Add support for static RTP payload types.

Some RTP foramts are statically assigned, so they don't have the rtpmap
attribute. Create the missing rtpmap attribute in this case.

PiperOrigin-RevId: 448239724

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

@@ -20,7 +20,6 @@ import static com.google.android.exoplayer2.source.rtsp.RtspMessageUtil.parseInt
 import static com.google.android.exoplayer2.source.rtsp.SessionDescription.ATTR_FMTP;
 import static com.google.android.exoplayer2.source.rtsp.SessionDescription.ATTR_RTPMAP;
 import static com.google.android.exoplayer2.util.Assertions.checkArgument;
-import static com.google.android.exoplayer2.util.Assertions.checkState;
 import static com.google.android.exoplayer2.util.Util.castNonNull;
 
 import androidx.annotation.Nullable;
@@ -103,6 +102,17 @@ import java.util.HashMap;
 
   /** Builder class for {@link MediaDescription}. */
   public static final class Builder {
+
+    /**
+     * RTPMAP attribute format: {@code <payloadType> <mediaEncoding>/<clockRate>/<channelCount>}.
+     */
+    private static final String RTP_MAP_ATTR_AUDIO_FMT = "%d %s/%d/%d";
+
+    private static final int RTP_STATIC_PAYLOAD_TYPE_PCMU = 0;
+    private static final int RTP_STATIC_PAYLOAD_TYPE_PCMA = 8;
+    private static final int RTP_STATIC_PAYLOAD_TYPE_L16_STEREO = 10;
+    private static final int RTP_STATIC_PAYLOAD_TYPE_L16_MONO = 11;
+
     private final String mediaType;
     private final int port;
     private final String transportProtocol;
@@ -197,15 +207,55 @@ import java.util.HashMap;
      */
     public MediaDescription build() {
       try {
-        // rtpmap attribute is mandatory in RTSP (RFC2326 Section C.1.3).
-        checkState(attributes.containsKey(ATTR_RTPMAP));
         RtpMapAttribute rtpMapAttribute =
-            RtpMapAttribute.parse(castNonNull(attributes.get(ATTR_RTPMAP)));
+            attributes.containsKey(ATTR_RTPMAP)
+                ? RtpMapAttribute.parse(castNonNull(attributes.get(ATTR_RTPMAP)))
+                : RtpMapAttribute.parse(getRtpMapStringByPayloadType(payloadType));
         return new MediaDescription(this, ImmutableMap.copyOf(attributes), rtpMapAttribute);
       } catch (ParserException e) {
         throw new IllegalStateException(e);
       }
     }
+
+    private static String getRtpMapStringByPayloadType(int rtpPayloadType) {
+      checkArgument(rtpPayloadType < 96);
+
+      switch (rtpPayloadType) {
+          // See RFC3551 Section 6.
+        case RTP_STATIC_PAYLOAD_TYPE_PCMU:
+          return constructAudioRtpMap(
+              RTP_STATIC_PAYLOAD_TYPE_PCMU,
+              /* mediaEncoding= */ "PCMU",
+              /* clockRate= */ 8_000,
+              /* channelCount= */ 1);
+        case RTP_STATIC_PAYLOAD_TYPE_PCMA:
+          return constructAudioRtpMap(
+              RTP_STATIC_PAYLOAD_TYPE_PCMA,
+              /* mediaEncoding= */ "PCMA",
+              /* clockRate= */ 8_000,
+              /* channelCount= */ 1);
+        case RTP_STATIC_PAYLOAD_TYPE_L16_STEREO:
+          return constructAudioRtpMap(
+              RTP_STATIC_PAYLOAD_TYPE_L16_STEREO,
+              /* mediaEncoding= */ "L16",
+              /* clockRate= */ 44_100,
+              /* channelCount= */ 2);
+        case RTP_STATIC_PAYLOAD_TYPE_L16_MONO:
+          return constructAudioRtpMap(
+              RTP_STATIC_PAYLOAD_TYPE_L16_MONO,
+              /* mediaEncoding= */ "L16",
+              /* clockRate= */ 44_100,
+              /* channelCount= */ 1);
+        default:
+          throw new IllegalStateException("Unsupported static paylod type " + rtpPayloadType);
+      }
+    }
+
+    private static String constructAudioRtpMap(
+        int payloadType, String mediaEncoding, int clockRate, int channelCount) {
+      return Util.formatInvariant(
+          RTP_MAP_ATTR_AUDIO_FMT, payloadType, mediaEncoding, clockRate, channelCount);
+    }
   }
 
   /** The media types allowed in a SDP media description. */

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

@@ -26,6 +26,7 @@ import static org.junit.Assert.assertThrows;
 
 import android.net.Uri;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
+import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.audio.AacUtil;
 import com.google.android.exoplayer2.util.MimeTypes;
@@ -80,6 +81,132 @@ public class RtspMediaTrackTest {
     assertThat(format).isEqualTo(expectedFormat);
   }
 
+  @Test
+  public void generatePayloadFormat_withPcmuMediaDescription_succeeds() {
+
+    MediaDescription mediaDescription =
+        new MediaDescription.Builder(
+                MEDIA_TYPE_AUDIO, /* port= */ 0, RTP_AVP_PROFILE, /* payloadType= */ 0)
+            .setConnection("IN IP4 0.0.0.0")
+            .addAttribute(ATTR_CONTROL, "track2")
+            .build();
+
+    RtpPayloadFormat format = RtspMediaTrack.generatePayloadFormat(mediaDescription);
+    RtpPayloadFormat expectedFormat =
+        new RtpPayloadFormat(
+            new Format.Builder()
+                .setSampleMimeType(MimeTypes.AUDIO_MLAW)
+                .setChannelCount(1)
+                .setSampleRate(8_000)
+                .build(),
+            /* rtpPayloadType= */ 0,
+            /* clockRate= */ 8_000,
+            /* fmtpParameters= */ ImmutableMap.of());
+
+    assertThat(format).isEqualTo(expectedFormat);
+  }
+
+  @Test
+  public void generatePayloadFormat_withPcmaMediaDescription_succeeds() {
+    // m=audio 0 RTP/AVP 0
+    // c=IN IP4 0.0.0.0
+    // a=control:track2
+    int pcmaPayloadType = 8;
+    int pcmaClockRate = 8_000;
+
+    MediaDescription mediaDescription =
+        new MediaDescription.Builder(
+                MEDIA_TYPE_AUDIO,
+                /* port= */ 0,
+                RTP_AVP_PROFILE,
+                /* payloadType= */ pcmaPayloadType)
+            .setConnection("IN IP4 0.0.0.0")
+            .addAttribute(ATTR_CONTROL, "track2")
+            .build();
+
+    RtpPayloadFormat format = RtspMediaTrack.generatePayloadFormat(mediaDescription);
+    RtpPayloadFormat expectedFormat =
+        new RtpPayloadFormat(
+            new Format.Builder()
+                .setSampleMimeType(MimeTypes.AUDIO_ALAW)
+                .setChannelCount(1)
+                .setSampleRate(pcmaClockRate)
+                .build(),
+            /* rtpPayloadType= */ pcmaPayloadType,
+            /* clockRate= */ pcmaClockRate,
+            /* fmtpParameters= */ ImmutableMap.of());
+
+    assertThat(format).isEqualTo(expectedFormat);
+  }
+
+  @Test
+  public void generatePayloadFormat_withL16StereoMediaDescription_succeeds() {
+    // m=audio 0 RTP/AVP 0
+    // c=IN IP4 0.0.0.0
+    // a=control:track2
+    int l16StereoPayloadType = 10;
+    int l16StereoClockRate = 44_100;
+
+    MediaDescription mediaDescription =
+        new MediaDescription.Builder(
+                MEDIA_TYPE_AUDIO,
+                /* port= */ 0,
+                RTP_AVP_PROFILE,
+                /* payloadType= */ l16StereoPayloadType)
+            .setConnection("IN IP4 0.0.0.0")
+            .addAttribute(ATTR_CONTROL, "track2")
+            .build();
+
+    RtpPayloadFormat format = RtspMediaTrack.generatePayloadFormat(mediaDescription);
+    RtpPayloadFormat expectedFormat =
+        new RtpPayloadFormat(
+            new Format.Builder()
+                .setSampleMimeType(MimeTypes.AUDIO_RAW)
+                .setChannelCount(2)
+                .setSampleRate(l16StereoClockRate)
+                .setPcmEncoding(C.ENCODING_PCM_16BIT_BIG_ENDIAN)
+                .build(),
+            /* rtpPayloadType= */ l16StereoPayloadType,
+            /* clockRate= */ l16StereoClockRate,
+            /* fmtpParameters= */ ImmutableMap.of());
+
+    assertThat(format).isEqualTo(expectedFormat);
+  }
+
+  @Test
+  public void generatePayloadFormat_withL16MonoMediaDescription_succeeds() {
+    // m=audio 0 RTP/AVP 0
+    // c=IN IP4 0.0.0.0
+    // a=control:track2
+    int l16MonoPayloadType = 11;
+    int l16MonoClockRate = 44_100;
+
+    MediaDescription mediaDescription =
+        new MediaDescription.Builder(
+                MEDIA_TYPE_AUDIO,
+                /* port= */ 0,
+                RTP_AVP_PROFILE,
+                /* payloadType= */ l16MonoPayloadType)
+            .setConnection("IN IP4 0.0.0.0")
+            .addAttribute(ATTR_CONTROL, "track2")
+            .build();
+
+    RtpPayloadFormat format = RtspMediaTrack.generatePayloadFormat(mediaDescription);
+    RtpPayloadFormat expectedFormat =
+        new RtpPayloadFormat(
+            new Format.Builder()
+                .setSampleMimeType(MimeTypes.AUDIO_RAW)
+                .setChannelCount(1)
+                .setSampleRate(l16MonoClockRate)
+                .setPcmEncoding(C.ENCODING_PCM_16BIT_BIG_ENDIAN)
+                .build(),
+            /* rtpPayloadType= */ l16MonoPayloadType,
+            /* clockRate= */ l16MonoClockRate,
+            /* fmtpParameters= */ ImmutableMap.of());
+
+    assertThat(format).isEqualTo(expectedFormat);
+  }
+
   @Test
   public void generatePayloadFormat_withFmtpTrailingSemicolon_succeeds() {
     MediaDescription mediaDescription =