Support RFC4566 SDP attribute.

Issue: #9430

The current supported SDP (RFC2327) spec only allows for alpha-numeric
characters in the attribute-field. RFC4566 (section 9, token type) allowed
extra characters, and this CL adds the support.

PiperOrigin-RevId: 397301173

RELEASENOTES.md

@@ -116,6 +116,8 @@
         ([#9416](https://github.com/google/ExoPlayer/issues/9416)).
     *   Fix RTSP WWW-Authenticate header parsing
         ([#9428](https://github.com/google/ExoPlayer/issues/9428)).
+    *   Support RFC4566 SDP attribute field grammar
+        ([#9430](https://github.com/google/ExoPlayer/issues/9430)).
 *   Extractors:
     *   ID3: Fix issue decoding ID3 tags containing UTF-16 encoded strings
         ([#9087](https://github.com/google/ExoPlayer/issues/9087)).

library/rtsp/src/main/java/com/google/android/exoplayer2/source/rtsp/SessionDescriptionParser.java

@@ -34,8 +34,11 @@ import java.util.regex.Pattern;
   // under the given tag follows an optional space.
   private static final Pattern SDP_LINE_PATTERN = Pattern.compile("([a-z])=\\s?(.+)");
   // Matches an attribute line (with a= sdp tag removed. Example: range:npt=0-50.0).
-  // Attribute can also be a flag, i.e. without a value, like recvonly.
-  private static final Pattern ATTRIBUTE_PATTERN = Pattern.compile("([0-9A-Za-z-]+)(?::(.*))?");
+  // Attribute can also be a flag, i.e. without a value, like recvonly. Reference RFC4566 Section 9
+  // Page 43, under "token-char".
+  private static final Pattern ATTRIBUTE_PATTERN =
+      Pattern.compile(
+          "([\\x21\\x23-\\x27\\x2a\\x2b\\x2d\\x2e\\x30-\\x39\\x41-\\x5a\\x5e-\\x7e]+)(?::(.*))?");
   // SDP media description line: <mediaType> <port> <transmissionProtocol> <rtpPayloadType>
   // For instance: audio 0 RTP/AVP 97
   private static final Pattern MEDIA_DESCRIPTION_PATTERN =

library/rtsp/src/test/java/com/google/android/exoplayer2/source/rtsp/SessionDescriptionTest.java

@@ -170,6 +170,24 @@ public class SessionDescriptionTest {
         .containsEntry(ATTR_CONTROL, "audio");
   }
 
+  @Test
+  public void parse_sdpStringWithSpecialAttributeField_succeeds() throws Exception {
+    String testMediaSdpInfo =
+        "v=0\r\n"
+            + "o=MNobody 2890844526 2890842807 IN IP4 192.0.2.46\r\n"
+            + "s=SDP Seminar\r\n"
+            + "t=0 0\r\n"
+            + "i=A Seminar on the session description protocol\r\n"
+            + "m=audio 3456 RTP/AVP 0\r\n"
+            + "a=rtpmap:97 AC3/44100\r\n"
+            + "a=A!#$%&'*+-.^_`{|}~:special\r\n";
+
+    SessionDescription sessionDescription = SessionDescriptionParser.parse(testMediaSdpInfo);
+
+    assertThat(sessionDescription.mediaDescriptionList.get(0).attributes)
+        .containsEntry("A!#$%&'*+-.^_`{|}~", "special");
+  }
+
   @Test
   public void parse_sdpStringWithDuplicatedSessionAttribute_recordsTheMostRecentValue()
       throws Exception {