[YouTube] Extract xtags of formats

Extracts the `xtags` field, which encodes additional data of the format, such
as if the format is using dynamic range compression.
This is required for using SABR.

Author: FineFindus

extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/ItagItem.java

@@ -269,6 +269,7 @@ public MediaFormat getMediaFormat() {
     private Locale audioLocale;
     private boolean isDrc;
     private long lastModified;
+    private String xtags;
 
     public int getBitrate() {
         return bitrate;
@@ -701,4 +702,26 @@ public void setLastModified(final long lastModified) {
         this.lastModified = lastModified;
     }
 
+    /**
+     * Extra tags about the stream.
+     *
+     * <p>
+     * Contains a Base64 encoded protobuf key-value list of additional tags for the stream,
+     * such as whether the stream is using {@link #isDrc()}.
+     * </p>
+     *
+     * @return Base64-encoded extra tags.
+     */
+    public String getXtags() {
+        return xtags;
+    }
+
+    /**
+     * Sets extra tags of the stream.
+     *
+     * @param xtags extra tags of the stream
+     */
+    public void setXtags(final String xtags) {
+        this.xtags = xtags;
+    }
 }

extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/extractors/YoutubeStreamExtractor.java

@@ -1423,6 +1423,7 @@ private ItagInfo buildAndAddItagInfoToList(
         itagItem.setCodec(codec);
         itagItem.setIsDrc(formatData.getBoolean("isDrc", false));
         itagItem.setLastModified(Long.parseLong(formatData.getString("lastModified", "-1")));
+        itagItem.setXtags(formatData.getString("xtags"));
 
         if (streamType == StreamType.LIVE_STREAM || streamType == StreamType.POST_LIVE_STREAM) {
             itagItem.setTargetDurationSec(formatData.getInt("targetDurationSec"));