gortmp/chunkstream.go

package rtmp

type OutboundChunkStream struct {
	Id                       uint32
	lastHeader               *Header
	lastOutAbsoluteTimestamp uint32
	lastInAbsoluteTimestamp  uint32
	startAtTimestamp         uint32
}

type InboundChunkStream struct {
	Id                       uint32
	lastHeader               *Header
	lastOutAbsoluteTimestamp uint32
	lastInAbsoluteTimestamp  uint32
	currentMessage           *Message
}

func NewOutboundChunkStream(id uint32) *OutboundChunkStream {
	return &OutboundChunkStream{
		Id: id,
	}
}

func NewInboundChunkStream(id uint32) *InboundChunkStream {
	return &InboundChunkStream{
		Id: id,
	}
}

func (cs *OutboundChunkStream) NewOutboundHeader(m *Message) *Header {
	h := &Header{
		ChunkStreamId:   cs.Id,
		MessageLength:   uint32(m.Buffer.Len()),
		MessageTypeId:   m.Type,
		MessageStreamId: m.StreamId,
	}

	ts := m.Timestamp
	if ts == TIMESTAMP_AUTO {
		ts = cs.GetTimestamp()
		m.Timestamp = ts
		m.AbsoluteTimestamp = ts
	}

	deltaTimestamp := uint32(0)
	if cs.lastOutAbsoluteTimestamp < m.Timestamp {
		deltaTimestamp = m.Timestamp - cs.lastOutAbsoluteTimestamp
	}

	if cs.lastHeader == nil {
		h.Format = HEADER_FORMAT_FULL
		h.Timestamp = ts
	} else {
		if h.MessageStreamId == cs.lastHeader.MessageStreamId {
			if h.MessageTypeId == cs.lastHeader.MessageTypeId && h.MessageLength == cs.lastHeader.MessageLength {
				switch cs.lastHeader.Format {
				case HEADER_FORMAT_FULL:
					h.Format = HEADER_FORMAT_SAME_LENGTH_AND_STREAM
					h.Timestamp = deltaTimestamp
				case HEADER_FORMAT_SAME_STREAM:
					fallthrough
				case HEADER_FORMAT_SAME_LENGTH_AND_STREAM:
					fallthrough
				case HEADER_FORMAT_CONTINUATION:
					if cs.lastHeader.Timestamp == deltaTimestamp {
						h.Format = HEADER_FORMAT_CONTINUATION
					} else {
						h.Format = HEADER_FORMAT_SAME_LENGTH_AND_STREAM
						h.Timestamp = deltaTimestamp
					}
				}
			} else {
				h.Format = HEADER_FORMAT_SAME_STREAM
				h.Timestamp = ts
			}
		}
	}

	if h.Timestamp >= TIMESTAMP_EXTENDED {
		h.ExtendedTimestamp = m.Timestamp
		h.Timestamp = TIMESTAMP_EXTENDED
	} else {
		h.ExtendedTimestamp = 0
	}

	cs.lastHeader = h
	cs.lastOutAbsoluteTimestamp = ts

	return h
}

func (cs *OutboundChunkStream) GetTimestamp() uint32 {
	if cs.startAtTimestamp == uint32(0) {
		cs.startAtTimestamp = GetCurrentTimestamp()
		return uint32(0)
	}

	return GetCurrentTimestamp() - cs.startAtTimestamp
}