add H265 decoder and encoder (#154)

examples/client-read-codec-lpcm/main.go

@@ -52,7 +52,7 @@ func main() {
 
 	// called when a RTP packet arrives
 	c.OnPacketRTP = func(ctx *gortsplib.ClientOnPacketRTPCtx) {
-		// decode an LPCM packet from the RTP packet
+		// decode LPCM samples from the RTP packet
 		op, _, err := dec.Decode(ctx.Packet)
 		if err != nil {
 			return