revid: wrote basics of a startRTSPCamera func

Currently just connecting to RTSP server, requesting OPTIONS, DESCRIBE, SETUP and PLAY. Also creating RTP client and giving
this to process from for the lexer.

revid/config.go

@@ -74,6 +74,9 @@ type Config struct {
 	Saturation         int
 	Exposure           string
 	AutoWhiteBalance   string
+	RTSPURL            string
+	RTPRecvAddr        string
+	RTCPAddr           string
 }
 
 // Possible modes for raspivid --exposure parameter.

revid/revid.go

@@ -43,6 +43,8 @@ import (
 	"bitbucket.org/ausocean/av/codec/lex"
 	"bitbucket.org/ausocean/av/container/flv"
 	"bitbucket.org/ausocean/av/container/mts"
+	"bitbucket.org/ausocean/av/protocol/rtp"
+	"bitbucket.org/ausocean/av/protocol/rtsp"
 	"bitbucket.org/ausocean/iot/pi/netsender"
 	"bitbucket.org/ausocean/utils/ioext"
 	"bitbucket.org/ausocean/utils/logger"
@@ -604,6 +606,48 @@ func (r *Revid) setupInputForFile() (func() error, error) {
 	return func() error { return f.Close() }, nil
 }
 
+func (r *Revid) startRTSPCamera() (func() error, error) {
+	rtspClt, err := rtsp.NewClient(r.config.RTSPURL)
+	if err != nil {
+		return nil, err
+	}
+
+	resp, err := rtspClt.Options()
+	if err != nil {
+		return nil, err
+	}
+	r.config.Logger.Log(logger.Info, pkg+"RTSP server OPTIONS response", "response", resp.String())
+
+	resp, err = rtspClt.Describe()
+	if err != nil {
+		return nil, err
+	}
+	r.config.Logger.Log(logger.Info, pkg+"RTSP server DESCRIBE response", "response", resp.String())
+
+	transport := fmt.Sprintf("RTP/AVP;unicast;client_port=%d-%d", strings.Split(r.config.RTPRecvAddr, ":")[1], strings.Split(r.config.RTCPAddr, ":")[1])
+	resp, err = rtspClt.Setup("track1", transport)
+	if err != nil {
+		return nil, err
+	}
+	r.config.Logger.Log(logger.Info, pkg+"RTSP server SETUP response", "response", resp.String())
+
+	resp, err = rtspClt.Play()
+	if err != nil {
+		return nil, err
+	}
+
+	// TODO(saxon): use rtcp client to maintain rtp stream.
+
+	rtpClt, err := rtp.NewClient(r.config.RTPRecvAddr)
+	if err != nil {
+		return nil, err
+	}
+
+	r.wg.Add(1)
+	go r.processFrom(rtpClt, time.Second/time.Duration(r.config.FrameRate))
+	return func() error { return nil }, nil
+}
+
 func (r *Revid) processFrom(read io.Reader, delay time.Duration) {
 	r.config.Logger.Log(logger.Info, pkg+"reading input data")
 	r.err <- r.lexTo(r.encoders, read, delay)