Merge pull request #35 from ittiam-systems:rtp-mpeg4

PiperOrigin-RevId: 438000682

RELEASENOTES.md

@@ -36,6 +36,8 @@
         dependency from the UI module to the ExoPlayer module. This is a
         breaking change.
 *   RTSP:
+    *   Add RTP reader for MPEG4
+        ([#35](https://github.com/androidx/media/pull/35))
     *   Add RTP reader for HEVC
         ([#36](https://github.com/androidx/media/pull/36)).
     *   Add RTP reader for AMR. Currently only mono-channel, non-interleaved

libraries/common/src/main/java/androidx/media3/common/util/CodecSpecificDataUtil.java

@@ -15,6 +15,8 @@
  */
 package androidx.media3.common.util;
 
+import static androidx.media3.common.util.Assertions.checkArgument;
+
 import android.util.Pair;
 import androidx.annotation.Nullable;
 import androidx.media3.common.C;
@@ -31,6 +33,12 @@ public final class CodecSpecificDataUtil {
   private static final String[] HEVC_GENERAL_PROFILE_SPACE_STRINGS =
       new String[] {"", "A", "B", "C"};
 
+  // MP4V-ES
+  private static final int VISUAL_OBJECT_LAYER = 1;
+  private static final int VISUAL_OBJECT_LAYER_START = 0x20;
+  private static final int EXTENDED_PAR = 0x0F;
+  private static final int RECTANGULAR = 0x00;
+
   /**
    * Parses an ALAC AudioSpecificConfig (i.e. an <a
    * href="https://github.com/macosforge/alac/blob/master/ALACMagicCookieDescription.txt">ALACSpecificConfig</a>).
@@ -72,6 +80,87 @@ public final class CodecSpecificDataUtil {
         && initializationData.get(0)[0] == 1;
   }
 
+  /**
+   * Parses an MPEG-4 Visual configuration information, as defined in ISO/IEC14496-2.
+   *
+   * @param videoSpecificConfig A byte array containing the MPEG-4 Visual configuration information
+   *     to parse.
+   * @return A pair of the video's width and height.
+   */
+  public static Pair<Integer, Integer> getVideoResolutionFromMpeg4VideoConfig(
+      byte[] videoSpecificConfig) {
+    int offset = 0;
+    boolean foundVOL = false;
+    ParsableByteArray scratchBytes = new ParsableByteArray(videoSpecificConfig);
+    while (offset + 3 < videoSpecificConfig.length) {
+      if (scratchBytes.readUnsignedInt24() != VISUAL_OBJECT_LAYER
+          || (videoSpecificConfig[offset + 3] & 0xF0) != VISUAL_OBJECT_LAYER_START) {
+        scratchBytes.setPosition(scratchBytes.getPosition() - 2);
+        offset++;
+        continue;
+      }
+      foundVOL = true;
+      break;
+    }
+
+    checkArgument(foundVOL, "Invalid input: VOL not found.");
+
+    ParsableBitArray scratchBits = new ParsableBitArray(videoSpecificConfig);
+    // Skip the start codecs from the bitstream
+    scratchBits.skipBits((offset + 4) * 8);
+    scratchBits.skipBits(1); // random_accessible_vol
+    scratchBits.skipBits(8); // video_object_type_indication
+
+    if (scratchBits.readBit()) { // object_layer_identifier
+      scratchBits.skipBits(4); // video_object_layer_verid
+      scratchBits.skipBits(3); // video_object_layer_priority
+    }
+
+    int aspectRatioInfo = scratchBits.readBits(4);
+    if (aspectRatioInfo == EXTENDED_PAR) {
+      scratchBits.skipBits(8); // par_width
+      scratchBits.skipBits(8); // par_height
+    }
+
+    if (scratchBits.readBit()) { // vol_control_parameters
+      scratchBits.skipBits(2); // chroma_format
+      scratchBits.skipBits(1); // low_delay
+      if (scratchBits.readBit()) { // vbv_parameters
+        scratchBits.skipBits(79);
+      }
+    }
+
+    int videoObjectLayerShape = scratchBits.readBits(2);
+    checkArgument(
+        videoObjectLayerShape == RECTANGULAR,
+        "Only supports rectangular video object layer shape.");
+
+    checkArgument(scratchBits.readBit()); // marker_bit
+    int vopTimeIncrementResolution = scratchBits.readBits(16);
+    checkArgument(scratchBits.readBit()); // marker_bit
+
+    if (scratchBits.readBit()) { // fixed_vop_rate
+      checkArgument(vopTimeIncrementResolution > 0);
+      vopTimeIncrementResolution--;
+      int numBitsToSkip = 0;
+      while (vopTimeIncrementResolution > 0) {
+        numBitsToSkip++;
+        vopTimeIncrementResolution >>= 1;
+      }
+      scratchBits.skipBits(numBitsToSkip); // fixed_vop_time_increment
+    }
+
+    checkArgument(scratchBits.readBit()); // marker_bit
+    int videoObjectLayerWidth = scratchBits.readBits(13);
+    checkArgument(scratchBits.readBit()); // marker_bit
+    int videoObjectLayerHeight = scratchBits.readBits(13);
+    checkArgument(scratchBits.readBit()); // marker_bit
+
+    scratchBits.skipBits(1); // interlaced
+
+    return Pair.create(videoObjectLayerWidth, videoObjectLayerHeight);
+  }
+
   /**
    * Builds an RFC 6381 AVC codec string using the provided parameters.
    *

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

@@ -43,6 +43,7 @@ public final class RtpPayloadFormat {
   private static final String RTP_MEDIA_AMR = "AMR";
   private static final String RTP_MEDIA_AMR_WB = "AMR-WB";
   private static final String RTP_MEDIA_MPEG4_GENERIC = "MPEG4-GENERIC";
+  private static final String RTP_MEDIA_MPEG4_VIDEO = "MP4V-ES";
   private static final String RTP_MEDIA_H264 = "H264";
   private static final String RTP_MEDIA_H265 = "H265";
   private static final String RTP_MEDIA_PCM_L8 = "L8";
@@ -59,6 +60,7 @@ public final class RtpPayloadFormat {
       case RTP_MEDIA_AMR_WB:
       case RTP_MEDIA_H264:
       case RTP_MEDIA_H265:
+      case RTP_MEDIA_MPEG4_VIDEO:
       case RTP_MEDIA_MPEG4_GENERIC:
       case RTP_MEDIA_PCM_L8:
       case RTP_MEDIA_PCM_L16:
@@ -86,10 +88,6 @@ public final class RtpPayloadFormat {
         return MimeTypes.AUDIO_AMR_NB;
       case RTP_MEDIA_AMR_WB:
         return MimeTypes.AUDIO_AMR_WB;
-      case RTP_MEDIA_H264:
-        return MimeTypes.VIDEO_H264;
-      case RTP_MEDIA_H265:
-        return MimeTypes.VIDEO_H265;
       case RTP_MEDIA_MPEG4_GENERIC:
         return MimeTypes.AUDIO_AAC;
       case RTP_MEDIA_PCM_L8:
@@ -99,6 +97,12 @@ public final class RtpPayloadFormat {
         return MimeTypes.AUDIO_ALAW;
       case RTP_MEDIA_PCMU:
         return MimeTypes.AUDIO_MLAW;
+      case RTP_MEDIA_H264:
+        return MimeTypes.VIDEO_H264;
+      case RTP_MEDIA_H265:
+        return MimeTypes.VIDEO_H265;
+      case RTP_MEDIA_MPEG4_VIDEO:
+        return MimeTypes.VIDEO_MP4V;
       case RTP_MEDIA_VP8:
         return MimeTypes.VIDEO_VP8;
       default:

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

@@ -25,6 +25,7 @@ import static androidx.media3.extractor.NalUnitUtil.NAL_START_CODE;
 
 import android.net.Uri;
 import android.util.Base64;
+import android.util.Pair;
 import androidx.annotation.Nullable;
 import androidx.annotation.VisibleForTesting;
 import androidx.media3.common.C;
@@ -44,19 +45,42 @@ import com.google.common.collect.ImmutableMap;
   // Format specific parameter names.
   private static final String PARAMETER_PROFILE_LEVEL_ID = "profile-level-id";
   private static final String PARAMETER_SPROP_PARAMS = "sprop-parameter-sets";
+
+  private static final String PARAMETER_AMR_OCTET_ALIGN = "octet-align";
+  private static final String PARAMETER_AMR_INTERLEAVING = "interleaving";
   private static final String PARAMETER_H265_SPROP_SPS = "sprop-sps";
   private static final String PARAMETER_H265_SPROP_PPS = "sprop-pps";
   private static final String PARAMETER_H265_SPROP_VPS = "sprop-vps";
   private static final String PARAMETER_H265_SPROP_MAX_DON_DIFF = "sprop-max-don-diff";
-  private static final String PARAMETER_AMR_OCTET_ALIGN = "octet-align";
+  private static final String PARAMETER_MP4V_CONFIG = "config";
-  private static final String PARAMETER_AMR_INTERLEAVING = "interleaving";
 
   /** Prefix for the RFC6381 codecs string for AAC formats. */
   private static final String AAC_CODECS_PREFIX = "mp4a.40.";
   /** Prefix for the RFC6381 codecs string for AVC formats. */
   private static final String H264_CODECS_PREFIX = "avc1.";
+  /** Prefix for the RFC6416 codecs string for MPEG4V-ES formats. */
+  private static final String MPEG4_CODECS_PREFIX = "mp4v.";
 
   private static final String GENERIC_CONTROL_ATTR = "*";
+  /**
+   * Default height for MP4V.
+   *
+   * <p>RFC6416 does not mandate 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/mpeg4_h263/C2SoftMpeg4Dec.cpp;l=130
+   * >Android's software MP4V decoder</a>.
+   */
+  private static final int DEFAULT_MP4V_WIDTH = 352;
+
+  /**
+   * Default height for MP4V.
+   *
+   * <p>RFC6416 does not mandate 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/mpeg4_h263/C2SoftMpeg4Dec.cpp;l=130
+   * >Android's software MP4V decoder</a>.
+   */
+  private static final int DEFAULT_MP4V_HEIGHT = 288;
 
   /**
    * Default width for VP8.
@@ -156,6 +180,10 @@ import com.google.common.collect.ImmutableMap;
             !fmtpParameters.containsKey(PARAMETER_AMR_INTERLEAVING),
             "Interleaving mode is not currently supported.");
         break;
+      case MimeTypes.VIDEO_MP4V:
+        checkArgument(!fmtpParameters.isEmpty());
+        processMPEG4FmtpAttribute(formatBuilder, fmtpParameters);
+        break;
       case MimeTypes.VIDEO_H264:
         checkArgument(!fmtpParameters.isEmpty());
         processH264FmtpAttribute(formatBuilder, fmtpParameters);
@@ -214,6 +242,23 @@ import com.google.common.collect.ImmutableMap;
             AacUtil.buildAacLcAudioSpecificConfig(sampleRate, channelCount)));
   }
 
+  private static void processMPEG4FmtpAttribute(
+      Format.Builder formatBuilder, ImmutableMap<String, String> fmtpAttributes) {
+    @Nullable String configInput = fmtpAttributes.get(PARAMETER_MP4V_CONFIG);
+    if (configInput != null) {
+      byte[] configBuffer = Util.getBytesFromHexString(configInput);
+      formatBuilder.setInitializationData(ImmutableList.of(configBuffer));
+      Pair<Integer, Integer> resolution =
+          CodecSpecificDataUtil.getVideoResolutionFromMpeg4VideoConfig(configBuffer);
+      formatBuilder.setWidth(resolution.first).setHeight(resolution.second);
+    } else {
+      // set the default width and height
+      formatBuilder.setWidth(DEFAULT_MP4V_WIDTH).setHeight(DEFAULT_MP4V_HEIGHT);
+    }
+    @Nullable String profileLevel = fmtpAttributes.get(PARAMETER_PROFILE_LEVEL_ID);
+    formatBuilder.setCodecs(MPEG4_CODECS_PREFIX + (profileLevel == null ? "1" : profileLevel));
+  }
+
   /** Returns H264/H265 initialization data from the RTP parameter set. */
   private static byte[] getInitializationDataFromParameterSet(String parameterSet) {
     byte[] decodedParameterNalData = Base64.decode(parameterSet, Base64.DEFAULT);

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

@@ -47,6 +47,8 @@ import androidx.media3.exoplayer.rtsp.RtpPayloadFormat;
         return new RtpH264Reader(payloadFormat);
       case MimeTypes.VIDEO_H265:
         return new RtpH265Reader(payloadFormat);
+      case MimeTypes.VIDEO_MP4V:
+        return new RtpMpeg4Reader(payloadFormat);
       case MimeTypes.VIDEO_VP8:
         return new RtpVp8Reader(payloadFormat);
       default:

libraries/exoplayer_rtsp/src/main/java/androidx/media3/exoplayer/rtsp/reader/RtpMpeg4Reader.java

@@ -0,0 +1,150 @@
+/*
+ * 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.util.Log;
+import androidx.media3.common.util.ParsableByteArray;
+import androidx.media3.common.util.UnstableApi;
+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 com.google.common.primitives.Bytes;
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+
+/**
+ * Parses an MPEG4 byte stream carried on RTP packets, and extracts MPEG4 Access Units. Refer to
+ * RFC6416 for more details.
+ */
+@UnstableApi
+/* package */ final class RtpMpeg4Reader implements RtpPayloadReader {
+  private static final String TAG = "RtpMpeg4Reader";
+
+  private static final long MEDIA_CLOCK_FREQUENCY = 90_000;
+
+  /** VOP (Video Object Plane) unit type. */
+  private static final int I_VOP = 0;
+
+  private final RtpPayloadFormat payloadFormat;
+  private @MonotonicNonNull TrackOutput trackOutput;
+  private @C.BufferFlags int bufferFlags;
+
+  /**
+   * 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;
+  private long startTimeOffsetUs;
+  private int sampleLength;
+
+  /** Creates an instance. */
+  public RtpMpeg4Reader(RtpPayloadFormat payloadFormat) {
+    this.payloadFormat = payloadFormat;
+    firstReceivedTimestamp = C.TIME_UNSET;
+    previousSequenceNumber = C.INDEX_UNSET;
+    sampleLength = 0;
+  }
+
+  @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) {
+    checkStateNotNull(trackOutput);
+    // Check that this packet is in the sequence of the previous packet.
+    if (previousSequenceNumber != C.INDEX_UNSET) {
+      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));
+      }
+    }
+
+    // Parse VOP Type and get the buffer flags
+    int limit = data.bytesLeft();
+    trackOutput.sampleData(data, limit);
+    if (sampleLength == 0) {
+      bufferFlags = getBufferFlagsFromVop(data);
+    }
+    sampleLength += limit;
+
+    // RTP marker indicates the last packet carrying a VOP.
+    if (rtpMarker) {
+      if (firstReceivedTimestamp == C.TIME_UNSET) {
+        firstReceivedTimestamp = timestamp;
+      }
+
+      long timeUs = toSampleUs(startTimeOffsetUs, timestamp, firstReceivedTimestamp);
+      trackOutput.sampleMetadata(timeUs, bufferFlags, sampleLength, 0, null);
+      sampleLength = 0;
+    }
+    previousSequenceNumber = sequenceNumber;
+  }
+
+  @Override
+  public void seek(long nextRtpTimestamp, long timeUs) {
+    firstReceivedTimestamp = nextRtpTimestamp;
+    startTimeOffsetUs = timeUs;
+    sampleLength = 0;
+  }
+
+  // Internal methods.
+
+  /**
+   * Returns VOP (Video Object Plane) Coding type.
+   *
+   * <p>Sets {@link #bufferFlags} according to the VOP Coding type.
+   */
+  private static @C.BufferFlags int getBufferFlagsFromVop(ParsableByteArray data) {
+    // search for VOP_START_CODE (00 00 01 B6)
+    byte[] inputData = data.getData();
+    byte[] startCode = new byte[] {0x0, 0x0, 0x1, (byte) 0xB6};
+    int vopStartCodePos = Bytes.indexOf(inputData, startCode);
+    if (vopStartCodePos != -1) {
+      data.setPosition(vopStartCodePos + 4);
+      int vopType = data.peekUnsignedByte() >> 6;
+      return vopType == I_VOP ? C.BUFFER_FLAG_KEY_FRAME : 0;
+    }
+    return 0;
+  }
+
+  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);
+  }
+}