Add video RTP reader

examples/rtp/README.md

@@ -0,0 +1,30 @@
+## Instructions
+
+### Download rtp-send example
+
+```
+go get github.com/pion/mediadevices/examples/rtp-send
+```
+
+### Listen RTP
+
+Install GStreamer and run:
+```
+gst-launch-1.0 udpsrc port=5000 caps=application/x-rtp,encode-name=VP8 \
+    ! rtpvp8depay ! vp8dec ! videoconvert ! autovideosink
+```
+
+Or run VLC media plyer:
+```
+vlc ./vp8.sdp
+```
+
+### Run rtp-send
+
+Run `rtp-send localhost:5000`
+
+A video should start playing in your GStreamer or VLC window.
+It's not WebRTC, but pure RTP.
+
+Congrats, you have used pion-MediaDevices! Now start building something cool
+

examples/rtp/main.go

@@ -0,0 +1,76 @@
+package main
+
+import (
+	"fmt"
+	"net"
+	"os"
+
+	"github.com/pion/mediadevices"
+	"github.com/pion/mediadevices/pkg/codec/vpx"       // This is required to use VP8/VP9 video encoder
+	_ "github.com/pion/mediadevices/pkg/driver/camera" // This is required to register camera adapter
+	"github.com/pion/mediadevices/pkg/frame"
+	"github.com/pion/mediadevices/pkg/prop"
+)
+
+const (
+	mtu = 1000
+)
+
+func must(err error) {
+	if err != nil {
+		panic(err)
+	}
+}
+
+func main() {
+	if len(os.Args) != 2 {
+		fmt.Printf("usage: %s host:port\n", os.Args[0])
+		return
+	}
+	dest := os.Args[1]
+
+	vp8Params, err := vpx.NewVP8Params()
+	must(err)
+	vp8Params.BitRate = 100000 // 100kbps
+
+	codecSelector := mediadevices.NewCodecSelector(
+		mediadevices.WithVideoEncoders(&vp8Params),
+	)
+
+	mediaStream, err := mediadevices.GetUserMedia(mediadevices.MediaStreamConstraints{
+		Video: func(c *mediadevices.MediaTrackConstraints) {
+			c.FrameFormat = prop.FrameFormat(frame.FormatYUY2)
+			c.Width = prop.Int(640)
+			c.Height = prop.Int(480)
+		},
+		Codec: codecSelector,
+	})
+	must(err)
+
+	videoTrack := mediaStream.GetVideoTracks()[0].(*mediadevices.VideoTrack)
+	defer videoTrack.Close()
+
+	rtpReader, err := videoTrack.NewRTPReader(vp8Params.RTPCodec().Name, mtu)
+	must(err)
+
+	addr, err := net.ResolveUDPAddr("udp", dest)
+	must(err)
+	conn, err := net.DialUDP("udp", nil, addr)
+	must(err)
+
+	buff := make([]byte, mtu)
+	for {
+		pkts, release, err := rtpReader.Read()
+		must(err)
+
+		for _, pkt := range pkts {
+			n, err := pkt.MarshalTo(buff)
+			must(err)
+
+			_, err = conn.Write(buff[:n])
+			must(err)
+		}
+
+		release()
+	}
+}

examples/rtp/vp8.sdp

@@ -0,0 +1,9 @@
+v=0
+o=- 1234567890 1234567890 IN IP4 0.0.0.0
+s=RTP-Send Example
+i=Example
+c=IN IP4 0.0.0.0
+t=0 0
+a=recvonly
+m=video 5000 RTP/AVP 100
+a=rtpmap:100 VP8/90000

rtpreader.go

@@ -0,0 +1,21 @@
+package mediadevices
+
+import "github.com/pion/rtp"
+
+type RTPReader interface {
+	Read() (pkts []*rtp.Packet, release func(), err error)
+	Close() error
+}
+
+type rtpReaderImpl struct {
+	readFn  func() ([]*rtp.Packet, func(), error)
+	closeFn func() error
+}
+
+func (r *rtpReaderImpl) Read() ([]*rtp.Packet, func(), error) {
+	return r.readFn()
+}
+
+func (r *rtpReaderImpl) Close() error {
+	return r.closeFn()
+}

track.go

@@ -11,6 +11,7 @@ import (
 	"github.com/pion/mediadevices/pkg/io/audio"
 	"github.com/pion/mediadevices/pkg/io/video"
 	"github.com/pion/mediadevices/pkg/wave"
+	"github.com/pion/rtp"
 	"github.com/pion/webrtc/v2"
 	"github.com/pion/webrtc/v2/pkg/media"
 )
@@ -259,6 +260,41 @@ func (track *VideoTrack) Unbind(pc *webrtc.PeerConnection) error {
 	return track.unbind(pc)
 }
 
+func (track *VideoTrack) NewRTPReader(codecName string, mtu int) (RTPReader, error) {
+	reader := track.NewReader(false)
+	inputProp, err := detectCurrentVideoProp(track.Broadcaster)
+	if err != nil {
+		return nil, err
+	}
+
+	encodedReader, selectedCodec, err := track.selector.selectVideoCodecByNames(reader, inputProp, codecName)
+	if err != nil {
+		return nil, err
+	}
+
+	sample := newVideoSampler(selectedCodec.ClockRate)
+
+	// FIXME: not sure the best way to get unique ssrc. We probably should have a global keeper that can generate a random ID and does book keeping?
+	packetizer := rtp.NewPacketizer(mtu, selectedCodec.PayloadType, rand.Uint32(), selectedCodec.Payloader, rtp.NewRandomSequencer(), selectedCodec.ClockRate)
+
+	return &rtpReaderImpl{
+		readFn: func() ([]*rtp.Packet, func(), error) {
+			encoded, release, err := encodedReader.Read()
+			if err != nil {
+				encodedReader.Close()
+				track.onError(err)
+				return nil, func() {}, err
+			}
+			defer release()
+
+			samples := sample()
+			pkts := packetizer.Packetize(encoded, samples)
+			return pkts, release, err
+		},
+		closeFn: encodedReader.Close,
+	}, nil
+}
+
 // AudioTrack is a specific track type that contains audio source which allows multiple readers to access, and
 // manipulate.
 type AudioTrack struct {