Merge pull request #47 from ittiam-systems:rtp-vp8

PiperOrigin-RevId: 437710223

RELEASENOTES.md

@@ -41,6 +41,8 @@
     *   Add RTP reader for AMR. Currently only mono-channel, non-interleaved 
         AMR streams are supported. Compound AMR RTP payload is not supported.
         ([#46](https://github.com/androidx/media/pull/46))
+    *   Add RTP reader for VP8
+        ([#47](https://github.com/androidx/media/pull/47)).
 *   Remove deprecated symbols:
     *   Remove `Player.Listener.onTracksChanged`. Use
         `Player.Listener.onTracksInfoChanged` instead.

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

@@ -42,6 +42,7 @@ public final class RtpPayloadFormat {
   private static final String RTP_MEDIA_MPEG4_GENERIC = "MPEG4-GENERIC";
   private static final String RTP_MEDIA_H264 = "H264";
   private static final String RTP_MEDIA_H265 = "H265";
+  private static final String RTP_MEDIA_VP8 = "VP8";
 
   /** Returns whether the format of a {@link MediaDescription} is supported. */
   public static boolean isFormatSupported(MediaDescription mediaDescription) {
@@ -52,6 +53,7 @@ public final class RtpPayloadFormat {
       case RTP_MEDIA_H264:
       case RTP_MEDIA_H265:
       case RTP_MEDIA_MPEG4_GENERIC:
+      case RTP_MEDIA_VP8:
         return true;
       default:
         return false;
@@ -79,6 +81,8 @@ public final class RtpPayloadFormat {
         return MimeTypes.VIDEO_H265;
       case RTP_MEDIA_MPEG4_GENERIC:
         return MimeTypes.AUDIO_AAC;
+      case RTP_MEDIA_VP8:
+        return MimeTypes.VIDEO_VP8;
       default:
         throw new IllegalArgumentException(mediaType);
     }

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

@@ -58,6 +58,25 @@ import com.google.common.collect.ImmutableMap;
 
   private static final String GENERIC_CONTROL_ATTR = "*";
 
+  /**
+   * Default width for VP8.
+   *
+   * <p>RFC7741 never uses codec specific data (like width and height) in the fmtp attribute. These
+   * values are taken from <a
+   * href=https://cs.android.com/android/platform/superproject/+/master:frameworks/av/media/codec2/components/vpx/C2SoftVpxDec.cpp;drc=749a74cc3e081c16ea0e8c530953d0a247177867;l=70>Android's
+   * software VP8 decoder</a>.
+   */
+  private static final int DEFAULT_VP8_WIDTH = 320;
+  /**
+   * Default height for VP8.
+   *
+   * <p>RFC7741 never uses codec specific data (like width and height) in the fmtp attribute. These
+   * values are taken from <a
+   * href=https://cs.android.com/android/platform/superproject/+/master:frameworks/av/media/codec2/components/vpx/C2SoftVpxDec.cpp;drc=749a74cc3e081c16ea0e8c530953d0a247177867;l=70>Android's
+   * software VP8 decoder</a>.
+   */
+  private static final int DEFAULT_VP8_HEIGHT = 240;
+
   /** The track's associated {@link RtpPayloadFormat}. */
   public final RtpPayloadFormat payloadFormat;
   /** The track's URI. */
@@ -144,8 +163,13 @@ import com.google.common.collect.ImmutableMap;
         checkArgument(!fmtpParameters.isEmpty());
         processH265FmtpAttribute(formatBuilder, fmtpParameters);
         break;
+      case MimeTypes.VIDEO_VP8:
+        // VP8 never uses fmtp width and height attributes (RFC7741 Section 6.2), setting default
+        // width and height.
+        formatBuilder.setWidth(DEFAULT_VP8_WIDTH).setHeight(DEFAULT_VP8_HEIGHT);
+        break;
       case MimeTypes.AUDIO_AC3:
-        // AC3 does not require a FMTP attribute. Fall through.
+        // AC3 does not require a fmtp attribute. Fall through.
       default:
         // Do nothing.
     }

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

@@ -43,6 +43,8 @@ import androidx.media3.exoplayer.rtsp.RtpPayloadFormat;
         return new RtpH264Reader(payloadFormat);
       case MimeTypes.VIDEO_H265:
         return new RtpH265Reader(payloadFormat);
+      case MimeTypes.VIDEO_VP8:
+        return new RtpVp8Reader(payloadFormat);
       default:
         // No supported reader, returning null.
     }

libraries/exoplayer_rtsp/src/main/java/androidx/media3/exoplayer/rtsp/reader/RtpVp8Reader.java

@@ -0,0 +1,206 @@
+/*
+ * 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 androidx.media3.common.C;
+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 VP8 byte stream carried on RTP packets, and extracts VP8 individual video frames as
+ * defined in RFC7741.
+ */
+/* package */ final class RtpVp8Reader implements RtpPayloadReader {
+  private static final String TAG = "RtpVP8Reader";
+
+  /** VP9 uses a 90 KHz media clock (RFC7741 Section 4.1). */
+  private static final long MEDIA_CLOCK_FREQUENCY = 90_000;
+
+  private final RtpPayloadFormat payloadFormat;
+
+  private @MonotonicNonNull TrackOutput trackOutput;
+
+  /**
+   * First received RTP timestamp. All RTP timestamps are dimension-less, the time base is defined
+   * by {@link #MEDIA_CLOCK_FREQUENCY}.
+   */
+  private long firstReceivedTimestamp;
+
+  private int previousSequenceNumber;
+  /** The combined size of a sample that is fragmented into multiple RTP packets. */
+  private int fragmentedSampleSizeBytes;
+
+  private long startTimeOffsetUs;
+  /**
+   * Whether the first packet of one VP8 frame is received. A VP8 frame can be split into two RTP
+   * packets.
+   */
+  private boolean gotFirstPacketOfVp8Frame;
+
+  private boolean isKeyFrame;
+  private boolean isOutputFormatSet;
+
+  /** Creates an instance. */
+  public RtpVp8Reader(RtpPayloadFormat payloadFormat) {
+    this.payloadFormat = payloadFormat;
+    firstReceivedTimestamp = C.TIME_UNSET;
+    previousSequenceNumber = C.INDEX_UNSET;
+    fragmentedSampleSizeBytes = C.LENGTH_UNSET;
+    // The start time offset must be 0 until the first seek.
+    startTimeOffsetUs = 0;
+    gotFirstPacketOfVp8Frame = false;
+    isKeyFrame = false;
+    isOutputFormatSet = false;
+  }
+
+  @Override
+  public void createTracks(ExtractorOutput extractorOutput, int trackId) {
+    trackOutput = extractorOutput.track(trackId, C.TRACK_TYPE_VIDEO);
+    trackOutput.format(payloadFormat.format);
+  }
+
+  @Override
+  public void onReceivingFirstPacket(long timestamp, int sequenceNumber) {}
+
+  @Override
+  public void consume(
+      ParsableByteArray data, long timestamp, int sequenceNumber, boolean rtpMarker) {
+    checkStateNotNull(trackOutput);
+
+    boolean isValidVP8Descriptor = validateVp8Descriptor(data, sequenceNumber);
+    if (isValidVP8Descriptor) {
+      //  VP8 Payload Header is defined in RFC7741 Section 4.3.
+      if (fragmentedSampleSizeBytes == C.LENGTH_UNSET && gotFirstPacketOfVp8Frame) {
+        isKeyFrame = (data.peekUnsignedByte() & 0x01) == 0;
+      }
+      if (!isOutputFormatSet) {
+        // Parsing frame data to get width and height, RFC6386 Section 19.1.
+        int currPosition = data.getPosition();
+        // Skips the frame_tag and start_code.
+        data.setPosition(currPosition + 6);
+        // RFC6386 Section 19.1 specifically uses little endian.
+        int width = data.readLittleEndianUnsignedShort() & 0x3fff;
+        int height = data.readLittleEndianUnsignedShort() & 0x3fff;
+        data.setPosition(currPosition);
+
+        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();
+      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,
+            /* cryptoData= */ null);
+        fragmentedSampleSizeBytes = C.LENGTH_UNSET;
+        gotFirstPacketOfVp8Frame = false;
+      }
+      previousSequenceNumber = sequenceNumber;
+    }
+  }
+
+  @Override
+  public void seek(long nextRtpTimestamp, long timeUs) {
+    firstReceivedTimestamp = nextRtpTimestamp;
+    fragmentedSampleSizeBytes = C.LENGTH_UNSET;
+    startTimeOffsetUs = timeUs;
+  }
+
+  /**
+   * Returns {@code true} and sets the {@link ParsableByteArray#getPosition() payload.position} to
+   * the end of the descriptor, if a valid VP8 descriptor is present.
+   */
+  private boolean validateVp8Descriptor(ParsableByteArray payload, int packetSequenceNumber) {
+    // VP8 Payload Descriptor is defined in RFC7741 Section 4.2.
+    int header = payload.readUnsignedByte();
+    if (!gotFirstPacketOfVp8Frame) {
+      // TODO(b/198620566) Consider using ParsableBitArray.
+      // For start of VP8 partition S=1 and PID=0 as per RFC7741 Section 4.2.
+      if ((header & 0x10) != 0x1 || (header & 0x07) != 0) {
+        Log.w(TAG, "RTP packet is not the start of a new VP8 partition, skipping.");
+        return false;
+      }
+      gotFirstPacketOfVp8Frame = true;
+    } else {
+      // Check that this packet is in the sequence of the previous packet.
+      int expectedSequenceNumber = RtpPacket.getNextSequenceNumber(previousSequenceNumber);
+      if (packetSequenceNumber != expectedSequenceNumber) {
+        Log.w(
+            TAG,
+            Util.formatInvariant(
+                "Received RTP packet with unexpected sequence number. Expected: %d; received: %d."
+                    + " Dropping packet.",
+                expectedSequenceNumber, packetSequenceNumber));
+        return false;
+      }
+    }
+
+    // Check if optional X header is present.
+    if ((header & 0x80) != 0) {
+      int xHeader = payload.readUnsignedByte();
+
+      // Check if optional I header is present.
+      if ((xHeader & 0x80) != 0) {
+        int iHeader = payload.readUnsignedByte();
+        // Check if I header's M bit is present.
+        if ((iHeader & 0x80) != 0) {
+          payload.skipBytes(1);
+        }
+      }
+
+      // Check if optional L header is present.
+      if ((xHeader & 0x40) != 0) {
+        payload.skipBytes(1);
+      }
+
+      // Check if optional T or K header(s) is present.
+      if ((xHeader & 0x20) != 0 || (xHeader & 0x10) != 0) {
+        payload.skipBytes(1);
+      }
+    }
+    return true;
+  }
+
+  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);
+  }
+}