private void completeHeader(RtmpHeader rtmpHeader)
{
prevousHeaders.TryGetValue(rtmpHeader.Csid, out RtmpHeader prev);
if (prev == null)
{
return;
}
switch (rtmpHeader.Fmt)
{
case Constants.CHUNK_FMT_1:
rtmpHeader.MessageStreamId = prev.MessageStreamId;
break;
case Constants.CHUNK_FMT_2:
rtmpHeader.MessageLength = prev.MessageLength;
rtmpHeader.MessageStreamId = prev.MessageStreamId;
rtmpHeader.MessageTypeId = prev.MessageTypeId;
break;
case Constants.CHUNK_FMT_3:
rtmpHeader.MessageStreamId = prev.MessageStreamId;
rtmpHeader.MessageTypeId = prev.MessageTypeId;
rtmpHeader.Timestamp = prev.Timestamp;
rtmpHeader.TimestampDelta = prev.TimestampDelta;
break;
default:
break;
}
}
protected override void Decode(IChannelHandlerContext context, IByteBuffer input, List <object> output)
{
var state = State;
if (state == DecodeState.NONE)
{
Checkpoint(DecodeState.STATE_HEADER);
}
else if (state == DecodeState.STATE_HEADER)
{
RtmpHeader rtmpHeader = ReadHeader(input);
completeHeader(rtmpHeader);
_currentCsid = rtmpHeader.Csid;
// initialize the payload
if (rtmpHeader.Fmt != Constants.CHUNK_FMT_3)
{
IByteBuffer buffer = Unpooled.Buffer(rtmpHeader.MessageLength, rtmpHeader.MessageLength);
inCompletePayload.Remove(rtmpHeader.Csid);
prevousHeaders.Remove(rtmpHeader.Csid);
inCompletePayload.Add(rtmpHeader.Csid, buffer);
prevousHeaders.Add(rtmpHeader.Csid, rtmpHeader);
}
_currentPayload = inCompletePayload.GetValueOrDefault(rtmpHeader.Csid);
if (_currentPayload == null)
{
RtmpHeader previousHeader = prevousHeaders.GetValueOrDefault(rtmpHeader.Csid);
_currentPayload = Unpooled.Buffer(previousHeader.MessageLength, previousHeader.MessageLength);
inCompletePayload.Add(rtmpHeader.Csid, _currentPayload);
}
Checkpoint(DecodeState.STATE_PAYLOAD);
}
else if (state == DecodeState.STATE_PAYLOAD)
{
byte[] bytes = new byte[Math.Min(_currentPayload.WritableBytes, _clientChunkSize)];
input.ReadBytes(bytes);
_currentPayload.WriteBytes(bytes);
Checkpoint(DecodeState.STATE_HEADER);
if (_currentPayload.IsWritable())
{
return;
}
inCompletePayload.Remove(_currentCsid, out IByteBuffer byteBuffer);
IByteBuffer payload = _currentPayload;
RtmpHeader header = prevousHeaders.GetValueOrDefault(_currentCsid);
var msg = RtmpMessageDecoder.Decode(header, payload);
if (msg == null)
{
return;
}
if (msg is SetChunkSize)
{
var scs = (SetChunkSize)msg;
_clientChunkSize = scs.ChunkSize;
}
else
{
output.Add(msg);
}
}
}
private RtmpHeader ReadHeader(IByteBuffer input)
{
RtmpHeader rtmpHeader = new RtmpHeader();
// alway from the beginning
int headerLength = 0;
byte firstByte = input.ReadByte();
headerLength += 1;
// CHUNK HEADER is divided into
// BASIC HEADER
// MESSAGE HEADER
// EXTENDED TIMESTAMP
// BASIC HEADER
// fmt and chunk steam id in first byte
int fmt = (firstByte & 0xff) >> 6;
int csid = (firstByte & 0x3f);
if (csid == 0)
{
// 2 byte form
csid = input.ReadByte() & 0xff + 64;
headerLength += 1;
}
else if (csid == 1)
{
// 3 byte form
byte secondByte = input.ReadByte();
byte thirdByte = input.ReadByte();
csid = (thirdByte & 0xff) << 8 + (secondByte & 0xff) + 64;
headerLength += 2;
}
else if (csid >= 2)
{
// that's it!
}
rtmpHeader.Csid = csid;
rtmpHeader.Fmt = fmt;
// basic header complete
// MESSAGE HEADER
switch (fmt)
{
case Constants.CHUNK_FMT_0:
{
int timestamp = input.ReadMedium();
int messageLength = input.ReadMedium();
short messageTypeId = (short)(input.ReadByte() & 0xff);
int messageStreamId = input.ReadIntLE();
headerLength += 11;
if (timestamp == Constants.MAX_TIMESTAMP)
{
long extendedTimestamp = input.ReadInt();
rtmpHeader.ExtendedTimestamp = extendedTimestamp;
headerLength += 4;
}
rtmpHeader.Timestamp = timestamp;
rtmpHeader.MessageTypeId = messageTypeId;
rtmpHeader.MessageStreamId = messageStreamId;
rtmpHeader.MessageLength = messageLength;
}
break;
case Constants.CHUNK_FMT_1:
{
int timestampDelta = input.ReadMedium();
int messageLength = input.ReadMedium();
short messageType = (short)(input.ReadByte() & 0xff);
headerLength += 7;
if (timestampDelta == Constants.MAX_TIMESTAMP)
{
long extendedTimestamp = input.ReadInt();
rtmpHeader.ExtendedTimestamp = extendedTimestamp;
headerLength += 4;
}
rtmpHeader.TimestampDelta = timestampDelta;
rtmpHeader.MessageLength = messageLength;
rtmpHeader.MessageTypeId = messageType;
}
break;
case Constants.CHUNK_FMT_2:
{
int timestampDelta = input.ReadMedium();
headerLength += 3;
rtmpHeader.TimestampDelta = timestampDelta;
if (timestampDelta == Constants.MAX_TIMESTAMP)
{
long extendedTimestamp = input.ReadInt();
rtmpHeader.ExtendedTimestamp = extendedTimestamp;
headerLength += 4;
}
}
break;
case Constants.CHUNK_FMT_3:
break;
default:
throw new ArgumentException("illegal fmt type:" + fmt);
}
rtmpHeader.HeaderLength = headerLength;
return(rtmpHeader);
}