improve examples (#703)

* add client-play-format-av1-to-jpeg
* improve client-play-format-av1 to decode frames
* improve speed of sample decoders by using pointers instead of copies
* improve client-record-format-h264 and client-record-format-h265 to encode frames
* add client-record-format-av1

examples/client-play-format-av1/main.go

@@ -1,3 +1,5 @@
+//go:build cgo
+
 package main
 
 import (
@@ -6,14 +8,18 @@ import (
 	"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/rtpvp9"
+	"github.com/bluenviron/gortsplib/v4/pkg/format/rtpav1"
+	"github.com/bluenviron/mediacommon/v2/pkg/codecs/av1"
 	"github.com/pion/rtp"
 )
 
 // This example shows how to
 // 1. connect to a RTSP server
 // 2. check if there's a AV1 format
-// 3. get access units of that format
+// 3. decode the AV1 stream into RGBA frames
+
+// This example requires the FFmpeg libraries, that can be installed with this command:
+// apt install -y libavformat-dev libswscale-dev gcc pkg-config
 
 func main() {
 	c := gortsplib.Client{}
@@ -44,18 +50,28 @@ func main() {
 		panic("media not found")
 	}
 
-	// create decoder
+	// setup RTP -> AV1 decoder
 	rtpDec, err := forma.CreateDecoder()
 	if err != nil {
 		panic(err)
 	}
 
+	// setup AV1 -> RGBA decoder
+	av1Dec := &av1Decoder{}
+	err = av1Dec.initialize()
+	if err != nil {
+		panic(err)
+	}
+	defer av1Dec.close()
+
 	// setup a single media
 	_, err = c.Setup(desc.BaseURL, medi, 0, 0)
 	if err != nil {
 		panic(err)
 	}
 
+	firstRandomReceived := false
+
 	// called when a RTP packet arrives
 	c.OnPacketRTP(medi, forma, func(pkt *rtp.Packet) {
 		// decode timestamp
@@ -68,13 +84,31 @@ func main() {
 		// extract AV1 temporal units from RTP packets
 		tu, err := rtpDec.Decode(pkt)
 		if err != nil {
-			if err != rtpvp9.ErrNonStartingPacketAndNoPrevious && err != rtpvp9.ErrMorePacketsNeeded {
+			if err != rtpav1.ErrNonStartingPacketAndNoPrevious && err != rtpav1.ErrMorePacketsNeeded {
 				log.Printf("ERR: %v", err)
 			}
 			return
 		}
 
-		log.Printf("received temporal unit with PTS %v and size %d\n", pts, len(tu))
+		// wait for a random access unit
+		if !firstRandomReceived && !av1.IsRandomAccess2(tu) {
+			log.Printf("waiting for a random access unit")
+			return
+		}
+		firstRandomReceived = true
+
+		// convert AV1 temporal units into RGBA frames
+		img, err := av1Dec.decode(tu)
+		if err != nil {
+			panic(err)
+		}
+
+		// wait for a frame
+		if img == nil {
+			return
+		}
+
+		log.Printf("decoded frame with PTS %v and size %v", pts, img.Bounds().Max)
 	})
 
 	// start playing