/// <summary>
/// This method creates as many checksum buffers as exist in the checksum array
/// </summary>
/// <param name="bytes">Array of buffer chunk that represents the data to encode</param>
/// <param name="checksum">Contains 1 BufferChunk, which should be Reset() before calling</param>
/// <returns>The checksum packet</returns>
public void Encode(BufferChunk[] data, BufferChunk[] checksum)
{
ValidateObjectNotNull(data);
ValidateObjectNotNull(checksum);
ValidateNullData(data, 0);
ValidateNullData(checksum, 0);
ValidateChecksumPacketCount(checksum.Length);
// Sort the BufferChunks from longest to shortest
ActiveColumns(data, data.Length);
// Add 2 bytes so the checksum packet can contain the length of the missing packet
int xorDataLength = activeColumns[0].Length + 2;
BufferChunk xorData = checksum[0];
int index = xorData.Index;
// Store the xor'd lengths of the data
xorData += (ushort)(XORLength() ^ xorDataLength);
xorData.Reset(index + 2, xorDataLength - 2);
// Populate the checksum buffer (xorData)
XORData(xorData, xorDataLength - 2);
// Set xorData.Index back to 0
xorData.Reset(index, xorDataLength);
}
/// <summary>
/// Set the payload; this version allows the payload to occupy the space
/// reserved for packet padding. This is used by encryption protocols.
/// </summary>
/// <param name="chunk"></param>
internal void SetPaddedPayload(BufferChunk chunk)
{
if (chunk.Length > (MaxPayloadSize + ReservedPaddingBytes))
{
throw new ArgumentOutOfRangeException(string.Format(CultureInfo.CurrentCulture,
Strings.ValueMaximumPayload, chunk.Length, MaxPayloadSize));
}
// Reset Buffer to just after the header because packets are re-used and so that
// operator+ works properly when copying the payload
buffer.Reset(0, HeaderSize);
buffer += chunk;
}
internal virtual void Reset()
{
buffer.Reset(0, HeaderSize);
// Initialize the first byte: V==2, P==0, X==0, CC==0
buffer[VPXCC_INDEX] = (byte)(Rtp.VERSION << 6);
}
/// <summary>
/// Encode the packets that are in the data BufferChunk array and place the
/// encoded result over GF16 in the checksum packets that are in
/// the result BufferChunk array. This method encode the size on the first 2
/// bytes of the checksum packet and the data after that. Every checksum BufferChunk
/// has the same size, which is the size of the largest BufferChunk in the data BufferChunk
/// array, plus one if this BufferChunk doesn't end on a 16 bits boundary, plus
/// two to store the encoded length
/// </summary>
/// <param name="data">The data BufferChunk array (left part of the multiplication)</param>
/// <param name="result"></param>
/// <param name="encode">The encoding Vandermonde GF16 matrix (right part of the multiplication)</param>
public static void EncodeRS(BufferChunk[] data, BufferChunk[] checksum, UInt16[,] encode)
{
// Get the length in byte of largest BufferChunk in the data BufferChunk array
// (which is an array of BufferChunk that could have different sizes)
int maxDataLength = GetMaxLength(data);
// The checksum packet as a even number of bytes so we can stay with GF16
// and not have to use GF8 for the last byte when length odd
int checksumNbRowsByte = maxDataLength;
if ((maxDataLength & 1) == 1)
{
checksumNbRowsByte += 1;
}
// Add 2 more bytes to store the length
checksumNbRowsByte += CFec.SIZE_OVERHEAD;
// Encode the length of the data and place that on the first 2 bytes
// of the checksum BufferChunk
EncodeRSLength(data, checksum, encode);
// Start to put encoded data at index + 2, because the 2 first bytes
// of the checksum already contain the encoded size
for (int i = 0; i < checksum.Length; i++)
{
BufferChunk bc = checksum[i];
bc.Reset(bc.Index + CFec.SIZE_OVERHEAD, checksumNbRowsByte - CFec.SIZE_OVERHEAD);
// Reset all of the checksum packets so they have no data
// TODO - Temporary workaround for column based approach - JVE 7/6/2004
bc.Clear();
}
// Place all the packets in a 16bits boundary to avoid byte operation
// Important: This suppose that the memory reserved for all the bc passed in param
// to this method ends on a 16bits boundary (so at least one addition availabe byte
// when the last item is on a even address)
Queue paddedData = new Queue();
AddPadding(data, 0, paddedData);
// Encode the data and place the encoded information in the checksum BufferChunk
EncodeRSData(data, checksum, encode, maxDataLength);
// Earlier, we changed the boundary of all data BufferChunk
// that was not ending on a 16 bits boundary in order to have
// better performance during the encoding. Now we need to
// restore the data to their original state to be clean.
RemovePadding(paddedData);
// Restore the BufferChunk index in the checksum checksum BufferChunk
// to 0 to be clean. Earlier, We changed the index in order to encode
// the data after the encoding length.
for (int i = 0; i < checksum.Length; i++)
{
BufferChunk bc = checksum[i];
bc.Reset(bc.Index - CFec.SIZE_OVERHEAD, checksumNbRowsByte);
}
}
/// <summary>
/// retrieve the next bufferchunk and timestamp for the stream. Return false if there are no more.
/// </summary>
public bool GetNextFrame(out BufferChunk outFrame, out long timestamp)
{
outFrame = null;
timestamp = 0;
bool ret = false;
if (streamEndReached)
{
return(false);
}
if (currentIndex >= indexCount)
{
FillBuffer();
}
if (currentIndex < indexCount)
{
int frameLength = 1 + indices[currentIndex].end - indices[currentIndex].start;
if (frameLength > 0)
{
if (indices[currentIndex].timestamp < end)
{
frame.Reset(indices[currentIndex].start - this.minOffset, frameLength);
outFrame = frame;
timestamp = indices[currentIndex].timestamp;
ret = true;
}
else
{
streamEndReached = true;
ret = false;
}
}
else
{
Debug.Fail("Frame of length zero found.");
ret = false;
}
++currentIndex;
return(ret);
}
else
{
return(false);
}
}
/// <summary>
/// Decoder: This method takes an array of BufferChunk in parameter with the data
/// and checksum received and returns the missing packets. Because it
/// is based on XOR, it can recover only from one packet lost. This method
/// is very similar than encoder, but differ in the validation part.
/// </summary>
/// <param name="bytes">Array of buffer chunk that represents the packets where
/// you might have lost a packet</param>
/// <param name="nbChecksumPackets">Should be always set to 1</param>
/// <returns>The missing packet</returns>
public void Decode(BufferChunk[] data, int nbChecksumPackets, BufferChunk[] recovery)
{
ValidateObjectNotNull(data);
ValidateObjectNotNull(data[data.Length - 1]); // Checksum packet can't be null
ValidateChecksumPacketCount(nbChecksumPackets);
ValidateNullData(data, 1);
// Sort the BufferChunks from longest to shortest
ActiveColumns(data, data.Length - 1);
int xorDataLength = XORLength() ^ data[data.Length - 1].NextUInt16();
BufferChunk xorData = recovery[0];
xorData.Reset(xorData.Index, xorDataLength);
XORData(xorData, xorDataLength);
}
/// <summary>
/// Decode to retrieve the missing data packet(s) (null entries) in the data BufferChunk array and place the
/// decoded result over GF16 in order in the recovery BufferChunk array with the right length (every
/// data packet can have a different length)
/// </summary>
/// <param name="checksum">The number of checksum packet(s) that were used to encode</param>
/// <param name="data">The data BufferChunk array</param>
/// <param name="decode">The decoding GF16 matrix</param>
/// <param name="recovery">The recovery BufferChunk array to place the recovered result</param>
public static void DecodeRS(int checksum, BufferChunk[] data, GF16[,] decode, BufferChunk[] recovery)
{
// TODO: Validation discussed with Jason:
// Check in data array if: the #data lost = # checksum and if this number = recovery.length
// Decode the length and set it to the recovery packets
DecodeRSLength(data, checksum, decode, recovery);
// ... and don't forget to adjust the index of the checksum BufferChunk because
// we don't want to take in account the length anymore
int dataLength = data.Length;
for (int i = dataLength - checksum; i < dataLength; i++)
{
BufferChunk bc = data[i];
if (bc != null)
{
bc.Reset(bc.Index + CFec.SIZE_OVERHEAD, bc.Length - CFec.SIZE_OVERHEAD);
}
}
// Adjust all of the data (and recovery) to a 16bit boundary to avoid byte operations
// Important: This assumes the provided BufferChunks have room to grow to 16bit boundary
Queue paddedBufferChunks = new Queue();
AddPadding(data, checksum, paddedBufferChunks);
AddPadding(recovery, 0, paddedBufferChunks);
// Decode the data and set the result into the recovery packets
DecodeRSData(data, checksum, decode, recovery);
// Reset all the packets back to their initial length
RemovePadding(paddedBufferChunks);
// The caller is responsible for resetting all BufferChunks so there is no need
// to reset the checksum packets
}
/// <summary>
/// This method is called to return buffers to the bufferPool
/// </summary>
/// <param name="buffer"></param>
private void ReturnBuffer(BufferChunk buffer)
{
buffer.Reset();
bufferPool.Push(buffer);
}
/// <summary>
/// Send all the frames that should be sent up to this point in time.
/// </summary>
/// <param name="bytesSent">Number of bytes sent.</param>
/// <param name="cumulativeLateness">Sum of temporal disparities over all frames sent.</param>
/// <param name="firstStoredTick">The 'start' time on the first index in this whole stream.</param>
/// <param name="sender">The RtpSender to send data on.</param>
/// <param name="startTimeTicks">The start time of sending, in ticks.</param>
/// <param name="timeUntilFrame">The temporal distance between the current frame and the next one to be sent, in ticks.</param>
/// <returns>Number of frames sent.</returns>
public int SendFrames(RtpSender sender, long timeBoundary, out long timeUntilFrame, ref long totalBytesSent, ref long cumulativeLateness)
{
if (this.populating)
{
throw new InvalidOperationException(Strings.BufferplayerSendframesError);
}
int framesSent = 0;
try
{
while (currentIndex < indexCount && indices[currentIndex].timestamp <= timeBoundary)
{
long startTimer = DateTime.Now.Ticks;
int frameLength = 1 + indices[currentIndex].end - indices[currentIndex].start;
if (frameLength > 0)
{
// Calculate how late the frame will be
long lateness = (timeBoundary - indices[currentIndex].timestamp) / Constants.TicksPerMs;
if (lateness > Constants.TicksSpent)
{
Trace.WriteLine(String.Format(CultureInfo.InvariantCulture,
"--- FRAME LATENESS OF: {0} ms", lateness));
}
cumulativeLateness += lateness;
// Send Frame
buffer.Reset(indices[currentIndex].start - indices[0].start, frameLength);
sender.Send(buffer);
}
else
{
// (pbristow) Why would this happen???
Debug.Fail("Frame of length zero found.");
}
totalBytesSent += frameLength;
++framesSent;
++currentIndex;
long takenTime = DateTime.Now.Ticks - startTimer;
if (takenTime > Constants.TicksSpent)
{
Trace.WriteLine(String.Format(CultureInfo.InvariantCulture,
"TIME WASTED TO SEND A FRAME: {0} ms, ID: {1}, bytes: {2}",
(takenTime / Constants.TicksPerMs), streamID, frameLength));
}
}
if (currentIndex == indexCount)
{
timeUntilFrame = 0;
}
else
{
timeUntilFrame = (indices[currentIndex].timestamp - timeBoundary);
}
}
catch (ObjectDisposedException)
{
// Sender is disposed by Stop being called
timeUntilFrame = long.MaxValue;
}
return(framesSent);
}
/// <summary>
/// This method is called to return buffers to the bufferPool
/// </summary>
/// <param name="buffer"></param>
private void ReturnBuffer(BufferChunk buffer)
{
buffer.Reset();
bufferPool.Push(buffer);
}
/// <summary>
/// Decode to retrieve the length of the missing data packet(s) (null entries) in the
/// data BufferChunk array and set the length of the packets in the recovery BufferChunk array.
/// We have to do that because every data packet could have a different length.
/// </summary>
/// <param name="data">The data BufferChunk array</param>
/// <param name="checksum">The number of checksum packet(s) that were used to encode</param>
/// <param name="decode">The decoding GF16 matrix</param>
/// <param name="recovery">The recovery BufferChunk array to set the length of the recovered packets</param>
private static void DecodeRSLength(BufferChunk[] data, int checksum, GF16[,] decode, BufferChunk[] recovery)
{
// Important! For now I assume the following in the firstMatrix:
// - The array is always of size data + checksum
// - #checksum not null entries = #packet lost
// - recovery.length is exactly the number of data packet lost
// - checksum param is # checksum packets that were used to encode
// Get the length once to avoid having the overhead of getting it again inside a inner (performance)
// Note that this value is also used outside of this method, so we could have had a parameter too,
// but I prefer to get it here to avoid inconsitencies
int dataLength = data.Length;
int recoveryColumn = 0;
for (int dataColumn = 0; dataColumn < dataLength - checksum; dataColumn++)
{
// recover only the missing column
if (data[dataColumn] == null)
{
// Inverted matrix row index
int imRowIndex = 0;
// length of the recovered buffer
UInt16 currentLength = 0;
for (int dataIndex = 0; dataIndex < dataLength; dataIndex++)
{
// Perform the core operation mult with add in GF16
// TODO: We could crunch the column so we avoid this test
if (data[dataIndex] != null)
{
UInt16 length = 0;
if (dataIndex < dataLength - checksum) // For the data part, we get the length of the BufferChunk
{
length = (UInt16)data[dataIndex].Length;
}
else // For the checksum part, the encoded length is inside the first 2 bytes
{
length = data[dataIndex].GetUInt16(0);
}
UInt16 currentValue = GF16.Multiply(length, decode[dataColumn, imRowIndex].Value);
currentLength = GF16.Add(currentLength, currentValue);
imRowIndex++;
} // if
} // for column (do elementary operations)
BufferChunk bc = recovery[recoveryColumn];
bc.Reset(bc.Index, currentLength);
// Reset all of the recovery packets so they have no data
// TODO - Temporary workaround for column based approach - JVE 7/6/2004
bc.Clear();
recoveryColumn++;
} // if
} // for dataColumn
}
override public void Run()
{
BufferChunk bc = new BufferChunk(7);
short s = 25000;
int i = 545434;
byte b = 56;
bc += s;
bc += i;
bc += b;
if (bc.NextInt16() != s)
throw new TestCaseException("Short failed for " + s);
if (bc.NextInt32() != i)
throw new TestCaseException("Int failed for " + i);
if (bc.NextByte() != b)
throw new TestCaseException("Byte failed for " + b);
bc.Reset();
s = short.MaxValue;
i = int.MaxValue;
b = byte.MaxValue;
bc += s;
bc += i;
bc += b;
if (bc.NextInt16() != s)
throw new TestCaseException("Short failed for " + s);
if (bc.NextInt32() != i)
throw new TestCaseException("Int failed for " + i);
if (bc.NextByte() != b)
throw new TestCaseException("Byte failed for " + b);
bc.Reset();
s = short.MinValue;
i = int.MinValue;
b = byte.MinValue;
bc += s;
bc += i;
bc += b;
if (bc.NextInt16() != s)
throw new TestCaseException("Short failed for " + s);
if (bc.NextInt32() != i)
throw new TestCaseException("Int failed for " + i);
if (bc.NextByte() != b)
throw new TestCaseException("Byte failed for " + b);
}
/// <summary>
/// This method is called to return buffers to the bufferPool
/// </summary>
/// <param name="buffer"></param>
private void ReturnBuffer(BufferChunk buffer)
{
buffer.Reset();
if (null != bufferPool)
{
bufferPool.Push(buffer);
}
else
{
Console.WriteLine("RtpListener.ReturnBuffer() - Buffer Pool is null");
}
}
/// <summary>
/// Called by RtcpSender when it is time to collect Rtcp data
/// </summary>
/// <returns>A CompoundPacketBuilder</returns>
CompoundPacketBuilder RtcpSender.IRtpSession.RtcpReportIntervalReached()
{
// Limit the frequency of the cleanup in order to avoid participants and streams being
// inappropriately designated as stale. This can happen if we start up a lot of senders at once.
// Each sender triggers an RTCP packet which without the frequency limitation could
// increment the stale counter to its limit and cause the participant or stream to be removed.
bool cleanUpNow = false;
if (DateTime.Now > this.lastCleanUp.AddSeconds(5)) {
cleanUpNow = true;
this.lastCleanUp = DateTime.Now;
}
// A stale participant is one who is not sending Rtcp data
if (cleanUpNow)
CheckForStaleParticipants();
// Add participant data
Debug.Assert(participant.SSRC != 0);
cpb.ParticipantData(participant);
// Add Rtp data
if(rtpTraffic)
{
// A stale stream is one not sending Rtp traffic
if (cleanUpNow)
CheckForStaleStreams();
// Collect SenderReportPackets and SDESReports from each Sender
lock(rtpSenders)
{
foreach(RtpSender sender in rtpSenders.Values)
{
// this adds the SR and SDES packets
sender.UpdateRtcpData();
}
}
// add a sdes (source description)
//cpb.Add_SDESReport(participant.SSRC, participant);
// Collect ReceiverReports from each of the streams
lock(streamsAndIPs)
{
foreach(IPStreamPairHashtable.IPStreamPair ipsp in streamsAndIPs.Values)
{
if( ipsp.stream != null )
{
ipsp.stream.AddReceiverReport(cpb);
}
}
}
}
#if USE_APP_PACKET
// andrew: Add an app packet that reflects the time and the current venue...
if ((VenueName != null) && (this.groupEP != null))
{
string appPayload = VenueName + "#" + this.groupEP.Address.ToString();
long time = DateTime.Now.Ticks;
// 8 bytes for time + venue name
int count = 8 + utf8.GetByteCount(appPayload);
// count must be 4-byte alligned
int mod = count % 4;
if (mod != 0)
{
count += (4 - mod);
}
BufferChunk buffer = new BufferChunk(count);
buffer.Reset(0, count);
buffer.Clear();
buffer.SetInt64(0, time);
buffer.SetUTF8String(8, appPayload);
byte[] rawBytes = buffer.Buffer;
cpb.Add_APPReport(participant.SSRC, Rtcp.APP_PACKET_NAME, Rtcp.VENUE_APP_PACKET_SUBTYPE, rawBytes);
}
#endif
return cpb;
}
override public void Run()
{
BufferChunk bc = new BufferChunk(7);
short s = 25000;
int i = 545434;
byte b = 56;
bc += s;
bc += i;
bc += b;
if (bc.NextInt16() != s)
{
throw new TestCaseException("Short failed for " + s);
}
if (bc.NextInt32() != i)
{
throw new TestCaseException("Int failed for " + i);
}
if (bc.NextByte() != b)
{
throw new TestCaseException("Byte failed for " + b);
}
bc.Reset();
s = short.MaxValue;
i = int.MaxValue;
b = byte.MaxValue;
bc += s;
bc += i;
bc += b;
if (bc.NextInt16() != s)
{
throw new TestCaseException("Short failed for " + s);
}
if (bc.NextInt32() != i)
{
throw new TestCaseException("Int failed for " + i);
}
if (bc.NextByte() != b)
{
throw new TestCaseException("Byte failed for " + b);
}
bc.Reset();
s = short.MinValue;
i = int.MinValue;
b = byte.MinValue;
bc += s;
bc += i;
bc += b;
if (bc.NextInt16() != s)
{
throw new TestCaseException("Short failed for " + s);
}
if (bc.NextInt32() != i)
{
throw new TestCaseException("Int failed for " + i);
}
if (bc.NextByte() != b)
{
throw new TestCaseException("Byte failed for " + b);
}
}
