108 lines
2.6 KiB
Go
108 lines
2.6 KiB
Go
|
package rtcp
|
||
|
|
|
||
|
|
import (
|
||
|
|
"encoding/binary"
|
||
|
|
"fmt"
|
||
|
|
)
|
||
|
|
|
||
|
|
// A FIREntry is a (SSRC, seqno) pair, as carried by FullIntraRequest.
|
||
|
|
type FIREntry struct {
|
||
|
|
SSRC uint32
|
||
|
|
SequenceNumber uint8
|
||
|
|
}
|
||
|
|
|
||
|
|
// The FullIntraRequest packet is used to reliably request an Intra frame
|
||
|
|
// in a video stream. See RFC 5104 Section 3.5.1. This is not for loss
|
||
|
|
// recovery, which should use PictureLossIndication (PLI) instead.
|
||
|
|
type FullIntraRequest struct {
|
||
|
|
SenderSSRC uint32
|
||
|
|
MediaSSRC uint32
|
||
|
|
|
||
|
|
FIR []FIREntry
|
||
|
|
}
|
||
|
|
|
||
|
|
const (
|
||
|
|
firOffset = 8
|
||
|
|
)
|
||
|
|
|
||
|
|
var _ Packet = (*FullIntraRequest)(nil)
|
||
|
|
|
||
|
|
// Marshal encodes the FullIntraRequest
|
||
|
|
func (p FullIntraRequest) Marshal() ([]byte, error) {
|
||
|
|
rawPacket := make([]byte, firOffset+(len(p.FIR)*8))
|
||
|
|
binary.BigEndian.PutUint32(rawPacket, p.SenderSSRC)
|
||
|
|
binary.BigEndian.PutUint32(rawPacket[4:], p.MediaSSRC)
|
||
|
|
for i, fir := range p.FIR {
|
||
|
|
binary.BigEndian.PutUint32(rawPacket[firOffset+8*i:], fir.SSRC)
|
||
|
|
rawPacket[firOffset+8*i+4] = fir.SequenceNumber
|
||
|
|
}
|
||
|
|
h := p.Header()
|
||
|
|
hData, err := h.Marshal()
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
|
||
|
|
return append(hData, rawPacket...), nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// Unmarshal decodes the TransportLayerNack
|
||
|
|
func (p *FullIntraRequest) 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 != TypePayloadSpecificFeedback || h.Count != FormatFIR {
|
||
|
|
return errWrongType
|
||
|
|
}
|
||
|
|
|
||
|
|
p.SenderSSRC = binary.BigEndian.Uint32(rawPacket[headerLength:])
|
||
|
|
p.MediaSSRC = binary.BigEndian.Uint32(rawPacket[headerLength+ssrcLength:])
|
||
|
|
for i := headerLength + firOffset; i < (headerLength + int(h.Length*4)); i += 8 {
|
||
|
|
p.FIR = append(p.FIR, FIREntry{
|
||
|
|
binary.BigEndian.Uint32(rawPacket[i:]),
|
||
|
|
rawPacket[i+4],
|
||
|
|
})
|
||
|
|
}
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// Header returns the Header associated with this packet.
|
||
|
|
func (p *FullIntraRequest) Header() Header {
|
||
|
|
return Header{
|
||
|
|
Count: FormatFIR,
|
||
|
|
Type: TypePayloadSpecificFeedback,
|
||
|
|
Length: uint16((p.len() / 4) - 1),
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
func (p *FullIntraRequest) len() int {
|
||
|
|
return headerLength + firOffset + len(p.FIR)*8
|
||
|
|
}
|
||
|
|
|
||
|
|
func (p *FullIntraRequest) String() string {
|
||
|
|
out := fmt.Sprintf("FullIntraRequest %x %x",
|
||
|
|
p.SenderSSRC, p.MediaSSRC)
|
||
|
|
for _, e := range p.FIR {
|
||
|
|
out += fmt.Sprintf(" (%x %v)", e.SSRC, e.SequenceNumber)
|
||
|
|
}
|
||
|
|
return out
|
||
|
|
}
|
||
|
|
|
||
|
|
// DestinationSSRC returns an array of SSRC values that this packet refers to.
|
||
|
|
func (p *FullIntraRequest) DestinationSSRC() []uint32 {
|
||
|
|
ssrcs := make([]uint32, 0, len(p.FIR))
|
||
|
|
for _, entry := range p.FIR {
|
||
|
|
ssrcs = append(ssrcs, entry.SSRC)
|
||
|
|
}
|
||
|
|
return ssrcs
|
||
|
|
}
|