parsing, not decryption)

Also add sample streams that use METHOD=SAMPLE-AES. Note that some of
the streams provide alternative EXT-X-KEY's. Support for alternative
decryption methods will be added in a later CL.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=166048858

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

@@ -306,7 +306,8 @@ import java.util.List;
     out.chunk = new HlsMediaChunk(mediaDataSource, dataSpec, initDataSpec, selectedUrl,
         muxedCaptionFormats, trackSelection.getSelectionReason(), trackSelection.getSelectionData(),
         startTimeUs, startTimeUs + segment.durationUs, chunkMediaSequence, discontinuitySequence,
-        isTimestampMaster, timestampAdjuster, previous, encryptionKey, encryptionIv);
+        isTimestampMaster, timestampAdjuster, previous, segment.keyFormat, encryptionKey,
+        encryptionIv);
   }
 
   /**

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

@@ -32,6 +32,7 @@ import com.google.android.exoplayer2.metadata.id3.Id3Decoder;
 import com.google.android.exoplayer2.metadata.id3.PrivFrame;
 import com.google.android.exoplayer2.source.chunk.MediaChunk;
 import com.google.android.exoplayer2.source.hls.playlist.HlsMasterPlaylist.HlsUrl;
+import com.google.android.exoplayer2.source.hls.playlist.HlsMediaPlaylist;
 import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.DataSpec;
 import com.google.android.exoplayer2.util.MimeTypes;
@@ -116,16 +117,19 @@ import java.util.concurrent.atomic.AtomicInteger;
    * @param isMasterTimestampSource True if the chunk can initialize the timestamp adjuster.
    * @param timestampAdjuster Adjuster corresponding to the provided discontinuity sequence number.
    * @param previousChunk The {@link HlsMediaChunk} that preceded this one. May be null.
-   * @param encryptionKey For AES encryption chunks, the encryption key.
-   * @param encryptionIv For AES encryption chunks, the encryption initialization vector.
+   * @param keyFormat A string describing the format for {@code keyData}, or null if the chunk is
+   *     not encrypted.
+   * @param keyData Data specifying how to obtain the keys to decrypt the chunk, or null if the
+   *     chunk is not encrypted.
+   * @param encryptionIv The AES initialization vector, or null if the chunk is not encrypted.
    */
   public HlsMediaChunk(DataSource dataSource, DataSpec dataSpec, DataSpec initDataSpec,
       HlsUrl hlsUrl, List<Format> muxedCaptionFormats, int trackSelectionReason,
       Object trackSelectionData, long startTimeUs, long endTimeUs, int chunkIndex,
       int discontinuitySequenceNumber, boolean isMasterTimestampSource,
-      TimestampAdjuster timestampAdjuster, HlsMediaChunk previousChunk, byte[] encryptionKey,
-      byte[] encryptionIv) {
-    super(buildDataSource(dataSource, encryptionKey, encryptionIv), dataSpec, hlsUrl.format,
+      TimestampAdjuster timestampAdjuster, HlsMediaChunk previousChunk, String keyFormat,
+      byte[] keyData, byte[] encryptionIv) {
+    super(buildDataSource(dataSource, keyFormat, keyData, encryptionIv), dataSpec, hlsUrl.format,
         trackSelectionReason, trackSelectionData, startTimeUs, endTimeUs, chunkIndex);
     this.discontinuitySequenceNumber = discontinuitySequenceNumber;
     this.initDataSpec = initDataSpec;
@@ -327,15 +331,16 @@ import java.util.concurrent.atomic.AtomicInteger;
   // Internal factory methods.
 
   /**
-   * If the content is encrypted, returns an {@link Aes128DataSource} that wraps the original in
-   * order to decrypt the loaded data. Else returns the original.
+   * If the content is encrypted using the "identity" key format, returns an
+   * {@link Aes128DataSource} that wraps the original in order to decrypt the loaded data. Else
+   * returns the original.
    */
-  private static DataSource buildDataSource(DataSource dataSource, byte[] encryptionKey,
+  private static DataSource buildDataSource(DataSource dataSource, String keyFormat, byte[] keyData,
       byte[] encryptionIv) {
-    if (encryptionKey == null || encryptionIv == null) {
-      return dataSource;
+    if (HlsMediaPlaylist.KEYFORMAT_IDENTITY.equals(keyFormat)) {
+      return new Aes128DataSource(dataSource, keyData, encryptionIv);
     }
-    return new Aes128DataSource(dataSource, encryptionKey, encryptionIv);
+    return dataSource;
   }
 
   private Extractor createExtractor() {

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

@@ -53,6 +53,10 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
      * Whether the segment is encrypted, as defined by #EXT-X-KEY.
      */
     public final boolean isEncrypted;
+    /**
+     * The key format as defined by #EXT-X-KEY, or null if the segment is not encrypted.
+     */
+    public final String keyFormat;
     /**
      * The encryption key uri as defined by #EXT-X-KEY, or null if the segment is not encrypted.
      */
@@ -73,7 +77,7 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
     public final long byterangeLength;
 
     public Segment(String uri, long byterangeOffset, long byterangeLength) {
-      this(uri, 0, -1, C.TIME_UNSET, false, null, null, byterangeOffset, byterangeLength);
+      this(uri, 0, -1, C.TIME_UNSET, false, null, null, null, byterangeOffset, byterangeLength);
     }
 
     /**
@@ -82,19 +86,21 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
      * @param relativeDiscontinuitySequence See {@link #relativeDiscontinuitySequence}.
      * @param relativeStartTimeUs See {@link #relativeStartTimeUs}.
      * @param isEncrypted See {@link #isEncrypted}.
+     * @param keyFormat See {@link #keyFormat}.
      * @param encryptionKeyUri See {@link #encryptionKeyUri}.
      * @param encryptionIV See {@link #encryptionIV}.
      * @param byterangeOffset See {@link #byterangeOffset}.
      * @param byterangeLength See {@link #byterangeLength}.
      */
     public Segment(String url, long durationUs, int relativeDiscontinuitySequence,
-        long relativeStartTimeUs, boolean isEncrypted, String encryptionKeyUri, String encryptionIV,
-        long byterangeOffset, long byterangeLength) {
+        long relativeStartTimeUs, boolean isEncrypted, String keyFormat, String encryptionKeyUri,
+        String encryptionIV, long byterangeOffset, long byterangeLength) {
       this.url = url;
       this.durationUs = durationUs;
       this.relativeDiscontinuitySequence = relativeDiscontinuitySequence;
       this.relativeStartTimeUs = relativeStartTimeUs;
       this.isEncrypted = isEncrypted;
+      this.keyFormat = keyFormat;
       this.encryptionKeyUri = encryptionKeyUri;
       this.encryptionIV = encryptionIV;
       this.byterangeOffset = byterangeOffset;
@@ -110,7 +116,12 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
   }
 
   /**
-   * Type of the playlist as defined by #EXT-X-PLAYLIST-TYPE.
+   * The identity key format, as defined by #EXT-X-KEY.
+   */
+  public static final String KEYFORMAT_IDENTITY = "identity";
+
+  /**
+   * Type of the playlist, as defined by #EXT-X-PLAYLIST-TYPE.
    */
   @Retention(RetentionPolicy.SOURCE)
   @IntDef({PLAYLIST_TYPE_UNKNOWN, PLAYLIST_TYPE_VOD, PLAYLIST_TYPE_EVENT})

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

@@ -69,7 +69,8 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
   private static final String TYPE_CLOSED_CAPTIONS = "CLOSED-CAPTIONS";
 
   private static final String METHOD_NONE = "NONE";
-  private static final String METHOD_AES128 = "AES-128";
+  private static final String METHOD_AES_128 = "AES-128";
+  private static final String METHOD_SAMPLE_AES = "SAMPLE-AES";
 
   private static final String BOOLEAN_TRUE = "YES";
   private static final String BOOLEAN_FALSE = "NO";
@@ -97,7 +98,8 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
   private static final Pattern REGEX_ATTR_BYTERANGE =
       Pattern.compile("BYTERANGE=\"(\\d+(?:@\\d+)?)\\b\"");
   private static final Pattern REGEX_METHOD = Pattern.compile("METHOD=(" + METHOD_NONE + "|"
-      + METHOD_AES128 + ")");
+      + METHOD_AES_128 + "|" + METHOD_SAMPLE_AES + ")");
+  private static final Pattern REGEX_KEYFORMAT = Pattern.compile("KEYFORMAT=\"(.+?)\"");
   private static final Pattern REGEX_URI = Pattern.compile("URI=\"(.+?)\"");
   private static final Pattern REGEX_IV = Pattern.compile("IV=([^,.*]+)");
   private static final Pattern REGEX_TYPE = Pattern.compile("TYPE=(" + TYPE_AUDIO + "|" + TYPE_VIDEO
@@ -314,6 +316,7 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
     int segmentMediaSequence = 0;
 
     boolean isEncrypted = false;
+    String keyFormat = null;
     String encryptionKeyUri = null;
     String encryptionIV = null;
 
@@ -360,11 +363,16 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
             (long) (parseDoubleAttr(line, REGEX_MEDIA_DURATION) * C.MICROS_PER_SECOND);
       } else if (line.startsWith(TAG_KEY)) {
         String method = parseStringAttr(line, REGEX_METHOD);
-        isEncrypted = METHOD_AES128.equals(method);
+        isEncrypted = METHOD_AES_128.equals(method) || METHOD_SAMPLE_AES.equals(method);
         if (isEncrypted) {
+          keyFormat = parseOptionalStringAttr(line, REGEX_KEYFORMAT);
+          if (keyFormat == null) {
+            keyFormat = HlsMediaPlaylist.KEYFORMAT_IDENTITY;
+          }
           encryptionKeyUri = parseStringAttr(line, REGEX_URI);
           encryptionIV = parseOptionalStringAttr(line, REGEX_IV);
         } else {
+          keyFormat = null;
           encryptionKeyUri = null;
           encryptionIV = null;
         }
@@ -400,7 +408,7 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
           segmentByteRangeOffset = 0;
         }
         segments.add(new Segment(line, segmentDurationUs, relativeDiscontinuitySequence,
-            segmentStartTimeUs, isEncrypted, encryptionKeyUri, segmentEncryptionIV,
+            segmentStartTimeUs, isEncrypted, keyFormat, encryptionKeyUri, segmentEncryptionIV,
             segmentByteRangeOffset, segmentByteRangeLength));
         segmentStartTimeUs += segmentDurationUs;
         segmentDurationUs = 0;