org.jitsi.impl.neomedia.RTCPFeedbackMessagePacket Maven / Gradle / Ivy
/*
* Copyright @ 2015 Atlassian Pty Ltd
*
* 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 org.jitsi.impl.neomedia;
import javax.media.rtp.*;
import org.jitsi.impl.neomedia.rtp.translator.*;
import org.jitsi.service.neomedia.event.*;
/**
* Represents an RTCP feedback message packet as described by RFC 4585
* "Extended RTP Profile for Real-time Transport Control Protocol
* (RTCP)-Based Feedback (RTP/AVPF)".
*
* @author Sebastien Vincent
* @author Lyubomir Marinov
*/
public class RTCPFeedbackMessagePacket
implements Payload
{
/**
* Feedback message type (FMT).
*/
private int fmt;
/**
* Packet type (PT).
*/
private int pt;
/**
* SSRC of packet sender.
*/
private long senderSSRC;
/**
* SSRC of media source.
*/
private long sourceSSRC;
/**
* The (command) sequence number of this Full Intra Request (FIR) RTCP
* feedback message as defined by RFC 5104 "Codec Control Messages in
* the RTP Audio-Visual Profile with Feedback (AVPF)". The sequence
* number space is unique for each pairing of the SSRC of command source and
* the SSRC of the command target. The sequence number SHALL be increased by
* 1 modulo 256 for each new command. A repetition SHALL NOT increase the
* sequence number. The initial value is arbitrary.
*/
private int seqNr;
/**
* Constructor.
*
* @param fmt feedback message type
* @param pt packet type
* @param senderSSRC SSRC of packet sender
* @param sourceSSRC SSRC of media source
*/
public RTCPFeedbackMessagePacket(
int fmt,
int pt,
long senderSSRC,
long sourceSSRC)
{
setFeedbackMessageType(fmt);
setPayloadType(pt);
setSenderSSRC(senderSSRC);
setSourceSSRC(sourceSSRC);
}
/**
* Gets the feedback message type (FMT) of this
* RTCPFeedbackMessagePacket.
*
* @return the feedback message type (FMT) of this
* RTCPFeedbackMessagePacket
*/
public int getFeedbackMessageType()
{
return fmt;
}
/**
* Gets the packet type (PT) of this RTCPFeedbackMessagePacket.
*
* @return the packet type (PT) of this RTCPFeedbackMessagePacket
*/
public int getPayloadType()
{
return pt;
}
/**
* Gets the synchronization source identifier (SSRC) of the originator of
* this packet.
*
* @return the synchronization source identifier (SSRC) of the originator of
* this packet
*/
public long getSenderSSRC()
{
return senderSSRC;
}
/**
* Gets the (command) sequence number of this Full Intra Request (FIR) RTCP
* feedback message as defined by RFC 5104 "Codec Control Messages in
* the RTP Audio-Visual Profile with Feedback (AVPF)". The sequence
* number space is unique for each pairing of the SSRC of command source and
* the SSRC of the command target. The sequence number SHALL be increased by
* 1 modulo 256 for each new command. A repetition SHALL NOT increase the
* sequence number. The initial value is arbitrary.
*
* @return the (command) sequence number of this Full Intra Request (FIR)
* RTCP feedback message
*/
public int getSequenceNumber()
{
return seqNr;
}
/**
* Gets the synchronization source identifier (SSRC) of the media source
* that this piece of feedback information is related to.
*
* @return the synchronization source identifier (SSRC) of the media source
* that this piece of feedback information is related to
*/
public long getSourceSSRC()
{
return sourceSSRC;
}
/**
* Sets the feedback message type (FMT) of this
* RTCPFeedbackMessagePacket.
*
* @param fmt the feedback message type (FMT) to set on this
* RTCPFeedbackMessagePacket
*/
public void setFeedbackMessageType(int fmt)
{
this.fmt = fmt;
}
/**
* Sets the packet type (PT) of this RTCPFeedbackMessagePacket.
*
* @param pt the packet type (PT) to set on this
* RTCPFeedbackMessagePacket
*/
public void setPayloadType(int pt)
{
this.pt = pt;
}
/**
* Sets the synchronization source identifier (SSRC) of the originator of
* this packet.
*
* @param senderSSRC the synchronization source identifier (SSRC) of the
* originator of this packet
*/
public void setSenderSSRC(long senderSSRC)
{
this.senderSSRC = senderSSRC;
}
/**
* Sets the (command) sequence number of this Full Intra Request (FIR) RTCP
* feedback message as defined by RFC 5104 "Codec Control Messages in
* the RTP Audio-Visual Profile with Feedback (AVPF)". The sequence
* number space is unique for each pairing of the SSRC of command source and
* the SSRC of the command target. The sequence number SHALL be increased by
* 1 modulo 256 for each new command.
*
* @param seqNr the (command) sequence number to set on this Full Intra
* Request (FIR) RTCP feedback message
*/
public void setSequenceNumber(int seqNr)
{
this.seqNr = seqNr;
}
/**
* Sets the synchronization source identifier (SSRC) of the media source
* that this piece of feedback information is related to.
*
* @param sourceSSRC the synchronization source identifier (SSRC) of the
* media source that this piece of feedback information is related to
*/
public void setSourceSSRC(long sourceSSRC)
{
this.sourceSSRC = sourceSSRC;
}
/**
* Writes a specific synchronization source identifier (SSRC) into a
* specific byte array starting at a specific offset.
*
* @param ssrc the synchronization source identifier (SSRC) to write into
* buf starting at off
* @param buf the byte array to write the specified ssrc
* into starting at off
* @param off the offset in buf at which the writing of
* ssrc is to start
*/
public static void writeSSRC(long ssrc, byte[] buf, int off)
{
buf[off++] = (byte) (ssrc >> 24);
buf[off++] = (byte) ((ssrc >> 16) & 0xFF);
buf[off++] = (byte) ((ssrc >> 8) & 0xFF);
buf[off] = (byte) (ssrc & 0xFF);
}
/**
* Write the RTCP packet representation of this instance into a specific
* OutputDataStream.
*
* @param out the OutputDataStream into which the RTCP packet
* representation of this instance is to be written
*/
public void writeTo(OutputDataStream out)
{
/*
* The length of this RTCP packet in 32-bit words minus one, including
* the header and any padding.
*/
int fmt = getFeedbackMessageType();
int pt = getPayloadType();
boolean fir = pt == RTCPFeedbackMessageEvent.PT_PS
&& fmt == RTCPFeedbackMessageEvent.FMT_FIR;
int rtcpPacketLength = 2;
if (fir)
{
/*
* RFC 5104 "Codec Control Messages in the RTP Audio-Visual Profile
* with Feedback (AVPF)" defines that The length of the FIR feedback
* message MUST be set to 2 + 2 * N, where N is the number of FCI
* entries.
*/
rtcpPacketLength += 2 * /* N */ 1;
}
int len = (rtcpPacketLength + 1) * 4;
byte[] buf = new byte[len];
int off = 0;
/*
* version (V): 2 bits,
* padding (P): 1 bit,
* feedback message type (FMT): 5 bits.
*/
buf[off++] = (byte) (0x80 /* RTP version */ | (fmt & 0x1F));
// packet type (PT): 8 bits
buf[off++] = (byte) pt;
// length: 16 bits
buf[off++] = (byte) ((rtcpPacketLength & 0xFF00) >> 8);
buf[off++] = (byte) (rtcpPacketLength & 0x00FF);
// SSRC of packet sender: 32 bits
writeSSRC(getSenderSSRC(), buf, off);
off += 4;
// SSRC of media source: 32 bits
long sourceSSRC = getSourceSSRC();
/*
* RFC 5104 "Codec Control Messages in the RTP Audio-Visual Profile with
* Feedback (AVPF)" defines that the "SSRC of media source" is not used
* by the FIR feedback message and SHALL be set to 0.
*/
writeSSRC(
fir ? 0 : sourceSSRC,
buf,
off);
off += 4;
// FCI entries
if (fir)
{
/*
* SSRC: 32 bits. The SSRC value of the media sender that is
* requested to send a decoder refresh point.
*/
writeSSRC(sourceSSRC, buf, off);
off += 4;
// Seq nr.: 8 bits
buf[off++] = (byte) (getSequenceNumber() % 256);
/*
* Reserved: 24 bits. All bits SHALL be set to 0 by the sender and
* SHALL be ignored on reception.
*/
buf[off++] = 0;
buf[off++] = 0;
buf[off++] = 0;
}
out.write(buf, 0, len);
}
}
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