/**
     * Removes receiver and sender feedback from RTCP packets.
     *
     * @param inPacket the <tt>RTCPCompoundPacket</tt> to filter.
     * @return the filtered <tt>RawPacket</tt>.
     */
    public RawPacket gateway(RTCPCompoundPacket inPacket) {
      if (inPacket == null || inPacket.packets == null || inPacket.packets.length == 0) {
        logger.info("Ignoring empty RTCP packet.");
        return null;
      }

      ArrayList<RTCPPacket> outPackets = new ArrayList<RTCPPacket>(inPacket.packets.length);

      for (RTCPPacket p : inPacket.packets) {
        switch (p.type) {
          case RTCPPacket.RR:
          case RTCPPacket.SR:
          case RTCPPacket.SDES:
            // We generate our own RR/SR/SDES packets. We only want
            // to forward NACKs/PLIs/etc.
            break;
          case RTCPFBPacket.PSFB:
            RTCPFBPacket psfb = (RTCPFBPacket) p;
            switch (psfb.fmt) {
              case RTCPREMBPacket.FMT:
                // We generate its own REMB packets.
                break;
              default:
                // We let through everything else, like NACK
                // packets.
                outPackets.add(psfb);
                break;
            }
            break;
          default:
            // We let through everything else, like BYE and APP
            // packets.
            outPackets.add(p);
            break;
        }
      }

      if (outPackets.size() == 0) {
        return null;
      }

      // We have feedback messages to send. Pack them in a compound
      // RR and send them. TODO Use RFC5506 Reduced-Size RTCP, if the
      // receiver supports it.
      Collection<RTCPRRPacket> rrPackets = makeRTCPRRPackets(System.currentTimeMillis());

      if (rrPackets != null && rrPackets.size() != 0) {
        outPackets.addAll(0, rrPackets);
      } else {
        logger.warn("We might be sending invalid RTCPs.");
      }

      RTCPPacket[] pkts = outPackets.toArray(new RTCPPacket[outPackets.size()]);
      RTCPCompoundPacket outPacket = new RTCPCompoundPacket(pkts);

      return generator.apply(outPacket);
    }
Exemplo n.º 2
0
  /**
   * Encapsulates {@code pkt} in the RTX format, using {@code rtxSsrc} as its SSRC, and transmits it
   * to {@link #channel} by injecting it in the {@code MediaStream}.
   *
   * @param pkt the packet to transmit.
   * @param rtxSsrc the SSRC for the RTX stream.
   * @return {@code true} if the packet was successfully retransmitted, {@code false} otherwise.
   */
  private boolean encapsulateInRtxAndTransmit(RawPacket pkt, long rtxSsrc) {
    byte[] buf = pkt.getBuffer();
    int len = pkt.getLength();
    int off = pkt.getOffset();
    byte[] newBuf = buf;
    if (buf.length < len + 2) {
      // FIXME The byte array newly allocated and assigned to newBuf must
      // be made known to pkt eventually.
      newBuf = new byte[len + 2];
    }

    int osn = pkt.getSequenceNumber();
    int headerLength = pkt.getHeaderLength();
    int payloadLength = len - headerLength;
    System.arraycopy(buf, off, newBuf, 0, headerLength);
    // FIXME If newBuf is actually buf, then we will override the first two
    // bytes of the payload bellow.
    newBuf[headerLength] = (byte) ((osn >> 8) & 0xff);
    newBuf[headerLength + 1] = (byte) (osn & 0xff);
    System.arraycopy(buf, off + headerLength, newBuf, headerLength + 2, payloadLength);
    // FIXME We tried to extend the payload of pkt by two bytes above but
    // we never told pkt that its length has increased by these two bytes.

    MediaStream mediaStream = channel.getStream();
    if (mediaStream != null) {
      pkt.setSSRC((int) rtxSsrc);
      // Only call getNextRtxSequenceNumber() when we're sure we're going
      // to transmit a packet, because it consumes a sequence number.
      pkt.setSequenceNumber(getNextRtxSequenceNumber(rtxSsrc));
      try {
        mediaStream.injectPacket(pkt, /* data */ true, /* after */ null);
      } catch (TransmissionFailedException tfe) {
        logger.warn("Failed to transmit an RTX packet.");
        return false;
      }
    }

    return true;
  }
Exemplo n.º 3
0
  /**
   * Creates a {@code RawPacket} which represents the original packet encapsulated in {@code pkt}
   * using the RTX format.
   *
   * @param pkt the packet from which to extract a media packet.
   * @return the extracted media packet.
   */
  private RawPacket createMediaPacket(RawPacket pkt) {
    RawPacket mediaPacket = null;
    long rtxSsrc = pkt.getSSRC() & 0xffffffffL;

    // We need to know the SSRC paired with rtxSsrc *as seen by the
    // receiver (i.e. this.channel)*. However, we only store SSRCs
    // that endpoints *send* with.
    // We therefore assume that SSRC re-writing has not introduced any
    // new SSRCs and therefor the FID mappings known to the senders
    // also apply to receivers.
    RtpChannel sourceChannel = channel.getContent().findChannelByFidSsrc(rtxSsrc);
    if (sourceChannel != null) {
      long mediaSsrc = sourceChannel.getFidPairedSsrc(rtxSsrc);
      if (mediaSsrc != -1) {
        byte apt = sourceChannel.getRtxAssociatedPayloadType();
        if (apt != -1) {
          mediaPacket = new RawPacket(pkt.getBuffer().clone(), pkt.getOffset(), pkt.getLength());

          // Remove the RTX header by moving the RTP header two bytes
          // right.
          byte[] buf = mediaPacket.getBuffer();
          int off = mediaPacket.getOffset();
          System.arraycopy(buf, off, buf, off + 2, mediaPacket.getHeaderLength());

          mediaPacket.setOffset(off + 2);
          mediaPacket.setLength(pkt.getLength() - 2);

          mediaPacket.setSSRC((int) mediaSsrc);
          mediaPacket.setSequenceNumber(pkt.getOriginalSequenceNumber());
          mediaPacket.setPayloadType(apt);
        }
      }
    }

    return mediaPacket;
  }
  /**
   * Makes <tt>RTCPRRPacket</tt>s using information in FMJ.
   *
   * @param time
   * @return A <tt>Collection</tt> of <tt>RTCPRRPacket</tt>s to inject to the <tt>MediaStream</tt>.
   */
  private Collection<RTCPRRPacket> makeRTCPRRPackets(long time) {
    RTCPReportBlock[] reportBlocks = makeRTCPReportBlocks(time);
    if (reportBlocks == null || reportBlocks.length == 0) {
      return null;
    }

    Collection<RTCPRRPacket> rrPackets = new ArrayList<RTCPRRPacket>();

    // We use the stream's local source ID (SSRC) as the SSRC of packet
    // sender.
    long streamSSRC = getLocalSSRC();

    // Since a maximum of 31 reception report blocks will fit in an SR
    // or RR packet, additional RR packets SHOULD be stacked after the
    // initial SR or RR packet as needed to contain the reception
    // reports for all sources heard during the interval since the last
    // report.
    if (reportBlocks.length > MAX_RTCP_REPORT_BLOCKS) {
      for (int offset = 0; offset < reportBlocks.length; offset += MAX_RTCP_REPORT_BLOCKS) {
        RTCPReportBlock[] blocks =
            (reportBlocks.length - offset < MAX_RTCP_REPORT_BLOCKS)
                ? new RTCPReportBlock[reportBlocks.length - offset]
                : MAX_RTCP_REPORT_BLOCKS_ARRAY;

        System.arraycopy(reportBlocks, offset, blocks, 0, blocks.length);

        RTCPRRPacket rr = new RTCPRRPacket((int) streamSSRC, blocks);
        rrPackets.add(rr);
      }
    } else {
      RTCPRRPacket rr = new RTCPRRPacket((int) streamSSRC, reportBlocks);
      rrPackets.add(rr);
    }

    return rrPackets;
  }
 /**
  * Ctor.
  *
  * @param ssrc
  * @param remoteTime
  * @param rtpTimestamp
  * @param frequencyHz
  */
 ReceivedRemoteClock(int ssrc, long remoteTime, int rtpTimestamp, int frequencyHz) {
   this.ssrc = ssrc;
   this.remoteClock = new RemoteClock(remoteTime, rtpTimestamp);
   this.frequencyHz = frequencyHz;
   this.receivedTime = System.currentTimeMillis();
 }
  /** {@inheritDoc} */
  @Override
  public RawPacket report() {
    garbageCollector.cleanup();

    // TODO Compound RTCP packets should not exceed the MTU of the network
    // path.
    //
    // An individual RTP participant should send only one compound RTCP
    // packet per report interval in order for the RTCP bandwidth per
    // participant to be estimated correctly, except when the compound
    // RTCP packet is split for partial encryption.
    //
    // If there are too many sources to fit all the necessary RR packets
    // into one compound RTCP packet without exceeding the maximum
    // transmission unit (MTU) of the network path, then only the subset
    // that will fit into one MTU should be included in each interval. The
    // subsets should be selected round-robin across multiple intervals so
    // that all sources are reported.
    //
    // It is impossible to know in advance what the MTU of path will be.
    // There are various algorithms for experimenting to find out, but many
    // devices do not properly implement (or deliberately ignore) the
    // necessary standards so it all comes down to trial and error. For that
    // reason, we can just guess 1200 or 1500 bytes per message.
    long time = System.currentTimeMillis();

    Collection<RTCPPacket> packets = new ArrayList<RTCPPacket>();

    // First, we build the RRs.
    Collection<RTCPRRPacket> rrPackets = makeRTCPRRPackets(time);
    if (rrPackets != null && rrPackets.size() != 0) {
      packets.addAll(rrPackets);
    }

    // Next, we build the SRs.
    Collection<RTCPSRPacket> srPackets = makeRTCPSRPackets(time);
    if (srPackets != null && srPackets.size() != 0) {
      packets.addAll(srPackets);
    }

    // Bail out if we have nothing to report.
    if (packets.size() == 0) {
      return null;
    }

    // Next, we build the REMB.
    RTCPREMBPacket rembPacket = makeRTCPREMBPacket();
    if (rembPacket != null) {
      packets.add(rembPacket);
    }

    // Finally, we add an SDES packet.
    RTCPSDESPacket sdesPacket = makeSDESPacket();
    if (sdesPacket != null) {
      packets.add(sdesPacket);
    }

    // Prepare the <tt>RTCPCompoundPacket</tt> to return.
    RTCPPacket rtcpPackets[] = packets.toArray(new RTCPPacket[packets.size()]);

    RTCPCompoundPacket cp = new RTCPCompoundPacket(rtcpPackets);

    // Build the <tt>RTCPCompoundPacket</tt> and return the
    // <tt>RawPacket</tt> to inject to the <tt>MediaStream</tt>.
    return generator.apply(cp);
  }