add example client-record-format-mjpeg-from-image (#489) (#512)

examples/client-record-format-mjpeg-from-image/main.go

@@ -0,0 +1,104 @@
+package main
+
+import (
+	"bytes"
+	"image"
+	"image/color"
+	"image/jpeg"
+	"time"
+
+	"github.com/bluenviron/gortsplib/v4"
+	"github.com/bluenviron/gortsplib/v4/pkg/description"
+	"github.com/bluenviron/gortsplib/v4/pkg/format"
+	"github.com/bluenviron/gortsplib/v4/pkg/rtptime"
+)
+
+// This example shows how to
+// 1. connect to a RTSP server, announce a M-JPEG format
+// 2. generate an image
+// 3. encode the image with JPEG
+// 4. generate RTP/M-JPEG packets from the JPEG image
+// 5. write packets to the server
+
+func main() {
+	// create a description that contains a M-JPEG format
+	forma := &format.MJPEG{}
+	desc := &description.Session{
+		Medias: []*description.Media{{
+			Type:    description.MediaTypeVideo,
+			Formats: []format.Format{forma},
+		}},
+	}
+
+	// connect to the server, announce the format and start recording
+	c := gortsplib.Client{}
+	err := c.StartRecording("rtsp://localhost:8554/mystream", desc)
+	if err != nil {
+		panic(err)
+	}
+	defer c.Close()
+
+	// setup JPEG -> RTP/M-JPEG encoder
+	rtpEnc, err := forma.CreateEncoder()
+	if err != nil {
+		panic(err)
+	}
+
+	// setup timestamp generator
+	rtpTime := rtptime.NewEncoder(forma.ClockRate(), 0)
+	start := time.Now()
+
+	// setup a ticker to sleep between frames
+	ticker := time.NewTicker(200 * time.Millisecond)
+	defer ticker.Stop()
+
+	i := 0
+
+	for range ticker.C {
+		// create a RGBA image
+		image := image.NewRGBA(image.Rect(0, 0, 640, 480))
+
+		// fill the image
+		var cl color.RGBA
+		switch i {
+		case 0:
+			cl = color.RGBA{255, 0, 0, 0}
+		case 1:
+			cl = color.RGBA{0, 255, 0, 0}
+		case 2:
+			cl = color.RGBA{0, 0, 255, 0}
+		}
+		for y := 0; y < image.Rect.Dy(); y++ {
+			for x := 0; x < image.Rect.Dx(); x++ {
+				image.SetRGBA(x, y, cl)
+			}
+		}
+		i = (i + 1) % 3
+
+		// encode the image with JPEG
+		var buf bytes.Buffer
+		err := jpeg.Encode(&buf, image, &jpeg.Options{Quality: 80})
+		if err != nil {
+			panic(err)
+		}
+
+		// generate RTP/M-JPEG packets from the JPEG image
+		pkts, err := rtpEnc.Encode(buf.Bytes())
+		if err != nil {
+			panic(err)
+		}
+
+		// get current timestamp
+		ts := rtpTime.Encode(time.Now().Sub(start))
+
+		// write packets to the server
+		for _, pkt := range pkts {
+			pkt.Timestamp = ts
+
+			err = c.WritePacketRTP(desc.Medias[0], pkt)
+			if err != nil {
+				panic(err)
+			}
+		}
+	}
+}