media

package
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 Go to latest Published: Oct 2, 2024 License: MPL-2.0 Imports: 16 Imported by: 1

README

media

Everything is io.Reader and io.Writer

We follow GO std lib and providing interface for Reader/Writer when it comes reading and writing media.
This optimized and made easier usage of RTP framework, by providing end user standard library io.Reader io.Writer to pass his media.

In other words chaining reader or writer allows to build interceptors, encoders, decoders without introducing overhead of contention or many memory allocations

Features:

  • Simple SDP build with formats alaw,ulaw,dtmf
  • RTP/RTCP receiving and logging
  • Extendable MediaSession handling for RTP/RTCP handling (ex microphone,speaker)
  • DTMF encoder, decoder via RFC4733
  • Minimal SDP package for audio
  • Media Session, RTP Session handling
  • RTCP monitoring
  • SDP codec fields manipulating
  • ... who knows

Concepts

  • Media Session represents mapping between SDP media description and creates session based on local/remote addr
  • RTP Session is creating RTP/RTCP session. It is using media session underneath to add networking layer.
  • RTP Packet Reader is depackatizing RTP packets and providing payload as io.Reader. Normally it should be chained to RTP Session
  • RTP Packet Writer is packatizing payload to RTP packets as io.Writer. Normally it should be chained to RTP Session

IO flow

Reader: AudioDecoder<->RTPPacketReader<->RTPSession<->MediaSession

Writer: AudioEncoder<->RTPPackerWriter<->RTPSession<->MediaSession

more docs...

Documentation

Index

Constants

This section is empty.

Variables

View Source 
var (
	CodecAudioUlaw          = Codec{PayloadType: 0, SampleRate: 8000, SampleDur: 20 * time.Millisecond}
	CodecAudioAlaw          = Codec{PayloadType: 8, SampleRate: 8000, SampleDur: 20 * time.Millisecond}
	CodecTelephoneEvent8000 = Codec{PayloadType: 101, SampleRate: 8000, SampleDur: 20 * time.Millisecond}
)
View Source 
var (
	// RTPPortStart and RTPPortEnd allows defining rtp port range for media
	RTPPortStart = 0
	RTPPortEnd   = 0

	// When reading RTP use at least MTU size. Increase this
	RTPBufSize = 1500

	RTPDebug  = false
	RTCPDebug = false
)
View Source 
var (
	ErrRTPSequenceOutOfOrder = errors.New("out of order")
	ErrRTPSequenceBad        = errors.New("bad sequence")
	ErrRTPSequnceDuplicate   = errors.New("sequence duplicate")
)

Functions

func CopyWithBuf 

func CopyWithBuf(reader io.Reader, writer io.Writer, payloadBuf []byte) (int64, error)

CopyWithBuf is simple and strict compared to io.CopyBuffer. ReadFrom and WriteTo is not considered and due to RTP buf requirement it can lead to different buffer size passing

func DTMFDecode 

func DTMFDecode(payload []byte, d *DTMFEvent) error

DecodeRTPPayload decodes an RTP payload into a DTMF event

func DTMFEncode 

func DTMFEncode(d DTMFEvent) []byte

func DTMFToRune 

func DTMFToRune(dtmf uint8) rune

func ErrorIsTimeout 

func ErrorIsTimeout(err error) bool

func FractionLostFloat 

func FractionLostFloat(f uint8) float64

func GetCurrentNTPTimestamp 

func GetCurrentNTPTimestamp() uint64

func NTPTimestamp 

func NTPTimestamp(t time.Time) uint64

func NTPToTime 

func NTPToTime(ntpTimestamp uint64) time.Time

func RTCPUnmarshal 

func RTCPUnmarshal(data []byte, packets []rtcp.Packet) (n int, err error)

RTCPUnmarshal is improved version based on pion/rtcp where we allow caller to define and control buffer of rtcp packets. This also reduces one allocation NOTE: data is still referenced in packet buffer

func RTPUnmarshal 

func RTPUnmarshal(buf []byte, p *rtp.Packet) error

Experimental

RTPUnmarshal temporarly solution to provide more optimized unmarshal version based on pion/rtp it does not preserve any buffer reference which allows reusage

TODO build RTP header unmarshaller for VOIP needs

func SendDummyRTP 

func SendDummyRTP(rtpConn *net.UDPConn, raddr net.Addr)

func StringRTCP added in v0.2.0 

func StringRTCP(p rtcp.Packet) string

Types

type Codec 

type Codec struct {
	PayloadType uint8
	SampleRate  uint32
	SampleDur   time.Duration
}

func CodecFromPayloadType 

func CodecFromPayloadType(payloadType uint8) Codec

func CodecFromSession 

func CodecFromSession(s *MediaSession) Codec

func (*Codec) SampleTimestamp 

func (c *Codec) SampleTimestamp() uint32

func (*Codec) String added in v0.2.0 

func (c *Codec) String() string

type DTMFEvent 

type DTMFEvent struct {
	Event      uint8
	EndOfEvent bool
	Volume     uint8
	Duration   uint16
}

DTMFEvent represents a DTMF event

func RTPDTMFEncode 

func RTPDTMFEncode(char rune) []DTMFEvent

RTPDTMFEncode creates series of DTMF redudant events which should be encoded as payload It is currently only 8000 sample rate considered for telophone event

func (*DTMFEvent) String 

func (ev *DTMFEvent) String() string

type MediaSession 

type MediaSession struct {
	// Raddr is our target remote address. Normally it is resolved by SDP parsing.
	// Checkout SetRemoteAddr
	Raddr *net.UDPAddr
	// Laddr our local address which has full IP and port after media session creation
	Laddr *net.UDPAddr

	// SDP stuff
	// Depending of negotiation this can change.
	// Formats will always try to match remote, to avoid different codec matching
	Formats sdp.Formats
	Mode    sdp.Mode
	// contains filtered or unexported fields
}

MediaSession represents active media session with RTP/RTCP TODO: multiple media descriptions. Consider https://datatracker.ietf.org/doc/rfc3388/ for grouping multiple media

Design: - It identfies single session Laddr <-> Raddr - With multi descriptions, or reinvites it should be forked and create new media Session

func NewMediaSession 

func NewMediaSession(laddr *net.UDPAddr) (s *MediaSession, e error)

func (*MediaSession) Close 

func (s *MediaSession) Close()

func (*MediaSession) Fork 

func (s *MediaSession) Fork() *MediaSession

Fork is special call to be used in case when there is session update It preserves pointer to same conneciton but rest is remobed After this call it still expected that

func (*MediaSession) LocalSDP 

func (s *MediaSession) LocalSDP() []byte

func (*MediaSession) ReadRTCP 

func (m *MediaSession) ReadRTCP(buf []byte, pkts []rtcp.Packet) (n int, err error)

ReadRTCP is optimized reads and unmarshals RTCP packets. Buffers is only used for unmarshaling. Caller needs to be aware of size this buffer and allign with MTU

func (*MediaSession) ReadRTCPRaw 

func (m *MediaSession) ReadRTCPRaw(buf []byte) (int, error)

func (*MediaSession) ReadRTCPRawDeadline 

func (m *MediaSession) ReadRTCPRawDeadline(buf []byte, t time.Time) (int, error)

func (*MediaSession) ReadRTP 

func (m *MediaSession) ReadRTP(buf []byte, pkt *rtp.Packet) error

ReadRTP reads data from network and parses to pkt buffer is passed in order to avoid extra allocs

func (*MediaSession) ReadRTPRaw 

func (m *MediaSession) ReadRTPRaw(buf []byte) (int, error)

func (*MediaSession) ReadRTPRawDeadline 

func (m *MediaSession) ReadRTPRawDeadline(buf []byte, t time.Time) (int, error)

func (*MediaSession) RemoteSDP 

func (s *MediaSession) RemoteSDP(sdpReceived []byte) error

func (*MediaSession) SetLogger 

func (s *MediaSession) SetLogger(log zerolog.Logger)

func (*MediaSession) SetRemoteAddr 

func (s *MediaSession) SetRemoteAddr(raddr *net.UDPAddr)

SetRemoteAddr is helper to set Raddr and rtcp address. It is not thread safe

func (*MediaSession) StartRTP 

func (s *MediaSession) StartRTP(rw int8) error

func (*MediaSession) StopRTP 

func (s *MediaSession) StopRTP(rw int8, dur time.Duration) error

func (*MediaSession) WriteRTCP 

func (m *MediaSession) WriteRTCP(p rtcp.Packet) error

func (*MediaSession) WriteRTCPDeadline 

func (m *MediaSession) WriteRTCPDeadline(p rtcp.Packet, deadline time.Time) error

func (*MediaSession) WriteRTCPRaw 

func (m *MediaSession) WriteRTCPRaw(data []byte) (int, error)

func (*MediaSession) WriteRTCPs 

func (m *MediaSession) WriteRTCPs(pkts []rtcp.Packet) error

Use this to write Multi RTCP packets if they can fit in MTU=1500

func (*MediaSession) WriteRTP 

func (m *MediaSession) WriteRTP(p *rtp.Packet) error

func (*MediaSession) WriteRTPRaw 

func (m *MediaSession) WriteRTPRaw(data []byte) (n int, err error)

type MediaStreamer 

type MediaStreamer interface {
	MediaStream(s *MediaSession) error
}

type RTCPReader 

type RTCPReader interface {
	ReadRTCP(buf []byte, pkts []rtcp.Packet) (n int, err error)
}

type RTCPWriter 

type RTCPWriter interface {
	WriteRTCP(p rtcp.Packet) error
}

type RTCPWriterRaw 

type RTCPWriterRaw interface {
	WriteRTCPRaw(buf []byte) (int, error) // -> io.Writer
}

type RTPCReaderRaw 

type RTPCReaderRaw interface {
	ReadRTCPRaw(buf []byte) (int, error)
}

type RTPDtmfReader 

type RTPDtmfReader struct {
	// contains filtered or unexported fields
}

func NewRTPDTMFReader 

func NewRTPDTMFReader(codec Codec, packetReader *RTPPacketReader, reader io.Reader) *RTPDtmfReader

RTP DTMF writer is midleware for reading DTMF events It reads from io Reader and checks packet Reader

func (*RTPDtmfReader) Read 

func (w *RTPDtmfReader) Read(b []byte) (int, error)

Write is RTP io.Writer which adds more sync mechanism

func (*RTPDtmfReader) ReadDTMF 

func (w *RTPDtmfReader) ReadDTMF() (rune, bool)

type RTPDtmfWriter 

type RTPDtmfWriter struct {
	// contains filtered or unexported fields
}

func NewRTPDTMFWriter 

func NewRTPDTMFWriter(codec Codec, rtpPacketizer *RTPPacketWriter, writer io.Writer) *RTPDtmfWriter

RTP DTMF writer is midleware for passing RTP DTMF event. If it is chained it uses to block writer while writing DTFM events

func (*RTPDtmfWriter) Write 

func (w *RTPDtmfWriter) Write(b []byte) (int, error)

Write is RTP io.Writer which adds more sync mechanism

func (*RTPDtmfWriter) WriteDTMF 

func (w *RTPDtmfWriter) WriteDTMF(dtmf rune) error

type RTPExtendedSequenceNumber 

type RTPExtendedSequenceNumber struct {
	// contains filtered or unexported fields
}

RTPExtendedSequenceNumber is embedable/ replacable sequnce number generator For thread safety you should wrap it

func NewRTPSequencer 

func NewRTPSequencer() RTPExtendedSequenceNumber

func (*RTPExtendedSequenceNumber) InitSeq 

func (sn *RTPExtendedSequenceNumber) InitSeq(seq uint16)

func (*RTPExtendedSequenceNumber) NextSeqNumber 

func (s *RTPExtendedSequenceNumber) NextSeqNumber() uint16

func (*RTPExtendedSequenceNumber) ReadExtendedSeq 

func (sn *RTPExtendedSequenceNumber) ReadExtendedSeq() uint64

func (*RTPExtendedSequenceNumber) UpdateSeq 

func (sn *RTPExtendedSequenceNumber) UpdateSeq(seq uint16) error

Based on https://datatracker.ietf.org/doc/html/rfc1889#appendix-A.2

type RTPPacketReader 

type RTPPacketReader struct {
	Sess       *MediaSession // TODO remove this
	RTPSession *RTPSession   // TODO remove this

	// PacketHeader is stored after calling Read
	// Safe to read only in same goroutine as Read
	PacketHeader rtp.Header
	// contains filtered or unexported fields
}

RTPPacketReader reads RTP packet and extracts payload and header

func NewRTPPacketReader 

func NewRTPPacketReader(reader RTPReader, codec Codec) *RTPPacketReader

func NewRTPPacketReaderMedia 

func NewRTPPacketReaderMedia(sess *MediaSession) *RTPPacketReader

NewRTPWriterMedia is left for backward compability. It does not add RTCP reporting It talks directly to network

func NewRTPPacketReaderSession 

func NewRTPPacketReaderSession(sess *RTPSession) *RTPPacketReader

RTP reader consumes samples of audio from RTP session Use NewRTPSession to construct RTP session

func (*RTPPacketReader) Read 

func (r *RTPPacketReader) Read(b []byte) (int, error)

Read Implements io.Reader and extracts Payload from RTP packet has no input queue or sorting control of packets Buffer is used for reading headers and Headers are stored in PacketHeader

NOTE: Consider that if you are passsing smaller buffer than RTP header+payload, io.ErrShortBuffer is returned

func (*RTPPacketReader) Reader 

func (r *RTPPacketReader) Reader() RTPReader

func (*RTPPacketReader) UpdateRTPSession 

func (r *RTPPacketReader) UpdateRTPSession(rtpSess *RTPSession)

func (*RTPPacketReader) UpdateReader added in v0.2.0 

func (r *RTPPacketReader) UpdateReader(reader RTPReader)

type RTPPacketWriter 

type RTPPacketWriter struct {

	// After each write this is set as packet.
	LastPacket rtp.Packet
	// SSRC is readOnly and it is not changed
	SSRC uint32
	// contains filtered or unexported fields
}

RTPPacketWriter packetize any payload before pushing to active media session It creates SSRC as identifier and all packets sent will be with this SSRC For multiple streams, multiple RTP Writer needs to be created

func NewRTPPacketWriter 

func NewRTPPacketWriter(writer RTPWriter, codec Codec) *RTPPacketWriter

RTPPacketWriter packetize payload in RTP packet before passing on media session Not having: - random Timestamp - allow different clock rate - CSRC contribution source - Silence detection and marker set updateClockRate- Padding and encryyption

func NewRTPPacketWriterSession 

func NewRTPPacketWriterSession(sess *RTPSession) *RTPPacketWriter

NewRTPPacketWriterSession creates RTPPacketWriter and attaches RTP Session expected values

func (*RTPPacketWriter) UpdateRTPSession 

func (w *RTPPacketWriter) UpdateRTPSession(rtpSess *RTPSession)

UpdateRTPSession updates rtp writer from current rtp session due to REINVITE It is expected that this is now new RTP Session and it is expected tha: - Statistics will be reset (SSRC=0) -> Fresh Start of Quality monitoring - Should not lead inacurate reporting - In case CODEC change than RTP should reset stats anyway

func (*RTPPacketWriter) Write 

func (p *RTPPacketWriter) Write(b []byte) (int, error)

Write implements io.Writer and does payload RTP packetization Media clock rate is determined For more control or dynamic payload WriteSamples can be used It is not thread safe and order of payload frames is required

func (*RTPPacketWriter) WriteSamples 

func (p *RTPPacketWriter) WriteSamples(payload []byte, sampleRateTimestamp uint32, marker bool, payloadType uint8) (int, error)

WriteSamples allows to skip default packet rate. This is useful if you need to write different payload but keeping same SSRC

func (*RTPPacketWriter) Writer 

func (w *RTPPacketWriter) Writer() RTPWriter

type RTPReadStats 

type RTPReadStats struct {
	SSRC                   uint32
	FirstPktSequenceNumber uint16
	LastSequenceNumber     uint16

	// tracks first pkt seq in this interval to calculate loss of packets
	IntervalFirstPktSeqNum uint16
	IntervalTotalPackets   uint16

	TotalPackets uint64

	// Round TRIP Time based on LSR and DLSR
	RTT time.Duration
	// contains filtered or unexported fields
}

Some of fields here are exported (as readonly) intentionally

type RTPReader 

type RTPReader interface {
	ReadRTP(buf []byte, p *rtp.Packet) error
}

type RTPReaderRaw 

type RTPReaderRaw interface {
	ReadRTPRaw(buf []byte) (int, error)
}

type RTPSession 

type RTPSession struct {
	// Keep pointers at top to reduce GC
	Sess *MediaSession

	// Experimental
	// this intercepts reading or writing rtcp packet. Allows manipulation
	OnReadRTCP  func(pkt rtcp.Packet, rtpStats RTPReadStats)
	OnWriteRTCP func(pkt rtcp.Packet, rtpStats RTPWriteStats)
	// contains filtered or unexported fields
}

RTP session is RTP ReadWriter with control (RTCP) reporting Session is identified by network address and port pair to which data should be sent and received Participant can be part of multiple rtp sessions. One for audio, one for media. So for different MediaSession (audio,video etc) different RTP session needs to be created TODO RTPSession can be different type: - unicast or multicase - replicated unicast (mixers audio) RTP session is attached to RTPReader and RTPWriter Now: - Designed for UNICAST sessions - Acts as RTP Reader Writer - Only makes sense for Reporting Quality media Roadmap: - Can handle multiple SSRC from Reader - Multiple RTCP Recever Blocks

func NewRTPSession 

func NewRTPSession(sess *MediaSession) *RTPSession

RTP session creates new RTP reader/writer from session

func (*RTPSession) Close 

func (s *RTPSession) Close() error

func (*RTPSession) Monitor 

func (s *RTPSession) Monitor() error

Monitor starts reading RTCP and monitoring media quality

func (*RTPSession) MonitorBackground 

func (s *RTPSession) MonitorBackground()

MonitorBackground is helper to keep monitoring in background MUST Be called after session REMOTE SDP is parsed

func (*RTPSession) ReadRTP 

func (s *RTPSession) ReadRTP(b []byte, readPkt *rtp.Packet) error

func (*RTPSession) ReadRTPRaw 

func (s *RTPSession) ReadRTPRaw(buf []byte) (int, error)

func (*RTPSession) WriteRTP 

func (s *RTPSession) WriteRTP(pkt *rtp.Packet) error

func (*RTPSession) WriteRTPRaw 

func (s *RTPSession) WriteRTPRaw(buf []byte) (int, error)

type RTPWriteStats 

type RTPWriteStats struct {
	SSRC uint32

	// RTCP stats
	PacketsCount uint32
	OctetCount   uint32
	// contains filtered or unexported fields
}

Some of fields here are exported (as readonly) intentionally

type RTPWriter 

type RTPWriter interface {
	WriteRTP(p *rtp.Packet) error
}

type RTPWriterRaw 

type RTPWriterRaw interface {
	WriteRTPRaw(buf []byte) (int, error) // -> io.Writer
}

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