update VP8/VP9 examples to decode/encode frames (#704)

examples/client-play-format-h265-to-disk/main.go

@@ -0,0 +1,108 @@
+package main
+
+import (
+	"log"
+
+	"github.com/bluenviron/gortsplib/v4"
+	"github.com/bluenviron/gortsplib/v4/pkg/base"
+	"github.com/bluenviron/gortsplib/v4/pkg/format"
+	"github.com/bluenviron/gortsplib/v4/pkg/format/rtph265"
+	"github.com/pion/rtp"
+)
+
+// This example shows how to
+// 1. connect to a RTSP server
+// 2. check if there's a H265 format
+// 3. save the content of the format in a file in MPEG-TS format
+
+func main() {
+	c := gortsplib.Client{}
+
+	// parse URL
+	u, err := base.ParseURL("rtsp://myuser:mypass@localhost:8554/mystream")
+	if err != nil {
+		panic(err)
+	}
+
+	// connect to the server
+	err = c.Start(u.Scheme, u.Host)
+	if err != nil {
+		panic(err)
+	}
+	defer c.Close()
+
+	// find available medias
+	desc, _, err := c.Describe(u)
+	if err != nil {
+		panic(err)
+	}
+
+	// find the H265 media and format
+	var forma *format.H265
+	medi := desc.FindFormat(&forma)
+	if medi == nil {
+		panic("media not found")
+	}
+
+	// setup RTP -> H265 decoder
+	rtpDec, err := forma.CreateDecoder()
+	if err != nil {
+		panic(err)
+	}
+
+	// setup H265 -> MPEG-TS muxer
+	mpegtsMuxer := &mpegtsMuxer{
+		fileName: "mystream.ts",
+		vps:      forma.VPS,
+		sps:      forma.SPS,
+		pps:      forma.PPS,
+	}
+	err = mpegtsMuxer.initialize()
+	if err != nil {
+		panic(err)
+	}
+	defer mpegtsMuxer.close()
+
+	// setup a single media
+	_, err = c.Setup(desc.BaseURL, medi, 0, 0)
+	if err != nil {
+		panic(err)
+	}
+
+	// called when a RTP packet arrives
+	c.OnPacketRTP(medi, forma, func(pkt *rtp.Packet) {
+		// decode timestamp
+		pts, ok := c.PacketPTS2(medi, pkt)
+		if !ok {
+			log.Printf("waiting for timestamp")
+			return
+		}
+
+		// extract access unit from RTP packets
+		au, err := rtpDec.Decode(pkt)
+		if err != nil {
+			if err != rtph265.ErrNonStartingPacketAndNoPrevious && err != rtph265.ErrMorePacketsNeeded {
+				log.Printf("ERR: %v", err)
+			}
+			return
+		}
+
+		// encode the access unit into MPEG-TS
+		err = mpegtsMuxer.writeH265(au, pts)
+		if err != nil {
+			log.Printf("ERR: %v", err)
+			return
+		}
+
+		log.Printf("saved TS packet")
+	})
+
+	// start playing
+	_, err = c.Play(nil)
+	if err != nil {
+		panic(err)
+	}
+
+	// wait until a fatal error
+	panic(c.Wait())
+}