diff options
Diffstat (limited to 'vendor/github.com/pion/rtcp/slice_loss_indication.go')
-rw-r--r-- | vendor/github.com/pion/rtcp/slice_loss_indication.go | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/vendor/github.com/pion/rtcp/slice_loss_indication.go b/vendor/github.com/pion/rtcp/slice_loss_indication.go new file mode 100644 index 0000000..7689309 --- /dev/null +++ b/vendor/github.com/pion/rtcp/slice_loss_indication.go @@ -0,0 +1,115 @@ +package rtcp + +import ( + "encoding/binary" + "fmt" + "math" +) + +// SLIEntry represents a single entry to the SLI packet's +// list of lost slices. +type SLIEntry struct { + // ID of first lost slice + First uint16 + + // Number of lost slices + Number uint16 + + // ID of related picture + Picture uint8 +} + +// The SliceLossIndication packet informs the encoder about the loss of a picture slice +type SliceLossIndication struct { + // SSRC of sender + SenderSSRC uint32 + + // SSRC of the media source + MediaSSRC uint32 + + SLI []SLIEntry +} + +var _ Packet = (*SliceLossIndication)(nil) // assert is a Packet + +const ( + sliLength = 2 + sliOffset = 8 +) + +// Marshal encodes the SliceLossIndication in binary +func (p SliceLossIndication) Marshal() ([]byte, error) { + if len(p.SLI)+sliLength > math.MaxUint8 { + return nil, errTooManyReports + } + + rawPacket := make([]byte, sliOffset+(len(p.SLI)*4)) + binary.BigEndian.PutUint32(rawPacket, p.SenderSSRC) + binary.BigEndian.PutUint32(rawPacket[4:], p.MediaSSRC) + for i, s := range p.SLI { + sli := ((uint32(s.First) & 0x1FFF) << 19) | + ((uint32(s.Number) & 0x1FFF) << 6) | + (uint32(s.Picture) & 0x3F) + binary.BigEndian.PutUint32(rawPacket[sliOffset+(4*i):], sli) + } + hData, err := p.Header().Marshal() + if err != nil { + return nil, err + } + + return append(hData, rawPacket...), nil +} + +// Unmarshal decodes the SliceLossIndication from binary +func (p *SliceLossIndication) Unmarshal(rawPacket []byte) error { + if len(rawPacket) < (headerLength + ssrcLength) { + return errPacketTooShort + } + + var h Header + if err := h.Unmarshal(rawPacket); err != nil { + return err + } + + if len(rawPacket) < (headerLength + int(4*h.Length)) { + return errPacketTooShort + } + + if h.Type != TypeTransportSpecificFeedback || h.Count != FormatSLI { + return errWrongType + } + + p.SenderSSRC = binary.BigEndian.Uint32(rawPacket[headerLength:]) + p.MediaSSRC = binary.BigEndian.Uint32(rawPacket[headerLength+ssrcLength:]) + for i := headerLength + sliOffset; i < (headerLength + int(h.Length*4)); i += 4 { + sli := binary.BigEndian.Uint32(rawPacket[i:]) + p.SLI = append(p.SLI, SLIEntry{ + First: uint16((sli >> 19) & 0x1FFF), + Number: uint16((sli >> 6) & 0x1FFF), + Picture: uint8(sli & 0x3F), + }) + } + return nil +} + +func (p *SliceLossIndication) len() int { + return headerLength + sliOffset + (len(p.SLI) * 4) +} + +// Header returns the Header associated with this packet. +func (p *SliceLossIndication) Header() Header { + return Header{ + Count: FormatSLI, + Type: TypeTransportSpecificFeedback, + Length: uint16((p.len() / 4) - 1), + } +} + +func (p *SliceLossIndication) String() string { + return fmt.Sprintf("SliceLossIndication %x %x %+v", p.SenderSSRC, p.MediaSSRC, p.SLI) +} + +// DestinationSSRC returns an array of SSRC values that this packet refers to. +func (p *SliceLossIndication) DestinationSSRC() []uint32 { + return []uint32{p.MediaSSRC} +} |