Add support for RTSP H263

Added H263 RTP Packet reader and added support for H263 playback through
RTSP.

Change-Id: I348cc4d8e974b5275409b816a9d52aa29f593233

libraries/exoplayer_rtsp/src/main/java/androidx/media3/exoplayer/rtsp/RtpPayloadFormat.java

@@ -38,6 +38,8 @@ public final class RtpPayloadFormat {
 
   private static final String RTP_MEDIA_AC3 = "AC3";
   private static final String RTP_MEDIA_MPEG4_GENERIC = "MPEG4-GENERIC";
+  private static final String RTP_MEDIA_H263_1998 = "H263-1998";
+  private static final String RTP_MEDIA_H263_2000 = "H263-2000";
   private static final String RTP_MEDIA_H264 = "H264";
   private static final String RTP_MEDIA_H265 = "H265";
 
@@ -45,6 +47,8 @@ public final class RtpPayloadFormat {
   public static boolean isFormatSupported(MediaDescription mediaDescription) {
     switch (Ascii.toUpperCase(mediaDescription.rtpMapAttribute.mediaEncoding)) {
       case RTP_MEDIA_AC3:
+      case RTP_MEDIA_H263_1998:
+      case RTP_MEDIA_H263_2000:
       case RTP_MEDIA_H264:
       case RTP_MEDIA_H265:
       case RTP_MEDIA_MPEG4_GENERIC:
@@ -65,6 +69,9 @@ public final class RtpPayloadFormat {
     switch (Ascii.toUpperCase(mediaType)) {
       case RTP_MEDIA_AC3:
         return MimeTypes.AUDIO_AC3;
+      case RTP_MEDIA_H263_1998:
+      case RTP_MEDIA_H263_2000:
+        return MimeTypes.VIDEO_H263;
       case RTP_MEDIA_H264:
         return MimeTypes.VIDEO_H264;
       case RTP_MEDIA_H265:

libraries/exoplayer_rtsp/src/main/java/androidx/media3/exoplayer/rtsp/RtspMediaTrack.java

@@ -56,6 +56,10 @@ import com.google.common.collect.ImmutableMap;
 
   private static final String GENERIC_CONTROL_ATTR = "*";
 
+  /** Default width and height for H263. */
+  private static final int DEFAULT_H263_WIDTH = 352;
+  private static final int DEFAULT_H263_HEIGHT = 288;
+
   /** The track's associated {@link RtpPayloadFormat}. */
   public final RtpPayloadFormat payloadFormat;
   /** The track's URI. */
@@ -121,6 +125,10 @@ import com.google.common.collect.ImmutableMap;
         checkArgument(!fmtpParameters.isEmpty());
         processAacFmtpAttribute(formatBuilder, fmtpParameters, channelCount, clockRate);
         break;
+      case MimeTypes.VIDEO_H263:
+        // H263 does not require a FMTP attribute. So Setting default width and height.
+        formatBuilder.setWidth(DEFAULT_H263_WIDTH).setHeight(DEFAULT_H263_HEIGHT);
+        break;
       case MimeTypes.VIDEO_H264:
         checkArgument(!fmtpParameters.isEmpty());
         processH264FmtpAttribute(formatBuilder, fmtpParameters);

libraries/exoplayer_rtsp/src/main/java/androidx/media3/exoplayer/rtsp/reader/DefaultRtpPayloadReaderFactory.java

@@ -36,6 +36,8 @@ import androidx.media3.exoplayer.rtsp.RtpPayloadFormat;
         return new RtpAc3Reader(payloadFormat);
       case MimeTypes.AUDIO_AAC:
         return new RtpAacReader(payloadFormat);
+      case MimeTypes.VIDEO_H263:
+        return new RtpH263Reader(payloadFormat);
       case MimeTypes.VIDEO_H264:
         return new RtpH264Reader(payloadFormat);
       case MimeTypes.VIDEO_H265:

libraries/exoplayer_rtsp/src/main/java/androidx/media3/exoplayer/rtsp/reader/RtpH263Reader.java

@@ -0,0 +1,197 @@
+/*
+ * Copyright 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package androidx.media3.exoplayer.rtsp.reader;
+
+import static androidx.media3.common.util.Assertions.checkStateNotNull;
+import static androidx.media3.common.util.Util.castNonNull;
+
+import androidx.media3.common.C;
+import androidx.media3.common.ParserException;
+import androidx.media3.common.util.Log;
+import androidx.media3.common.util.ParsableByteArray;
+import androidx.media3.common.util.Util;
+import androidx.media3.exoplayer.rtsp.RtpPacket;
+import androidx.media3.exoplayer.rtsp.RtpPayloadFormat;
+import androidx.media3.extractor.ExtractorOutput;
+import androidx.media3.extractor.TrackOutput;
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+
+/**
+ * Parses a H263 byte stream carried on RTP packets, and extracts H263 individual video frames as
+ * defined in RFC4629.
+ */
+/* package */ final class RtpH263Reader implements RtpPayloadReader {
+  private static final String TAG = "RtpH263Reader";
+
+  private static final long MEDIA_CLOCK_FREQUENCY = 90_000;
+
+  /** VOP unit type. */
+  private static final int I_VOP = 0;
+
+  private final RtpPayloadFormat payloadFormat;
+
+  private @MonotonicNonNull TrackOutput trackOutput;
+
+  private long firstReceivedTimestamp;
+  private int previousSequenceNumber;
+  /** The combined size of a sample that is fragmented into multiple RTP packets. */
+  private int fragmentedSampleSizeBytes;
+  private static int width;
+  private static int height;
+  private static boolean isKeyFrame;
+  private boolean isOutputFormatSet;
+  private long startTimeOffsetUs;
+
+  /** Creates an instance. */
+  public RtpH263Reader(RtpPayloadFormat payloadFormat) {
+    this.payloadFormat = payloadFormat;
+    firstReceivedTimestamp = C.TIME_UNSET;
+    previousSequenceNumber = C.INDEX_UNSET;
+    fragmentedSampleSizeBytes = 0;
+    isKeyFrame = false;
+    isOutputFormatSet = false;
+  }
+
+  @Override
+  public void createTracks(ExtractorOutput extractorOutput, int trackId) {
+    trackOutput = extractorOutput.track(trackId, C.TRACK_TYPE_VIDEO);
+    castNonNull(trackOutput).format(payloadFormat.format);
+  }
+
+  @Override
+  public void onReceivingFirstPacket(long timestamp, int sequenceNumber) {}
+
+  @Override
+  public void consume(ParsableByteArray data, long timestamp, int sequenceNumber, boolean rtpMarker)
+      throws ParserException {
+    checkStateNotNull(trackOutput);
+
+    // H263 Header Payload Header, RFC4629 Section 5.1.
+    //    0                   1
+    //    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+    //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    //    |   RR    |P|V|   PLEN    |PEBIT|
+    //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    int currPosition = data.getPosition();
+    int header = data.readUnsignedShort();
+    boolean pBit = ((header & 0x400) == 0x400);
+
+    // Check if optional Video Redundancy Coding or PLEN or PEBIT is present, RFC4629 Section 5.1.
+    if ((header & 0x200) != 0 || (header & 0x1f8) != 0 || (header & 0x7) != 0) {
+      Log.w(TAG, "Packet discarded due to (VRC != 0) or (PLEN != 0) or (PEBIT != 0)");
+      return;
+    }
+    int startCodePayload = data.peekUnsignedByte() & 0xfc;
+    if (pBit == true) {
+      if (startCodePayload < 128) {
+        Log.w(TAG, "Picture start Code (PSC) missing, Dropping packet.");
+        return;
+      } else {
+        // Setting first two bytes of the start code. Refer RFC4629 Section 5.1.
+        data.getData()[currPosition] = 0;
+        data.getData()[currPosition + 1] = 0;
+        data.setPosition(currPosition);
+      }
+    } else {
+      // Check that this packet is in the sequence of the previous packet.
+      int expectedSequenceNumber = RtpPacket.getNextSequenceNumber(previousSequenceNumber);
+      if (sequenceNumber != expectedSequenceNumber) {
+        Log.w(
+            TAG,
+            Util.formatInvariant(
+                "Received RTP packet with unexpected sequence number. Expected: %d; received: %d."
+                    + " Dropping packet.",
+                expectedSequenceNumber, sequenceNumber));
+        return;
+      }
+    }
+
+    if (fragmentedSampleSizeBytes == 0) {
+      getBufferFlagsAndResolutionFromVop(data, isOutputFormatSet);
+      if (!isOutputFormatSet && isKeyFrame == true) {
+        if (width != payloadFormat.format.width || height != payloadFormat.format.height) {
+          trackOutput.format(
+              payloadFormat.format.buildUpon().setWidth(width).setHeight(height).build());
+        }
+        isOutputFormatSet = true;
+      }
+    }
+    int fragmentSize = data.bytesLeft();
+    // Write the video sample.
+    trackOutput.sampleData(data, fragmentSize);
+    fragmentedSampleSizeBytes += fragmentSize;
+
+    if (rtpMarker) {
+      if (firstReceivedTimestamp == C.TIME_UNSET) {
+        firstReceivedTimestamp = timestamp;
+      }
+      long timeUs = toSampleUs(startTimeOffsetUs, timestamp, firstReceivedTimestamp);
+      trackOutput.sampleMetadata(
+          timeUs,
+          isKeyFrame ? C.BUFFER_FLAG_KEY_FRAME : 0,
+          fragmentedSampleSizeBytes,
+          /* offset= */ 0,
+          /* encryptionData= */ null);
+      fragmentedSampleSizeBytes = 0;
+      isKeyFrame = false;
+    }
+    previousSequenceNumber = sequenceNumber;
+  }
+
+  @Override
+  public void seek(long nextRtpTimestamp, long timeUs) {
+    firstReceivedTimestamp = nextRtpTimestamp;
+    fragmentedSampleSizeBytes = 0;
+    startTimeOffsetUs = timeUs;
+  }
+
+  // Internal methods.
+  /**
+   * Parses VOP Coding type and resolution.
+   */
+  private void getBufferFlagsAndResolutionFromVop(ParsableByteArray data, boolean gotResolution) {
+    // Search for SHORT_VIDEO_START_MARKER (0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0).
+    int currPosition = data.getPosition();
+    if (data.readUnsignedInt() >> 10 == 0x20) {
+      int header = data.peekUnsignedByte();
+      int vopType = ((header >> 1) & 0x01);
+      if (!gotResolution && vopType == I_VOP) {
+        int sourceFormat  = ((header >> 2) & 0x07);
+        if (sourceFormat == 1) {
+          width = 128;
+          height = 96;
+        } else {
+          width = (short) (176 << (sourceFormat - 2));
+          height = (short) (144 << (sourceFormat - 2));
+        }
+      }
+      data.setPosition(currPosition);
+      isKeyFrame = (vopType == I_VOP ? true : false);
+      return;
+    }
+    data.setPosition(currPosition);
+    isKeyFrame = false;
+  }
+
+  private static long toSampleUs(
+      long startTimeOffsetUs, long rtpTimestamp, long firstReceivedRtpTimestamp) {
+    return startTimeOffsetUs
+        + Util.scaleLargeTimestamp(
+            (rtpTimestamp - firstReceivedRtpTimestamp),
+            /* multiplier= */ C.MICROS_PER_SECOND,
+            /* divisor= */ MEDIA_CLOCK_FREQUENCY);
+  }
+}